Symmetrical compensation precision grinding equipment and method for ceramic wedge knife tip bottleneck

Abstract

This invention discloses a symmetrical compensation precision grinding device and method for the bottleneck of a ceramic chopping tool tip. The grinding device includes a bed, a workpiece spindle system, a first grinding unit, a second grinding unit, a radial runout measurement system, and a control system. The workpiece spindle system is mounted on the bed and is used to clamp the ceramic chopping tool workpiece and drive it to rotate around its axis of rotation. The first and second grinding units are arranged symmetrically about the axis of rotation of the workpiece spindle system, with the grinding ends of both units facing the bottleneck area to be processed on the workpiece tip. The beneficial effects of this invention are: through the symmetrical arrangement of the dual grinding wheels and phase compensation based on runout, the inherent error caused by workpiece runout during unilateral grinding is actively offset, theoretically reducing concentricity error by more than 70% and achieving sub-micron level concentricity machining.

Description

Technical Field

[0001] This invention relates to the field of precision machining technology, specifically to a precision grinding device and method for symmetrical compensation of the bottleneck at the tip of a ceramic chopping tool. Background Technology

[0002] Ceramic cleavers are critical tools in semiconductor packaging, fiber optic coupling, and other fields. The dimensional accuracy (especially concentricity) of their tip bottleneck section directly affects performance and lifespan. Currently, machining this part mainly relies on high-precision cylindrical grinding machines. Traditional processes use a single grinding wheel to grind a rotating workpiece. However, due to unavoidable residual radial runout after workpiece clamping, during unilateral grinding, the actual center of rotation of the workpiece deviates from the theoretical center of rotation, resulting in uneven grinding depth along the circumferential direction. After one revolution, the machined bottleneck section is asymmetrically elliptical with poor concentricity (typically greater than 3μm), severely affecting product quality.

[0003] In existing technologies, to improve roundness, methods such as improving spindle accuracy, multiple fine dressing of the grinding wheel, or reducing the single feed rate are usually adopted. However, traditional single grinding wheels cannot solve the causal chain of runout → ellipticity → concentricity difference, and cannot fundamentally eliminate the asymmetric grinding problem caused by the runout of the workpiece itself. There is a contradiction between processing efficiency and accuracy.

[0004] Therefore, in order to address the above-mentioned technical problems, it is necessary to provide a precision grinding device and method for symmetrical compensation of the bottleneck at the tip of a ceramic chopping tool. Summary of the Invention

[0005] In view of the shortcomings of the prior art, the purpose of this invention is to provide a precision grinding device and method for symmetrical compensation of the bottleneck at the tip of a ceramic chopping tool, so as to solve the problems mentioned in the background art.

[0006] To solve the above-mentioned technical problems, the present invention adopts the following technical solution: This invention provides a precision grinding device for symmetrical compensation of the bottleneck at the tip of a ceramic chopping tool, comprising a bed, a workpiece spindle system, a first grinding unit, a second grinding unit, a radial runout measurement system, and a control system, wherein... The workpiece spindle system is mounted on the bed and is used to clamp the ceramic chopping tool workpiece and drive the workpiece to rotate around the axis of rotation. The first grinding unit and the second grinding unit are arranged symmetrically about the rotation axis of the workpiece spindle system. The grinding ends of the first grinding unit and the second grinding unit are directly facing the bottleneck part of the workpiece tip. The first grinding unit and the second grinding unit both include a grinding wheel spindle and a precision feed axis that drives the grinding wheel spindle to make linear feed motion along the radial direction of the workpiece. The radial runout measurement system is used to collect the radial runout and corresponding rotation phase angle data of the tip bottleneck section during the workpiece rotation process in real time. The control system is electrically connected to the workpiece spindle system, the first grinding unit, the second grinding unit, and the radial runout measurement system. Based on the real-time radial runout and phase angle data collected by the radial runout measurement system, the control system synchronously and differentially controls the movement of the precision feed axes of the first and second grinding units, dynamically adjusts the grinding feed depth of the grinding wheels on both sides, so that the material removal on the left and right sides of the workpiece compensates for each other under any rotation phase angle, and cancels the asymmetric grinding error caused by the radial runout of the workpiece.

[0007] In one or more embodiments of the present invention, the workpiece spindle system is a high-precision air-bearing spindle or a hydrostatic spindle.

[0008] In one or more embodiments of the present invention, the precision feed axes of the first grinding unit and the second grinding unit are driven by linear motors.

