Non-destructive testing based quality control method for parallel process and quality inspection based on real-time physical characteristics of inductor bar

Abstract

A quality control method may include: an operation of driving a spindle motor to rotate a rotating wheel at a predetermined RPM in response to receiving a start input for grinding a workpiece from a user terminal; an operation of measuring in real time an eddy current signal corresponding to the magnetic flux density and copper winding state of the workpiece using a magnetic sensor array and an eddy current sensor disposed on one side of a chuck table on which the workpiece is adsorbed; an operation of checking a comparison result by comparing the real-time quality of the workpiece confirmed based on the magnetic flux density and the eddy current signal with a predefined quality table; and, if the workpiece is determined to be defective based on the comparison result, an operation of stopping the driving of the spindle motor and providing a warning notification to the user terminal.

Description

Technology Field

[0001] The present invention relates to a non-destructive testing-based quality control method that performs process and quality inspection in parallel based on the physical properties of an inductor bar measured in real time during a process, and a dry grinding device that performs the same. Background Technology

[0002] Generally, a grinding process is essential in the manufacturing of electrical components such as inductor bars, and during this process, the thickness and surface condition of the product act as critical factors determining the final quality. However, in conventional technology, the grinding and quality inspection processes were performed separately, leading to a problem of reduced process efficiency.

[0003] Conventional quality inspection methods primarily rely on sampling using separate inspection equipment after the completion of the process. This approach has limitations, such as the difficulty of real-time quality control and the detection of defective products only after they have already been produced. Consequently, this leads to problems including increased defect rates and higher rework costs.

[0004] In particular, for products where the internal structure is critical, such as inductor bars, non-destructive testing technology is required; however, existing non-destructive testing technologies face the problem of being difficult to apply in real-time during the manufacturing process, making it challenging to simultaneously satisfy both productivity and inspection accuracy.

[0005] In addition, although dust generated during the grinding process can deteriorate the working environment and affect product surface quality, conventional technology had a problem in that it could not efficiently separate and control magnetic and non-magnetic dust.

[0006] Furthermore, despite the fact that the characteristics of dust generated vary depending on process conditions, existing systems failed to respond flexibly to time intervals or dust concentrations, resulting in a problem of reduced energy efficiency and dust collection efficiency.

[0007] The grinding process for inductor bars has primarily focused on ensuring dimensional quality, such as target thickness, flatness, and surface roughness. Quality evaluation has often been performed out-of-line using separate inspection equipment after the process is completed. However, since this out-of-line inspection method inspects only after grinding is finished, defects are often detected only after the grinding process has already begun. This can lead to rework, waste, and process delays, which can negatively impact productivity and yield. Furthermore, if operators inspect only a portion of the material using a sampling method, there is a quality risk involved as they may miss localized defects or temporary process anomalies (e.g., momentary wheel wobble, feed instability, increased device vibration, etc.) occurring during the process.

[0008] Furthermore, the grinding process for inductor bars has primarily relied on a wet method to control dust, but this results in high wastewater treatment costs and environmental pollution issues. Although dry grinding methods are being introduced to address this, there have been limitations in effectively capturing the ultrafine mixed dust generated when the magnetic core material and the non-magnetic copper winding are simultaneously cut during the grinding process. In particular, simple suction dust collection systems have low collection efficiency, and fine dust with small particle sizes scatters into the workplace, causing equipment malfunctions and quality issues in the inductor bar grinding process.

[0009] Various factors can affect the quality of inductor bars during the grinding process, such as changes in magnetic flux distribution of the magnetic material, internal defects (e.g., microcracks, pores), abnormalities in the condition of the windings (e.g., copper windings), poor joints, non-uniform material composition, or changes in characteristics due to thermal history. These factors may not be immediately apparent visually, or it may be difficult to determine the presence of defects based solely on thickness measurements immediately after grinding. Consequently, even if process conditions appear normal, this can lead to performance degradation or reliability issues with the final product. Therefore, there is an increasing technical need for a system that performs nondestructive testing (NDT) simultaneously with grinding to evaluate quality immediately during the process and rapidly control or halt operations in the event of an anomaly.

[0010] However, the grinding process can present an unstable measurement environment due to factors such as high-speed wheel rotation, dust dispersion, machine vibration, changes in electromagnetic fields (e.g., electromagnet-based dust collection systems), and workpiece movement, making it difficult to reliably perform real-time quality measurements during the process. In particular, if sensors are directly exposed to the grinding environment, contamination, wear, and interference may occur, and increased noise in sensor data can make it difficult to obtain reliable judgments. Furthermore, improvements are required for an integrated quality management method that links quality standards (e.g., magnetic flux density range, winding condition judgment criteria, allowable thickness variation range, etc.) with process variables to implement real-time judgment logic, and includes control procedures to safely stop the device upon detecting a defect.

[0011] Therefore, there is an urgent need to develop a control logic that classifies dust by type according to the progress of the grinding process, accurately and efficiently collects it to primarily improve the quality of the grinding process, and secondarily provides stable process stoppage and warning notifications if it is confirmed that the quality in real time is defective. The problem to be solved

[0012] According to the present invention, by immediately determining quality based on thickness information measured in real time during the grinding process, the process and quality inspection can be performed in parallel, thereby significantly improving production efficiency.

[0013] According to the present invention, real-time measurement using a non-contact probe sensor enables high-precision non-destructive inspection while preventing damage to the product, thereby improving quality reliability.

[0014] According to the present invention, by additionally utilizing magnetic flux density and eddy current signals, it is possible to perform precise quality evaluation that reflects not only simple external inspection but also internal conditions.

[0015] According to the present invention, a quality control method based on non-destructive inspection measures quality indicators in real time using a magnetic sensor array, an eddy current sensor, and a non-contact thickness sensor simultaneously with an inductor bar grinding process, and determines quality immediately during the process by comparing the measurement results with a predefined quality table. Accordingly, it improves upon the limitations of conventional methods that detect defects only after grinding is completed, enabling the early detection of defect occurrence and the immediate cessation or modification of the process conditions. As a result, it has the effect of preventing additional processing of defective products, reducing rework and scrap, and improving the throughput and yield of the entire production line.

[0016] According to the present invention, a safety procedure may be included in which, when a workpiece to be ground is determined to be defective, the operation of the spindle motor is stopped, and after confirming whether the rotating wheel has completely stopped using a rotation detection sensor, power to the vacuum suction device of the chuck table is cut off. This significantly improves safety by reducing the risk of the workpiece deviating or colliding during the inertial rotation section of the grinding process and preventing damage to the device and the workpiece. Furthermore, since a step-by-step response based on sensor data during the process can be implemented, operational flexibility can be secured compared to a simple stop.

[0017] According to the present invention, dust collection (e.g., first dust collection based on an electromagnet, second dust collection based on an electrode) and quality measurement can be performed in parallel or linked within the same process, thereby maintaining sensor reliability in dusty environments and enhancing process stability. For example, reducing airborne dust around the sensor through dust collection operations can decrease measurement noise and improve judgment accuracy; conversely, if a quality anomaly is detected, dust collection and grinding operations can be immediately stopped to prevent the spread of contamination within the device. Consequently, the present invention enables comprehensive management of not only grinding quality but also functional quality, such as electromagnetic characteristics and winding conditions, thereby contributing to ensuring the reliability of inductor bar products.

[0018] The technical problems of the present invention are not limited to those mentioned above, and other unmentioned technical problems will be clearly understood by those skilled in the art from the description below. means of solving the problem

[0019] A quality control method for collecting ultrafine dust generated during the process of grinding an inductor bar by classifying it by type through a double-separated dust collection device, wherein the dry grinding device including a processor according to one embodiment of the present invention performs the following operations: the processor drives a first servo motor and a second servo motor to move a chuck table on which the workpiece is placed to a grinding target position in response to receiving a start input for grinding a workpiece from a user terminal; the processor checks a reference line extending the center point of the workpiece in the z-axis direction based on the real-time position of the workpiece confirmed using a first sensor; the processor drives a third servo motor to lower the rotating wheel in response to confirming that the reference line penetrates the center point of the rotating wheel for grinding the workpiece; the processor drives a spindle motor to rotate the rotating wheel at a predetermined RPM in response to confirming that the rotating wheel contacts the surface of the workpiece using a second sensor. The processor may include an operation of collecting first dust and second dust generated from the workpiece by the rotation of the rotating wheel, respectively, using a first dust collection device electrically connected to a first power supply and a second dust collection device electrically connected to a second power supply when the rotation of the rotating wheel begins, and an operation of the processor transmitting a power supply interruption command to the first power supply and the second power supply when the rotation of the rotating wheel ends, thereby inducing the first dust and the second dust collected by the first dust collection device and the second dust collection device to escape to the dust collection device.For example, the first dust collection device is configured to collect the first dust corresponding to magnetic dust based on magnetic force and includes an electromagnet that receives current from the first power supply device, and the second dust collection device is configured to collect the second dust corresponding to non-magnetic dust based on electrostatic force and may include an electrode that forms an electric field by receiving voltage from the second power supply device.

[0020] According to one embodiment, the quality control method comprises: the processor checking the grinding time included in the start input; the processor checking the grinding time by dividing it into a first time interval, a second time interval after the first time interval, and a third time interval after the second time interval based on a preset time ratio; and when the first time interval, the second time interval, and the third time interval are all greater than or equal to a preset threshold time: the processor transmitting a first power supply command instructing to supply a predetermined current to the first dust collection device during the first time interval only to the first power supply device; the processor transmitting the first power supply command instructing to supply the predetermined current to the first dust collection device during the second time interval to the first power supply device, and transmitting a second power supply command instructing to apply a predetermined voltage to the second dust collection device to the second power supply device; and the processor, the third During the time interval, the operation of transmitting the second power supply command only to the second power supply device and the operation of the processor to move the second dust to the dust collection device using a vibration device included in the second dust collection device when the third time interval has elapsed and the rotation of the rotating wheel has ended may further include

[0021] According to one embodiment, the quality control method may further include, when any one of the first time interval, the second time interval, and the third time interval is less than a critical time, the processor checking the first concentration and the second concentration of the first dust and the second dust, respectively, using a first concentration sensor included in the first dust collection device and a second concentration sensor included in the second dust collection device while the rotating wheel is rotating; the processor transmitting the first power supply command to the first power supply device only when the first concentration exceeds the first critical concentration during the grinding time; and the processor transmitting the second power supply command to the second power supply device only when the second concentration exceeds the second critical concentration during the grinding time.

[0022] According to one embodiment, the quality control method may further include the operation of the processor checking the rotational speed of the rotating wheel using a rotation detection sensor while the rotating wheel is rotating, the operation of the processor adjusting the magnitude of the predetermined current in proportion to the rotational speed of the rotating wheel and the first concentration, and the operation of the processor adjusting the magnitude of the predetermined voltage in proportion to the rotational speed of the rotating wheel and the second concentration.

[0023] According to one embodiment, the quality control method may further include the operation of the processor irradiating a laser light onto the side of the workpiece to be ground using a non-contact probe sensor placed in an area adjacent to the spindle motor, and receiving a reflected signal to determine the real-time thickness of the workpiece to be ground, and the operation of the processor adjusting the magnitude of the predetermined current and the predetermined voltage in proportion to the difference between the initial thickness of the workpiece to be ground included in the start input and the real-time thickness.

[0024] The above quality control method is,

[0025] The above processor performs the operation of checking the rotational speed of the rotating wheel using a rotation detection sensor while the rotating wheel is rotating;

[0026] The above processor performs the operation of adjusting the magnitude of the predetermined current to be proportional to the rotational speed of the rotating wheel and the first concentration; and

[0027] The above processor may further include an operation of adjusting the magnitude of the predetermined voltage in proportion to the rotational speed of the rotating wheel and the second concentration.

[0028] The above quality control method is,

[0029] The processor may further include an operation of adjusting the magnitude of the predetermined current and the predetermined voltage in proportion to the difference between the initial thickness and the real-time thickness of the object to be ground.

[0030] The above quality control method is,

[0031] The above processor may further include the operation of transmitting an opening command to the upper opening / closing part of the dust collection device immediately before transmitting the power supply interruption command to the first power supply device, and transmitting a closing command to the upper opening / closing part after a preset time has elapsed.

[0032] The above quality control method is,

[0033] When the processor receives a warning signal indicating that the amount of accumulated dust has exceeded a threshold from a dust amount detection sensor installed inside the dust collection device, it may further include an operation to provide a "dust bin needs to be emptied" notification to the user terminal and transmit an opening command to the side opening / closing part of the dust processing device to release the dust inside the dust collection device to the outside.

[0034] The above quality control method is,

[0035] The operation of the processor measuring the surface temperature of the first dust collection device in real time based on a heat sensing sensor disposed adjacent to the first dust collection device; and

[0036] The above processor further includes the operation of transmitting the first power supply command to the first power supply device, which instructs the device to reduce the predetermined current when it is determined that the surface temperature exceeds a critical temperature.

[0037] The above quality control method is,

[0038] The above processor performs the operation of verifying the material information of the object to be ground included in the start input; and

[0039] The above processor further includes the operation of transmitting the first power supply command to the first power supply device, which instructs to increase the predetermined current when the magnetic strength identified based on the material information is less than the critical magnetic strength.

[0040] The above quality control method is,

[0041] The above processor further includes an operation in which, when the grinding time has elapsed and the rotation of the rotating wheel has ended, a vibration generating device positioned around the first dust collection device or on a frame supporting the first dust collection device generates vibration for a predetermined time, thereby inducing the first dust collected by the first dust collection device for the predetermined time after the power supply is interrupted to escape to the dust collection device.

[0042] The above quality control method is,

[0043] The above processor further includes the operation of opening a solenoid valve for a predetermined time immediately after transmitting the power supply interruption command to spray a high-pressure air pulse downward along the upper surface of the first dust collection device and the second dust collection device.

[0044] The above quality control method is,

[0045] The above processor drives a third servo motor connected to the rotating wheel at predetermined time intervals during a reference time from the point in time when the rotation of the rotating wheel begins, thereby lowering the rotating wheel by a predetermined length; and

[0046] The above processor further includes an operation in which, when the above reference time has elapsed, it stops driving the spindle motor and, in response to confirming that the rotation of the rotating wheel has ended using the rotation detection sensor, drives the third servo motor to raise the rotating wheel back to the starting position.

[0047] The above quality control method is,

[0048] The operation of the processor, when it identifies that the rotating wheel is rotating using the rotation detection sensor, measuring the thickness of the workpiece to be ground in real time using only the non-contact probe sensor and providing a first measurement result to the user terminal; and

[0049] The above processor further includes an operation in which, when it identifies that the rotation of the rotating wheel has ended using the third sensor, it measures the thickness of the workpiece to be ground in real time using both the contact probe sensor and the non-contact probe sensor and provides a second measurement result to the user terminal.

[0050] The above quality control method is,

[0051] When the processor identifies that the rotation of the rotating wheel has ended using the rotation detection sensor, the operation of confirming the first real-time thickness and the second real-time thickness measured through the contact probe sensor and the non-contact probe sensor, respectively; and

[0052] The above processor further includes an operation of providing only the first real-time thickness to the user terminal when the difference between the first real-time thickness and the second real-time thickness is greater than or equal to a threshold difference.

[0053] The above quality control method is,

[0054] The above processor further includes an operation of providing a warning notification to the user terminal indicating that maintenance of the internal environment of the dry grinding device is required when the difference between the first real-time thickness and the second real-time thickness is greater than or equal to the threshold difference.

[0055] The above quality control method is,

[0056] The above processor further includes an operation of adjusting the above predetermined current based on the following mathematical formula 1, and

[0057] [Mathematical Formula 1]

[0058]

[0059] I(N, C_1) is the magnitude of a predetermined current when the rotational speed (RPM) of the rotating wheel is N and the first concentration is C_1, I_min is a predefined lower current limit, I_max is a predefined upper current limit, N_ref is the rotational speed normalization reference value, C_1,ref is the first concentration normalization reference value, and k_I, a, and b are tuning parameters.

[0060] The above quality control method is,

[0061] The above processor further includes an operation of adjusting the above predetermined current based on the following mathematical formula 2, and

[0062] [Mathematical Formula 2]

[0063]

[0064] V(N, C_2) is the magnitude of a predetermined voltage when the rotational speed (RPM) of the rotating wheel is N and the second concentration is C_2, V_min is a predefined lower voltage limit, V_max is a predefined upper voltage limit, N_ref is a rotational speed normalization reference value, C_2,ref is a second concentration normalization reference value, and k_V, c, and d are tuning parameters.

[0065] The above quality control method is,

[0066] The above processor performs the operation of checking the surface area of ​​the workpiece to be ground using a first sensor;

[0067] The above processor performs the operation of checking the grinding time included in the start input and checking a first time and a second time based on the grinding time and the area;

[0068] The above processor further includes the operation of transmitting a power supply command to a first power supply device instructing it to repeat the operation of supplying power to the first dust collection device for the first time period from the time when the rotation of the rotating wheel begins, and then cutting off the power supply to the first dust collection device for the second time period during the grinding time. Effects of the invention

[0069] The effects of the quality control method according to the embodiments of the present invention are described as follows.

[0070] According to the present invention, by immediately determining quality based on thickness information measured in real time during the grinding process, the process and quality inspection can be performed in parallel, thereby significantly improving production efficiency.

[0071] According to the present invention, real-time measurement using a non-contact probe sensor enables high-precision non-destructive inspection while preventing damage to the product, thereby improving quality reliability.

[0072] According to the present invention, by additionally utilizing magnetic flux density and eddy current signals, it is possible to perform precise quality evaluation that reflects not only simple external inspection but also internal conditions.

[0073] According to the present invention, a quality control method based on non-destructive inspection measures quality indicators in real time using a magnetic sensor array, an eddy current sensor, and a non-contact thickness sensor simultaneously with an inductor bar grinding process, and determines quality immediately during the process by comparing the measurement results with a predefined quality table. Accordingly, it improves upon the limitations of conventional methods that detect defects only after grinding is completed, enabling the early detection of defect occurrence and the immediate cessation or modification of the process conditions. As a result, it has the effect of preventing additional processing of defective products, reducing rework and scrap, and improving the throughput and yield of the entire production line.

[0074] According to the present invention, a safety procedure may be included in which, when a workpiece to be ground is determined to be defective, the operation of the spindle motor is stopped, and after confirming whether the rotating wheel has completely stopped using a rotation detection sensor, power to the vacuum suction device of the chuck table is cut off. This significantly improves safety by reducing the risk of the workpiece deviating or colliding during the inertial rotation section of the grinding process and preventing damage to the device and the workpiece. Furthermore, since a step-by-step response based on sensor data during the process can be implemented, operational flexibility can be secured compared to a simple stop.

[0075] According to the present invention, dust collection (e.g., first dust collection based on an electromagnet, second dust collection based on an electrode) and quality measurement can be performed in parallel or linked within the same process, thereby maintaining sensor reliability in dusty environments and enhancing process stability. For example, reducing airborne dust around the sensor through dust collection operations can decrease measurement noise and improve judgment accuracy; conversely, if a quality anomaly is detected, dust collection and grinding operations can be immediately stopped to prevent the spread of contamination within the device. Consequently, the present invention enables comprehensive management of not only grinding quality but also functional quality, such as electromagnetic characteristics and winding conditions, thereby contributing to ensuring the reliability of inductor bar products.

[0076] According to the present invention, by selectively driving a first dust collection device (e.g., an electromagnet-based collection unit) and a second dust collection device (e.g., an electrostatic force-based collection unit) during grinding, the concentration of dust scattered around the grinding area can be reduced, and adhesion and deposition around the sensor can be suppressed. Accordingly, spatial distribution distortion of the magnetic flux density signal acquired from the magnetic sensor array is reduced, irregular fluctuations in the amplitude / phase components of the eddy current signal acquired from the eddy current sensor are reduced, and the signal-to-noise ratio of the reflected signal of the non-contact probe sensor can be improved. That is, a technical effect is provided in which the reproducibility and accuracy of real-time quality judgment are improved through the causal relationship of dust collection, reduction of sensor contamination, reduction of measurement noise, and improvement of the accuracy of comparison results between quality tables.

