Method and system for controlling a grinding / polishing machine tool

Abstract

The application discloses a control method and a control system of a grinding and polishing machine tool. The control method of the grinding and polishing machine tool comprises an initialization step, a judgment step and a processing step. The initialization step is used for specifying a processing standard to avoid a large parameter gap of a workpiece after processing. The judgment step is used for judging whether a work to be processed is processed. The processing step is used for adjusting the thickness of the workpiece. The control method and the control system of the grinding and polishing machine tool solve the problem that the prior art cannot monitor the pressing force of the main shaft in real time during the processing process and cannot adjust the pressing force of the grinding and polishing disc within a set range, so that the quality and precision of the plane grinding and polishing processing of the organic glass plate cannot be ensured.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of lapping and polishing machine tool control, in particular to a lapping and polishing machine tool control method and system. BACKGROUND

[0002] The super-large aperture organic glass lapping and polishing machine tool is a special equipment for lapping and polishing the surface of large-size organic glass. Its working principle is to add lapping slurry between the lapping and polishing disc and the organic glass fixed on the workbench, and to realize lapping and polishing of the organic glass plate by lapping and rotation of the workbench and swinging of the swing arm, so as to improve the optical quality of the whole plate, eliminate defects, and improve the thickness uniformity, so as to ensure the optical quality of the final formed transparent part. Therefore, in the lapping and polishing process, the stability of the lapping and polishing disc pressure is directly related to the flatness of the organic glass plate and the thickness uniformity of the organic glass plate.

[0003] The common lapping and polishing machine tool adopts a motor-driven screw stepping feed control mode for vertical lifting movement of the main shaft. When this mode is used in the super-large aperture lapping and polishing machine tool, in the lapping and polishing process, as the surface material of the organic glass is removed by lapping and polishing, the thickness of the workpiece becomes thinner, the lapping and polishing force of the main shaft decreases, which leads to uneven distribution of the lapping and polishing force, and further leads to larger errors in the flatness and thickness uniformity of the organic glass plane, which seriously affects the quality and precision of the lapping and polishing process of the machine tool. That is to say, the screw stepping feed control mode for vertical lifting movement of the main shaft cannot monitor the lapping and polishing force of the main shaft in real time during the process, and cannot adjust the lapping and polishing disc pressure within a set range, so as to ensure the quality and precision of the flat lapping and polishing process of the organic glass plate. SUMMARY

[0004] The main purpose of the present application is to provide a lapping and polishing machine tool control method and system to at least solve the problem that the screw stepping feed control mode for vertical lifting movement of the main shaft cannot monitor the lapping and polishing force of the main shaft in real time during the process, and cannot adjust the lapping and polishing disc pressure within a set range, so as to ensure the quality and precision of the flat lapping and polishing process of the organic glass plate.

[0005] According to one aspect of the present application, a lapping and polishing machine tool control method is provided, characterized in that it comprises:

[0006] A judging step of judging whether the thickness T of the workpiece to be processed is greater than the thickness T0 of the finished workpiece. If the thickness T of the workpiece to be processed is not greater than the thickness T0 of the finished workpiece, the processing is completed, otherwise the processing step is executed.

[0007] The processing step includes: detecting a current working current I and a current working voltage U of a spindle motor of the lapping and polishing machine tool, calculating a current pressing force N of the lapping and polishing disc according to the current working current I and the current working voltage U; judging whether the current pressing force N is within a pressing force allowable fluctuation range X; if the current pressing force N is within the pressing force allowable fluctuation range X, executing a judging step; if the current pressing force N is out of the pressing force allowable fluctuation range X, judging whether a difference between the current pressing force N and a pressing force standard value N0 is greater than zero; if the difference between the current pressing force N and the pressing force standard value N0 is greater than zero, controlling the lapping and polishing disc to move a single-cycle feed amount δ away from a worktable of the lapping and polishing machine tool, and re-executing the processing step; if the difference between the current pressing force N and the pressing force standard value N0 is less than or equal to zero, controlling the lapping and polishing disc to move the single-cycle feed amount δ towards the worktable, and executing the judging step again.