[0009] In one or more embodiments of the present invention, the radial runout measurement system includes at least one non-contact displacement sensor, which is a laser displacement sensor or a capacitive displacement sensor.

[0010] In one or more embodiments of the present invention, the grinding equipment further includes an online measuring device for real-time monitoring of the workpiece machining dimensions. The online measuring device is connected to the control system and is used to detect the bottleneck outer diameter of the workpiece in real time and feed it back to the control system to form a closed-loop control of the machining dimensions.

[0011] A precision grinding method for symmetrical compensation of the bottleneck at the tip of a ceramic chopping tool includes the following steps: S1: Clamp the workpiece and drive it to rotate, and obtain complete radial runout data of the workpiece through the radial runout measurement system; S2: Start the grinding wheel spindles of the first and second grinding units, control the feed axes of the first and second grinding units to feed synchronously with the same basic feed amount, and then superimpose the differentiated dynamic compensation amount. At the same time, based on the runout data obtained in S1 and the real-time rotation phase angle of the workpiece, calculate the dynamic compensation amount of the feed axes of the first and second grinding units, and superimpose it into the control command to grind the workpiece. S3: During the grinding process, the workpiece dimensions are fed back in real time, and closed-loop control is performed until the target dimensions are achieved.

[0012] In one or more embodiments of the present invention, in step S2, the calculation basis of the dynamic compensation amount is: to keep the sum of the theoretical grinding depths on both sides of the workpiece constant at any phase angle.

[0013] In one or more embodiments of the present invention, in step S2, the grinding process includes a rough grinding stage, a fine grinding stage, and a finishing stage; the dynamic compensation is applied in both the rough grinding stage and the fine grinding stage.

[0014] In one or more embodiments of the present invention, when the control system performs dynamic compensation, it applies the workpiece at any rotation phase angle. The radial runout at this phase is Then the feed compensation amount of the first grinding unit is:

[0015] The feed compensation for the second grinding unit is:

[0016] in, This is the grinding depth compensation coefficient, used to adjust the compensation intensity, and its value range is 0 < k ≤ 1.

[0017] In one or more embodiments of the present invention, in step S1, after acquiring the radial runout data, a radial runout error model of the workpiece is also established, and in step S2, feedforward compensation is performed based on the error model and the real-time phase angle.

[0018] The beneficial effects of this invention are as follows: 1. By using a symmetrical dual-grinding wheel layout and phase compensation based on runout, the inherent error caused by workpiece runout during unilateral grinding is actively offset, which theoretically reduces concentricity error by more than 70%, achieving submicron level concentricity machining. 2. Under the same accuracy requirements, the stringent requirements for workpiece clamping accuracy can be relaxed, reducing setup and adjustment time. Compensation grinding allows for a larger feed rate in the rough grinding stage, while intelligent compensation ensures accuracy in the fine grinding stage, thus improving the overall process stability. 3. It integrates closed-loop control of measurement, modeling and compensation, realizing the leap from passive processing to active correction, and has the flexible processing capability to adapt to different runout error modes; 4. It can achieve high precision under normal clamping accuracy, reducing the stringent requirements on tooling and environment. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art 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.

[0020] Figure 1This is a schematic diagram of the structure of a precision grinding device for symmetrical compensation of the bottleneck at the tip of a ceramic chopping tool, according to an embodiment of the present invention. Figure 2 This invention relates to the logic control of a precision grinding method for symmetrical compensation of the bottleneck at the tip of a ceramic chopping tool, as described in one embodiment of the present invention. Figure 1 ; Figure 3 This invention relates to the logic control of a precision grinding method for symmetrical compensation of the bottleneck at the tip of a ceramic chopping tool, as described in one embodiment of the present invention. Figure 2 ; Figure 4 This invention relates to the logic control of a precision grinding method for symmetrical compensation of the bottleneck at the tip of a ceramic chopping tool, as described in one embodiment of the present invention. Figure 3 .

[0021] Explanation of reference numerals in the attached figures: 1. Bed; 2. Workpiece spindle system; 3. First grinding unit; 4. Second grinding unit. Detailed Implementation

[0022] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0023] Example 1: like Figure 1 As shown, a symmetrical compensation precision grinding device for the bottleneck of the tip of a ceramic chopping tool according to one embodiment of the present invention includes a bed 1, a workpiece spindle system 2, a first grinding unit 3, a second grinding unit 4, a radial runout measurement system, and a control system.

