A quality control method, device and system for printed circuit boards

Abstract

This invention discloses a quality control method, apparatus, and system for printed circuit boards (PCBs), relating to the field of PCB manufacturing technology. The method includes: acquiring data collected by various sensors of a PCB manufacturing equipment at each time point within a preset time period; calculating the process capability index of the PCB manufacturing equipment at each time point; connecting the process capability indices at all time points to form a real-time process capability index curve; comparing the real-time process capability index curve with historical process capability index curves; determining whether the PCB manufacturing equipment is abnormal based on the comparison result; if the PCB manufacturing equipment is abnormal, calculating the abnormality level based on the comparison result, and generating control instructions for controlling the PCB manufacturing equipment to perform corresponding actions based on the abnormality level. This method can effectively avoid the problems of PCB defects and increased PCB production costs caused by abnormal process capability indices.

Description

Technical Field

[0001] This invention relates to the field of circuit board manufacturing technology, and in particular to a method, apparatus and system for quality control of printed circuit boards. Background Technology

[0002] With the advent of Industry 4.0 and the era of intelligent manufacturing, the manufacturing industry has begun to develop towards automation, digitalization and intelligence. In the automated production workshop of printed circuit boards, the automation level of equipment is getting higher and higher, which places high demands on the process capability index (CPK) of the production equipment. Once the CPK of the equipment decreases, if it is not detected in time, it will cause the circuit boards to be scrapped or reworked in batches.

[0003] To avoid the above problems, the traditional approach is to test the CPK value of the equipment regularly or periodically during the production process. If the CPK value of the equipment is found to be less than the target value, the corresponding equipment is maintained or repaired. However, the time when the CPK value of the equipment decays is random. If the CPK value of the equipment is already less than the target value before the test time, it will cause the circuit boards produced by the equipment to be unqualified, increasing the production cost of the circuit boards. Summary of the Invention

[0004] Therefore, it is necessary to provide a quality control method, apparatus, and system for printed circuit boards to address the above-mentioned technical problems. This would solve the problem that if the CPK value of existing printed circuit board equipment is already lower than the target value before the testing time, the circuit boards produced by the equipment will be unqualified, increasing the production cost of the circuit boards.

[0005] In a first aspect, the present invention provides a quality control method for printed circuit boards, comprising:

[0006] The process capability index of the printed circuit board equipment is calculated based on the collected data of each sensor of the printed circuit board equipment at each time point within a preset time period.

[0007] Connect the process capability indices at all time points to form a real-time process capability index curve, and obtain the historical process capability index curve of the printed circuit board equipment within the historical time period corresponding to the preset time period.

[0008] The real-time process capability index curve is compared with the historical process capability index curve to obtain a comparison result. Based on the comparison result, it is determined whether the printed circuit board equipment is abnormal.

[0009] If the printed circuit board equipment malfunctions, the malfunction level is calculated based on the comparison result, and control instructions for controlling the printed circuit board equipment to perform corresponding actions are generated based on the malfunction level.

[0010] Optionally, the quality control method for the printed circuit board further includes:

[0011] Obtain the current count value of the switch sensor of the printed circuit board equipment within a preset time period;

[0012] Calculate the standard count value of the switch sensor within the preset time period based on the speed at which the printed circuit board equipment conveys the circuit board.

[0013] Calculate the absolute value of the difference between the current count value and the standard count value. If the absolute value of the difference is greater than the preset error threshold of the switch sensor, determine that the switch sensor is abnormal.

[0014] Optionally, the step of acquiring the data collected by each sensor of the printed circuit board equipment at each time point within a preset time period, and calculating the process capability index of the printed circuit board equipment at any given time point based on the data collected at that time point, includes:

[0015] The first data collected by the digital sensor of the printed circuit board equipment is acquired, and the N first data collected at the last N times are stored in a register of length N in chronological order of acquisition time, where N is an integer greater than 1.

[0016] The first data acquired again is stored in the first data bit of the register, and all the original data is shifted backward, overflowing the last data bit of the register;

[0017] The process capability index of the printed circuit board equipment is calculated based on the first acquired data in the register.