[0008] Further, the step of calculating the current pressing force N of the lapping and polishing disc includes:

[0009] calculating an output power P of the spindle motor according to the current working current I and the current working voltage U;

[0010] calculating a load torque M of the spindle of the lapping and polishing machine tool according to the output power P of the spindle motor and a rotational speed n of the spindle motor;

[0011] calculating a load force F of the spindle according to the load torque M of the spindle and a radius r of the lapping and polishing disc;

[0012] calculating the current pressing force N of the lapping and polishing disc according to a friction coefficient μ between the lapping and polishing disc and a workpiece to be processed and the load force F of the spindle.

[0013] Further, the output power P of the spindle motor is calculated by the following formula:

[0014]

[0015] wherein A represents a constant;

[0016] I represents the current working current of the spindle motor;

[0017] U represents the current working voltage of the spindle motor.

[0018] Further, the load torque M of the spindle is calculated by the following formula:

[0019]

[0020] wherein B represents a constant;

[0021] n represents the rotational speed of the spindle motor.

[0022] Further, the load force F of the spindle is calculated by the following formula:

[0023]

[0024] wherein M represents the load moment of the spindle;

[0025] r represents the radius of the polishing disc.

[0026] Further, the current pressing force N of the polishing disc is calculated by the following formula:

[0027]

[0028] wherein f represents the friction force between the polishing disc and the workpiece;

[0029] μ represents the friction coefficient between the polishing disc and the workpiece.

[0030] Further, in the machining step, the current pressing force N of the polishing disc is calculated by the following formula:

[0031]

[0032] wherein C represents a constant;

[0033] μ represents the friction coefficient between the polishing disc and the workpiece;

[0034] r represents the radius of the polishing disc;

[0035] n represents the rotating speed of the spindle motor;

[0036] I represents the current working current of the spindle motor;

[0037] U represents the current working voltage of the spindle motor.

[0038] On the other hand, the application also provides a control system of a polishing machine tool, which comprises a control module, and the control module is used for executing the control method of the polishing machine tool.

[0039] Further, the control module comprises:

[0040] a current detection element, which is respectively electrically connected with the control module and the spindle motor, and is used for detecting the current working current I of the spindle motor and transmitting the current working current I of the spindle motor to the control module;

[0041] a voltage detection element, which is respectively electrically connected with the control module and the spindle motor, and is used for detecting the current working voltage U of the spindle motor and transmitting the current working voltage U of the spindle motor to the control module;

[0042] a first signal conversion unit, the first signal conversion unit being electrically connected with the current detection element, the voltage detection element and the control module, and being configured to convert the current working current I and the current working voltage U into digital signals;

[0043] a second signal conversion unit, the second signal conversion unit being electrically connected with the control module and the lifting motor of the lapping and polishing machine tool, and being configured to convert the value of the difference between the current pressing force N and the pressing force standard value N0 into an electric signal;

[0044] a control unit, the control unit being electrically connected with the second signal conversion unit and the lifting motor, and being configured to control the lifting motor;

[0045] a data processing unit, the data processing unit being electrically connected with the first signal conversion unit and the second signal conversion unit to perform data processing.

[0046] Further, the first signal conversion unit and the second signal conversion unit both comprise an RS485 communication interface.