[0077] According to the present invention, a quality table may include a plurality of quality items corresponding to magnetic flux density measurements, eddy current-based winding condition measurements, and real-time thickness measurements, along with an allowable range or threshold for each item and a corresponding defect type when the threshold is exceeded. For example, for magnetic flux density, characteristic values ​​such as a maximum value, average value, standard deviation, or non-uniformity of distribution by location may be defined, and for eddy current signals, the amount of change in impedance at a reference frequency or multiple frequencies, the amount of deviation from the reference, or the amount of temporal variation may be defined. A processor may derive a comparison result by comparing the characteristic values ​​calculated in real time with the allowable range of the quality table, and if the comparison result satisfies a defect condition, it may perform subsequent control, such as stopping the spindle motor or providing a warning notification to a user terminal.

[0078] According to the present invention, an electrode for electrostatic force-based dust collection is equipped with an insulating housing, a grounding structure, and a bleed path to suppress arcing and leakage current, and the sensor measurement signal can be configured to reduce the effects of electromagnetic interference (EMI) caused by the spindle motor and high voltage application through shielded wiring and grounding design. In addition, a wear-resistant protective cover or thin film coating can be applied to the sensor detection surface, and if necessary, dust adhesion to the detection surface can be further reduced through air purging or intermittent vibration / brushing, thereby enabling stable real-time measurement and quality judgment even during the grinding process.

[0079] In addition, various effects identified directly or indirectly through this document may be provided. Brief explanation of the drawing

[0080] FIG. 1 is a block diagram showing the components of a dry grinding device according to one embodiment of the present invention. FIG. 2 is a conceptual diagram showing the layers between the components of a dry grinding device according to one embodiment of the present invention. FIG. 3 is a conceptual diagram showing the arrangement structure of the workbench, the rotation structure of the rotating wheel, and the movement structure of the chuck table of a dry grinding device according to one embodiment of the present invention. FIG. 4 is a conceptual diagram showing the arrangement structure of an electromagnet included in a dry grinding device according to one embodiment of the present invention. FIG. 5 is a flowchart of a quality control method according to one embodiment of the present invention. FIG. 6 is a flowchart of a quality control method according to one embodiment of the present invention. In relation to the description of the drawings, the same or similar reference numerals may be used for identical or similar components. Specific details for implementing the invention

[0081] Hereinafter, some embodiments of the present invention will be described in detail with reference to exemplary drawings. It should be noted that in assigning reference numerals to the components of each drawing, the same components are given the same reference numeral whenever possible, even if they are shown in different drawings. Furthermore, in describing the embodiments of the present invention, if it is determined that a detailed description of related known components or functions would hinder understanding of the embodiments of the present invention, such detailed description is omitted.

[0082] In describing the components of the embodiments of the present invention, terms such as first, second, A, B, (a), (b), etc., may be used. These terms are intended merely to distinguish the components from other components, and the essence, order, or sequence of the components is not limited by the terms. Furthermore, unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as generally understood by those skilled in the art to which the present invention pertains. Terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with their meaning in the context of the relevant technology, and should not be interpreted in an ideal or overly formal sense unless explicitly defined in this application.

[0083] Hereinafter, embodiments of the present invention will be described in detail with reference to FIGS. 1 to 5.

[0085] FIG. 1 is a block diagram showing the components of a dry grinding device according to one embodiment of the present invention.

[0086] According to one embodiment, the dry grinding device (100) may include a memory (110), a processor (120), a communication interface (130), and / or a display device (140). The configuration of the dry grinding device (100) shown in FIG. 1 is exemplary and the embodiments of the present invention are not limited thereto. For example, the dry grinding device (100) may further include components not shown in FIG. 1 (e.g., a chuck table, a dressing board, a grinding head, a wheel mount, a rotary wheel, a contact probe sensor, a non-contact probe sensor, a first servo motor, a second servo motor, a third servo motor, a spindle motor, a first sensor, a second sensor, a second sensor and a third sensor, an electromagnet, a first power supply, and a dust collection device).

[0087] According to one embodiment, the memory (110) may store instructions or data. For example, the memory (110) may store one or more instructions that cause the dry grinding device (100) to perform various operations when executed by the processor (120).

[0088] For example, the memory (110) may be implemented as a single chipset with the processor (120). The processor (120) may include at least one of a communication processor or a modem.

[0089] For example, the memory (110) can store various information related to the dry grinding device (100). For example, the memory (110) can store information regarding the operation history of the processor (120). For example, the memory (110) can store input data acquired by the dry grinding device (100) (e.g., start input), output data output by the dry grinding device (100) (e.g., notifications, warnings, starting thickness information before grinding and final thickness information after grinding, etc.), data acquired from an external server and / or user terminal, etc.

[0090] For example, the memory (110) may include multiple storage devices of different types. For example, the memory (110) may include volatile and / or non-volatile storage media. For example, the memory (110) may include at least one of RAM (random-access memory), ROM (read only memory), eMMC (Embedded Multi-Media Card), or any combination thereof.

[0091] The steps of the method or algorithm described in connection with the embodiments disclosed in this specification may be directly implemented in hardware, software modules, or a combination of both, executed by the processor (120). The software modules may reside in a storage medium (i.e., memory (110)) such as RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, a hard disk, a removable disk, or a CD-ROM.

[0092] For example, the memory (110) is coupled to a processor (120), and the processor (120) can read information from a storage medium and write information to a storage medium. Alternatively, the memory (110) may be integrated with the processor (120). The memory (110) and the processor (120) may reside within an application-specific integrated circuit (ASIC). The ASIC may reside within a user terminal. Alternatively, the memory (110) and the processor (120) may reside as separate components within the user terminal.

[0093] According to one embodiment, the processor (120) may be operatively connected to the memory (110), the communication interface (130), and / or the display device (140). For example, the processor (120) may control the operation of the memory (110), the communication interface (130), and / or the display device (140).

[0094] According to one embodiment, the communication interface (130) may support the establishment of a direct (e.g., wired) communication channel or a wireless communication channel between the dry grinding device (100) and an external device (e.g., user terminal, external server and database, etc.), and the performance of communication through the established communication channel. The communication interface (130) may include one or more communication processors that operate independently of the processor (120) (e.g., application processor) and support direct (e.g., wired) communication or wireless communication. According to one embodiment, the communication interface (130) may include a wireless communication module (e.g., cellular communication module, short-range wireless communication module, or GNSS (global navigation satellite system) communication module) or a wired communication module (e.g., LAN (local area network) communication module, or power line communication module). The corresponding communication module among these communication modules can communicate with an external dry grinding device through a first network (e.g., a short-range communication network such as Bluetooth, WiFi (wireless fidelity) direct, or IrDA (infrared data association)) or a second network (e.g., a legacy cellular network, a 5G network, a next-generation communication network, the Internet, or a computer network (e.g., a LAN or WAN)). These various types of communication modules may be integrated into a single component (e.g., a single chip) or implemented as multiple separate components (e.g., multiple chips). The wireless communication module can identify or authenticate the dry grinding device (100) within a communication network, such as the first network or the second network, using subscriber information (e.g., International Mobile Subscriber Identifier (IMSI)) stored in the subscriber identification module.

[0095] The user terminal may correspond to a manager terminal that transmits and receives various data to and from the dry grinding device (100) through a communication interface. For example, the user terminal may correspond to a manager's mobile terminal that transmits parameters for grinding the workpiece (e.g., initial thickness of the workpiece, target processing thickness, target thickness deviation, target grinding time, type of workpiece, etc.) to the dry grinding device (100).

[0096] According to one embodiment, the display device (140) may include at least one output device that provides various information and a user interface to the user.

[0097] For example, the display device (140) may include a display device, an audio output device, a virtual reality output device, etc.

[0098] For example, the display device (140) may provide the administrator with various types of user interfaces described in the present disclosure visually and / or audibly. The user may input (or transmit) a start input for grinding a workpiece to the dry grinding device (100) by operating the interface included in the display device (140).

[0099] The components of the dry grinding device (100) illustrated in FIG. 1 are exemplary, and the embodiments of the present disclosure are not limited thereto.

[0100] At least some of the embodiments of the present disclosure may be implemented as artificial intelligence (AI) through the processor (120) and memory (110) of the dry grinding device (100). The processor (120) may be composed of one or more processors, and the one or more processors may be general-purpose processors such as a CPU, AP, DSP (digital signal processor), etc., graphics-dedicated processors such as a GPU, VPU (vision processing unit), or artificial intelligence-dedicated processors such as an NPU. The one or more processors may be controlled to process input data according to predefined operation rules or artificial intelligence models stored in the memory (110). Alternatively, if the one or more processors are artificial intelligence-dedicated processors, the artificial intelligence-dedicated processors may be designed with a hardware structure specialized for processing a specific artificial intelligence model.

[0101] The predefined operation rules or artificial intelligence models are characterized by being created through learning. Here, being created through learning means that a basic artificial intelligence model is trained using a number of learning data by a learning algorithm, thereby creating predefined operation rules or artificial intelligence models configured to perform desired characteristics (or objectives). Such learning may be performed within the dry grinding device (100) itself, where the artificial intelligence according to the present disclosure is performed, or through a separate server and / or system. Examples of learning algorithms include supervised learning, unsupervised learning, semi-supervised learning, or reinforcement learning, but are not limited to the examples described above.

[0102] An artificial intelligence model may be composed of multiple neural network layers. Each of the multiple neural network layers has multiple weight values ​​and can perform neural network operations through operations between the results of previous layers and the multiple weights. The multiple weights possessed by the multiple neural network layers can be optimized based on the learning results of the artificial intelligence model. For example, the multiple weights can be updated so that the loss value or cost value obtained from the artificial intelligence model during the learning process is reduced or minimized. Artificial neural networks may include, but are not limited to, deep neural networks (DNN), convolutional neural networks (CNN), recurrent neural networks (RNN), restricted Boltzmann machines (RBM), deep belief networks (DBN), bidirectional recurrent deep neural networks (BRDNN), or deep Q-networks.

[0104] FIG. 2 is a conceptual diagram showing the layers between the components of a dry grinding device according to one embodiment of the present invention.

[0105] According to various embodiments, the dry grinding device (100) may include a main frame having an overall rectangular shape and a dust collector.

[0106] The main frame may be implemented in a form that includes two rectangular frames (or two rectangular frames combined), and an operation interface for operating the grinding process may be placed on the top of the first frame included in the main frame, and various components for grinding operations and dust collection may be placed inside the second frame. The components of the dry grinding device (100) described below may be placed within the empty space formed inside the second frame among the main frame.

[0107] The main frame is made of a metal material capable of ensuring rigidity and stability, and is structured such that multiple frame members are combined to form an internal hollow space.

[0108] The main frame can be formed with a six-sided structure including the top, bottom, front, rear, left, and right sides, and key components such as a base frame, workbench, chuck table, dressing board, grinding head, spindle shaft, wheel mount, rotary wheel, air blower, suction port, and dust collection duct are arranged inside.

[0109] The main frame protects internal components from vibrations and external shocks while maintaining the rigidity of the entire device. Additionally, an opening communicating with the dust collection duct is formed on a portion of the main frame's outer surface to facilitate the smooth discharge of metal dust into the dust collector.

[0110] The bottom surface of the main frame is equipped with multiple wheels (e.g., four wheels placed at each of the four corners of the bottom surface) so that the main frame can be easily moved within the workspace. This allows the device to be easily transported to a location where grinding work on a workpiece (e.g., an inductor bar) is required, and improves the flexibility of the installation environment.

[0111] The dust collector can be connected to the main frame through a dust collection duct communicating with a first opening formed in an area of ​​the outer surface of the main frame.

[0112] The dust collector communicates with the interior of the main frame through a dust collection duct and can effectively suck in and capture metal dust and floating particles generated during the grinding process.

[0113] The dust collector includes an internal filter and a dust collection unit, enabling the even separation and accumulation of inhaled metal dust. The dust collector can be designed with a detachable structure, allowing for easy replacement or cleaning once a certain amount of dust accumulates. This enhances the maintenance efficiency of the device and ensures the continuous cleanliness of the working environment.

[0114] The dust collector is equipped with a fan and a motor capable of controlling the suction flow rate, so that it can achieve optimal dust collection performance depending on the material, size, and amount of dust generated of the workpiece to be ground.

[0115] For example, when the inductor bar is large, the amount of dust generated increases, and in this case, the processor (120) can maintain sufficient suction power by increasing the fan speed of the dust collector in proportion to the size of the inductor bar. Conversely, when precision machining of small components, the fan speed can be reduced to prevent unnecessary energy consumption.

[0116] The dry grinding device (100) according to the present embodiment is configured to secure mechanical rigidity and stability through a main frame, while also effectively removing metal dust and floating particles generated during the grinding process by providing a dust collector. This ensures the safety of the worker, maintains the cleanliness of the working environment, and stably secures grinding quality for a long period.

[0117] The dry grinding device (100) can grind a workpiece based on various components placed in the main frame (particularly, the interior of the second frame described above among the two rectangular frames included in the main frame).

[0118] According to FIG. 2, the dry grinding device may include a base frame (210), a chuck table (220), a grinding section including a rotating wheel (242) and a wheel mount (244), a spindle shaft (250), and a grinding head (260). FIG. 2 shows an inductor bar (230) (workpiece) placed on the chuck table (220).

[0119] The base frame (210) may correspond to a main base structure located at the bottom of the main frame. The base frame (210) is formed in a rectangular shape and may be configured to support the load of the entire device using a high-strength metal material. Additionally, the base frame (210) is implemented with a structure having sufficient thickness and mass to provide vibration suppression, and provides stability so that vibrations generated during grinding are not transmitted to the upper structure. The base frame (210) supports a workbench and a chuck table (220) in the vertical direction, including a central portion where the chuck table (220) can move, and may function as a foundation structure for the entire device. A workbench (e.g., a flat portion accommodating the chuck table (220)) is placed in a space spaced upward from the base frame (210), and the workbench may be placed on the upper part of the base frame (210) spaced apart from the base frame (210) through two support structures in the form of vertical support columns. The base frame (210) can absorb and disperse the grinding reaction force and spindle vibration generated from the upper part to suppress mode resonance and maintain a constant flatness of the chuck table (220). Additionally, leveling bolts and pads are placed on the lower part of the base frame (210), and leveling correction (or leveling) is possible by controlling the leveling bolts and pads based on data obtained through a levelness detection sensor placed in one area of ​​the base frame (210) by a processor. Additionally, vibration isolation pads may be inserted on the lower part of the base frame (210).

[0120] The chuck table (220) may be positioned on the upper part of the base frame (210) spaced apart from the base frame (210). The chuck table (220) may be moved in the x-axis direction (e.g., vertical direction of the y-axis direction (391)) and the y-axis direction by the first servo motor and the second servo motor, respectively, within the central part of the workbench of FIG. 3. That is, the processor can drive the first servo motor and the second servo motor to move the chuck table (220) finely in the x-axis and y-axis directions, thereby allowing for precise control of the relative position with respect to the rotating wheel (242). The chuck table (220) may be coupled with the first servo motor and the second servo motor by having at least two rails of linear guide and a ball screw attached to the lower part. The chuck table (220) may be positioned in the central part of the workbench to stably fix the workpiece (230). Grid grooves and annular channels may be arranged on the upper surface of the chuck table (220), and vacuum ports and check valves may be arranged on the sides. Through this, the chuck table (220) can implement a vacuum suction system to vacuum suction and fix the workpiece (230) placed on the upper surface. On the upper surface of the chuck table (220), two reference edge structures (or stoppers) may be arranged on two sides parallel to each other to guide the placement of the workpiece (230). Meanwhile, an air blower may be arranged in a central area of ​​the workbench where the chuck table (220) is placed, and metal dust and floating particles generated during the grinding process of the workpiece (230) may be moved to the suction port by the air discharged from the air blower.

[0121] The object to be ground (230) may correspond to an inductor bar in the shape of a rectangular parallelepiped having a predetermined length, width, and thickness. The object to be ground (230) may be made of copper, copper alloy, iron-based alloy, magnetic material, etc.

[0122] The rotating wheel (242) may correspond to a CBN (Cubic Boron Nitride) wheel or a diamond wheel. The rotating wheel (242) corresponds to a circular wheel and rotates together with the spindle axis (250) as it rotates to grind and flatten the surface of the workpiece (230) placed at the bottom. A balancing groove including an annular groove or a partial pocket groove for dynamic balancing of mass imbalance may be formed on the outer surface or side of the rotating wheel (242), and / or two or more balancing screws may be further included in screw fastening holes formed radially at symmetrical positions on the outer surface of the rotating wheel (242). During the dynamic balancing process, the user can correct the mass distribution of the rotating wheel (242) by inserting weights into the balancing grooves or optionally fastening balancing screws into the screw holes based on vibration measurement results through a vibration detection sensor included in the dry grinding device. Through this, the rotating wheel (242) can minimize axial wobble and vibration even during high-speed rotation, thereby improving grinding precision and spindle durability. For example, the diameter of the rotating wheel may be 200 mm.

[0123] The wheel mount (244) corresponds to a connecting structure in which the upper surface is coupled to the spindle shaft (250) and the lower surface is coupled to the rotating wheel (242). The wheel mount (244) can be positioned to transmit spindle torque generated by the rotation of the spindle shaft (250) to the rotating wheel (242) without loss, and to ensure rigidity against bending and twisting that may occur when the rotational speed exceeds a critical speed. The wheel mount (244) can be formed from high-strength alloy steel or lightweight aluminum alloy material and is implemented as a structure having rigidity to transmit rotational torque and axial load transmitted through the spindle shaft (250) to the rotating wheel (242) without loss. Additionally, the wheel mount (244) may include a tapered hole or flange structure for coupling the spindle shaft (250) on the upper surface, and a bolt fastening part and a circular centering pocket for fixing the rotating wheel (242) may be formed on the lower surface. Through this, precise positional alignment and center axis alignment are ensured when replacing the rotating wheel (242), thereby minimizing run-out of the rotating wheel (242) during the grinding process. In addition, the wheel mount (244) is designed with a symmetrical structure that excludes asymmetric mass distribution to ensure sufficient durability against centrifugal force and vibration generated during high-speed rotation, and in some embodiments, at least one small-diameter screw fastening hole may be formed on the outer periphery to assist in dynamic balancing.

[0124] The spindle axis (250) corresponds to a rotary drive axis extending downward from within the grinding head (260). The spindle axis (250) extends downward from one point of the grinding head (260) and can be configured to move in the z-axis direction (e.g., up and down direction) which is perpendicular to the x-axis and y-axis directions via a third servo motor. It may be driven (e.g., z-axis movement and rotation) by being directly connected to the third servo motor and / or high-speed spindle motor, or indirectly connected via a belt pulley and gear train in some embodiments. The spindle axis (250) rotates the rotating wheel (242) and wheel mount (244) at high speed and provides grinding force to the workpiece (230). The spindle axis (250) is multi-point supported by high-precision angular contact ball bearings, ceramic hybrid bearings, etc., and suppresses vibration, shaft wobble, and thermal deformation that occur during high-speed rotation. Additionally, the spindle shaft (250) may have a built-in cooling channel or be forcibly cooled by an external fan, and is supported with a minimum clearance in both the axial and radial directions to maintain precision. The spindle shaft (250) is designed to be raised and lowered by a third servo motor in the z-axis direction, allowing for variable depth grinding on the upper surface of the workpiece (230).

[0125] The grinding head (260) corresponds to an upper housing structure in which the spindle shaft (250) and the third servo motor are housed. The grinding head (260) is installed at the top of the main frame (or at the top within the internal empty space of the main frame) and is composed of a high-precision rigid frame to absorb vibrations and external forces generated during grinding and to ensure the stability of the spindle shaft (250), the rotating wheel (242), and the wheel mount (244). The interior of the grinding head (260) may include a third servo motor, a bearing housing, a lubrication system, and a structure supporting the spindle shaft (250). Additionally, an inspection cover for maintenance, electrical wiring, and cooling pipe connection ports may be provided on the exterior of the grinding head (260). In some embodiments, a non-contact probe sensor (e.g., a laser sensor) is attached to the side or outer frame of the grinding head (260) so that the surface condition and thickness of the workpiece (230) to be ground can be measured in real time during the grinding process.