[0018] Optionally, the process capability index of the printed circuit board equipment is calculated based on the first acquired data in the register, including:

[0019] Set upper and lower limits for the quality characteristics of the circuit board, and calculate the specification tolerance and specification center value based on the upper and lower limits.

[0020] The operating status of the printed circuit board equipment is obtained. If the operating status of the printed circuit board equipment is "running", the standard deviation and average value of the first data are calculated based on the first collected data in the register.

[0021] The process capability index is calculated based on the specification tolerance, the specification center value, the standard deviation, and the average value.

[0022] Optionally, the specification tolerance and specification center value are calculated based on the upper limit and lower limit of the specification, including:

[0023] Calculate the difference between the upper limit of the specification and the lower limit of the specification to obtain the specification tolerance; calculate the ratio of the specification tolerance to 2 to obtain the specification center value.

[0024] Optionally, the standard deviation of the first data can be calculated according to the sample standard deviation formula.

[0025] Optionally, the process capability index is calculated based on the specification tolerance, the specification center value, the standard deviation, and the average value, including:

[0026] Calculate the first difference between the average value and the specification center value, and the first ratio of the specification tolerance to 2. Calculate the ratio of the first difference to the first ratio to obtain the process accuracy.

[0027] The process precision is obtained by calculating the ratio of the specified tolerance to 6 times the standard deviation.

[0028] Calculate the second difference between 1 and the absolute value of the process accuracy, and calculate the product of the process precision and the second difference to obtain the process capability index.

[0029] Optionally, the real-time process capability index curve is compared with the historical process capability index curve to obtain a comparison result. Based on the comparison result, it is determined whether the printed circuit board equipment is abnormal, including:

[0030] Place the real-time process capability index curve and the historical process capability index curve in the same coordinate system, calculate the deviation value between the process capability index curve and the historical process capability index curve, and if the deviation value is greater than the preset process capability index curve deviation threshold, then determine that the process capability index of the printed circuit board equipment is abnormal.

[0031] In a second aspect, the present invention provides a quality control device for printed circuit boards, comprising:

[0032] The index calculation module is used to acquire the data collected by each sensor of the printed circuit board equipment at each time point within a preset time period, and to calculate the process capability index of the printed circuit board equipment at any time point based on the data collected at that time point.

[0033] The curve plotting module is used to connect the process capability indices at all time points to form a real-time process capability index curve, and to obtain the historical process capability index curve of the printed circuit board equipment within the historical time period corresponding to the preset time period.

[0034] An anomaly detection module is used to compare the real-time process capability index curve with the historical process capability index curve to obtain a comparison result, and to determine whether the printed circuit board equipment is abnormal based on the comparison result.

[0035] The instruction generation module is used to calculate the abnormality level based on the comparison result if the printed circuit board equipment is abnormal, and to generate control instructions for controlling the printed circuit board equipment to perform corresponding actions based on the abnormality level.

[0036] Thirdly, the present invention provides a quality control system for printed circuit boards, including a programmable logic controller (PLC). The PLC includes a processor, a memory, and a controller program stored in the memory and executable on the processor. When the processor executes the controller program, it implements the quality control method for printed circuit boards as described in the first aspect.

[0037] The above solution has the following beneficial effects:

[0038] The present invention discloses a method, apparatus, and system for quality control of printed circuit boards (PCBs). This method acquires sensor data from PCB equipment, monitors the process capability index of the PCB equipment in real time based on the sensor data, determines the abnormality level of the process capability index when an abnormality occurs, and generates control commands to control the PCB equipment to perform corresponding actions based on the abnormality level. This method effectively avoids the problems of PCB defects and increased PCB production costs caused by abnormal process capability indices. Attached Figure Description

[0039] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments of the present invention will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0040] Figure 1 This is a flowchart of a quality control method for printed circuit boards provided in one embodiment of the present invention;

[0041] Figure 2 This is a schematic diagram of a switch sensor setting provided in one embodiment of the present invention;

[0042] Figure 3 This is a schematic diagram of an anomaly level control framework provided in one embodiment of the present invention;

[0043] Figure 4 This is a schematic diagram of a quality control device for a printed circuit board provided in one embodiment of the present invention; Detailed Implementation

[0044] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are some embodiments of the present invention, but not all embodiments.