[0047] Compared with the prior art, the control method and system of the lapping and polishing machine tool in the present application are characterized in that the control module is electrically connected with the lapping and polishing machine tool, and the functions of the current detection element, the voltage detection element, the first signal conversion unit, the second signal conversion unit, the control unit and the data processing unit in the control module are utilized. In this way, the current pressing force of the lapping and polishing disc can be monitored in real time, and the current pressing force of the lapping and polishing disc can be adjusted and maintained within the ideal range through signal conversion, data processing and control process, so as to ensure the processing quality and precision of the lapping and polishing machine tool. BRIEF DESCRIPTION OF DRAWINGS

[0048] The accompanying drawings, which are included to provide a further understanding of the present application and constitute a part of this application, illustrate certain illustrative embodiments of the present application and together with the general description of the present application and the detailed description of the illustrative embodiments provided in the specification, serve to explain the principles of the present application. In the drawings:

[0049] Figure 1 FIG. 1 is a structural schematic diagram of the lapping and polishing machine tool disclosed in the present application;

[0050] Figure 2 FIG. 2 is a structural schematic diagram of the lapping and polishing assembly of the lapping and polishing machine tool disclosed in the present application;

[0051] Figure 3 FIG. 3 is a logic schematic diagram of the control method of the lapping and polishing machine tool disclosed in the present application;

[0052] Figure 4 FIG. 4 is a flowchart of the control method of the lapping and polishing machine tool disclosed in the present application.

[0053] Wherein, the above-mentioned drawings include the following reference signs:

[0054] 10, main shaft motor; 11, mounting seat; 12, main shaft; 13, support sleeve; 14, lifting motor; 15, lifting transmission component; 16, polishing disc; 21, current detection element; 22, voltage detection element; 23, first signal conversion unit; 24, data processing unit; 25, second signal conversion unit; 26, control unit; 30, workbench; 40, cantilever. DETAILED DESCRIPTION

[0055] It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict. The present application will be described in detail below with reference to the drawings and in combination with the embodiments.

[0056] It should be noted that the terms used herein are only for describing specific embodiments, and are not intended to limit the exemplary embodiments according to the present application. As used herein, the singular form is intended to include the plural form, unless the context clearly indicates otherwise, and it should also be understood that when the terms "comprise" and / or "include" are used in the specification, there is a presence of a feature, step, operation, device, component and / or combination thereof.

[0057] Unless specifically stated otherwise, the relative arrangements of the components and steps illustrated in these embodiments and the numerical expressions and values set forth herein are not limiting of the scope of the present application. It should be understood that the various parts of the drawings are not necessarily drawn to scale, and that, for the purpose of convenience and clarity, not all components can be shown in the drawings with precise scaling. Techniques, methods, and devices known to those of ordinary skill in the relevant art can not be discussed in detail, but rather can be assumed to be known by those of ordinary skill in the art. In all examples shown and discussed herein, any specific value should be interpreted as merely an example, and not as a limitation. Thus, other examples of the exemplary embodiments can have different values. It should be noted that like reference numerals and letters refer to like items in the following drawings, and thus, once an item is defined in one drawing, it need not be discussed further in subsequent drawings.

[0058] Referring to Figures 1 to 4 As shown, according to the embodiments of the present application, a control system of a polishing machine tool is provided. The control system of the polishing machine tool includes a polishing machine tool.

[0059] As Figure 1As shown, the polishing machine in the present application comprises a worktable 30 and a polishing mechanism. The worktable 30 is used to fix the workpiece to be processed. The polishing mechanism comprises a cantilever 40 and a polishing assembly. The cantilever 40 is arranged above the worktable 30. The polishing assembly comprises a support sleeve 13, a mounting seat 11, a spindle motor 10, a spindle 12, a lifting transmission component 15, a lifting motor 14, a polishing disc 16 and a control module (not shown in the figure). The support sleeve 13 is fixedly installed on the cantilever 40, and the axis of the support sleeve 13 is perpendicular to the worktable 30. The mounting seat 11 is supported by the lifting transmission component 15 and arranged on the top of the support sleeve 13. The mounting seat 11 is lifted along the axial direction of the support sleeve 13 under the driving of the lifting transmission component 15. The spindle motor 10 is installed on the mounting seat 11. The spindle 12 is rotatably arranged in the support sleeve 13. The top end of the spindle 12 is connected with the spindle motor 10, and the bottom end of the spindle 12 is fixedly connected with the polishing disc 16. The lifting motor 14 is arranged in the support sleeve 13 and drivingly connected with the lifting transmission component 15 to drive the mounting seat 11 to be lifted along the axial direction of the support sleeve 13. The control module is electrically connected with the spindle motor 10 and the lifting motor 14.