[0126] Although not shown in FIG. 2, the dry grinding device may further include an air blower, an intake port, a dust collection duct, and a dust collector.

[0127] The air blower may be placed in a central area of ​​the workbench where the chuck table (220) is positioned (e.g., the bottom surface of the workbench). That is, the air blower may be placed in a first area facing the rotating wheel and a second area on the side of the chuck table, respectively, within the central area of ​​the workbench. The air blower includes a blower motor and a nozzle structure and performs the function of blowing fine metal dust and floating particles generated on the surface of the workpiece (230) in a specific direction (e.g., the direction in which the suction port is positioned). The air blower is positioned to discharge air from the central area of ​​the workbench toward the end, and in particular, by inducing an airflow in conjunction with the suction port, it ensures that dust is stably discharged without being re-dispersed inside the machine. Additionally, in some embodiments, it includes a nozzle angle adjustment motor configured to adjust the angle of the discharge nozzle and directly connected to the nozzle, thereby allowing the optimal blowing path to be set according to the size and grinding position of the workpiece (230).

[0128] The suction port is positioned at the central end of the workbench and directly collects metal dust and floating particles moved by air blown from an air blower. Here, the end may correspond to the other end among the first end adjacent to the chuck table (220) and the other end opposite to the first end when the first workpiece (230) is placed on the chuck table (220). The suction port is formed in the shape of a rectangular or annular opening and may include an inclined surface or guide duct inside to smoothly guide the dust to the dust collector. A backflow prevention flap or filter mesh may be installed inside the suction port to prevent metal dust from flowing back.

[0129] The dust collection duct may serve as a passage connecting the intake port and a dust collector located outside the main frame. The dust collection duct may be formed of wear-resistant alloy steel or corrosion-resistant aluminum alloy, and in some embodiments, may be made of transparent acrylic or reinforced plastic so that the dust movement status can be visually checked. One end of the dust collection duct communicates with a first opening formed in the outer wall of the main frame and transports metal dust and suspended matter introduced from the intake port to the dust collector. Here, the first opening may correspond to at least a part of the intake port.

[0130] The dust collector is connected to the other end of the dust collection duct and is a device that ultimately captures metal dust and suspended particles. The dust collector can be configured using a centrifugal dust collection method, a bag filter dust collection method, or a vacuum suction method, and can efficiently separate and store dust. The interior of the dust collector is equipped with a filter cartridge or a cyclone separator, allowing it to capture even fine metal particles. In addition, the dust collector is equipped with a sensor that detects the amount of dust in real time, and can automatically trigger an alarm if the amount accumulates beyond a certain limit. A detachable recovery container or drawer structure is provided at the bottom of the dust collector, allowing the collected metal dust to be easily discharged and recycled.

[0131] Additionally, the dry grinding device (100) may further include a contact probe sensor and a non-contact probe sensor.

[0132] A contact probe sensor may be positioned in the upper part of the chuck table and configured to measure the thickness of the workpiece by contacting the upper surface of the workpiece through a probe.

[0133] For example, a contact probe sensor can be placed near the edge of the upper surface of the chuck table or in an area where the upper surface of the workpiece to be ground is easy to measure (e.g., an area of ​​the outer circumference of the grinding head).

[0134] For example, the main body of the contact probe sensor can be fixed to a frame next to the chuck table, and the probe tip is positioned inside a protective housing and can descend by passing through a second opening of the protective housing when necessary to contact the upper surface of the workpiece to be ground.

[0135] A non-contact probe sensor may be positioned facing the side of the grinding head or the outer circumference of the lower part of the spindle axis, and configured to measure the thickness of the workpiece in real time by receiving the reflected signal after irradiating a laser beam onto the surface of the workpiece. If the rotating wheel is rotating while in contact with the surface of the workpiece (or is in the process of grinding), the non-contact probe sensor can measure the thickness of the workpiece in real time by irradiating a laser onto the side of the workpiece.

[0136] For example, the non-contact probe sensor can be fixedly positioned on the side of the grinding head or on the lower outer periphery of the spindle axis. That is, the non-contact probe sensor can be designed so that laser light is irradiated onto the top or side of the workpiece at a position facing the rotating wheel. As an example, the non-contact probe sensor may be positioned at a horizontal or inclined angle with respect to the rotating wheel to receive reflected light without interference with the wheel's rotation.

[0137] Therefore, a non-contact probe sensor is responsible for real-time non-contact measurement, while a contact probe sensor mounted on a chuck table performs auxiliary high-precision thickness measurement; these two measurement methods can be used in combination. This combination enhances the reliability of thickness detection during the pre-, mid-, and post-grinding processes and effectively maintains grinding quality stably over a long period.

[0138] Additionally, the dry grinding device (100) may further include a blocking member comprising a protective housing that surrounds the probe portion to prevent the probe portion of the contact probe sensor from contacting the object to be ground, and a rotating arm or sliding block configured to open and close the protective housing.

[0139] The dry grinding device (100) may further include a sensor that detects in real time whether the rotating wheel is rotating and a fourth servo motor that is fixedly positioned on a bracket attached to the side of the grinding head and configured to move a rotating arm or a sliding block based on a driving signal corresponding to the result identified through the sensor.

[0140] For example, if the sensor identifies that the rotating wheel is rotating in real time, the rotating arm or sliding block can automatically move the protective housing to a closed position by the fourth servo motor so that the probe does not approach the surface of the workpiece to be ground. That is, the processor identifies that the rotating wheel is rotating through the sensor and drives the fourth servo motor to move the protective housing to a closed position.

[0141] For example, if it is identified through a sensor that the rotating wheel is not rotating in real time, the rotating arm or sliding block can be moved by the fourth servo motor to a position where the protective housing is opened so that the probe can contact the surface of the workpiece to be ground. That is, the processor identifies through a sensor that the rotating wheel is not rotating and drives the fourth servo motor to move the protective housing to an open position.

[0142] Additionally, the dry grinding device (100) may further include a drive link that mechanically receives the driving force generated by the driving of the fourth servo motor.

[0143] The dry grinding device (100) may include at least one of a sliding block coupled to the end of a drive link to perform linear reciprocating motion, or a rotating arm coupled to the rotational center axis of a drive link to perform rotational motion.

[0144] For example, the sliding block may be coupled to one side of the outer surface of the protective housing and configured to move the protective housing in a straight line back and forth.

[0145] For example, the sliding block may be configured such that the protective housing is guided to move linearly in a direction parallel to the surface of the workpiece by being supported by a sliding guide block that moves along a guide rail fixed to the outer frame of the grinding head.

[0146] For example, the rotating arm may be formed in the shape of a crank arm and configured to receive the driving force of the fourth servo motor through a drive link and a connecting rod to perform a swinging motion and open or close the protective housing.

[0147] For example, the protective housing is formed in a square tube shape and configured to surround the probe portion of the contact probe sensor, and a second opening may be formed on the bottom surface of the protective housing.

[0148] For example, the central axis of the second opening may be positioned so that it coincides with the central axis of the probe when the protective housing is positioned in the open position, thereby allowing the probe to descend and come into contact with the object to be ground.

[0149] For example, the central axis of the second opening may be configured so that the central axis of the probe cannot descend when the protective housing is positioned in the closed position, thereby becoming misaligned with the central axis of the probe.

[0150] For example, a Teflon (PTFE) coating layer may be formed on the inner surface of the protective housing to reduce interference with the probe.

[0151] That is, according to the components described above, the dry grinding device (100) may further include a blocking structure (or, blocking member) for protecting the probe portion of the contact probe sensor.

[0152] Specifically, the probe is structured to descend for measuring the thickness of the workpiece to be ground, but there is a high risk of damage if it is unnecessarily exposed while the rotating wheel is rotating at high speed. To prevent this, a protective housing is placed around the probe, and a rotating arm or sliding block is provided to open and close the protective housing.

[0153] Whether the rotating wheel is rotating is detected in real time by a rotation detection sensor. For example, an optical or magnetic sensor measures the rotational speed of the rotating wheel, and the measured result is transmitted to a fourth servo motor fixed on a bracket mounted on the side of the grinding head.

[0154] The fourth servo motor automatically controls the protective housing to a closed or open position based on the sensor signal. When it is detected that the rotating wheel is rotating, the fourth servo motor drives the rotating arm or sliding block to move the protective housing to a closed position so that the probe cannot approach the surface of the object. Conversely, when the rotating wheel is identified as being stopped, the protective housing opens to an open position so that the probe can descend, pass through the second opening, and come into contact with the surface of the object.

[0155] That is, a processor electrically connected to the electronic components of the dry grinding device (100) can be configured to drive a fourth servo motor to move the protective housing to a closed position when the rotational speed of the rotating wheel obtained through the sensor exceeds a threshold speed (e.g., 0).

[0156] This structure prevents damage to the sensor during high-speed rotation and ensures sensor lifespan and measurement stability by exposing the probe only when measurement is required.

[0157] Additionally, the drive mechanism for opening and closing the protective housing of the dry grinding device (100) may include a mechanical transmission structure leading to a fourth servo motor, a drive link, and a rotating arm / sliding block.

[0158] First, the driving force of the fourth servo motor is transmitted through a drive link. A sliding block or a rotary arm may be optionally coupled to the end of the drive link.

[0159] First, the sliding block is directly connected to the outer surface of the protective housing and receives linear driving force from the fourth servo motor to reciprocate the protective housing. The sliding block moves along a guide rail fixed to the outer frame of the grinding head, and is supported by the sliding guide block to guide the protective housing to move stably in a direction parallel to the surface of the workpiece to be ground.

[0160] Here, the sliding block and the sliding guide block supporting it perform different functions while operating in conjunction. Specifically, the sliding block is the main driving member that directly receives the linear driving force transmitted from the fourth servo motor via a drive link to reciprocate the protective housing. On the other hand, to suppress shaking or tilting that may occur during the movement of the sliding block, the outer or lower surface of the sliding block is supported by sliding guide blocks arranged along the guide rails. In this case, the sliding guide blocks do not drive independently but function merely as auxiliary supports that guide the linear motion of the sliding block while moving along the rails. Therefore, the two elements are not identical parts; rather, one acts as the driving body (sliding block) and the other as the guide body (sliding guide block), forming a mutually complementary relationship.

[0161] Secondly, the rotary arm is formed in the shape of a crank arm and receives rotational driving force from the fourth servo motor through a drive link and a connecting rod. The rotary arm performs a swinging motion around a rotational center axis, and through this motion, the protective housing can be opened and closed.

[0162] In particular, the protective housing is formed in the shape of a square tube and is positioned to surround the probe. A second opening is formed on the bottom surface of the protective housing. When the protective housing is in the open position, the center axis of the second opening coincides with the center axis of the probe, allowing the probe to descend and come into contact with the surface of the object. Conversely, when the protective housing is in the closed position, the center axis of the second opening does not coincide with the center axis of the probe, thereby blocking the descent of the probe.

[0163] In addition, a Teflon (PTFE) coating layer is formed on the inner surface of the protective housing to minimize interference and friction with the probe. This prevents damage to the probe even during repetitive opening and closing operations and improves the durability of the protective housing.

[0164] Therefore, the protective housing is reliably driven via linear or rotational motion, and the approach of the probe is precisely controlled. This increases the reliability of the measurement process and effectively reduces the risk of device damage that may occur during the grinding process.

[0165] Additionally, the dry grinding device (100) may further include a wheel mount and an air blower.

[0166] The wheel mount is a rotary drive transmission member coupled to the lower end of the spindle shaft extending from a point on the lower surface of the grinding head, and is positioned coaxially (along the same Z-axis) with the rotational center of the spindle shaft. A rotating wheel is attached to the lower part of the wheel mount, and a tapered coupling (e.g., a tapered hole) or a flange coupling is formed on the upper part for attachment to the spindle shaft and centering. The wheel mount faces the upper part of the chuck table in the Z-axis direction and is located in the upper path of the airflow generated from the air blower. Accordingly, metal dust and / or floating particles generated at the lower part of the rotating wheel are guided toward the intake along the blowing direction of the air blower.

[0167] The wheel mount can transmit the rotational torque and axial load of the spindle motor to the rotating wheel without loss, and can minimize axial and radial runout by precisely aligning the wheel center through a taper, centering pocket, and alignment pin. Furthermore, it may be provided with at least one groove on the outer circumference to accommodate at least one balancing screw or balancing ring (or balancing disc), and weight adjustment can be performed in real time on-site in response to imbalance measured by the device's vibration sensor.

[0168] The wheel mount may include a symmetrical rib structure and reinforcing ribs to accommodate thermal expansion caused by centrifugal force during high-speed rotation, and may homogenize the mass distribution to minimize vibration transmission of the spindle bearing.

[0169] The wheel mount may be configured with a surface treated by at least one of anodizing, nickel, or chrome plating to inhibit corrosion and dust adhesion.

[0170] An air blower is positioned at the bottom or side of the center of the workbench to form a continuous airflow extending from the bottom of the rotating wheel to the top surface of the chuck table and to the intake. The air blower is positioned in close proximity to the bottom of the rotating wheel to blow out dust and guide it to the intake at the end of the workbench (communicating with the dust collection duct). Additionally, one or more air blowers may be placed on the sides of the chuck table, in which case the side nozzles are configured to push fine dust scattered from the top surface at a horizontal or downward angle to join the main flow.

[0171] The air blower can immediately detach fine metal dust and floating particles generated around the grinding point from the blowing area below the rotating wheel, thereby creating a linear flow path in the direction of the suction port. The direction of air discharge through the air blower may be the same as the direction of the grinding process in which the chuck table moves the workpiece for grinding.

[0172] The air blower may include an integrated nozzle of an electric blower (e.g., a small turbo or centrifugal fan), or a jet nozzle or slit nozzle based on compressed air (e.g., plant air) (e.g., a nozzle including a regulator).

[0173] The air blower can adjust the air discharge angle in the up and down direction through a pivot-type angle adjustment bracket.

[0174] By using an air blower, the dry grinding device can mitigate the temperature rise of the grinding parts, such as the rotating wheel and wheel mount, by using only air cooling without cooling water, thereby suppressing thermal deformation and burning.

[0176] FIG. 3 is a conceptual diagram showing the arrangement structure of the workbench, the rotation structure of the rotating wheel, and the movement structure of the chuck table of a dry grinding device according to one embodiment of the present invention.

[0177] Reference number 301 can be understood as a conceptual diagram of a dry grinding device including the components of FIG. 2.

[0178] Referring to reference number 301, the dry grinding device may include a base frame (310), a workbench (399) positioned on the upper part of the base frame (310) and spaced apart from the base frame (310) through two support structures in the form of vertical support columns, and a chuck table (e.g., chuck table (220) of FIG. 2) that is movable in the x-axis direction (e.g., vertical direction of the y-axis direction (391)) and y-axis direction (391) from the center of the workbench (399) by driving a first servo motor and a second servo motor.

[0179] Referring to reference number 301, the dry grinding device may include a spindle axis configured to be movable in the z-axis direction (392) perpendicular to the x-axis direction and the y-axis direction through a third servo motor included in the grinding head (330).

[0180] Referring to reference number 301, the dry grinding device may further include a wheel balancer (350) which is installed by screw fastening on the outer circumference of the grinding head (330) and / or wheel mount and is implemented in the form of a balancing disc or a balancing ring. The wheel balancer (350) contains a small mass (e.g., a ball or weight) inside, and the mass can perform dynamic balancing by being automatically distributed by centrifugal force while the rotating wheel rotates for grinding.

[0181] Reference number 302 can be understood as an enlarged conceptual diagram of the area of ​​the workbench (399) of reference number 301.

[0182] Referring to reference number 302, the spindle axis is configured to be movable in the z-axis direction (392), and as the spindle axis rotates, the rotating wheel likewise rotates in a predetermined rotational direction (393) to grind the workpiece. The processor (120) can rotate the spindle axis in a predetermined rotational direction (393) by driving a spindle motor that is positioned within the grinding head and coupled to the spindle axis to rotate the spindle axis.

[0183] Referring to reference number 302, the chuck table (320) may be configured to be finely movable in the y-axis direction (391) or the x-axis direction (e.g., a horizontal direction perpendicular to the y-axis direction (391)).

[0184] Referring to reference number 302, within the central part of the workbench (399) on which the chuck table (320) moves, an air blower for discharging air to move metal dust and floating debris in a specific direction may be placed in part of the entire area below the movement path of the chuck table (320) (or, the bottom surface of the workbench). An air blower may also be placed on the side of the chuck table (320).

[0185] Referring to FIGS. 3 and 4, an electromagnet (300) (or a first dust collection device) may be further disposed in the central part of the workbench (399) and extended in the y-axis direction along the target movement path where the chuck table (320) moves in the y-axis direction. That is, the electromagnet (300) may be disposed extending in the y-axis direction at the bottom of the chuck table (320) in the central part of the workbench (399), and when power is supplied from the first power supply, it can collect ultrafine dust generated during the grinding process through magnetic force. The ultrafine dust may include, for example, magnetic dust with a particle size of 10 μm or less.

[0186] The dry grinding device (100) may further include a first power supply electrically connected to the electromagnet (300) and a dust collection device positioned below the electromagnet (300).

[0187] For example, the first power supply unit performs the role of supplying or cutting off the power required for the electromagnet based on the control of the processor (120).

[0188] The first power supply unit is electrically connected to the electromagnet (300) and can supply or cut off power to the electromagnet (300) according to a power supply command or a power supply interruption command received from the processor (120).

[0189] Specifically, when the grinding operation begins, the first power supply unit receives a power supply command from the processor (120) to activate (turn on) the electromagnet and support the dust collection function, and when the grinding operation ends, it receives a power supply cutoff command from the processor (120) to cut off the power supply to the electromagnet (300), thereby deactivating (turning off) the electromagnet (300) and allowing the collected dust to escape (or fall). Additionally, the first power supply unit may include a variable control function capable of precisely adjusting the intensity of the current supplied to the electromagnet (300) in response to a control signal from the processor (120).

[0190] For example, the dust collection device can perform the role of finally collecting and storing magnetic dust that has been ejected (or fallen) through the collection and ejection mechanism of the electromagnet (300).

[0191] The dust collection device is positioned below the electromagnet (300) so that it can efficiently collect magnetic dust falling due to gravity when the power supply to the electromagnet is cut off and the magnetic force disappears.

[0192] The dust collection device prevents contamination of the work environment and protects the precision parts of the device by safely isolating and storing the collected dust from the external environment. The collected dust is temporarily stored inside the dust collection device and can then be discharged and processed through the openings on the side and bottom surfaces, which are opened and closed at regular intervals under the control of the processor (120).

[0194] FIG. 5 is a flowchart of a dry grinding method according to one embodiment of the present invention.

[0195] The “double-separated first dust collection device and second dust collection device” of the present disclosure refers to a first dust collection device (magnetic force-based) and a second dust collection device (electrostatic force-based) that utilize different physical principles to collect dust generated during a grinding process by classifying it by type.

[0196] Here, the first dust (e.g., magnetic dust) includes, for example, dust containing iron (Fe)-based components or having high magnetic properties, and the second dust (e.g., non-magnetic / low-magnetic dust) includes, for example, dust containing copper (Cu)-based components or having relatively low magnetic properties, so that the collection efficiency is low by magnetic force alone.

[0197] However, since dust types may vary depending on the material and / or process conditions, this disclosure describes a functional classification in terms of magnetic / non-magnetic or magnetic properties.

[0198] In addition, the meaning of inducing the dust collected by the first dust collection device and the second dust collection device to escape to the dust collection device can be understood as a configuration in which the dust collected by the first dust collection device and the second dust collection device falls and is transported by a common storage unit (e.g., dust container, dust collection bin, dust collection box) where it is finally stored; in the following description, this may be referred to as a “common dust storage unit” to prevent confusion.