[0045] It should be understood that the embodiments described below represent essential information to enable those skilled in the art to implement the embodiments and to illustrate the best mode of implementation. Upon reading the following description in conjunction with the accompanying drawings, those skilled in the art will understand the concepts of this disclosure and recognize the applications of these concepts not specifically mentioned herein. It should be understood that these concepts and applications fall within the scope of this disclosure and the appended claims.

[0046] It should also be understood that although the terms first, second, etc., may be used herein to describe various elements, these elements should not be limited by these terms. These terms are used only to distinguish one element from another. For example, a first element may be referred to as a second element, and similarly, a second element may be referred to as a first element, without departing from the scope of this disclosure. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0047] It should also be understood that when a component is referred to as "connected" or "coupled" to another component, it can be directly connected or coupled to the other component, or there may be intermediate components. Conversely, when an element is referred to as "directly connected" or "directly coupled" to another element, there are no intermediate components.

[0048] It should also be understood that the terms “upper,” “lower,” “left,” “right,” “front,” “back,” “bottom,” “middle,” “center,” “top,” etc., may be used herein to describe various elements, indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings. They are used only for the convenience of describing the invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, these elements should not be limited by these terms.

[0049] These terms are used only to distinguish one element from another. For example, a first element may be referred to as the “upper” element, and similarly, a second element may be referred to as the “upper” element depending on the relative orientation of these elements, without departing from the scope of this disclosure.

[0050] To be further understood, the terms “comprising,” “including,” “including,” and / or “include” as used herein specify the presence of the said feature, integer, step, operation, element, and / or component, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof.

[0051] Unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure pertains. It will be further understood that the terms used herein should be interpreted as having the same meaning as they mean in the context of this specification and related art, and will not be interpreted in an idealized or overly formal sense unless expressly defined herein.

[0052] In one embodiment, a method such as Figure 1 A quality control method for printed circuit boards is shown, the method comprising:

[0053] Step S100: Obtain the data collected by each sensor of the printed circuit board equipment at each time point within a preset time period. For any given time point, calculate the process capability index of the printed circuit board equipment at that time point based on the collected data.

[0054] In this embodiment, two types of sensors are installed on the printed circuit board equipment: one is a switching sensor, which detects two states, 0 and 1, to achieve a counting function; the other is a digital sensor, which converts analog signals into digital signals for output. The process capability index of the printed circuit board equipment needs to be calculated for both types of sensors separately. The fault diagnosis method for the switching sensor includes the following steps:

[0055] Step S101: Obtain the current count value of the switch sensor of the printed circuit board equipment within a preset time period.

[0056] See Figure 2 A switch quantity sensor A and a switch quantity sensor B are respectively set at preset distances above the conveyor belt of the printed circuit board equipment. The current count value of the switch quantity sensor can be collected by a data acquisition module, such as a programmable logic controller (PLC).

[0057] Step S102: Calculate the standard count value of the switch sensor within a preset time period based on the speed at which the printed circuit board is conveyed by the printed circuit board equipment.

[0058] Based on the parameters of the printed circuit board equipment, the speed at which the printed circuit board equipment conveys products can be obtained, thereby obtaining the theoretical standard count value of the switching transistor sensor within a preset time period; in this embodiment, for the switching quantity sensor, its counting method can be either an accumulation method or a subtraction method, both of which can realize the counting function.

[0059] Step S103: Calculate the absolute value of the difference between the current count value and the standard count value. If the absolute value of the difference is greater than the preset error threshold of the switch sensor, determine that the switch sensor is abnormal.

[0060] First, set the error threshold of the switch sensor in the control program of the printed circuit board equipment. Then, calculate the difference between the current count value of the switch sensor and the theoretical standard count value. Then, take the absolute value of the difference and compare it with the set error threshold of the switch sensor. If the absolute value of the difference is greater than the error threshold of the switch sensor, it means that the counting deviation of the switch sensor is large and the switch sensor has failed.