[0060] In the present embodiment, the polishing machine is used for polishing and grinding of the super-large-caliber organic glass. Specifically, the polishing machine comprises a driving motor, which can drive the cantilever 40 to swing above the worktable 30. At the same time, the cantilever 40 can drive the polishing assembly fixedly connected with the cantilever 40 to swing when the cantilever 40 swings. Specifically, the cantilever 40 is fixedly connected with the support sleeve 13 of the polishing assembly. The spindle motor 10 of the polishing assembly drives the spindle 12 to rotate, so as to drive the polishing disc 16 fixedly connected with the spindle 12 to rotate, thereby achieving the polishing and grinding of the organic glass. The lifting motor 14 is arranged on the support sleeve 13, and the lifting transmission component 15 is arranged on the lifting motor 14. In the present embodiment, the lifting transmission component 15 is a lifting screw. The lifting screw is connected with the lifting motor 14 and the mounting seat 11. When the lifting motor 14 works, the polishing disc 16 can be lifted or lowered through the action of the lifting screw, so as to control the grinding thickness of the workpiece to be processed.

[0061] Further, the control module comprises: a current detection element 21 and a voltage detection element 22. The current detection element 21 is electrically connected with the control module and the main shaft motor 10 respectively, and is used for detecting the current working current I of the main shaft motor 10 and transmitting the current working current I of the main shaft motor 10 to the control module. The voltage detection element 22 is electrically connected with the control module and the main shaft motor 10 respectively, and is used for detecting the current working voltage U of the main shaft motor 10 and transmitting the current working voltage U of the main shaft motor 10 to the control module. Specifically, the current detection element 21 and the voltage detection element 22 monitor the main shaft motor 10 in real time, and transmit the monitoring data to the control module, so that the control module calculates and feeds back the current pressing force N, and controls the lifting motor 14, thereby ensuring the machining quality and machining precision of the finished workpiece.

[0062] Further, the control module in the embodiment further comprises: a first signal conversion unit 23, a second signal conversion unit 25, a control unit 26 and a data processing unit 24. The first signal conversion unit 23 is electrically connected with the current detection element 21, the voltage detection element 22 and the control module, and is used for converting the current working current I and the current working voltage U into digital signals. The second signal conversion unit 25 is electrically connected with the control module and the lifting motor 14, and is used for converting the difference between the current pressing force N and the standard value N0 of the pressing force into an electric signal. The control unit 26 is electrically connected with the second signal conversion unit 25 and the lifting motor 14, and is used for controlling the lifting motor 14. The data processing unit 24 is electrically connected with the first signal conversion unit 23 and the second signal conversion unit 25 for data processing. Specifically, after the current detection element 21 and the voltage detection element 22 transmit the electric signals to the first signal conversion unit 23, the first signal conversion unit 23 converts the electric signals into digital signals and transmits them to the data processing unit 24 for processing. Then, the data processing unit 24 transmits the processed digital signals to the second signal conversion unit 25, which converts the digital signals into electric signals and transmits them to the control unit 26. At this time, the control unit 26 controls the lifting motor 14 according to the electric signals. In the embodiment, the data processing unit 24 is a PLC controller, and the monitoring and feedback functions can be realized by programming in the PLC controller.

[0063] Further, in the embodiment, the first signal conversion unit 23 and the second signal conversion unit 25 both comprise RS485 communication interfaces. The RS485 communication interfaces can have the functions of converting electric signals into digital signals or converting digital signals into electric signals. Meanwhile, in the embodiment, the main shaft motor 10 comprises a three-phase motor.