[0024] Specifically, the bed 1, as the core support base, adopts a marble bed, which has the characteristics of high damping, small thermal deformation and stable rigidity. An air damping pad is installed at the bottom of the table, which can effectively filter the micro-vibration of the workshop floor, provide a stable processing environment for ultra-precision grinding, and completely eliminate the interference of external vibration on the processing accuracy.

[0025] The workpiece spindle system 2 is fixedly installed at the center of the table of the marble bed 1. It adopts an imported ultra-precision air-bearing spindle with a radial runout error of ≤0.1μm and a rotational accuracy of submicron level. It supports low-speed and medium-high-speed dual-mode speed adjustment with an adjustable speed range of 2000-8000rpm, which can adapt to the grinding needs of ceramic wedges of different specifications. The front end of the spindle is equipped with a special elastic chuck, which uses a stress-free clamping method to hold the ceramic wedge workpiece 6, avoiding workpiece deformation caused by excessive clamping force and eliminating secondary processing errors caused by clamping stress.

[0026] The first grinding unit 3 and the second grinding unit 4 are arranged in a mirror-symmetrical configuration with the rotation axis of the workpiece spindle system 2 as the axis of symmetry. The two grinding units have completely identical structures and performance, ensuring the uniformity of grinding force on both sides. Each grinding unit is equipped with a high-frequency electric spindle grinding wheel with a maximum speed of 60,000 rpm, suitable for ultra-precision grinding of hard and brittle ceramic materials such as zirconia and alumina. The grinding wheel is a special diamond grinding wheel, and the abrasive grain size and bonding agent are optimized according to the ceramic cleaver material to balance grinding efficiency and surface quality.

[0027] The precision radial feed axes of the first grinding unit 3 and the second grinding unit 4 both adopt a linear motor direct drive structure, eliminating the backlash and motion lag problems of traditional ball screw drives. They are equipped with high-precision grating rulers to achieve full-stroke closed-loop feedback. The feed axis positioning resolution reaches 0.01μm, the repeatability is ≤±0.1μm, and the feed response time is ≤8ms. It can follow the workpiece rotation phase to achieve millisecond-level dynamic feed adjustment, ensuring the real-time performance and accuracy of dynamic compensation and avoiding machining errors caused by compensation lag.

[0028] The radial runout measurement system uses a laser displacement sensor 5, which is fixed on the bed 1 by an adjustable bracket. The sensor probe beam is vertically aligned with the processing area of ​​the bottleneck at the tip of the workpiece 6. The sampling frequency is set to 20kHz, which can capture the radial runout data of each rotation phase angle of the workpiece in real time. The displacement detection accuracy reaches 0.03μm. The entire process adopts non-contact detection, which will not scratch the surface of the workpiece or affect the normal rotation of the workpiece.

[0029] The online dimension monitoring device uses a high-precision contact probe 7, which is placed on the side of the grinding area to reasonably avoid the movement trajectory of the grinding wheel and avoid interfering with the grinding operation. The probe can accurately contact the outer diameter of the workpiece bottleneck and collect the machining dimension data in real time. The dimension detection accuracy is ≤0.08μm. It also has an initial tool setting function. The initial tool setting between the grinding wheel and the workpiece is completed by positioning the probe, eliminating the error of manual tool setting.

[0030] The control system employs an industrial-grade CNC system, incorporating three core algorithm modules: error modeling, dynamic compensation, and dimensional closed-loop control. Coupled with a touch-screen human-machine interface, it allows for intuitive setting of grinding parameters, retrieval of real-time fluctuation data, and monitoring of compensation amounts and machining dimensions, achieving intelligent control throughout the entire process from error acquisition and model building to dynamic compensation and dimensional correction. The control system dynamically and differentially controls the feed axis movements of the first grinding unit 3 and the second grinding unit 4, thereby achieving mutual compensation of the grinding effects on both sides of the workpiece at any phase angle of workpiece rotation.

[0031] Example 2: This embodiment describes in detail a method for machining the bottleneck of a ceramic chopping tool tip using the aforementioned equipment. The core of this method lies in actively compensating for and eliminating asymmetric grinding errors caused by workpiece runout. Specifically, it includes the following steps: S1: First, clamp the ceramic chopping tool workpiece 6 onto the workpiece spindle system 2 and drive it to rotate smoothly at a low speed (e.g., 60-120 rpm). Activate the laser displacement sensor 5 to perform a full-cycle scan measurement of the radial runout at the bottleneck of the workpiece. The control system collects data at different phase angles within one complete rotation cycle. radial runout at the location Furthermore, a precise radial runout error model is established using harmonic analysis or interpolation algorithms. This model describes the deviation distribution of the actual outer surface of the workpiece relative to the theoretical center of rotation.