[0061] If a digital sensor malfunctions, a corresponding control command is generated to control the printed circuit board equipment to perform the corresponding action; for example, triggering, locking, or pausing the action.

[0062] In this embodiment, the calculation of the process capability index of the printed circuit board equipment for digital sensors includes the following steps:

[0063] Step S1001: Obtain the first acquisition data of the digital sensor of the printed circuit board equipment, and store the N first acquisition data acquired at the last N times in the order of acquisition time into a register of length N, where N is an integer greater than 1.

[0064] In this embodiment, a register of fixed length is set to store the first data collected at each moment. For example, the length of the register is set to 32, and the last 32 sets of first data collected are stored in the register. The data is stored in the order of collection of the first data. The first data collected in the 32 sets is placed in the 32nd bit of the register, and the last set of first data collected is placed in the 1st bit of the register.

[0065] Step S1002: Store the newly acquired first data into the first data bit of the register, shift all the original data backward, and overflow the last data bit of the register.

[0066] In step S1001, the collected first data has been stored in each data bit of the memory. If new first data is collected, the previously stored first data is shifted sequentially to the right, and the last bit of data in the memory overflows. At this time, the first data bit of the memory is empty, and the newly collected first data is stored in the first data bit of the memory. This storage method can keep the stored first data always the latest data, improve the real-time performance of data acquisition, and thus improve the accuracy of calculating the process capability index of the printed circuit board equipment.

[0067] Step S1003: Calculate the process capability index of the printed circuit board equipment based on the first acquired data in the register.

[0068] In this embodiment, the process capability index of the printed circuit board equipment is calculated using the following method:

[0069] Set the upper and lower limits of the quality characteristics of the printed circuit board. Based on the set upper and lower limits, calculate the specification tolerance using the formula T = USL - LSL. Calculate the specification center value using the formula U = (USL - LSL) / 2, where T is the specification tolerance, USL is the upper limit, LSL is the lower limit, and U is the specification center value.

[0070] Based on the first data stored in the register, the standard deviation of the sampled data is automatically calculated using the "STDEV" function according to the sample standard deviation calculation formula, and the average value of the first data in the register is also calculated. The process accuracy is calculated according to the formula Ca=(XU) / (T / 2), where Ca is the process accuracy and X is the average value. The process precision is calculated according to the formula Cp=T / 6σ, where Cp is the process precision and σ is the standard deviation. Finally, the process capability index is calculated according to the formula CPK=Cp(1-|Ca|), where CPK is the process capability index.

[0071] Step S200: Connect the process capability indices at all time points to form a real-time process capability index curve, and obtain the historical process capability index curve of the printed circuit board equipment within the historical time period corresponding to the preset time period.

[0072] The above steps allow for the calculation of the process capability index at each time point by collecting data from the digital sensor. By connecting the process capability indices at each time point within a preset time period in a coordinate system, the real-time process capability index curve of the printed circuit board can be obtained.

[0073] For printed circuit board equipment, during normal operation, the process capability index of the normal operation is recorded. The historical process capability of the printed circuit board equipment within a preset time period is obtained and connected in the same coordinate system to obtain the historical process capability index curve of the printed circuit board equipment.

[0074] Step S300: Compare the real-time process capability index curve with the historical process capability index curve to obtain the comparison result. Based on the comparison result, determine whether the printed circuit board equipment is abnormal.

[0075] Place the real-time process capability index curve obtained in the above steps and the historical process capability index curve in the same coordinate system, and calculate the deviation between the real-time process capability index curve and the historical process capability index curve. When calculating the deviation, the minimum deviation and the maximum deviation between the real-time process capability index curve and the historical process capability index curve can be calculated. Then, the average of the maximum and minimum deviation values ​​is calculated to obtain the deviation between the real-time process capability index curve and the historical process capability index curve. If the deviation value is greater than the preset process capability index curve deviation threshold, the process capability index of the printed circuit board equipment is judged to be abnormal.