[0064] In another aspect, the embodiments of the present application also provide a control method of a grinding and polishing machine tool. The control method is executed on the control system of the grinding and polishing machine tool in the above embodiments. Specifically, the control method of the grinding and polishing machine tool comprises:

[0065] An initialization step: setting a down pressure standard value N0 of a grinding and polishing disc 16 of the grinding and polishing machine tool, a down pressure allowable fluctuation range X, a single cycle feed amount δ of the grinding and polishing disc 16, a thickness T of a workpiece to be processed, and a thickness T0 of a finished workpiece on a control module of the grinding and polishing machine tool.

[0066] A judgment step: judging whether the thickness T of the workpiece to be processed is greater than the thickness T0 of the finished workpiece. If the thickness T of the workpiece to be processed is not greater than the thickness T0 of the finished workpiece, the processing is completed. Otherwise, a processing step is executed.

[0067] The processing step: detecting a current working current I and a current working voltage U of a main shaft motor 10 of the grinding and polishing machine tool by using the control module, calculating a current down pressure N of the grinding and polishing disc 16 according to the current working current I and the current working voltage U, and judging whether the current down pressure N is within the down pressure allowable fluctuation range X.

[0068] If the current down pressure N is within the down pressure allowable fluctuation range X, the judgment step is executed. If the current down pressure N is out of the down pressure allowable fluctuation range X, it is judged whether a difference between the current down pressure N and the down pressure standard value N0 is greater than zero.

[0069] If the difference between the current down pressure N and the down pressure standard value N0 is greater than zero, the control module is used to control the grinding and polishing disc 16 to move a single cycle feed amount δ away from a worktable 30 of the grinding and polishing machine tool, and the processing step is executed again. If the difference between the current down pressure N and the down pressure standard value N0 is less than or equal to zero, the control module is used to control the grinding and polishing disc 16 to move a single cycle feed amount δ towards the worktable 30, and the judgment step is executed again.

[0070] In the embodiments, the control module is used to detect and control the grinding and polishing machine tool. Specifically, before the grinding and polishing machine tool processes, an operator can set the down pressure standard value N0 of the grinding and polishing disc 16, the down pressure allowable fluctuation range X, the single cycle feed amount δ of the grinding and polishing disc 16, the thickness T of the workpiece to be processed, and the thickness T0 of the finished workpiece in the control module according to different types of workpieces. The initialization step can be used to specify the processing standard, so as to avoid that the parameters of the workpiece after the processing are too different. The finished workpiece represents the workpiece after the processing, and the single cycle feed amount δ of the grinding and polishing disc 16 represents that the grinding and polishing disc 16 moves towards or away from the worktable 30 by δ per step in one processing.

[0071] After the initialization step is completed, a judgment step is needed. Considering that the single cycle feed amount δ of the polishing disc 16 is usually a very small value, when the difference between the thickness T of the workpiece and the thickness T0 of the finished workpiece is within the single cycle feed amount δ error, it can be considered that the processing is completed. That is, whether the thickness T of the workpiece to be processed is greater than the thickness T0 of the finished workpiece is judged. If the thickness T of the workpiece is not greater than the thickness T0 of the finished workpiece, the processing is completed, otherwise the processing step is executed.

[0072] In the processing step, the control module detects the current working current I and the current working voltage U of the spindle motor 10, and calculates the current pressing force N of the polishing disc 16 by using the current working current I and the current working voltage U of the spindle motor 10.

[0073] Further, the step of calculating the current pressing force N of the polishing disc 16 includes: calculating the output power P of the spindle motor 10 according to the current working current I and the current working voltage U. Calculating the load torque M of the spindle 12 of the polishing machine tool according to the output power P of the spindle motor 10 and the speed n of the spindle motor 10. Calculating the load force F of the spindle 12 according to the load torque M of the spindle 12 and the radius r of the polishing disc. Calculating the current pressing force N of the polishing disc 16 according to the friction coefficient μ between the polishing disc 16 and the workpiece to be processed and the load force F of the spindle 12.