[0032] S2: Start the grinding wheel spindles of the first grinding unit 3 and the second grinding unit 4 to the working speed. The control system sends motion commands to the precision feed axes of the first grinding unit (3) and the second grinding unit (4). The command consists of two parts: one part is the preset basic feed amount, which is used to achieve a fixed ratio of material removal; the other part is the dynamic compensation amount based on the runout data and the real-time phase angle.

[0033] The core of its control strategy lies in ensuring that the sum of the theoretical grinding depths on both sides of the workpiece remains constant at any phase angle. To achieve this, this embodiment employs the following compensation algorithm: The control system determines the phase angle of the workpiece. bounce at point The compensation amount for controlling the feed axis of the first grinding unit 3 is:

[0034] Simultaneously, the compensation amount of the feed axis of the second grinding unit 4 is controlled as follows:

[0035] in, The compensation coefficient is between 0 and 1. Its value can be adjusted according to the grinding stage (rough grinding, fine grinding). For example, a smaller value (such as 0.5) is taken in the rough grinding stage to maintain process stability, and a larger value (such as 0.9 or 1) is taken in the fine grinding stage to achieve optimal concentricity correction.

[0036] When a point on the workpiece "protrudes" due to vibration (i.e.) (For positive), the feed rate of the grinding wheel in the first grinding unit 3 is increased to perform intensified grinding on the protrusion; at the same time, on the other side, which is 180° out of phase with the point, due to If the value is negative (i.e., "dent"), the feed rate of the grinding wheel in the second grinding unit 4 will be reduced accordingly to avoid over-grinding. As the workpiece rotates, the grinding wheels on both sides are continuously and dynamically adjusted according to the real-time phase, ultimately achieving uniform removal of material along the circumferential direction.

[0037] S3: Closed-loop size control Throughout the grinding process, especially in the fine grinding stage, an online measuring device is activated to monitor the bottleneck diameter of the workpiece in real time. The control system compares the measured value with the target size. When a size deviation is detected, the basic feed amount of the feed axes of the first grinding unit (3) and the second grinding unit (4) is adjusted synchronously to achieve closed-loop control of the size until the workpiece reaches the preset target size and accuracy.

[0038] The entire grinding process can be divided into rough grinding, fine grinding, and finishing stages. The aforementioned dynamic compensation is applied in both the rough grinding and fine grinding stages, while in the finishing stage, the compensation coefficient k can be reduced and the feed rate lowered to primarily obtain excellent surface quality.

[0039] Example 3: Using the aforementioned equipment and methods, a machining test was conducted on the bottleneck of a zirconia ceramic chopping tool with a diameter of 0.5 mm and a length of 2 mm. The workpiece spindle was an air-bearing spindle, and the first grinding unit 3 and the second grinding unit 4 were driven by linear motors. The grinding wheel was a resin-bonded diamond grinding wheel.

[0040] In traditional single-wheel grinding processes, due to residual runout during workpiece clamping, the concentricity of the bottleneck after machining is typically around 3-5 μm, which is insufficient to meet the requirements of high-end applications.

[0041] Using the equipment and method of this embodiment, the vibration data acquisition and modeling are first completed in approximately 1 second. Then, the compensation grinding program is initiated. After grinding, the finished product is inspected using a high-precision roundness meter. The results show that the concentricity of the processed ceramic chopping blade bottleneck is consistently below 0.8 μm, the roundness is better than 0.5 μm, and the surface roughness Ra < 0.08 μm.

[0042] This processing example demonstrates that the present invention, through a symmetrical layout of dual grinding wheels and a dynamic compensation grinding method based on phase information, fundamentally solves the problem of asymmetric grinding caused by workpiece runout, and can stably achieve sub-micron level concentricity processing, significantly improving the processing quality and consistency of the bottleneck at the tip of the ceramic wedge.

[0043] Obviously, the above-described embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. 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 or all of the technical features therein; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention also intends to include these modifications and variations.