[0076] Step S400: If the printed circuit board equipment is abnormal, calculate the abnormality level based on the comparison results, and generate control instructions for controlling the printed circuit board equipment to perform corresponding actions based on the abnormality level.

[0077] In this embodiment, if the process capability index of the printed circuit board equipment is abnormal, the abnormality level of the equipment is calculated based on the deviation between the real-time process capability index curve and the historical process capability index curve. Figure 3 As shown, management intervention and process intervention are performed on the printed circuit board equipment according to the anomaly level, and the triggering, locking, pausing and unlocking of the control-related system functions are executed.

[0078] The management intervention settings have three levels of functions: automatic triggering of nonconforming orders, automatic locking of the first piece, and automatic locking of the product, which are triggered in the quality management system (QMS) for management.

[0079] Based on the quality impact level, the process intervention automatically suspends relevant systems in on-site production, such as machine planning systems, production logistics systems, and supervisory control and data acquisition and control systems (SCDAD), respectively suspending on-site machine planning and scheduling, product logistics transportation, and equipment material feeding; when the process capability index of the equipment is normal, or after manual unlocking, each system resumes operation.

[0080] The quality control method for printed circuit boards in this embodiment has the following characteristics:

[0081] (1) By conducting real-time detection of the process capability index of the printed circuit board equipment, the manual periodic inspection is eliminated, avoiding the problems of unqualified circuit boards and increased circuit board production costs caused by abnormal process capability index.

[0082] (2) Classify the process capability index of printed circuit board equipment into abnormal levels, and carry out hierarchical management according to the abnormal level, conduct management intervention and process intervention, and execute the triggering, locking, pausing and unlocking of control related system functions to improve the accuracy and pertinence of management;

[0083] (3) Real-time detection of the switching sensors of the printed circuit board equipment can improve the counting accuracy and avoid abnormalities in the printed circuit board equipment caused by the failure of the switching sensors.

[0084] In one embodiment, a method such as Figure 4 The quality control device for the printed circuit board shown includes:

[0085] The index calculation module 41 is used to acquire the data collected by each sensor of the printed circuit board equipment at each time point within a preset time period, and to calculate the process capability index of the printed circuit board equipment at any time point based on the data collected at that time point.

[0086] The curve plotting module 42 is used to connect the process capability indices at all time points to form a real-time process capability index curve, and to obtain the historical process capability index curve of the printed circuit board equipment within the historical time period corresponding to the preset time period.

[0087] The anomaly detection module 43 is used to compare the real-time process capability index curve with the historical process capability index curve to obtain a comparison result, and to determine whether the printed circuit board equipment is abnormal based on the comparison result.

[0088] The instruction generation module 44 is used to calculate the abnormality level based on the comparison result if the printed circuit board equipment is abnormal, and generate control instructions for controlling the printed circuit board equipment to perform corresponding actions based on the abnormality level.

[0089] Optionally, the above-mentioned index calculation module 41 includes:

[0090] The counting value acquisition unit is used to acquire the current counting value of the switch sensor of the printed circuit board equipment within a preset time period.

[0091] The counting unit is used to calculate the standard count value of the switch sensor within a preset time period based on the speed at which the printed circuit board is conveyed by the printed circuit board equipment.

[0092] The anomaly detection unit is used to calculate the absolute value of the difference between the current count value and the standard count value. If the absolute value of the difference is greater than the preset error threshold of the switch sensor, the switch sensor is judged to be abnormal.

[0093] Optionally, the index calculation module 41 mentioned above also includes:

[0094] The data storage unit is used to acquire the first data collected by the digital sensor of the printed circuit board equipment. The N first data collected at the last N times are stored in a register of length N in chronological order of acquisition time, where N is an integer greater than 1.

[0095] The data shifting unit is used to store the newly acquired first data into the first data bit of the register, shift all the original data backward, and overflow the last bit of the register.

[0096] The first calculation unit is used to calculate the process capability index of the printed circuit board equipment based on the first acquired data in the register.

[0097] Optionally, the index calculation module 41 mentioned above also includes:

[0098] The limit setting unit is used to set the upper and lower limits of the circuit board quality characteristics, and calculates the specification tolerance and specification center value based on the upper and lower limits.