[0074] Specifically, the current pressing force N of the polishing disc 16 is calculated as follows:

[0075] In this embodiment, the relationship between the output power P of the motor and the current working current I and the current working voltage U of the spindle motor 10 is calculated by the following formula:

[0076]

[0077] Wherein A represents a constant, and when the motor is a three-phase motor, the specific value is I represents the current working current of the spindle motor 10, and U represents the current working voltage of the spindle motor 10. The power factor of the spindle motor 10 is represented by cosφ, and the power factor The value of cosφ is between 0 and 1, and the power factor of the three-phase motor is usually The value of cosφ is between 0.8 and 0.95, and the specific value needs to be determined according to the model of the three-phase motor.

[0078] At the same time, the output power P of the spindle motor 10 and the load torque M of the spindle 12 have the following relationship:

[0079]

[0080] wherein B is a constant, in this embodiment B is 9.55, and n represents the rotating speed of the spindle motor 10. The load torque M of the spindle 12 and the load force F of the spindle 12 have the following relationship:

[0081]

[0082] wherein ds represents the infinitesimal arc length, and r represents the radius of the polishing disc 16. According to the mechanics principle, the current pressing force N of the polishing disc 16 and the load force F of the spindle 12 have the following relationship:

[0083]

[0084] wherein f represents the friction force between the polishing disc 16 and the workpiece, and μ represents the friction coefficient between the polishing disc 16 and the workpiece.

[0085] According to the above formula, the relationship between the current pressing force N of the polishing disc 16 and the current working current I and the current working voltage U of the spindle motor 10 can be derived as:

[0086]

[0087] wherein C represents a constant, when the motor is a three-phase motor, C is the product of B and .

[0088] After the current pressing force N of the polishing disc 16 is calculated, it is necessary to determine whether the current pressing force N is within the pressing force allowable fluctuation range X. If the absolute value of the difference between the current pressing force N and the pressing force standard value N0 is less than or equal to the pressing force allowable fluctuation range X, the current pressing force N is within the pressing force allowable fluctuation range X, the machining is normal, and the control module will not send a signal to make the lifting motor 14 change the position. At the same time, when the workpiece is normally machined, the control module will perform a judgment step to determine whether the machining of the workpiece reaches the standard. If the absolute value of the difference between the current pressing force N and the pressing force standard value N0 is greater than the pressing force allowable fluctuation range X, it is necessary to further determine whether the difference between the current pressing force N and the pressing force standard value N0 is greater than zero, so as to control the moving direction of the lifting motor 14.

[0089] Specifically, if the difference between the current down pressure N and the down pressure standard value N0 is greater than zero, it means that the current down pressure N is too large. At this time, the control module controls the lifting motor 14 to move the polishing disc 16 away from the workbench 30 by a single cycle feed amount δ, and the lifting motor 14 rises so that the current down pressure N of the polishing disc 16 is reduced. At the same time, the lifting motor 14 rises to reduce the current in the circuit, resulting in a decrease in the current working current I of the main shaft motor 10. Subsequently, the workpiece being processed is processed again, and when the absolute value of the difference between the current down pressure N and the down pressure standard value N0 is less than or equal to the down pressure allowable fluctuation range X, the judgment step is performed. If the difference between the current down pressure N and the down pressure standard value N0 is less than zero, it means that the current down pressure N is too small. At this time, the control module controls the lifting motor 14 to move the polishing disc 16 towards the workbench 30 by a single cycle feed amount δ, and the lifting motor 14 descends so that the current down pressure N of the polishing disc 16 is increased. At the same time, the lifting motor 14 descends to reduce the current in the circuit, thereby reducing the current working current I of the main shaft motor 10 to ultimately increase the current down pressure N of the polishing disc 16. Subsequently, the workpiece being processed is processed again, and the processing of the workpiece is determined.