Claims

1. A precision grinding device for symmetrical compensation of the bottleneck at the tip of a ceramic chopping tool, characterized in that, It includes a bed (1), a workpiece spindle system (2), a first grinding unit (3), a second grinding unit (4), a radial runout measurement system, and a control system; The workpiece spindle system (2) is mounted on the bed (1) and is used to clamp the ceramic chopping knife workpiece and drive the workpiece to rotate around the axis of rotation. The first grinding unit (3) and the second grinding unit (4) are arranged symmetrically with the rotation axis of the workpiece spindle system (2) as the axis of symmetry. The grinding ends of the first grinding unit (3) and the second grinding unit (4) are directly facing the bottleneck part of the workpiece tip. The first grinding unit (3) and the second grinding unit (4) both include a grinding wheel spindle and a precision feed axis that drives the grinding wheel spindle to make linear feed motion along the radial direction of the workpiece. The radial runout measurement system is used to collect the radial runout and corresponding rotation phase angle data of the tip bottleneck section during the workpiece rotation process in real time. The control system is electrically connected to the workpiece spindle system (2), the first grinding unit (3), the second grinding unit (4), and the radial runout measurement system, respectively. Based on the real-time radial runout and phase angle data collected by the radial runout measurement system, the control system synchronously and differentially adjusts the motion of the precision feed axis of the first grinding unit (3) and the second grinding unit (4), dynamically adjusts the grinding feed depth of the grinding wheels on both sides, so that the material removal amount on the left and right sides of the workpiece can compensate each other under any rotation phase angle, and offset the asymmetric grinding error caused by the radial runout of the workpiece.

2. The precision grinding equipment for symmetrical compensation of the bottleneck at the tip of a ceramic chopping tool as described in claim 1, characterized in that, The workpiece spindle system (2) is an air-bearing spindle or a hydrostatic spindle.

3. The precision grinding equipment for symmetrical compensation of the bottleneck at the tip of a ceramic chopping tool as described in claim 1, characterized in that, The precision feed axes of the first grinding unit (3) and the second grinding unit (4) are driven by linear motors.

4. The precision grinding equipment for symmetrical compensation of the bottleneck at the tip of a ceramic chopping tool as described in claim 1, characterized in that, The radial runout measurement system includes at least one non-contact displacement sensor, which is either a laser displacement sensor or a capacitive displacement sensor.

5. The precision grinding equipment for symmetrical compensation of the bottleneck at the tip of a ceramic chopping tool as described in claim 1, characterized in that, The grinding equipment also includes an online measuring device for real-time monitoring of the workpiece machining dimensions. The online measuring device is connected to the control system and is used to detect the outer diameter of the workpiece bottleneck in real time and feed it back to the control system to form a closed-loop control of the machining dimensions.

6. A precision grinding method for symmetrical compensation of the bottleneck at the tip of a ceramic cleaver, using the grinding equipment described in any one of claims 1-5, characterized in that, Includes the following steps: S1: Clamp the workpiece and drive it to rotate, and obtain complete radial runout data of the workpiece through the radial runout measurement system; S2: Start the grinding wheel spindles of the first grinding unit (3) and the second grinding unit (4), control the feed axes of the first grinding unit (3) and the second grinding unit (4) to feed synchronously with the same basic feed amount, and then superimpose the differentiated dynamic compensation amount. At the same time, according to the runout data obtained by S1 and the real-time rotation phase angle of the workpiece, calculate the dynamic compensation amount of the feed axes of the first grinding unit (3) and the second grinding unit (4), and superimpose it into the control command to grind the workpiece. S3: During the grinding process, the workpiece dimensions are fed back in real time, and closed-loop control is performed until the target dimensions are achieved.

7. The symmetrical compensation precision grinding method for the bottleneck of the tip of a ceramic chopping tool as described in claim 6, characterized in that, In step S2, the calculation of the dynamic compensation amount is based on the principle that the sum of the theoretical grinding depths on both sides of the workpiece remains constant at any phase angle.

8. The symmetrical compensation precision grinding method for the bottleneck of the tip of a ceramic chopping tool as described in claim 7, characterized in that, In step S2, the grinding process includes a rough grinding stage, a fine grinding stage, and a finishing stage; the dynamic compensation is applied in both the rough grinding stage and the fine grinding stage.

9. A precision grinding method for symmetrical compensation of the bottleneck at the tip of a ceramic chopping tool as described in claim 8, characterized in that, When the control system performs dynamic compensation, it applies any rotation phase angle of the workpiece. The radial runout at this phase is Then the feed compensation amount of the first grinding unit is: The feed compensation for the second grinding unit is: ;in, This is the grinding depth compensation coefficient, used to adjust the compensation intensity, and its value range is 0 < k ≤ 1.

10. A precision grinding method for symmetrical compensation of the bottleneck at the tip of a ceramic chopping tool as described in claim 6, characterized in that, In step S1, after acquiring the radial runout data, a radial runout error model of the workpiece is also established. In step S2, feedforward compensation is performed based on the error model and the real-time phase angle.

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