[0099] The second calculation unit is used to obtain the operating status of the printed circuit board equipment. If the operating status of the printed circuit board equipment is running, it calculates the standard deviation and average value of the first data based on the first acquired data in the register.

[0100] The third calculation unit is used to calculate the process capability index based on specification tolerances, specification center values, standard deviations, and average values.

[0101] Optionally, the index calculation module 41 mentioned above also includes:

[0102] The specification tolerance calculation unit is used to calculate the difference between the upper limit and lower limit of the specification to obtain the specification tolerance; and to calculate the ratio of the specification tolerance to 2 to obtain the specification center value.

[0103] Optionally, the index calculation module 41 mentioned above also includes:

[0104] The process accuracy calculation unit is used to calculate the first difference between the average value and the specification center value, and the first ratio of the specification tolerance to 2, and to calculate the ratio of the first difference to the first ratio to obtain the process accuracy.

[0105] The process precision calculation unit is used to calculate the ratio of the specification tolerance to 6 times the standard deviation to obtain the process precision.

[0106] The fourth calculation unit is used to calculate the second difference between 1 and the absolute value of process accuracy, and to calculate the product of process precision and the second difference to obtain the process capability index.

[0107] Optionally, the above-mentioned anomaly detection module 43 includes:

[0108] The anomaly detection unit is used to place the real-time process capability index curve and the historical process capability index curve in the same coordinate system, calculate the deviation value between the real-time process capability index curve and the historical process capability index curve, and determine that the process capability index of the printed circuit board equipment is abnormal if the deviation value is greater than the preset process capability index curve deviation threshold.

[0109] In one embodiment, a quality control system for printed circuit boards is provided, including a programmable logic controller (PLC). The PLC includes a processor, a memory, and a controller program stored in the memory and executable on the processor. When the processor executes the controller program, it implements the quality control method for printed circuit boards as described in the above embodiment.

[0110] The above-described embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be included within the protection scope of the present invention.

Claims

1. A quality control method for printed circuit boards, characterized in that, include: Acquire the data collected by each sensor of the printed circuit board equipment at each time point within a preset time period. For any time point, calculate the process capability index of the printed circuit board equipment at the time point based on the data collected at the time point. This includes: acquiring the first data collected by the digital sensors of the printed circuit board equipment, and storing the N first data collected at the last N times in the order of acquisition time into a register of length N, where N is an integer greater than 1. The first data acquired again is stored in the first data bit of the register, and all the original data is shifted backward, overflowing the last data bit of the register; The process capability index of the printed circuit board equipment is calculated based on the first collected data in the register. The process capability index of the printed circuit board equipment is calculated based on the first acquired data in the register, including: Set upper and lower limits for the quality characteristics of the circuit board, and calculate the specification tolerance and specification center value based on the upper and lower limits. The operating status of the printed circuit board equipment is obtained. If the operating status of the printed circuit board equipment is "running", the standard deviation and average value of the first data are calculated based on the first collected data in the register. The process capability index is calculated based on the specification tolerance, the specification center value, the standard deviation, and the average value. The process capability index is calculated based on the specification tolerance, the specification center value, the standard deviation, and the average value, including: Calculate the first difference between the average value and the specification center value, and the first ratio of the specification tolerance to 2. Calculate the ratio of the first difference to the first ratio to obtain the process accuracy. The process precision is obtained by calculating the ratio of the specified tolerance to 6 times the standard deviation. Calculate the second difference between 1 and the absolute value of the process accuracy, and calculate the product of the process precision and the second difference to obtain the process capability index; Connect the process capability indices at all time points to form a real-time process capability index curve, and obtain the historical process capability index curve of the printed circuit board equipment within the historical time period corresponding to the preset time period. The real-time process capability index curve is compared with the historical process capability index curve to obtain a comparison result. Based on the comparison result, it is determined whether the printed circuit board equipment is abnormal. If the printed circuit board equipment malfunctions, the malfunction level is calculated based on the comparison result, and control instructions for controlling the printed circuit board equipment to perform corresponding actions are generated based on the malfunction level.