[0199] In one embodiment, dust generated during the grinding process may be classified into first dust and second dust depending on the degree of inclusion of magnetic components. For example, the first dust contains magnetic dust (e.g., iron (Fe)-based core cutting dust), and the second dust contains non-magnetic dust (e.g., copper (Cu)-based winding cutting dust). In this embodiment, to quantify the magnetic tendency of the dust, a magnetic index (MI) calculated based on sensor output may be defined. The magnetic index (MI) may be calculated, for example, as a change in output of a Hall sensor / magnetic flux sensor placed around an electromagnet (or first dust collection device), a current / magnetic flux correlation value when the electromagnet is driven, or an equivalent physical quantity, and the calculation method may be implemented in various ways depending on the device configuration.

[0200] In one embodiment, if the magnetic index (MI) is greater than or equal to a first threshold value, the dust can be determined as first dust and guided to a first dust collection device. Additionally, if the magnetic index (MI) is less than or equal to a second threshold value, the dust can be determined as second dust and guided to a second dust collection device. At this time, by setting the first threshold value to be greater than the second threshold value to separate the threshold interval, a phenomenon (e.g., chatter) in which the magnetic / non-magnetic determination is repeatedly switched in the boundary region can be suppressed.

[0201] Additionally, if the magnetic index (MI) falls between the first threshold and the second threshold, the dust can be defined as mixed dust (or low-magnitude dust). In the mixed dust section, the system may be configured to perform simultaneous collection by operating the first dust collection device and the second dust collection device in parallel, or to guide the mixed dust to a separate collection unit for post-processing separation. For example, parallel operation in the mixed dust section may be weighted control according to process conditions.

[0202] In one embodiment, the first threshold and the second threshold may be set based on the results of pre-calibration or sampling analysis. For example, the device may collect dust samples at the beginning of the process or during periodic inspections and calculate the Fe content or magnetic properties of the dust through sampling analysis (e.g., XRF, ICP, magnetic susceptibility measurement, etc.). The processor (120) may determine the threshold to satisfy the target purity (e.g., magnetic purity of Fe dust or non-magnetic purity of Cu dust) by storing the correlation between the analysis results and the magnetic index (MI) in a learning or lookup table. Additionally, since the sensor output may fluctuate depending on changes in environmental conditions such as temperature, humidity, and airflow, the processor (120) may be configured to correct the threshold according to environmental conditions or the device usage time.

[0203] In addition, the first and second critical concentrations described below may be set based on workplace contamination prevention standards, internal contamination tolerances of the device, target capture efficiency, or target power consumption. For example, the processor (120) may be configured to store a reference value in a reference state (e.g., no load or reference load) for the concentration sensor output (e.g., optical scattering / differential pressure / electrode current change / Hall sensor indirect measurement, etc.) during the initial setting stage, and to determine that the increase relative to the reference value exceeds a predetermined level as "critical concentration exceeded." In addition, the critical time may be set as the minimum time for the grinding time interval control to operate meaningfully, and may be calculated by taking into account the device's response time (e.g., power application / deactivation delay, sensor stabilization time).

[0204] According to one embodiment, a dry grinding device (e.g., the dry grinding device (100) of FIG. 1) can perform the operations disclosed in FIG. 5. For example, at least some of the components included in the dry grinding device (e.g., the memory (110), processor (120), communication interface (130), display device (140) of FIG. 1) may be configured to perform the operations of FIG. 5.

[0205] In the following embodiments, the operations S510 to S560 may be performed sequentially, but are not necessarily performed sequentially. For example, the order of each operation may be changed, and at least two operations may be performed in parallel. Additionally, content corresponding to or overlapping with the content described above in relation to FIG. 4 may be briefly explained or omitted.

[0206] According to one embodiment, the processor (120) can drive the first servo motor and the second servo motor in response to receiving a start input for grinding a workpiece from a user terminal to move the chuck table on which the workpiece is placed to the grinding workpiece position (S510).

[0207] For example, the object to be ground may correspond to a rectangular inductor bar.

[0208] For example, the processor (120) can transmit a start input for grinding a workpiece to the dry grinding device (100) by the operator touching a start button within a grinding interface displayed on the screen of a user terminal (e.g., tablet, PC HMI, mobile terminal).

[0209] For example, the start input may include information for grinding the workpiece (e.g., target machining thickness, target grinding time, target deviation, etc.).

[0210] For example, the processor (120) can move the chuck table to a grinding target position by transmitting a driving signal to a first servo motor (e.g., a servo motor for x-axis movement of the chuck table) and a second servo motor (e.g., a servo motor for y-axis movement of the chuck table) based on a start input.

[0211] For example, the chuck table can move the workpiece to a processing position (or grinding target position) located in the lower region of the rotating wheel by moving along the linear guide and the ball screw by driving the first servo motor and the second servo motor.

[0212] For example, the chuck table can fix the workpiece to the upper surface based on a vacuum suction system during movement.

[0213] For example, the start input may be obtained based on voice commands and / or gesture recognition acquired through a microphone and / or camera included in the dry grinding device.

[0214] For example, the start input may be automatically transmitted from the factory MES (Manufacturing Execution System) server according to the work schedule.

[0215] According to one embodiment, the processor (120) can determine a reference line extending the center point of the workpiece in the z-axis direction based on the real-time position of the workpiece confirmed using the first sensor (S520).

[0216] For example, the processor (120) can detect the real-time coordinates of an object based on information obtained through a first sensor (e.g., an optical position sensor or a vision sensor) placed on the bottom surface of the grinding head while the chuck table is moving.

[0217] For example, the processor (120) can identify the center point of the object to be ground based on information obtained through the first sensor.

[0218] For example, the processor (120) can identify a virtual reference line (e.g., a straight line extending vertically from the center point in the z-axis direction (or, up and down direction)) based on the identified center point, and can determine whether this reference line is aligned with the center point (or, center axis) of the rotating wheel.

[0219] For example, if the reference line does not pass through the center point of the rotating wheel (or, if the workpiece to be ground is not placed in the appropriate grinding position), the processor (120) can realign the chuck table by finely correcting the first servo motor and the second servo motor.

[0220] This process is designed to compensate even if one corner of the inductor bar is mechanically misaligned, thereby minimizing the center alignment error between the rotating wheel and the workpiece.

[0221] In addition, the first sensor may be implemented as various sensors such as a laser displacement sensor, an LVDT sensor, a 3D vision camera, and a microwave distance sensor.

[0222] Furthermore, the processor (120) may determine the coordinates of the center point of the object to be ground using an image processing algorithm (e.g., CNN-based) for an image obtained by a high-resolution camera placed on the bottom surface of the grinding head.

[0223] According to one embodiment, the processor (120) can drive a third servo motor to lower the rotating wheel in response to confirming that a reference line extending the center point of the object to be ground in the z-axis direction passes through the center point of the rotating wheel (S530).

[0224] For example, the rotating wheel may correspond to a CBN wheel or a diamond wheel.

[0225] For example, when the processor (120) confirms the alignment between the rotating wheel and the workpiece to be ground based on information obtained through the first sensor, it can drive the third servo motor to bring the rotating wheel into contact with the surface of the workpiece to be ground.

[0226] For example, the third servo motor lowers the spindle axis in the z-axis direction, and accordingly, the wheel mount and the rotating wheel can also be lowered together.

[0227] For example, the rotating wheel is still stationary and slowly descends to approach the upper surface of the workpiece to be ground.

[0228] For example, the processor (120) limits the descent speed to below a critical speed so that the rotating wheel reaches the surface of the workpiece in a manner that minimizes impact between the rotating wheel and the workpiece.

[0229] For example, the processor (120) can lower the spindle axis based on a speed determined based on a curved acceleration profile (S-curve acceleration), and after moving the rotating wheel to the workpiece at an initial first speed, it can then move the rotating wheel to the workpiece at a speed that gradually decreases from a second speed smaller than the first speed from the point where the distance between the rotating wheel and the workpiece becomes less than a critical distance. Through this, mechanical shock can be minimized.

[0230] According to one embodiment, the processor (120) can drive a spindle motor to rotate the rotating wheel at a predetermined RPM in response to confirming that the rotating wheel has come into contact with the surface of the workpiece to be ground using a second sensor (S540).

[0231] For example, the processor (120) can detect that the rotating wheel has come into contact with the surface of the inductor bar by using a second sensor (e.g., force sensor, contact sensor, current sensor) placed at the bottom of the spindle axis or near the rotating wheel.

[0232] For example, the second sensor includes a force sensor, and the processor (120) can determine that the rotating wheel has come into contact with the surface of the object to be ground when it confirms a predetermined repulsive force through the force sensor.

[0233] For example, the second sensor includes a current sensor, and the processor (120) can determine that the rotating wheel has come into contact with the surface of the object to be ground when it detects a predetermined current peak through the current sensor.

[0234] For example, when a contact signal is detected, the processor (120) can drive the spindle motor to accelerate the rotating wheel to a predetermined RPM.

[0235] For example, a predetermined RPM may correspond to 2,000 RPM, which corresponds to a rotational speed preset by the manager. 2,000 RPM is an intermediate range between low and high speeds, and it is the optimal speed in terms of ensuring stable cutting force while preventing surface damage when grinding rectangular metal parts such as inductor bars, as well as ensuring machining stability, optimizing thermal management, maximizing dust control capabilities, optimizing grinding wheel life, and ensuring control system responsiveness.

[0236] For example, the processor (120) can adjust the RPM in real time within a predetermined range (e.g., 1,500 to 2,500 RPM) during the grinding target time included in the start input based on the RPM variable instruction included in the start input. The magnitude of the change in RPM can be used to adjust the strength of the power to be supplied to the electromagnet (300) by the processor (120) using the first power supply unit, as described below, and the magnitude of the RPM can be proportional to the strength of the power to be supplied.

[0237] According to one embodiment, the processor (120) can collect the first dust and the second dust generated from the object to be ground by the rotation of the rotating wheel, respectively, by using a first dust collection device electrically connected to a first power supply and a second dust collection device electrically connected to a second power supply (S550).

[0238] For example, when the rotation of the rotating wheel (242) is started by the spindle motor drive, the processor (120) can transmit a power supply command to the first power supply and the second power supply for the dual dust collection device (e.g., the first dust collection device (e.g., the electromagnet (300) of FIG. 3) and the second dust collection device) so that the dual dust collection device can be controlled to collect magnetic dust and non-magnetic dust generated from the workpiece (e.g., an inductor bar). This step can be understood as a key process for ensuring process stability and worker safety by immediately collecting ultrafine dust generated during the dry grinding process without scattering it outside the working environment.

[0239] For example, the time at which a power supply command is transmitted can be defined as immediately after the second sensor detects contact of the rotating wheel with the surface of the workpiece to be ground and the spindle motor begins to accelerate the rotating wheel to a predetermined RPM. This is intended to minimize the initial gap during which dust can scatter by synchronizing the time at which dust generation begins with the time at which dust collection by the dual dust collection device begins.

[0240] For example, when the rotation of the rotating wheel begins, the processor (120) collects the first dust and the second dust generated from the workpiece by the rotation of the rotating wheel using a first dust collection device electrically connected to the first power supply and a second dust collection device electrically connected to the second power supply. At this time, the first dust collection device is configured to collect magnetic dust (or the first dust) based on magnetic force and includes an electromagnet that receives current from the first power supply. For example, the electromagnet includes a coil and a magnetic core (or an iron core) to form a magnetic flux and is placed at a location where magnetic dust passes, such as around the grinding point or under the chuck table movement path, to selectively attract magnetic particles. The first power supply is composed of a power source capable of variable DC current output (e.g., a rectifier, a switching power source, or a current regulator) and can set and / or maintain the current magnitude according to the command of the processor (120).

[0241] For example, the second dust collection device is configured to collect non-magnetic dust (or second dust) based on electrostatic force and includes an electrode that forms an electric field by receiving voltage from the second power supply. As an example, the second dust collection device may be composed of (i) a combination of a discharge electrode (e.g., corona electrode) and a dust collection electrode (e.g., collection electrode), or (ii) a multi-pole electrode structure that forms an electric field. As an example, the processor (120) uses the second power supply to apply a high voltage to the discharge electrode to charge the dust, and collects the dust by causing it to adhere to the opposite collection electrode (e.g., ground or opposite potential). The second power supply may provide a high voltage low current output (e.g., kV class DC or pulsed DC) and may include an insulating structure (e.g., insulator, creep distance securing structure) and a discharge safety device (e.g., leakage detection device, arc detection device).

[0242] Additionally or generally, while the rotating wheel grinds the surface of the workpiece, ultrafine dust is scattered from the grinding point and guided to the collection area by an air blower and suction flow. At this time, dust with a large magnetic component (e.g., first dust) is preferentially collected by an electromagnet, reducing the amount remaining in the air, while relatively non-magnetic (and / or low-magnetic) dust is collected by the electric field of an electrostatic electrode. Consequently, the two devices perform “type-specific collection” according to their respective physical principles, thereby improving collection efficiency and the cleanliness of the working environment compared to a single method.

[0243] For example, if the start input includes the strength of the power supply for the electromagnet (300), the processor (120) may transmit a power supply command to the first power supply and the second power supply instructing to apply power (or a predetermined current and a predetermined voltage, respectively) to the first dust collection device and the second dust collection device based on the strength (e.g., the magnitude of a predetermined current and / or a predetermined voltage) while the rotating wheel is rotating.

[0244] For example, if the above intensity is not included in the start input, the processor (120) can check the rotational speed of the rotating wheel in real time using a rotation detection sensor, check the first concentration and the second concentration of the first dust and the second dust, respectively, using a first concentration sensor included in the first dust collection device and a second concentration sensor included in the second dust collection device while the rotating wheel is rotating, and transmit a power supply command to the first power supply device and the second power supply device instructing to apply power to the first dust collection device and the second dust collection device by adjusting the intensity in proportion to the rotational speed of the rotating wheel, the first concentration, and the second concentration.

[0245] For example, as the RPM of the spindle motor increases (or as the rotation speed of the rotating wheel increases), the amount of dust generated and the scattering speed increase, so the processor (120) can, in the absence of a separate instruction from the user, command the first power supply to increase the supply current to the first dust collection device from 10A to 12.5A as the RPM increases from 2,000 RPM to 2,500 RPM, thereby supporting the provision of a collection power optimized for the increased amount of dust generated.

[0246] For example, the processor (120) can check the real-time thickness of the workpiece to be ground using a non-contact probe sensor and adjust the intensity in proportion to the difference between the initial thickness of the workpiece to be ground and the real-time thickness included in the start input.

[0247] That is, the processor (120) can perform dynamic control logic of the capture strength of the electromagnet (300) to ensure energy efficiency by maintaining the strength to the maximum during the initial stage of grinding, when the amount of grinding is large and dust generation is severe, and gradually lowering the strength as the amount of dust generation decreases as the grinding depth approaches the target thickness.

[0248] In summary, when an operator inputs the start of grinding on a user terminal (e.g., HMI, tablet, PC, etc.), the dry grinding device performs the following: (i) moves the chuck table to the grinding position; (ii) checks the position of the workpiece using a sensor and aligns it with the center of the rotating wheel; (iii) lowers the rotating wheel to detect contact; and (iv) rotates the rotating wheel to the target RPM using a spindle motor to perform grinding. At this time, the ultrafine dust generated during grinding is immediately collected by type by the first dust collection device and the second dust collection device. When the grinding is finished and the rotating wheel stops, the processor (120) issues a power interruption command (e.g., including cutoff / discharge) to each power supply unit to induce the collected dust to escape to a common dust storage unit without residual adhesion.

[0249] In the present disclosure, the first dust collection device includes an electromagnet, and current may be supplied to the electromagnet from a first power supply. The collection intensity of the electromagnet may be adjusted according to the supply current, for example, the electromagnet driving current may be set in the range of 0.2A to 8A, preferably in the range of 0.5A to 5A. Additionally, considering the heat generation of the electromagnet and the stability of continuous operation, the processor (120) may be configured to limit the current upper limit or adjust the duty when the electromagnet surface temperature or coil temperature (e.g., based on a heat sensing sensor) approaches a critical temperature.

[0250] In the present disclosure, the second dust collection device includes an electrode (e.g., a discharge electrode and / or a dust collection electrode), and a high voltage may be applied from the second power supply to form an electric field. For example, the electrode application voltage may be set to a direct current (DC) or pulsating voltage in the range of 2 kV to 30 kV, preferably in the range of 5 kV to 20 kV, depending on the process scale and electrode spacing. Additionally, to prevent arcing and overcurrent situations, the processor (120) may be configured to gradually increase the application voltage through a voltage rise slope (soft-start) or leakage current monitoring logic, or to immediately cut off the voltage in an abnormal state.

[0251] In the present disclosure, the rotational speed of the rotating wheel can be set according to the material of the workpiece to be ground and the target roughness, and, for example, the rotating wheel driven by a spindle motor can be controlled in the range of 1,000 RPM to 30,000 RPM.

[0253] FIG. 6 is a flowchart of a dry grinding method according to one embodiment of the present invention.

[0254] According to one embodiment, a dry grinding device (e.g., the dry grinding device (100) of FIG. 1) can perform the operations disclosed in FIG. 6. For example, at least some of the components included in the dry grinding device (e.g., the memory (110), processor (120), communication interface (130), display device (140) of FIG. 1) may be configured to perform the operations of FIG. 6.

[0255] In the following embodiments, the operations of S610 to S640 may be performed sequentially, but are not necessarily performed sequentially. For example, the order of each operation may be changed, and at least two operations may be performed in parallel. Additionally, content corresponding to or overlapping with the above description in relation to FIG. 6 may be briefly explained or omitted.

[0256] According to one embodiment, the processor (120) can drive a spindle motor to rotate a rotating wheel at a predetermined RPM in response to receiving a start input for grinding a workpiece from a user terminal (S610).

[0257] For example, the processor (120) can control the dry grinding device (100) to enter an “inspection-grinding simultaneous execution mode” by receiving a start input from a user terminal instructing the start of a grinding process.

[0258] For example, the start input may include identification information of the target inductor bar (e.g., LOT, serial, etc.), target RPM, target grinding time or termination condition (e.g., reaching target thickness, time elapsed, stopping immediately upon occurrence of quality defects), inspection standard profile (e.g., quality table selection value), sensor measurement cycle (e.g., any one of 10ms to 1s), warning notification method (e.g., screen pop-up, buzzer, tower lamp, log saving, etc.). The start input may further include a series of recipe data including material characteristics of the workpiece (230) to be ground (e.g., iron core density, number of copper windings, etc.) and target processing dimensions.

[0259] For example, the processor (120) can verify the validity of the start input (e.g., door interlock, whether the workpiece is adsorbed to the chuck table, release of emergency stop, temperature range of the spindle motor), apply a drive command to the spindle motor to accelerate the rotating wheel to a predetermined RPM, and at this time, ensure device stability by monitoring vibration or overcurrent in the acceleration section (e.g., based on a rotation detection sensor or current sensor).

[0260] For example, if a standard recipe exists according to the material and / or specifications of the workpiece to be ground, the processor (120) can be implemented in such a way that it increases the RPM stepwise based on the recipe selected at the user terminal, and when the target RPM is reached, sets a “grinding in progress” status flag to immediately activate the real-time NDT measurement operation in the subsequent steps.

[0261] Micro-vibrations of the spindle axis (250) and dynamic imbalances of the wheel mount (244) that may occur during this process are offset in real time through the movement of a mass within the wheel balancer (350). Rotation at a predetermined RPM has the significance of creating an electromagnetic base environment that allows an eddy current sensor to stably scan the surface of the workpiece and the internal conductor layer in the subsequent non-destructive inspection step, beyond simply providing physical cutting force.

[0262] According to one embodiment, the processor (120) can measure the magnetic flux density and copper winding condition of the workpiece in real time using a magnetic sensor array and an eddy current sensor disposed on one side of a chuck table on which the workpiece is adsorbed (S620).

[0263] For example, the processor (120) can measure the quality indicators of the workpiece to be ground in real time using a magnetic sensor array and an eddy current sensor placed on a chuck table (or, one side / one area of ​​the chuck table) while the grinding process is in progress.