2. The quality control method for printed circuit boards according to claim 1, characterized in that, The quality control method for the printed circuit board also includes: Obtain the current count value of the switch sensor of the printed circuit board equipment within a preset time period; Calculate the standard count value of the switch sensor within the preset time period based on the speed at which the printed circuit board equipment conveys the circuit board. Calculate the absolute value of the difference between the current count value and the standard count value. If the absolute value of the difference is greater than the preset error threshold of the switch sensor, determine that the switch sensor is abnormal.

3. The quality control method for printed circuit boards according to claim 1, characterized in that, The specification tolerance and specification center value are calculated based on the upper and lower specification limits, including: Calculate the difference between the upper limit of the specification and the lower limit of the specification to obtain the specification tolerance; calculate the ratio of the specification tolerance to 2 to obtain the specification center value.

4. The quality control method for printed circuit boards according to claim 1, characterized in that, Calculate the standard deviation of the first data according to the sample standard deviation formula.

5. The quality control method for printed circuit boards according to claim 1, characterized in that, The real-time process capability index curve is compared with the historical process capability index curve to obtain a comparison result. Based on the comparison result, it is determined whether the printed circuit board equipment is abnormal, including: Place the real-time process capability index curve and the historical process capability index curve in the same coordinate system, calculate the deviation between the real-time process capability index curve and the historical process capability index curve, and if the deviation is greater than the preset process capability index curve deviation threshold, then determine that the process capability index of the printed circuit board equipment is abnormal.

6. A quality control device for printed circuit boards, characterized in that, include: The index calculation module is used to acquire the data collected by each sensor of the printed circuit board equipment at each time point within a preset time period. For any time point, based on the data collected at the time point, the process capability index of the printed circuit board equipment at the time point is calculated. The calculation includes: acquiring the first data collected by the digital sensors of the printed circuit board equipment, and storing the N first data collected at the last N time points in a register of length N in the order of acquisition time, where N is an integer greater than 1. The first data acquired again is stored in the first data bit of the register, and all the original data is shifted backward, overflowing the last data bit of the register; The process capability index of the printed circuit board equipment is calculated based on the first collected data in the register. The process capability index of the printed circuit board equipment is calculated based on the first acquired data in the register, including: Set upper and lower limits for the quality characteristics of the circuit board, and calculate the specification tolerance and specification center value based on the upper and lower limits. The operating status of the printed circuit board equipment is obtained. If the operating status of the printed circuit board equipment is "running", the standard deviation and average value of the first data are calculated based on the first collected data in the register. The process capability index is calculated based on the specification tolerance, the specification center value, the standard deviation, and the average value. The process capability index is calculated based on the specification tolerance, the specification center value, the standard deviation, and the average value, including: Calculate the first difference between the average value and the specification center value, and the first ratio of the specification tolerance to 2. Calculate the ratio of the first difference to the first ratio to obtain the process accuracy. The process precision is obtained by calculating the ratio of the specified tolerance to 6 times the standard deviation. Calculate the second difference between 1 and the absolute value of the process accuracy, and calculate the product of the process precision and the second difference to obtain the process capability index; The curve plotting module is used to connect the process capability indices at all time points to form a real-time process capability index curve, and to obtain the historical process capability index curve of the printed circuit board equipment within the historical time period corresponding to the preset time period. An anomaly detection module is used to compare the real-time process capability index curve with the historical process capability index curve to obtain a comparison result, and to determine whether the printed circuit board equipment is abnormal based on the comparison result. The instruction generation module is used to calculate the abnormality level based on the comparison result if the printed circuit board equipment is abnormal, and to generate control instructions for controlling the printed circuit board equipment to perform corresponding actions based on the abnormality level.

7. A quality control system for printed circuit boards, characterized in that, The system includes a programmable logic controller (PLC), which includes a processor, a memory, and a controller program stored in the memory and executable on the processor. When the processor executes the controller program, it implements the quality control method for printed circuit boards as described in any one of claims 1 to 5.

Images