[0264] For example, the magnetic sensor array can be implemented in a structure in which multiple Hall sensors, fluxgate sensors, magnetic reluctance sensors, etc. are arranged, and the distribution of magnetic flux density (or magnetic field component) corresponding to a specific location of the workpiece to be ground can be acquired “spatially.” That is, the processor (120) can capture magnetic flux fluctuations caused by non-uniformity of the magnetic core (e.g., local magnetization reduction, magnetic flux leakage near defects) or changes in heat and / or stress during processing by continuously sampling the magnetic flux state of the workpiece to be ground during grinding through multi-point sensors fixed to the chuck table, rather than measuring only one point with a single sensor.

[0265] For example, an eddy current sensor is configured to detect the condition of a copper winding (or a conductive member) non-contactually. By detecting changes in eddy currents induced on the surface and / or vicinity of a workpiece by an alternating magnetic field emitted by the sensor as changes in impedance, it can measure abnormal signs sensitive to “conductivity, shape, and gap,” such as open circuits, delamination, poor bonding, changes in gap, and surface defects of the winding. For example, a normal winding exhibits a stable impedance pattern at a specific frequency, but if the winding is partially lifted, the gap between the sensor and the winding may increase instantaneously, causing the signal to change rapidly. In the event of micro-cracks and / or open circuits, the effective conduction path changes, and the response may differ from the reference pattern. Accordingly, the processor (120) can perform sensor-specific offset and gain correction (e.g., initial zero setting), filtering of grinding environment noise (e.g., motor drive, wheel rotation, dust, vibration) (e.g., moving average, low-pass, outlier removal), and data fusion between sensors (e.g., aligning magnetic flux distribution and eddy current signals based on the same timestamp). The dry grinding device (100) can be implemented in such a way that the top of the eddy current sensor is covered with a protective film (e.g., wear-resistant cover, thin non-conductive insulating layer, etc.) to minimize direct exposure of the eddy current sensor to dust, thereby increasing signal stability.

[0266] That is, the magnetic sensor array is composed of a multi-point array of Hall effect sensors or giant magnetoresistance (GMR) sensors to measure the magnetic flux density distribution inside the workpiece in the form of a two-dimensional mapping, thereby detecting distortion of magnetic field lines caused by internal pores or microcracks. Furthermore, the eddy current sensor can simultaneously identify whether there is a break in the copper winding embedded inside the magnetic core, a short circuit between windings, or damage to the coating by identifying the induced eddy current signal by applying a high-frequency alternating magnetic field to the workpiece. Since this measurement operation is performed in a somewhat dynamic environment where load and vibration are applied as the rotating wheel cuts the surface of the workpiece, the processor (120) can perform a digital signal processing process in parallel to filter mechanical noise from the raw signals received from the sensors and extract only the signals attributable to the actual material properties.

[0267] According to one embodiment, the processor (120) can compare the real-time quality of the object to be ground with a predefined quality table based on magnetic flux density and copper winding state to check the comparison result (S630).

[0268] For example, the processor (120) can immediately determine a quality pass or fail grade during the process by comparing the “real-time quality” calculated from the magnetic flux density and copper winding state with a quality table predefined in memory or external storage.

[0269] For example, the quality table is not limited to a simple threshold list and may be configured to include (i) average / maximum / minimum magnetic flux density and allowable deviation ranges, (ii) an indicator of the spatial uniformity of the magnetic flux distribution (e.g., deviation between array sensors), (iii) error relative to the reference impedance trajectory of the eddy current sensor (e.g., allowable error bands by frequency), and (iv) variable allowable criteria based on the grinding section (e.g., time, position, or rotational speed) (e.g., applying loose criteria to the initial processing section, applying strict criteria to the finishing section).

[0270] For example, the quality table may be implemented as multidimensional reference data that provides different criteria based on product families (e.g., model / specification of the workpiece), process conditions (e.g., rotary wheel RPM, feed rate, grinding time, target removal amount, etc.), sensor configurations (e.g., sensor type, batch, sampling period), and environmental conditions (e.g., temperature, electromagnetic noise level, etc.), rather than a simple list of pass / fail thresholds. As an example, since the magnetic flux density distribution and eddy current response characteristics differ even for the same type of workpiece if the winding structure or core material is different, the quality table may be configured to select a set of criteria corresponding to a combination of “workpiece identifier + process recipe + sensor profile.”

[0271] For example, the quality table may include table identification information for each reference set, which may include a table ID, applicable model / specification, applicable process recipe range (e.g., RPM tolerance, feed rate tolerance), sensor placement / channel configuration information (e.g., number and spacing of magnetic sensor array channels, eddy current sensor frequency / coil diameter, laser probe installation position and measurement angle), and a sampling period (e.g., 1 kHz or 5 kHz) and filtering conditions (e.g., moving average interval, low-pass filter cutoff, etc.). Additionally, by storing the reference coordinate system for calculating reference values ​​(e.g., chuck table reference origin, XY axis direction, Z=0 reference plane) and the position synchronization method (e.g., servo encoder-based position tagging, time stamp-based correction, etc.), it is possible to match the real-time measurement value with the references in the table to determine "which position / which interval" the value was acquired from.

[0272] For example, a quality table may include multiple items for determining magnetic flux density quality. For instance, items may be defined such as the absolute range (minimum / maximum) of magnetic flux density (B) or magnetic field (H) measured by a magnetic sensor array, the average value, the standard deviation (uniformity index), the deviation between array channels (ΔB per channel), the slope of the edge relative to the center (gradient), the presence and duration of local peaks (spikes) at specific locations, and the rate of change in magnetic flux density due to grinding progress (dB / dt). Additionally, to reflect defect types, a “magnetic flux density spatial pattern criterion” may be included, such as the correlation coefficient with the magnetic flux distribution map of a normal product, the allowable deviation in specific location sections (e.g., winding start, core edge), and symmetry (match of left / right or front / back patterns). These items can be utilized as criteria to sensitively detect cases where the magnetic flux path is abnormally deformed due to core cracks, magnetic material damage, or core-winding coupling defects.

[0273] For example, the quality table may include multi-layered quality items for eddy current sensor signals. For instance, impedance change (ΔZ) obtained from the eddy current sensor, signal amplitude and phase, frequency response (when driving multiple frequencies), the fundamental / harmonic component ratio of the signal, signal-to-noise ratio (SNR), baseline drift (due to temperature / environmental influence), and whether there is a sudden phase jump at a specific location during grinding may be defined as table items. Additionally, to determine the “copper winding condition,” features of the eddy current signal pattern may be defined according to defect types, such as open circuits, partial open circuits, poor contact, or traces of local overheating. For instance, cases where the phase delay relative to normal exceeds a specific range, cases where the amplitude drops sharply in a specific section, or cases where the slope of the frequency response curve deviates from the normal range may each be configured as separate judgment items. These items can be used as criteria for non-destructively evaluating changes in the conduction path of the winding, damage to the winding surface, and changes in the state between the winding and the insulation layer during the process.

[0274] For example, the quality table may include quality items using real-time thickness measurements. The processor (120) may define items such as the amount of grinding (ΔT = T_initial - T_current), the rate of change of the amount of grinding over time (dT / dt), and the thickness deviation per grinding section (e.g., difference in average thickness between the first / second / third time sections) by comparing the real-time thickness (T_current) measured by a non-contact probe sensor (e.g., laser displacement sensor) along the side or reference plane of the workpiece to be ground with the initial thickness (T_initial) and the target amount of grinding (or target thickness) included in the start input. Additionally, it may generate a position-based thickness profile (e.g., a thickness map based on an X-direction scan) and include overgrinding / undergrinding tolerances for specific sections, edge deviations, and surface flatness (e.g., standard deviation of thickness or maximum-minimum difference) in the quality table. Through this, it is possible to determine in real time not only whether the “target thickness has been reached” but also the “uniformity of the processed surface” and the “risk of overprocessing.”

[0275] For example, the quality table may not process magnetic flux density, eddy current signals, and real-time thickness only as “individual judgments,” but may include composite items for combined multi-sensor judgments. For example, (i) a rule classifying cases where the thickness is within the normal range but the magnetic flux density pattern is abnormal as a defect based on core damage or magnetic path anomalies, (ii) a rule classifying cases where the magnetic flux density is within the normal range but the eddy current phase / amplitude pattern is abnormal as a defect based on winding conduction path anomalies, and (iii) a rule classifying cases where the eddy current signal noise increases rapidly while the rate of change in thickness increases abnormally as a defect based on local overheating during grinding or surface damage, etc., may be defined as “defect type mapping” items within the quality table.

[0276] For example, the processor (120) can increase the accuracy of comparison by generating a feature value for judgment based on the raw signal instead of directly comparing the raw signal itself. For example, the processor (120) can compare the magnetic flux value after reference temperature correction, and the eddy current value can be compared with the allowable range of a table by calculating the distance (e.g., RMS error) from the reference spectrum set through a standard specimen.

[0277] For example, the comparison result may be determined as a value at a single point in time, or it may be determined in a way that reduces misjudgment caused by instantaneous noise by reflecting whether there is a continuous exceedance in a certain time window (e.g., last 1 to 3 seconds), the duration of the exceedance, and the frequency of the exceedance.

[0278] As an example, the processor (120) may include a multi-stage logic in the quality table that records the event as a “warning (caution)” and continues the grinding process when an eddy current signal pops up only at a specific moment during grinding, but promotes the event to a “defect” and stops the rotation of the rotating wheel if the same pattern occurs N times in a row or the duration exceeds a threshold.

[0279] According to one embodiment, the processor (120) can measure the thickness (or thickness-related dimensions) in real time by using a non-contact probe sensor placed in an area adjacent to the spindle motor (e.g., a frame near the grinding head, a side bracket of the spindle housing, or a fixing part around the chuck table) to irradiate laser light toward the side of the workpiece to be ground and receiving the reflected signal that returns. The technical significance of this operation is that it can contribute to detecting immediately during the process whether the amount of grinding is excessive or insufficient compared to the plan, or whether the dimensions change rapidly in a specific section (e.g., over-grinding, uneven wheel wear, tilting due to poor chuck fixation, etc.), thereby determining defects early and stopping the process or correcting conditions. In particular, since dry grinding has less optical interference from the cooling water but a large amount of dust can contaminate the optical sensor window, the dry grinding device (100) may further include a cover and / or window to protect the optical window of the sensor.

[0280] For example, various non-contact sensors, such as laser displacement sensors (e.g., based on triangulation), confocal displacement sensors, and interferometer-based sensors, can be utilized for real-time thickness measurement methods. As an example, since thickness observation from the side of a workpiece may involve changes in surface reflectance, a sensor with a reflectance correction function may be used, or the measurement point may be set to a fixed position to perform sampling over a specific interval in response to the movement of the chuck table (or changes in the position of the workpiece).

[0281] For example, “real-time thickness” does not necessarily mean only an absolute thickness value, and depending on the embodiment, it may be defined as a change in distance from a reference plane (e.g., a chuck table reference), a change in distance compared to before grinding, a thickness deviation due to multi-point measurement (e.g., taper and / or parallelism indicator), etc.

[0282] According to one embodiment, the processor (120) calculates a “real-time quality index” by considering together the real-time thickness obtained from a non-contact probe sensor, the initial thickness included in the start input (e.g., reference thickness before grinding), and the difference between the initial thickness and the real-time thickness (i.e., real-time grinding amount), and can verify the comparison result by comparing it with a predefined quality table.

[0283] Here, the quality table may include product model specifications (e.g., specifications of the workpiece to be ground), target grinding amount, allowable tolerance, process steps, or multidimensional criteria combined with magnetic flux density and eddy current sensor measurement results.

[0284] For example, the quality table may be configured to include a final target thickness range (e.g., target 2.00 mm, allowable ±0.03 mm), an allowable removal range during the process (e.g., grinding amount at 30 seconds after start is 0.10 to 0.20 mm), a rate of change in grinding amount (e.g., if the grinding amount per second exceeds a certain range, it is determined that there is a possibility of wheel overload or eccentricity), and a thickness deviation during multi-point measurement (e.g., left-right deviation of 0.02 mm or less). The processor (120) may determine the comparison result as “defective” or “warning” if it is determined that the real-time thickness deviates from the target range, the difference in grinding amount exceeds the allowable range, or the change in grinding amount is abnormally rapid. The processor (120) may be implemented to immediately stop grinding if the comparison result is defective and to display an action guide on the user terminal along with the reason for the defect (e.g., estimated overcutting, insufficient target thickness, excessive taper, etc.). In addition, the quality table is stored in the device's internal memory, but can be operated in a way that the table is automatically loaded when an operator selects a product type on the user terminal.

[0285] This quality table-based comparison structure can also be operated by selecting and / or downloading tables by product type from a user terminal, or by updating (or versioning) the tables according to production history.

[0286] That is, the quality table corresponds to a database in which the standard magnetic flux density curve measured in a normal product, the allowable range of winding impedance, and the attenuation characteristics of the sensor signal according to the processing depth are precisely quantified, and the processor (120) can further combine real-time thickness information measured through a non-contact probe sensor with the judgment logic to detect whether there is a defect based on the comparison result.

[0287] As an example, the processor (120) considers the decrease in the absolute amount of magnetic flux density as the thickness decreases due to grinding as a normal change, and can determine it as an internal defect (e.g., crack) only when the magnitude of the decrease in magnetic flux density relative to the decrease in thickness deviates from the correlation coefficient defined in the quality table. Through this comparison operation, the processor (120) can implement an intelligent QC system capable of precisely detecting even dynamic defects (e.g., winding expansion due to thermal deformation) that appear only during processing.

[0288] As an example, the processor (120) may determine a defect if, even though it confirms that the real-time thickness measured by a non-contact probe sensor during grinding is stably included within the target range of the quality table (e.g., target thickness ± tolerance), the magnetic flux density distribution measured by the magnetic sensor array simultaneously deviates from the criteria of the quality table (e.g., minimum / maximum magnetic flux density at a specific location, deviation limit per location). For example, if a pattern is observed where the magnetic flux density drops sharply in a specific section of the workpiece to be ground, or where the magnetic flux density gradient becomes excessively large in the left-right or front-back directions, this indicates a possibility of a magnetic circuit abnormality caused by a core assembly defect, internal crack, local defect in the magnetic material, or residual stress, rather than a problem with the grinding dimensions themselves. In this case, the processor (120) may be configured to set a defect flag according to a judgment rule corresponding to the “thickness normal + magnetic flux density defective” combination of the quality table, and to stop the process and notify the user terminal.

[0289] As an example, the processor (120) may determine a defect if the magnetic flux density value is within the normal range of the quality table, but the signal from the eddy current sensor placed on the chuck table deviates from the standards of the quality table (e.g., impedance magnitude / phase, specific frequency component, amplitude of variation over time). For example, if the phase of the eddy current signal changes rapidly at a specific location during grinding, or if the signal fluctuates periodically and unstably, this may indicate a break in the copper winding / partial contact failure, damage to the winding sheath, a change in local conductivity (e.g., oxidation, foreign matter adhesion), or the possibility that the winding arrangement differs from the design. In particular, since a situation where the thickness satisfies the target range but the electrical continuity or surface / near-surface conductivity characteristics deviate from the standards can be fatal to the final product performance (e.g., resistance, inductance, heat generation), the processor may be configured to ultimately determine a defect based on the combination of “normal magnetic flux + defective eddy current” defined in the quality table.

[0290] As one example, the processor (120) can more reliably determine a defect by checking whether the magnetic flux density and eddy current signal simultaneously deteriorate to the auxiliary conditions of the quality table in that state when the real-time thickness deviates from the target range (e.g., excessive overcutting or insufficient undercutting) and first violates the dimensional conditions of the quality table. For example, if overcutting occurs, the geometry of the winding part or magnetic part may differ from the design, causing the magnetic flux density distribution to change, and at the same time, the eddy current signal may also differ from the standard due to changes in shape / distance near the copper winding. As such, the pattern of “thickness defect + magnetic flux / eddy current accompanying abnormality” is more likely to be a process setup factor such as chuck fixation defect, wheel uneven wear, feed condition setting error, or baseline alignment problem rather than a simple material defect, so the processor (120) can be implemented to classify this as a “process cause defect” in the quality table, immediately stop grinding, and provide the defect type (e.g., estimated overcutting, setup check required) to the user terminal.

[0291] As an example, the processor (120) may determine a defect or warning if the interrelationship between the magnetic flux density, eddy current signal, and real-time thickness each appear to fall within the acceptable range of the quality table individually, but violates the “consistency rule” of the quality table. For example, when grinding proceeds and the thickness decreases by a certain amount (i.e., the amount of grinding increases), the magnetic flux density and eddy current signal may generally change gradually in a specific direction according to the change in the geometric relationship between the sensor and the object, and the normal pattern may be defined in the table. However, if the thickness change is normal but the magnetic flux jumps in the opposite direction or the eddy current drifts sharply in a specific section, it may not be measurement noise but actual internal structural deformation (e.g., partial delamination, change in conductivity due to local overheating, change in permeability due to residual stress, etc.). Accordingly, the processor (120) can be configured to compare with the “thickness-flux-eddy current correlation conditions (e.g., rate of change, co-occurrence / reverse pattern, positional simultaneity)” defined in the quality table, and if the consistency violation is repeated or the reliability condition is satisfied, determine it as defective, and if it is a one-time / minor case, process it as a warning (e.g., additional measurement notification, deceleration request, re-measurement inducement notification).

[0292] According to one embodiment, if the processor (120) determines that the workpiece to be ground is defective based on the comparison result, it may stop the operation of the spindle motor and provide a warning notification to the user terminal (S640).

[0293] For example, if the processor (120) determines that the workpiece to be ground is defective based on the comparison result, it can prevent the spread of defects and the accumulation of defects during the process by immediately stopping the operation of the spindle motor and providing a warning notification to the user terminal.

[0294] Here, “defect” may be defined as, for example, when the magnetic flux density value deviates from the allowable range (e.g., abnormality of the magnetic core, demagnetization, leakage due to cracks, etc.), when the eddy current-based winding condition indicator continuously deviates from the reference pattern (e.g., open winding, delamination, joint defect, excessive gap change, etc.), or when multiple indicators appear as abnormalities simultaneously (e.g., complex defect).

[0295] For example, the processor (120) can select either a sudden stop or a gradual stop when stopping the operation of the spindle motor, for example, if the start input includes a "safety priority condition," the spindle motor may be suddenly stopped, and if the start input includes a "device protection priority condition," the RPM may be lowered by a preset deceleration ramp and then stopped.

[0296] For example, the warning notification can be implemented to provide the “cause of defect judgment (e.g., magnetic flux deviation exceeding, eddy current anomaly, judgment time, sensor ID, measured value / allowable value)” on the user terminal screen so that the operator can immediately identify the cause, and simultaneously perform the additional tasks of turning on the buzzer and / or tower lamp and transmitting event logs to the MES.

[0297] Additionally, the processor (120) can link subsequent procedures for process safety along with defect determination. For example, the processor (120) can cut off the vacuum suction power of the chuck table after confirming that the wheel has completely stopped using a rotation detection sensor, or, considering the risk of workpiece detachment, can perform an action of cutting off the vacuum suction power only after operator approval while maintaining the vacuum suction of the workpiece to be ground on the chuck table.

[0298] For example, if the processor (120) determines that the workpiece to be ground is defective based on non-destructive inspection results (e.g., magnetic flux density, eddy current sensor measurements, or quality table comparison results), it first stops the operation of the spindle motor, but does not assume that the process has become safe merely by "issuing a stop command," and can complete a safe stop scenario by checking the actual rotation state of the rotating wheel with a rotation detection sensor. That is, even if the drive signal to the spindle motor is cut off, the rotating wheel may continue to rotate for a certain period of time due to inertia, and if the attachment of the chuck table is released or access by an operator is allowed in this state, risks such as workpiece flying, wheel contact accidents, and dust scattering may occur. Therefore, this operation functions as a procedure to increase safety in the process of responding to quality defects, with "sensor-based actual stop verification" as the core rather than "command-based stop."

[0299] For example, the rotation detection sensor is implemented in a form capable of detecting the rotational speed and whether the rotating wheel has stopped. Examples include an optical (or magnetic) encoder coupled to the spindle axis, a Hall sensor corresponding to a magnet attached to the rotating wheel, a light sensor (e.g., a photointerruptor) that detects a rotation marker, and a current and / or back EMF-based rotation estimation sensor that indirectly detects the rotational state of the rotating wheel. Here, the “rotational state” may be defined not only by a simple rotation / stop binary value, but also by the current RPM, deceleration trend, and whether stopping is imminent. According to an embodiment, the processor (120) may be configured to determine that “rotation has substantially ended” by checking whether “the RPM is maintained at a predetermined stop threshold (e.g., 10 RPM or less) for a certain period of time (e.g., 0.5 to 2 seconds).” Additionally, since dust, vibration, and electromagnetic noise may interfere with the sensor values, the dry grinding device (100) may be implemented in a form in which the sensor is placed inside the spindle housing or inside the protective cover.

[0300] For example, the processor (120) may be configured to cut off the power supply to the vacuum suction device of the chuck table only after confirming that the rotating wheel has completely stopped (or has been decelerated to a safe rotational speed or lower) based on the rotational state from the rotation detection sensor. This sequence is intended to ensure the “safe release of the workpiece” in the event of a quality defect, as releasing the suction of the workpiece while the rotating wheel is still rotating may cause the workpiece to move even slightly, resulting in interference with the wheel, surface damage, or scattering of the workpiece, which can affect not only equipment damage but also worker safety. Therefore, the processor (120) operates through the aforementioned safety chain.

[0301] For example, the vacuum suction device may be composed of a vacuum passage inside the chuck table, a vacuum pump (or ejector), a valve (e.g., a solenoid valve), a vacuum sensor, etc., and “power supply cutoff” may be realized in various ways depending on the structure of the device. For example, the power supply cutoff operation may be implemented by cutting off the power to drive the vacuum pump, by controlling a valve that closes the vacuum passage or opens it to the atmosphere (or vents) to release the suction force, or by combining the pump power cutoff and the vent valve opening. When a defect occurs, the processor (120) does not drop the workpiece immediately, but releases the suction only after confirming that the rotating wheel has stopped, and after the suction is released, provides a “workpiece retrieval possible” notice to the user terminal.

[0303] According to one embodiment, the processor (120) can collect the first dust and the second dust generated from the object to be ground by the rotation of the rotating wheel, respectively, by using a first dust collection device electrically connected to a first power supply and a second dust collection device electrically connected to a second power supply.

[0304] The above operation is a process of separating and collecting heterogeneous fine dust generated during the grinding process in real time according to its physical properties, and can be understood as a step of performing organic cooperation between a first dust collection device (magnetic force-based) and a second dust collection device (electrostatic force-based).

[0305] For example, the processor (120) can control the first power supply in synchronization with the rotation start signal of the rotating wheel to apply current to the electromagnet provided inside the first dust collection device.

[0306] For example, the applied current forms strong magnetic field lines through an electromagnet coil, and these magnetic field lines can be designed to pass through the grinding space (or, machining point) between the chuck table and the rotating wheel.

[0307] For example, magnetic dust (or first dust) generated from the core material of an inductor bar receives a strong magnetic attraction in the direction of magnetic field lines at the moment of scattering. At this time, the magnetic particles receive a magnetic force greater than the air resistance, causing them to deviate from the scattering trajectory and be guided and attached to the collection surface of the first dust collection device.

[0308] For example, the processor (120) can prevent the collection of dust by amplifying the applied current of the electromagnet in proportion to the RPM value, taking into account that the higher the RPM of the rotating wheel, the faster the initial scattering speed of the dust.

[0309] For example, the processor (120) can introduce the remaining non-magnetic dust (or, second dust (e.g., copper powder) that has passed through the first dust collection device without reacting to magnetic force into a second dust collection device area arranged in series.

[0310] For example, the processor (120) applies a high voltage (in kV units) to a discharge electrode placed inside the device through a second power supply. This causes a corona discharge phenomenon in which the air around the electrode is ionized, and the incoming second dust particles collide with the ions and acquire a strong (-) or (+) charge (e.g., charging stage).

[0311] For example, the charged second dust particles receive a Coulomb force within an electric field and rapidly move to a dust collection plate having a polarity opposite to that of the discharge electrode. Since copper (Cu) has excellent conductivity and very high charging efficiency, it is captured on the surface of the dust collection plate with high efficiency even in the state of fine particles.

[0312] For example, a dry grinding device further includes the following mechanical features to efficiently perform the aforementioned collection process.

[0313] For example, a dry grinding device includes a series flow path configuration, and the dust collection load can be distributed by placing a first device for capturing magnetic materials upstream and a second device for capturing non-magnetic materials downstream along the dust movement path.

[0314] For example, the dry grinding device includes an electrical shielding structure, and a magnetic shielding barrier may be installed between the two devices so that the magnetic field of the first device does not disturb the electric field (e.g., ion movement trajectory) of the second device. The processor (120) can suppress noise caused by mutual interference by controlling the output frequencies of the two power supplies differently.

[0315] For example, the dry grinding device further includes an air blower for pneumatic assistance, and the air blower can maximize collection efficiency by forming a constant laminar flow so that dust generated at the processing point can stably enter the capture zone of the first dust collection device and the second dust collection device.

[0316] For example, when the processor (120) identifies that the rotation of the rotating wheel has started due to the drive of the spindle motor (e.g., confirming that the RPM exceeds 0 through a rotation detection sensor or spindle encoder signal), it can control the first power supply and the second power supply, respectively, to activate the first dust collection device and the second dust collection device to functionally distinguish and collect ultrafine dust generated at the grinding point into magnetic dust (first dust) and non-magnetic or low-magnetic dust (second dust). At this time, the processor (120) can synchronize control so that the collection function precedes the scattering of dust, by starting power supply from the acceleration section of the rotating wheel (e.g., before reaching the target RPM), or at least starting power supply without delay immediately after the rotating wheel contacts the surface of the object.

[0317] For example, the first dust collection device may include an electromagnet that forms a magnetic flux by a current supplied from the first power supply, and the processor (120) may apply a current to the electromagnet so that it selectively adsorbs dust of magnetic components generated during the grinding process (e.g., fine metal dust containing Fe-based components or having a relatively high magnetic susceptibility). For example, the electromagnet may be implemented with a structure including a coil and a magnetic core (or an iron core) and may be placed in an area where dust passes, such as below the rotating wheel or below the chuck table movement path, so that magnetic dust generated at the grinding point is exposed to a magnetic field while moving by an airflow (e.g., blowing or suction flow). Accordingly, the magnetic dust is attracted to and attached to the collection surface of the electromagnet (e.g., the top surface of the electromagnet or the collection plate), and as a result, the concentration of airborne dust in the process space is reduced, and the possibility of dust penetration into the precision drive unit inside the device is suppressed. Additionally, the processor (120) can be implemented so that the first power supply performs constant current control (e.g., current feedback-based regulation) so that the capturing force of the electromagnet is stably maintained even if there is a rise in coil temperature or load fluctuation.

[0318] For example, the second dust collection device may include an electrode that forms an electric field by a voltage applied from the second power supply, and the processor (120) may apply voltage to the electrode to control non-magnetic or low-magnetic dust (e.g., ultrafine dust containing Cu-based components or having low magnetic attraction and thus low collection efficiency with electromagnets alone) to be collected by electrostatic force. Specifically, the second dust collection device may be implemented in a form including (i) a discharge electrode (e.g., corona electrode) that charges the dust and (ii) a dust collection electrode (e.g., collection electrode, dust collection plate) to which the charged dust adheres, and the second power supply may form an electric field by applying a high voltage (e.g., kV class DC or pulsed DC) to the discharge electrode or the dust collection electrode. Fine dust generated at the grinding point and scattered into the air may be collected by becoming charged while passing through the electric field region or by moving toward the dust collection electrode in an already charged state and adhering to the surface of the electrode. At this time, the processor (120) may be configured to include protection logic that controls the voltage rise time in a ramp form (soft-start) to prevent arc or abnormal discharge, or limits or cuts off the voltage based on a leakage current detection signal.

[0319] For example, a dry grinding device may be implemented such that the operating areas of the first dust collection device and the second dust collection device are physically separated (e.g., an electrostatic collection area is placed after the electromagnet collection area) or functionally separated within the same flow path (e.g., the electromagnet removes magnetic dust first, and then the residual dust passes through the electrostatic electrode area) so that a dual collection channel is substantially implemented. For example, in an embodiment where dust generated at a grinding point is guided in a certain direction by an air blower or suction flow, the effect of type-specific collection can be enhanced by placing an electromagnet-based collection unit in the upstream area to remove magnetic dust first, and placing an electrostatic electrode-based collection unit in the downstream area to additionally remove residual non-magnetic / low-magnetic dust. By such an arrangement, the collection limit of the electromagnet for non-magnetic dust and the inefficiency or electrode contamination problems that electrostatic dust collection may have for magnetic dust / large metal pieces can be mutually compensated for.

[0320] For example, the processor (120) can dynamically set the magnitude of the current supplied to the first dust collection device through the first power supply and the magnitude of the voltage applied to the second dust collection device through the second power supply based on parameters or sensor-based status values ​​included in the start input to stably maintain the collection power according to changes in grinding conditions. For example, as the RPM of the rotating wheel increases, the dust scattering speed and amount of dust generated may increase, so the processor (120) may increase the electromagnet driving current in proportion to the RPM or increase the applied voltage of the electrostatic electrode to increase the electric field strength. In addition, as dust collection proceeds, dust may accumulate on the surface of the electromagnet or electrode, and the collection efficiency may decrease, so the processor (120) may apply a control scenario that corrects the current / voltage under certain conditions (e.g., accumulation time, concentration sensor value, power load change, etc.) or periodically regenerates the collection surface in conjunction with power cutoff and detachment operations in a subsequent step.

[0321] As a result, the processor (120) can perform a dust management operation that separates and collects ultrafine dust generated during the grinding process by type by driving an electromagnet-based first dust collection device and an electrostatic-based second dust collection device, respectively, in synchronization with the rotational state of the rotating wheel, suppresses scattering outside the workspace, and simultaneously reduces internal contamination of the device and worker exposure.

[0322] According to one embodiment, when the rotation of the rotating wheel ends, the processor (120) can send a power supply interruption command to the first power supply and the second power supply to induce the first dust and the second dust collected in the first dust collection device and the second dust collection device to escape to the dust collection device.

[0323] For example, the processor (120) may transmit a power supply interruption command (including cutoff / discharge) to the first power supply and the second power supply in order to safely remove the first dust and the second dust collected in the first dust collection device and the second dust collection device from the process space without leaving them in the process space, based on the point in time when grinding is finished and the rotation of the rotating wheel is completed. At this time, the meaning of the rotation of the rotating wheel being finished is not determined by the elapsed timer, but may be defined as the point in time when it is confirmed that the RPM of the rotating wheel is 0 (or below a threshold RPM) based on, for example, a rotation detection sensor or a spindle encoder signal, thereby minimizing the problem of re-dispersion that may occur during the dust removal process being reattached to the grinding surface or re-entered into the machine.

[0324] For example, when the processor (120) confirms that the rotation has ended, it may send a power supply interruption command to the first power supply to cut off the current supplied to the electromagnet included in the first dust collection device. When the coil current of the electromagnet is cut off, the magnetic flux of the electromagnet decreases rapidly, and as a result, the magnetic dust (first dust) attached to the collection surface of the electromagnet (e.g., the upper surface of the electromagnet or the magnetic collection plate) may fall naturally due to gravity as the previously maintained attractive force weakens or disappears, or may be easily detached by micro-vibrations and airflow formed inside the device and move to the dust collection device below. In addition, in some embodiments, the processor (120) may be configured so that the first power supply uses a freewheel diode, a snubber circuit, a discharge resistor, etc. to stabilize the interruption in order to prevent an overvoltage from occurring at the moment of interruption due to the inductive energy stored in the coil, and may apply a reverse current or a demagnetizing pulse for a short time to reduce the residual magnetic force more quickly after the current is cut off.

[0325] For example, the processor (120) may simultaneously or sequentially transmit a power supply interruption command to the second power supply to cut off the voltage applied to the electrode included in the second dust collection device. In an electrostatic dust collection method, dust (second dust) can be attached to and maintained on the electrode surface by the electric field formed on the electrode and the charged state of the dust, so simply turning off the voltage may result in the attachment force remaining due to residual charge. Therefore, the power supply interruption may be implemented to include not only the cessation of voltage application but also a discharge sequence to remove the residual charge remaining on the electrode or high-voltage line through a discharge path within a predetermined time for safety and secure removal. For example, immediately after transmitting the interruption command to the second power supply, the processor (120) may reduce the residual potential of the electrode by (i) turning on a relay connecting a discharge resistor, (ii) driving a switching element that shorts the electrode to ground, or (iii) automatically switching the high-voltage output terminal to an internal discharge circuit. In this way, when the electric field is removed and the residual charge is discharged, the second dust attached to the electrode surface has its electrostatic adhesion weakened and can fall due to gravity or be effectively detached by subsequent mechanical aids and moved to a dust collection device.

[0326] For example, the expression of inducing dust to escape to a dust collection device does not mean that the collected dust always falls off immediately with 100% force, but rather means control that creates physical conditions (e.g., magnetic field extinction, electric field extinction, and discharge) for escape to occur so that the dust can fall off without residual adhesion. Accordingly, the processor (120) may selectively drive a vibration device (e.g., tapping device, eccentric motor, solenoid hammer, etc.) or an air pulse nozzle (solenoid valve-based) included in the first dust collection device and / or the second dust collection device to assist in ensuring that the second dust on the electrode surface is reliably separated, in case the escape is insufficient with only power cutoff. On the electromagnet side, a modified embodiment is possible in which, if necessary, vibration is transmitted to the electromagnet support frame or an air pulse is sprayed downward along the electromagnet surface to promote the fall of the first dust.

[0327] For example, the processor (120) may control a shutter or flap that opens / closes the upper opening of the dust collection device to prevent dust from scattering outward while the dust escape operation is being performed. For example, the upper shutter may be opened immediately before the power is cut off to secure a falling path, and the shutter may be closed after a predetermined time (e.g., 0.5 to 5 seconds) to prevent the dust from flowing back upward or re-floating. Alternatively, in a structure equipped with a dust collection duct and a fan, the fan speed may be temporarily increased during the escape section to strengthen downward suction, thereby preventing the re-scattering of the falling dust.

[0328] Consequently, the processor (120) can induce dust collected in the first dust collection device and the second dust collection device, respectively, to escape to the dust collection device without residual adhesion by triggering the current cutoff (or magnetic field extinguishing) of the first power supply and the voltage cutoff and discharge (or electric field extinguishing and residual charge removal) of the second power supply with the confirmation of the rotation wheel stop. This escape induction control minimizes manual cleaning intervention by the operator and enables automated process operation that can immediately switch to the next grinding cycle.

[0330] According to one embodiment, the processor (120) can check the grinding time included in the start input and, based on a preset time ratio, divide the grinding time into a first time interval, a second time interval after the first time interval, and a third time interval after the second time interval.

[0331] For example, the processor (120) first checks the grinding time included in the start input received from the user terminal. Here, the grinding time can be defined as the total time during which the rotating wheel actually performs grinding, and, for example, can be entered by the operator in the HMI as 60 seconds, 90 seconds, etc., or can be included as a recipe parameter transmitted as an MES work instruction. Based on this grinding time, the processor (120) divides the time into a first time interval / a second time interval / a third time interval according to a preset time ratio (e.g., 30% : 40% : 30%). At this time, the preset time ratio can be implemented in the form of a lookup table or recipe file stored in the device's internal memory, and can be selectively applied depending on the type of workpiece (e.g., type with a high magnetic component / type with a high copper ratio) or the target grinding amount.

[0332] Subsequently, the processor (120) determines whether each divided time interval is greater than or equal to the threshold time. The threshold time (e.g., 3 seconds) can be understood as the minimum duration during which each device operates meaningfully to produce a capture effect, and at the same time, the system does not become unstable due to switching operations (ON / OFF). If the first to third time intervals are all greater than or equal to the threshold time, the processor (120) executes a time interval sequential operation scenario.

[0333] For example, if the first time interval, the second time interval, and the third time interval are all longer than a preset threshold time, the processor (120) may transmit a first power supply command instructing to supply a predetermined current to the first dust collection device only during the first time interval, transmit the first power supply command instructing to supply the predetermined current to the first dust collection device to the first power supply device during the second time interval, transmit a second power supply command instructing to apply a predetermined voltage to the second dust collection device to the second power supply device, and transmit the second power supply command only to the second power supply device during the third time interval.

[0334] For example, when the third time interval has elapsed and the rotation of the rotating wheel has ended, the processor (120) can use a vibration device included in the second dust collection device to induce the second dust to escape into the dust collection device.

[0335] For example, during the first time interval, the processor (120) transmits a first power supply command only to the first power supply unit, thereby supplying a predetermined current to the first dust collection device (electromagnet). This step can be described as an operational scenario for stabilizing airborne dust in the workspace at an early stage by first rapidly collecting magnetic dust (first dust) in a section where the cutting load is high and dust generation begins rapidly during the initial grinding stage. For instance, in a recipe where it is assumed that a relatively large amount of iron-based dust is generated immediately after the start of grinding, the electromagnet is activated first to preemptively remove the magnetic dust.

[0336] Next, during the second time interval, the processor (120) continues to transmit a first power supply command to the first power supply to maintain electromagnet operation, while simultaneously transmitting a second power supply command to the second power supply to cause the second dust collection device (electrostatic electrode) to form an electric field. This step operates as a period that “maintains magnetic dust collection while simultaneously collecting residual non-magnetic / low-magnetic dust.” That is, it can be described as a configuration to ensure that electrostatic dust collection operates stably under relatively clean flow conditions formed by the electromagnet-based primary collection, and consequently to increase the overall collection efficiency.

[0337] Subsequently, during the third time interval, the processor (120) transmits a second power supply command only to the second power supply to maintain electrostatic electrode operation, and the operation of the first dust collection device may be stopped or minimized. This interval may be configured as a scenario in which “as grinding enters the finishing stage, finely remaining non-magnetic dust is finished by electrostatic collection.” It may also include the operational purpose of reducing heat generation (coil temperature rise) and energy consumption when the electromagnet is operated continuously for a long time.

[0338] Finally, when the third time interval has elapsed and the rotation of the rotating wheel has ended (e.g., RPM = 0 or below the threshold RPM), the processor (120) can drive a vibration device included in the second dust collection device to dislodge the second dust into the dust collection device. Here, the vibration device may be implemented, for example, by an eccentric motor, a solenoid striker (or tapping), a piezo vibrator, etc., and provides “mechanical dislodgement assistance” in consideration of situations where dust attached to the surface of an electrostatic electrode does not easily fall off due to residual charge or surface adhesion force. The frequency / time of the vibration (e.g., 0.2 to 2 seconds, hundreds of Hz to several kHz) may be set by a recipe or implemented in a way that is enhanced only when the amount of collected is large.

[0339] If any of the first to third time intervals is less than the critical time, sequential control based on time interval division may cause frequent switching, resulting in instability or reduced effectiveness, so the processor (120) may switch to a concentration sensor-based conditional driving mode as an alternative control logic. That is, in situations where it is difficult to execute sequential control based on time interval division because the time is too short, the system operates by observing the real-time dust situation and turning on only the necessary devices.

[0340] For example, if any one of the first time interval, the second time interval, and the third time interval is less than the threshold time, the processor (120) can check the first concentration and the second concentration of the first dust and the second dust, respectively, using the first concentration sensor included in the first dust collection device and the second concentration sensor included in the second dust collection device while the rotating wheel is rotating, and during the grinding time, transmit the first power supply command to the first power supply device only when the first concentration exceeds the first threshold concentration, and transmit the second power supply command to the second power supply device only when the second concentration exceeds the second threshold concentration.

[0341] For example, the processor (120) checks the concentration (or accumulation / suspension concentration) of the first dust and the second dust, respectively, through a first concentration sensor placed on the side of the first dust collection device and a second concentration sensor placed on the side of the second dust collection device while the rotating wheel is rotating. The first concentration sensor may be implemented using, for example, an indirect measurement based on a Hall sensor, an optical scattering method, or a dust collection plate accumulation sensor (e.g., weight, pressure, capacitance, etc.) to detect the amount of magnetic dust passing through or the amount of accumulation. The second concentration sensor may be implemented as an optical dust sensor, a differential pressure sensor, a dust collection electrode current change detection sensor (based on ion current / leakage current change), etc., placed in the flow path of the electrostatic dust collector.

[0342] Next, the processor (120) transmits a first power supply command to the first power supply unit to turn on the electromagnet only when the first concentration exceeds the first threshold concentration during the grinding time. That is, the electromagnet is operated only when there is actually a large amount of magnetic dust, thereby reducing unnecessary heat generation and power waste and extending the coil life. Likewise, the processor (120) transmits a second power supply command to the second power supply unit to activate the electrostatic electrode only when the second concentration exceeds the second threshold concentration during the grinding time. At this time, the threshold concentration may be set according to workplace environment standards (e.g., allowable amount of airborne dust), process quality standards (e.g., allowable reattachment limit), or standards for preventing internal contamination of the device.

[0343] This conditional driving method can be understood as a way to ensure efficiency by turning on the capture device only when necessary, even in short processes, and it can be understood as a method that operates advantageously, particularly in processes with short processing times or large fluctuations in dust generation amounts.

[0345] According to one embodiment, the processor (120) checks the rotational speed of the rotating wheel using a rotation detection sensor while the rotating wheel is rotating, and the processor can adjust the magnitude of the predetermined current in proportion to the rotational speed of the rotating wheel and the first concentration, and adjust the magnitude of the predetermined voltage in proportion to the rotational speed of the rotating wheel and the second concentration.

[0346] For example, the processor (120) can check the rotational speed (RPM) of the rotating wheel in real time using a rotation detection sensor (e.g., encoder, optical RPM sensor, Hall sensor, etc.) while the rotating wheel is rotating. Since RPM has a high correlation with the amount of dust generated and the scattering speed, the processor (120) can automatically adjust the collection intensity by combining RPM and dust concentration information, thereby ensuring stable collection performance without excessive operation (e.g., energy waste / heat generation).

[0347] For example, the processor (120) can adjust the magnitude of a predetermined current supplied to the first dust collection device in proportion to the rotational speed and the first concentration. For example, if the RPM (or rotational speed) is high and the first concentration is high, the electromagnet current is increased to strengthen the magnetic flux, and if the RPM is low or the first concentration is low, the current is reduced to suppress heat generation. At this time, the first power supply can be implemented as a DC power supply capable of constant current control (e.g., switching power supply + current feedback, current control driver).

[0348] For example, the processor (120) can adjust the magnitude of a predetermined voltage applied to the second dust collection device in proportion to the rotational speed and the second concentration. For example, when the second concentration increases, the high voltage is increased to increase the electric field strength, and when the second concentration is low, the voltage is lowered to reduce the risk of unnecessary discharge and power consumption. At this time, the second power supply is a high-voltage DC power supply (e.g., kV-class HV PSU) and may include voltage feedback control and leakage current detection protection functions.

[0349] In this way, the processor (120) operates with a logic that automatically optimizes the collection intensity by simultaneously reflecting the dust state and process conditions (e.g., the rotation speed of the rotating wheel), and this can provide differentiation in terms of process responsiveness and energy efficiency compared to simple ON / OFF-based dust collection.

[0350] According to one embodiment, the processor (120) can adjust a predetermined current based on the following mathematical formula 1.

[0351]

[0352] For example, I(N, C_1) is the magnitude of a predetermined current when the rotational speed (RPM) of the rotating wheel is N and the first concentration is C_1, I_min is a predefined lower current limit, I_max is a predefined upper current limit, N_ref is a rotational speed normalization reference value, C_1,ref is a first concentration normalization reference value, and k_I, a, and b are tuning parameters.

[0353] According to one embodiment, the processor (120) can adjust a predetermined current based on the following mathematical formula 2.

[0354]

[0355] For example, I(N, C_2) is the magnitude of a predetermined voltage when the rotational speed (RPM) of the rotating wheel is N and the second concentration is C_2, V_min is a predefined lower voltage limit, I_max is a predefined upper voltage limit, N_ref is a rotational speed normalization reference value, C_1,ref is a first concentration normalization reference value, and k_V, c, and d are tuning parameters.

[0356] In one embodiment, the processor (120) can calculate the magnitude of a predetermined current supplied to a first dust collection device (or electromagnet) and the magnitude of a predetermined voltage applied to a second dust collection device (or electrode) using the rotational speed of the rotating wheel and the dust concentration as inputs. In this case, the term within the exponential function may be composed of a value obtained by combining the normalized values ​​of the rotational speed of the rotating wheel and the dust concentration, respectively, by applying weights. With this structure, the calculated current or voltage increases as the rotational speed or dust concentration increases, but the calculated value may be configured to gradually approach the upper limit of the current or the upper limit of the voltage due to the exponential saturation characteristic.

[0357] In one embodiment, Equations 1 and 2 ensure that the calculated current and voltage always exist between a set lower limit and an upper limit. Specifically, as the input term increases, the exponential term approaches 0, and accordingly, as the bracket term approaches 1, the current or voltage gradually approaches the upper limit. Therefore, even if the dust concentration increases instantaneously or the rotational speed surges, it is possible to prevent the current or voltage from exceeding the upper limit, and in the range where the dust concentration is low, the current or voltage is maintained near the lower limit, thereby suppressing unnecessary increases in power consumption. In other words, the calculation formula of this embodiment can mathematically implement energy efficiency control by setting the power magnitude strongly when necessary and minimally when not necessary.

[0358] In one embodiment, Equations 1 and 2 are implemented to ensure stability of heat generation and capture strength in electromagnet-based capture, and to maintain capture performance while suppressing the risks of insulation breakdown, arcing, and abnormal discharge in electrostatic-based capture. For example, the current calculation formula increases the electromagnet capture force as the rotational speed and the first concentration (magnetic dust concentration index) increase, but does not exceed the current upper limit, thereby preventing a decrease in stability due to coil heating and magnetic saturation. Additionally, the voltage calculation formula increases the electric field strength as the rotational speed and the second concentration (non-magnetic dust concentration index) increase, but does not exceed the voltage upper limit, thereby reducing the possibility of failure due to discharge between electrodes or insulation degradation. Consequently, this embodiment can achieve closed-loop control in which the current and voltage automatically track changes in process conditions (e.g., changes in rotational speed, dust generation amount) while complying with safety limits.

[0359] In one embodiment, the normalization reference value and tuning factor can be set through pre-calibration according to the device specifications and process recipe. For example, the rotational speed normalization reference value can be set to 10,000 revolutions / min or 15,000 revolutions / min, and the first concentration normalization reference value and the second concentration normalization reference value can be set to 1.0 times (reference load) or 2.0 times (relative concentration reference) relative to the sensor reference output, respectively. In addition, the tuning factor (or exponential internal factor) determining the sensitivity of current / voltage can be set in the range of, for example, 0.3 to 3.0, the rotational speed weighting index can be set in the range of, for example, 0.5 to 1.5, and the concentration weighting index can be set in the range of, for example, 0.7 to 2.0. For example, if the rotational speed weighting index is set to 1.0 and the concentration weighting index is set to 1.2, the control response to changes in concentration can be given relatively more than to changes in rotational speed, and if the index internal coefficient is set to 1.5, the collection power can be quickly secured in the section of rapid dust increase through a relatively fast saturation response. These normalized reference values ​​and tuning coefficients can be input from the user terminal within the range described above.

[0360] According to one embodiment, the processor (120) can determine the real-time thickness of the workpiece by receiving a reflected signal after irradiating a laser light onto the side of the workpiece using a non-contact probe sensor placed in an area adjacent to the spindle motor, and can adjust the magnitude of the predetermined current and the predetermined voltage in proportion to the difference between the initial thickness of the workpiece included in the start input and the real-time thickness.

[0361] For example, the processor (120) can irradiate a laser beam onto the side of the workpiece to be ground using a non-contact probe sensor (e.g., laser displacement sensor, laser triangulation method, interferometer method, etc.) placed in an area adjacent to the spindle motor, and receive the reflected signal to determine the real-time thickness of the workpiece to be ground. The reason for using the side here can be understood as being to stably estimate the real-time grinding amount through side measurement, which has relatively less interference, because the upper surface direction sensor may be vulnerable to dust and wheel interference while the rotating wheel is grinding the upper surface.

[0362] For example, the processor (120) can calculate the difference between the initial thickness (or reference thickness before grinding) included in the start input and the real-time thickness (or measured thickness during grinding) to calculate the grinding amount or the degree of approach to the target thickness up to that point. Subsequently, the processor (120) can adjust the magnitude of the first dust collection device driving current and the second dust collection device driving voltage in proportion to the difference. For example, at the beginning of grinding, the thickness difference increases rapidly (large grinding amount) and generates a large amount of dust, so the current / voltage is maintained at a relatively high level. Then, as the grinding amount decreases as it approaches the target thickness, the amount of dust generated decreases, so the current / voltage is gradually lowered to ensure energy efficiency. Alternatively, if reattachment is more critical to quality during the finishing stage, additional dynamic adjustments based on a lookup table may be possible, such as a recipe to increase the electrostatic voltage in the finishing section to strongly capture residual dust.

[0364] Additionally or generally, the processor (120) may send an opening command to the upper opening / closing part (e.g., shutter or flap) of the dust collection device immediately before sending a power supply interruption command to the first power supply, and may send a closing command to the upper opening / closing part after a preset time (e.g., 5 seconds) has elapsed when it is determined that dust has fallen and collection is complete. By doing so, the dry grinding device (100) prevents the collected dust from scattering back into the machine.

[0365] Additionally or generally, when the processor (120) receives a warning signal indicating that the amount of accumulated dust has exceeded a threshold from a dust amount detection sensor installed inside the dust collection device, it can provide a "dust container needs to be emptied" notification to the user terminal and transmit an opening command to the side opening of the dust processing device to control the transfer of dust inside the dust collection device to the waste processing system.

[0367] Additionally, the processor (120) can use the first sensor to check the surface area of ​​the object to be ground, check the grinding target time included in the start input, check the first time and the second time based on the grinding target time and the area, and transmit a power supply command to the first power supply device instructing to repeat the operation of supplying power to the electromagnet for the first time from the time when the rotation of the rotating wheel starts, and then cutting off the power supply to the electromagnet for the second time during the grinding target time.

[0368] The first time is the ON time of the electromagnet (300), which may mean the time during which magnetic force is generated and dust can be collected as power is supplied to the electromagnet (300).

[0369] The second time is the electromagnet (300) OFF time, which means a rest period during which the power supply to the electromagnet (300) is cut off so that the magnetic force is extinguished, and this period may be set for the purpose of escaping the collected dust and cooling the electromagnet (300).

[0370] That is, the processor (120) can control the first power supply to periodically repeat the application and cutoff of power to the electromagnet (300) at each time cycle calculated based on the surface area of ​​the object to be ground and the target grinding time. This is to prevent overheating of the electromagnet and to prevent saturation of dust collection on the electromagnet surface by dislodging some of the temporarily collected dust, while at the same time temporarily utilizing the dust transport flow (e.g., transport path by an air blower). For example, by repeating a 5-second ON / 2-second OFF cycle, it is possible to support maintaining the collection power and stable dust discharge simultaneously. Here, the first time may be set longer than the second time.

[0371] The surface area of ​​the workpiece to be ground (e.g., the upper surface area of ​​an inductor bar) has a direct correlation with the total amount of dust generated during the grinding process and the grinding load. In particular, the larger the area, the more dust is generated during the grinding process, and the load applied to the electromagnet (300) can also increase. Therefore, the surface area of ​​the workpiece to be ground is used as a key input variable to determine the control cycle of the electromagnet (300).

[0372] The processor (120) can identify the contour of the object to be ground using a first sensor (e.g., a vision sensor) positioned to scan the entire object to be ground, and can automatically calculate the area inside the contour using an image processing algorithm (e.g., CNN-based).

[0373] When the processor (120) receives a start input from a user terminal, it may receive the width and length of the object to be ground as parameters and calculate the area by multiplying them.

[0374] Since the larger the grinding area, the greater the amount of dust generated, and thus the greater the risk of overloading and overheating of the electromagnet, the processor (120) may set the first time for continuously keeping the electromagnet (300) in the ON state to be inversely proportional to the surface area of ​​the workpiece to be ground. Meanwhile, the second time may correspond to a value fixed in advance, and the processor (120) may set the first time to exceed at least the second time. Through this, it is possible to more clearly implement the fact that the priority of dust management during the grinding process is to maintain the collection power.

[0375] The processor (120) can determine the first time through a lookup table or a predefined formula between the surface area, the grinding target time, and the capture time (or, the first time).

[0376] The processor (120) measures the surface temperature of the electromagnet (300) in real time based on a heat sensing sensor placed adjacent to the electromagnet (300), and if it is determined that the surface temperature exceeds a critical temperature, it can dynamically perform heat management by temporarily doubling the second time to support the continuous execution of stable dust collection logic.

[0377] The processor (120) can check the material information of the object to be ground (e.g., iron alloy, copper alloy ratio) included in the start input and transmit a power supply command to the first power supply device instructing to increase the intensity of the current applied during the first time period if the magnetic strength of the material is less than the critical magnetic strength. For example, at the start of the first time period, if the object to be ground is a weak magnetic material, the processor (120) can reinforce the instantaneous collection power during the first time period by controlling the first power supply device to apply 10% more power intensity (or current) than usual to increase the saturation magnetic flux density of the electromagnet (300). This can be understood as a correction logic to minimize deviations in collection power according to the magnetic characteristics of the dust.

[0378] The dry grinding device (100) may further include a vibration device and / or an air jet device configured to efficiently remove magnetic dust collected on one side of the electromagnet (300) (e.g., the top side facing the rotating wheel).

[0379] For example, the dry grinding device (100) can forcibly shake off magnetic dust collected by the electromagnet (300) for a short time after the power supply is interrupted by generating vibrations during a second time through a vibration generating device placed around the electromagnet (300) or on a frame supporting the electromagnet (300). The vibration generating device may be implemented in a form including an electric motor-based eccentric weight or an ultrasonic vibrator on the lower frame of the workbench where the electromagnet (300) is placed. For example, immediately after transmitting a power supply interruption command, the processor (120) transmits a driving signal to the vibration generating device to generate vibrations at a predetermined frequency (e.g., 500 Hz to 1 kHz) for a predetermined time (e.g., 0.5 seconds). This high-frequency vibration is configured to instantaneously destroy the static friction and adhesion forces between the surface of the electromagnet (300) and the dust particles, thereby effectively shaking the dust downward.

[0380] For example, the dry grinding device (100) may further utilize an air jet nozzle that instantaneously sprays high-pressure air near the dust collection device or around the electromagnet (300) to help magnetic dust fall more efficiently into the dust collection device. The dry grinding device (100) may further include an air jet spraying device connected to an air compressor, a solenoid valve capable of instantaneously spraying air, and a jet nozzle positioned to face the surface of the electromagnet (300). For example, immediately after transmitting a power supply interruption command, the processor (120) opens the solenoid valve for a predetermined time (e.g., 0.5 seconds) to spray a high-pressure air pulse downward along the top surface (or collection surface) of the electromagnet (300). This strong airflow provides kinetic energy added to the gravity fall, which can help the magnetic dust be transported more quickly into the dust collection device. Meanwhile, if the processor (120) identifies that the temperature of the electromagnet (300) exceeds a critical temperature, it may discharge more air through an air blower in response to the grinding target time elapsed and the rotation of the rotating wheel being stopped. Through this, the dry grinding device (100) can effectively manage the heat of the electromagnet (300) and isolate magnetic dust.

[0382] Additionally or generally, the processor (120) can drive the third servo motor at predetermined time intervals during a reference time (or, a grinding target time included in the start input) from the time the rotation of the rotating wheel begins, thereby lowering the rotating wheel by a predetermined length.

[0383] For example, the processor (120) can perform grinding during a reference time (or, grinding target time) included in the start input. That is, the processor (120) can process (or grind) the surface of the object to be ground using a spindle motor and a third servo motor during the reference time.

[0384] For example, the processor (120) can lower the third servo motor by a predetermined length (e.g., 10 μm) at predetermined intervals during a reference time. That is, the rotating wheel can precisely grind the top of the workpiece by gradually descending deeper by a predetermined length. Here, the predetermined interval corresponds to one-third of the reference time; in other words, the processor (120) can identify the predetermined interval based on the reference time obtained from the user terminal and then lower the rotating wheel by a predetermined length three times during the reference time. Additionally, the processor (120) can control the third servo motor to lower the rotating wheel by setting the descent speed to a predetermined speed (e.g., 20 mm / s). As an example, the predetermined length can be set as a pre-profile according to the hardness of the workpiece, the wheel material (e.g., CBN, diamond), and the target machining thickness.

[0385] For example, the processor (120) can identify a predetermined length corresponding to one-third of the length of the target machining thickness after checking the target machining thickness included in the start input. That is, the processor (120) can perform a stable grinding algorithm by dividing the target machining thickness corresponding to the total grinding depth into three parts for split control. As a result, the processor (120) can evenly distribute the grinding depth by dividing the reference time into one-third intervals to perform a downward movement, thereby minimizing heat generation and vibration.

[0386] For example, the processor (120) can push metal dust and / or floating particles generated on the surface of the workpiece to be ground toward the suction port by operating the air blower for a reference time, and collect them using a dust collection duct and a dust collector.

[0387] Additionally or generally, when a reference time has elapsed, the processor (120) may stop driving the spindle motor and, after confirming using a third sensor that the rotation of the rotating wheel has ended, drive the third servo motor to raise the rotating wheel back to the starting position.

[0388] For example, the processor (120) can stop the rotation of the spindle axis and the rotating wheel by sending a stop signal to the spindle motor when the reference time ends. Accordingly, the rotating wheel can rotate for a short time due to inertia and then stop.

[0389] For example, the processor (120) can monitor the rotational speed of the rotating wheel in real time based on information obtained through a third sensor (e.g., an optical rotation sensing sensor, a magnetic RPM sensor) included in the grinding head, and identify the point in time when the RPM becomes 0 (or, the point in time when the rotational speed becomes 0), that is, the point in time when the rotating wheel stops rotating and comes to a stop.

[0390] For example, when the processor (120) confirms that the rotating wheel has completely stopped, it may reverse drive the third servo motor to move the spindle axis upward along the z-axis. By doing so, the rotating wheel can return to the initial standby position (or, starting position) to prepare for the next grinding cycle.

[0391] According to one embodiment, the dry grinding device (100) may further include a contact probe sensor that is placed on a chuck table and configured to measure the thickness of the workpiece by contacting the upper surface of the workpiece through a probe.

[0392] According to one embodiment, the dry grinding device (100) is configured to measure the thickness of the workpiece by receiving a reflected signal after irradiating a laser light onto the side of the workpiece to be ground, and may further include a non-contact probe sensor disposed on the side of the grinding head.

[0393] For example, when the processor (120) identifies that the rotating wheel is rotating using the third sensor, it can measure the thickness of the workpiece to be ground in real time using only the non-contact probe sensor and provide the first measurement result to the user terminal.

[0394] For example, the processor (120) can obtain a first measurement result by using a laser displacement sensor included in a non-contact probe sensor to irradiate a laser onto the side of the object to be ground, and by analyzing the phase difference of the reflected light to measure the thickness in real time.

[0395] For example, the processor (120) may measure the thickness of the workpiece to be ground using an ultrasonic non-contact sensor instead of an optical sensor. This allows the laser scattering effect to be minimized even in a dusty environment.

[0396] For example, if the non-contact sensor data is momentarily unstable (or if some of the time-series sensor data increases or decreases by exceeding a threshold change amount), the processor (120) may apply a moving average or a Kalman filter to obtain a stabilized first measurement result and then provide it to a user terminal.

[0397] For example, when the processor (120) identifies that the rotation of the rotating wheel has ended using the third sensor, it can measure the thickness of the workpiece to be ground in real time using both the contact probe sensor and the non-contact probe sensor and provide the second measurement result to the user terminal.

[0398] For example, when the rotating wheel stops, the processor (120) can measure the absolute thickness by contacting the probe included at one end of the contact probe sensor to the upper surface of the workpiece to be ground, and then measure the thickness of the workpiece to be ground using a non-contact sensor and perform mutual cross-verification.

[0399] For example, the processor (120) can provide the average value of the two measured thicknesses to the user terminal only when the difference between the two measured thicknesses of the probe sensors is less than or equal to a threshold difference.

[0401] Additionally or generally, when the dry grinding device (100) identifies that the rotation of the rotating wheel has ended using the third sensor, it checks the first real-time thickness and the second real-time thickness measured through the contact probe sensor and the non-contact probe sensor, respectively, and if the difference between the first real-time thickness and the second real-time thickness is greater than or equal to a threshold difference, it may provide only the first real-time thickness to the user terminal.

[0402] For example, if the difference between the two measurement results is greater than a threshold difference, the processor (120) determines that the accuracy of the second real-time thickness is reduced due to issues such as dust or temperature during the detection process of the non-contact probe sensor, and may provide only the first real-time thickness obtained by the contact probe sensor as the final value.

[0403] Alternatively, the processor (120) may provide the first real-time thickness to the user terminal while simultaneously providing the user terminal with a warning notification containing a text phrase corresponding to "decreased reliability of non-contact sensor." Furthermore, the processor (120) may provide the user terminal with a text phrase stating "dust filter inspection required," and may store internal environmental data (e.g., temperature, vibration, amount of dust, etc.) at the time the warning notification was provided in memory.

[0404] Additionally, the processor (120) can perform an automatic shutdown mode that allows subsequent grinding cycles only when it receives a maintenance completion input via the "maintenance complete" button after confirming a warning notification on the user terminal.

[0405] Through this, the dry grinding device (100) can prevent quality degradation due to defective data and provide only safe thickness information to the user.

[0406] Additionally or generally, the processor (120) can move the chuck table using the first servo motor and the second servo motor after moving the rotating wheel back to the starting position, so that the center point of the dressing board attached to one end of the chuck table corresponds to the center point of the rotating wheel. Afterward, the processor (120) can drive the third servo motor to lower the spindle axis so that the rotating wheel comes into contact with the dressing board, and then drive the spindle motor to rotate the rotating wheel to perform a wheel regeneration (or dressing) algorithm for a predetermined dressing time (e.g., 1 minute).

[0407] Additionally or generally, the processor (120) can move the rotating wheel back to its initial standby position after the wheel regeneration algorithm is terminated, and drive an air blower while moving the rotating wheel to remove the internal heat generated by the rotating wheel.

[0409] According to one embodiment, the processor (120) can obtain a first initial thickness and a second initial thickness of the workpiece through a contact probe sensor and a non-contact probe sensor, respectively, in response to confirming that a reference line extending the center point of the workpiece in the z-axis direction penetrates the center point of the rotating wheel.

[0410] For example, the processor (120) can measure the thickness of the workpiece through at least one probe sensor before driving the spindle motor in response to identifying that the workpiece is positioned to perform a grinding process through a rotating wheel as the chuck table is moved through the first servo motor and the second servo motor.

[0411] For example, a contact probe sensor may be placed on a chuck table, and a processor (120) may measure a first initial thickness by bringing a probe portion placed at one end of the contact probe sensor into contact with the upper surface of the workpiece to be ground. At this time, the processor (120) may collect a displacement signal when the probe portion contacts the surface of the workpiece to be ground, convert it into a reference thickness, and calculate the first initial thickness.

[0412] For example, the processor (120) can obtain a second initial thickness by irradiating laser light onto the side of the workpiece to be ground through a non-contact probe sensor placed on the side of the grinding head and receiving the reflected light. For example, the non-contact probe sensor can obtain thickness information by measuring the distance between the side height of the workpiece to be ground and the reference plane in a non-contact manner, and the processor (120) can convert this into a thickness value.

[0413] That is, the first initial thickness and the second initial thickness may refer to the thickness of the object to be ground obtained through a contact probe sensor and a non-contact probe sensor, respectively, before starting the grinding process through the rotation of the rotary wheel.

[0414] Additionally or generally, the processor (120) can compare the difference between the first initial thickness and the second initial thickness and determine that sensor correction is required if the deviation is large. By acquiring the initial thickness using both a contact probe sensor and a non-contact probe sensor simultaneously before grinding begins, measurement errors that may occur when relying on a single method of measurement can be effectively reduced.

[0415] In particular, since contact measurement can ensure absolute accuracy and non-contact measurement can be performed quickly in a non-contact state, the reliability of thickness data before grinding can be maximized by mutually correcting the two measurement results.

[0416] Accordingly, the present invention can simultaneously improve overall grinding quality and production efficiency by preventing the accumulation of thickness deviations from the initial process stage.

[0417] In conventional technology, since it relied solely on measurements from a single method (e.g., a contact displacement gauge) before grinding began, it was difficult to compensate for thickness deviations caused by equipment thermal deformation or installation errors.

[0418] However, by introducing a heterogeneous sensor fusion method in the present invention, it is possible to secure robust initial thickness data even with changes in the measurement environment, which is a point that clearly distinguishes it from conventional technology.

[0419] According to one embodiment, when the processor (120) confirms that the rotation of the rotating wheel has ended using the third sensor, it can drive the third servo motor to raise the rotating wheel back to the starting position.

[0420] For example, the processor (120) can stop driving the spindle motor after a reference time has elapsed and confirm through the third sensor that the rotation of the rotating wheel has ended.

[0421] For example, the third sensor includes an encoder attached to the spindle axis, and the processor (120) can analyze the encoder signal to determine that the RPM of the rotating wheel has converged to 0.

[0422] For example, the third sensor can detect whether the wheel is rotating in a non-contact manner, including an optical RPM sensor or a magnetic rotation sensor.

[0423] For example, when the processor (120) confirms that the rotating wheel has completely stopped, it can drive the third servo motor to raise the spindle axis in the z-axis direction. This allows the processor (120) to secure a gap between the rotating wheel and the chuck table, and then drive the first servo motor and the second servo motor to move the chuck table to an initial position.

[0424] Additionally, the processor (120) can immediately stop the operation of the third servo motor and provide a warning to the user terminal if an overcurrent or vibration exceeding a predetermined value is detected during the process of raising the spindle axis.

[0425] According to the present invention, unnecessary friction or collision between the rotating wheel and the workpiece can be prevented by driving the third servo motor to raise the rotating wheel only after verifying through the third sensor that the rotating wheel has completely stopped.

[0426] In this way, mechanical shock that may occur during the rotation wheel lifting process can be minimized, thereby protecting the surface quality of the workpiece and extending the wheel's lifespan. Furthermore, rotation stop detection using a third sensor offers higher accuracy compared to simple timer control, ensuring both safety and reliability simultaneously.

[0427] Conventional dry grinding devices primarily used a method of raising the wheel immediately after a certain period of time without accurately detecting whether the spindle had stopped.

[0428] This method had problems where lifting occurred before the wheel had completely stopped, causing scratches on the edges of the workpiece or vibration of the device.

[0429] On the other hand, the present invention fundamentally solves these conventional problems by introducing a safety control method based on real-time rotation termination detection.

[0430] According to one embodiment, the processor (120) can obtain a first final thickness and a second final thickness of the object to be ground, respectively, through a contact probe sensor and a non-contact probe sensor.

[0431] For example, the processor (120) can obtain the first final thickness and the second final thickness of the workpiece to be ground, respectively, through a contact probe sensor and a non-contact probe sensor after completing the raising of the rotating wheel to the starting position via the third servo motor.

[0432] For example, a contact probe sensor measures a displacement amount by contacting a probe portion to the upper surface of the workpiece to be ground, and the processor (120) can calculate a first final thickness based on this. The contact probe sensor can measure multiple values ​​based on four side center points along four corners and / or four sides as well as the center of the workpiece to be ground, and the processor (120) can calculate the average value of the multiple measured values ​​or a flat conformation value as the first final thickness.

[0433] For example, the processor (120) can obtain a second final thickness by scanning the side of the workpiece to be ground or performing point measurements through a non-contact probe sensor. The non-contact probe sensor can rapidly scan multiple points on the side of the workpiece to be ground, and the processor (120) can calculate the second final thickness by averaging them. The non-contact probe sensor can measure four values ​​through scanning each of the four sides of the workpiece to be ground, which corresponds to a rectangular prism, and the processor (120) can calculate the average of the four measured values ​​as the second final thickness.

[0434] For example, the processor (120) may first provide the first final thickness obtained through the contact probe sensor when the difference between the first final thickness and the second final thickness exceeds a predetermined threshold.

[0435] The initial processor (120) may initiate at least some of the operations of FIG. 4 and FIG. 5 described above in response to receiving a start input from a user terminal through a communication interface, and the start input may include a target processing thickness for a grinding object, a type of grinding object, a reference time, and a target deviation entered by the user.

[0436] According to the present invention, the limitations of a single measurement method can be overcome by obtaining the final thickness using both a contact probe sensor and a non-contact probe sensor after the grinding is finished.

[0437] Contact measurement provides high absolute accuracy, while non-contact measurement enables multi-point, high-speed measurement across the entire surface; therefore, combining the two results ensures more precise and reliable final thickness data.

[0438] Through this, the present invention enables objective verification of grinding quality and minimizes the defect rate.

[0439] In conventional technology, thickness was mostly measured using only contact probe sensors after grinding was completed. However, this method had limitations in that it was difficult to accurately determine the thickness when the surface was uneven or the probe position was limited.

[0440] The present invention collects auxiliary information about the entire surface by using a non-contact probe sensor in parallel, thereby ensuring both the reliability and precision of the thickness data.

[0441] Therefore, the present invention has the advantage of significantly simplifying the post-grinding inspection process compared to conventional devices and enabling automatic quality assurance (Automatic QA) on the production line.

[0442] It features sensor fusion, real-time safety control, and the utilization of multiple measurement results in each of the three stages: initial thickness measurement, safe rise after rotation completion, and final thickness measurement.

[0443] Through this configuration, the present invention can simultaneously achieve technical effects such as stability of grinding quality, extension of device lifespan, and automation of the inspection process, which can be considered an innovative feature clearly distinct from conventional technology.

[0445] According to one embodiment, the processor (120) can determine whether to perform additional grinding based on the difference between the first initial thickness and the second final thickness, the difference between the second initial thickness and the second final thickness, the target processing thickness, and the target deviation, or to terminate the grinding algorithm after providing a grinding success notification to the user terminal.

[0446] For example, the processor (120) can identify a first difference between a first initial thickness and a first final thickness and a second difference between a second initial thickness and a second final thickness, and then determine whether the deviation between the first difference and the second difference exceeds a predetermined value.

[0447] For example, if the deviation between the first difference and the second difference exceeds a predetermined value, the processor (120) compares the first final thickness with the target processing thickness entered by the user, and if the deviation between the first final thickness and the target processing thickness is less than or equal to the target deviation, it can provide a grinding success notification to the user terminal.

[0448] For example, if the deviation between the first difference and the second difference exceeds a predetermined value, the processor (120) compares the first final thickness with the target processing thickness entered by the user, and if the deviation between the first final thickness and the target processing thickness exceeds the target deviation, the third servo motor and spindle motor can be driven to perform additional grinding equal to the target deviation.

[0449] For example, if the deviation between the first difference and the second difference is less than or equal to a predetermined value, the processor (120) can compare the average value of the first final thickness and the second final thickness with the target processing thickness.

[0450] If the deviation between the average value and the target processing thickness is less than or equal to the target deviation, the processor (120) can provide a grinding success notification to the user terminal.

[0451] If the deviation between the average value and the target processing thickness exceeds the target deviation, the processor (120) can drive the third servo motor and spindle motor to perform additional grinding equal to the target deviation.

[0452] Through the above operations, the processor (120) receives the target processing thickness of the workpiece, the type of workpiece, the reference time, and the target deviation together at the start input stage, so that the grinding process can be performed with the processing conditions optimized in advance.

[0453] Since grinding parameters optimized for different materials and shapes can be automatically applied depending on the type of workpiece, the ability to handle a wide variety of parts is improved.

[0454] In addition, by setting a target deviation in advance, the system can immediately determine whether the result falls within the deviation range after the grinding process is completed, enabling the automation of quality control.

[0455] In conventional technology, because workers manually checked the target thickness or determined quality through a separate external inspection process, productivity was low and the likelihood of defective products being discharged was high.

[0456] On the other hand, since the present invention integrally reflects target values ​​and process conditions from the initial input stage, real-time quality control during the processing process is possible, which is a point that clearly distinguishes it from conventional technology.

[0457] In addition, according to the present invention, the reliability of the sensor measurement results can be verified by identifying the difference between a first initial thickness and a first final thickness (e.g., a first difference) and the difference between a second initial thickness and a second final thickness (e.g., a second difference), respectively.

[0458] In cases where there is a large deviation between the results of the two sensors, the influence of uncertain data can be excluded by utilizing the first final thickness based on the absolute accuracy of the contact sensor and directly comparing it with the target thickness.

[0459] As a result, the system can reliably determine grinding quality even if deviations occur, and can achieve the target thickness by automatically controlling additional grinding when necessary.

[0460] In conventional technology, since the determination of whether grinding had ended relied solely on the result of a single sensor, incorrect quality judgments could occur due to sensor errors or environmental factors (e.g., heat, dust).

[0461] The present invention secures much higher reliability and precision than conventional technology by comparing and analyzing differences between heterogeneous sensors and performing control based on the absolute reliability of the contact sensor when an error occurs.

[0462] Furthermore, according to the present invention, if the deviation between the first difference and the second difference is less than or equal to a predetermined value, the processor (120) can calculate the average value of the first final thickness and the second final thickness and compare it with the target thickness.

[0463] This allows for the utilization of a high-precision average value combining the advantages of both sensors when both operate normally, thereby significantly enhancing the reliability of the results.

[0464] Performing average-value-based comparisons minimizes the impact of transient noise or measurement errors from specific sensors on the results, and improves process stability and repeatability.

[0465] Conventional technology relied only on single sensor data or an arbitrarily selected value from multiple sensors when determining thickness, so it was not possible to obtain mutual correction effects between data.

[0466] The present invention realizes data fusion-based precise control through an algorithm that utilizes the average value of two sensor results, which is a new approach distinct from conventional technology.

[0467] Consequently, the dry grinding device (100) according to the present invention realizes data-based intelligent control in the start input step, thickness identification step, and final thickness determination step.

[0468] Through this, the target value is clearly reflected before the grinding process, the difference between sensors is verified during the process, and the final thickness can be determined by fusing sensor data after the process.

[0469] Therefore, unlike conventional simple machine control methods, the present invention provides distinctive technical features such as sensor fusion, automatic correction, and target-oriented control, thereby dramatically improving both the reliability of grinding quality and productivity.

[0471] The above description is merely an illustrative explanation of the technical concept of the present invention, and those skilled in the art to which the present invention pertains will be able to make various modifications and variations within the scope of the essential characteristics of the present invention without departing from its nature.

[0472] Accordingly, the embodiments disclosed in this invention are intended to illustrate, not limit, the technical concept of the invention, and the scope of the technical concept of the invention is not limited by these embodiments. The scope of protection of this invention shall be interpreted by the claims below, and all technical concepts within an equivalent scope shall be interpreted as being included within the scope of rights of this invention.

Claims

Claim 1 A quality control method based on non-destructive testing, wherein a dry grinding device including a processor performs the process and performs the process and quality inspection in parallel based on the physical properties of an inductor bar measured in real time during the process, the method comprising: the processor driving a spindle motor to rotate a rotating wheel at a predetermined RPM in response to receiving a start input for grinding a workpiece from a user terminal; the processor irradiating a laser light onto the side of the workpiece using a non-contact probe sensor placed in an area adjacent to the spindle motor and receiving a reflected signal to determine the real-time thickness of the workpiece; the processor comparing the real-time quality of the workpiece, determined based on the real-time thickness, the initial thickness of the workpiece included in the start input, and the difference between the initial thickness and the real-time thickness, with a predefined quality table to determine a comparison result; and if the workpiece is determined to be defective based on the comparison result, the processor stopping the driving of the spindle motor and providing a warning notification to the user terminal. Claim 2 In claim 1, the quality control method further comprises: an operation in which the processor checks the rotational state of the rotating wheel using a rotation detection sensor after stopping the operation of the spindle motor; and an operation in which, when the processor confirms that the rotation of the rotating wheel has completely ended based on the rotational state, cuts off the power supply to the vacuum suction device of the chuck table on which the workpiece to be ground is adsorbed; and the quality control method further comprises: an operation in which, when the rotation of the rotating wheel begins, the processor collects the first dust and the second dust generated from the workpiece to be ground by the rotation of the rotating wheel, respectively, using a first dust collection device electrically connected to a first power supply and a second dust collection device electrically connected to a second power supply. A quality control method comprising: the processor transmitting a power supply interruption command to the first power supply and the second power supply when the rotation of the rotating wheel ends, thereby inducing the first dust and the second dust collected in the first dust collection device and the second dust collection device to escape to the dust collection device; wherein the first dust collection device is configured to collect the first dust corresponding to magnetic dust based on magnetic force and includes an electromagnet that receives current from the first power supply; and the second dust collection device is configured to collect the second dust corresponding to non-magnetic dust based on electrostatic force and includes an electrode that receives voltage from the second power supply to form an electric field. Claim 3 In paragraph 2, the quality control method comprises: an operation in which the processor checks the grinding time included in the start input; an operation in which the processor checks the grinding time by dividing it into a first time interval, a second time interval after the first time interval, and a third time interval after the second time interval based on a preset time ratio; if the first time interval, the second time interval, and the third time interval are all greater than or equal to a preset threshold time: an operation in which the processor transmits a first power supply command instructing to supply a predetermined current to the first dust collection device during the first time interval only to the first power supply device; an operation in which the processor transmits the first power supply command instructing to supply the predetermined current to the first dust collection device during the second time interval to the first power supply device, and transmits a second power supply command instructing to apply a predetermined voltage to the second dust collection device to the second power supply device; and an operation in which the processor transmits the second power supply command instructing to apply a predetermined voltage to the second dust collection device only to the second power supply device during the third time interval The operation of transmitting a power supply command; and further comprising the operation of the processor, when the third time interval elapses and the rotation of the rotating wheel ends, using a vibration device included in the second dust collection device to remove the second dust to the dust collection device, and when any one of the first time interval, the second time interval, and the third time interval is less than a threshold time: the operation of the processor, while the rotating wheel is rotating, checking the first concentration and the second concentration of the first dust and the second dust, respectively, using a first concentration sensor included in the first dust collection device and a second concentration sensor included in the second dust collection device; the operation of the processor, during the grinding time, transmitting the first power supply command to the first power supply device only when the first concentration exceeds a first threshold concentration;A quality control method further comprising the operation of the processor transmitting the second power supply command to the second power supply device only when the second concentration exceeds the second threshold concentration during the grinding time. Claim 4 In paragraph 3, the quality control method further comprises: an operation in which the processor checks the rotational speed of the rotating wheel using a rotation detection sensor while the rotating wheel is rotating; an operation in which the processor adjusts the magnitude of the predetermined current so as to be proportional to the rotational speed of the rotating wheel and the first concentration; and an operation in which the processor adjusts the magnitude of the predetermined voltage so as to be proportional to the rotational speed of the rotating wheel and the second concentration, and the quality control method further comprises an operation in which the processor adjusts the magnitudes of the predetermined current and the predetermined voltage so as to be proportional to the difference between the initial thickness and the real-time thickness of the workpiece to be ground. Claim 5 In claim 4, the quality control method further comprises: an operation in which the processor measures in real time an eddy current signal corresponding to the magnetic flux density and copper winding state of the workpiece using a magnetic sensor array and an eddy current sensor disposed on one surface of a chuck table on which the workpiece is adsorbed; and an operation in which the processor confirms the comparison result by comparing the real-time quality confirmed based on the magnetic flux density and the eddy current signal with the predefined quality table.

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