[0090] In the embodiment, the control method of the polishing machine tool is used to monitor and control the processing of the polishing machine tool in real time, which not only ensures the processing quality and precision of the polishing machine tool, but also makes the processing more intelligent and effectively improves the processing efficiency.

[0091] In one specific embodiment in the embodiment, the thickness T of the workpiece to be processed is 52 mm, the thickness T0 of the finished workpiece is 50 mm, the down pressure standard value N0 is 5000 N, the down pressure allowable fluctuation range X is 20% of the down pressure standard value N0, X is 1000 N, and the single cycle feed amount δ of the polishing disc 16 is 0.05 mm. At the same time, the current working voltage U of the main shaft motor 10 is constant at 380 V, the main shaft motor 10 is a three-phase motor, and the power factor of the motor is 0.85. The current working current I of the main shaft motor 10 is 7.5 A, and the current working torque T of the main shaft motor 10 is 0.5 Nm. The coefficient of friction μ between the grinding and polishing disc 16 and the workpiece is 0.85, the rotational speed n of the spindle motor 10 is 120 revolutions per minute, the coefficient of friction μ between the grinding and polishing disc 16 and the workpiece is 0.3, and the radius r of the grinding and polishing disc 16 is 0.75m. After testing by the current detection element 21, the current operating current I of the spindle motor 10 is 14.55A. According to the above formula, the current downward pressure N of the grinding and polishing disc 16 can be calculated as 3840N. At this time, the difference between the standard value N0 of the downward pressure and the current downward pressure N is greater than the allowable fluctuation range X of the downward pressure, and the difference between the current downward pressure N and the standard value N0 of the downward pressure is less than zero. Therefore, under the action of the control unit 26, the lifting motor 14 descends, driving the grinding and polishing disc 16 to move closer to the worktable 30 by a single cycle feed amount δ. The current downward pressure of the grinding and polishing disc 16 increases, the current in the circuit increases, and then the judgment step is executed.

[0092] In another specific embodiment of this example, the thickness T of the workpiece to be processed is 52mm, the thickness T0 of the finished workpiece is 50mm, the standard value of the downward pressure N0 is 5000N, the allowable fluctuation range of the downward pressure X is 20% of the standard value of the downward pressure N0, X is 1000N, and the single-cycle feed amount δ of the grinding and polishing disc 16 is 0.05mm. Meanwhile, the current operating voltage U of the spindle motor 10 is constant at 380V, the spindle motor 10 is a three-phase motor, and the power factor of the motor is... The coefficient of friction μ between the grinding and polishing disc 16 and the workpiece is 0.85, the rotational speed n of the spindle motor 10 is 120 rpm, the friction coefficient r between the grinding and polishing disc 16 and the workpiece is 0.3, and the radius r of the grinding and polishing disc 16 is 0.75 m. After testing by the current detection element 21, the current operating current I of the spindle motor 10 is 23.71 A. According to the above formula, the current downward pressure N of the grinding and polishing disc 16 can be calculated as 6255 N. At this time, the difference between the current downward pressure N and the standard downward pressure value N0 is greater than the allowable fluctuation range X of the downward pressure, and the difference between the current downward pressure N and the standard downward pressure value N0 is greater than zero. Therefore, under the action of the control unit 26, the lifting motor 14 rises, driving the grinding and polishing disc 16 to move away from the worktable 30 by a single cycle feed amount δ. The current downward pressure N of the grinding and polishing disc 16 decreases, the current in the circuit decreases, and then the processing step is executed again.

[0093] In this embodiment, the control method of the grinding and polishing machine tool involves electrically connecting a control module to the grinding and polishing machine tool and utilizing the functions of the current detection element 21, voltage detection element 22, first signal conversion unit 23, second signal conversion unit 25, control unit 26, and data processing unit 24 within the control module. This allows for real-time monitoring of the current downward pressure N of the grinding and polishing disc 16. Through signal conversion, data processing, and control processes, the current downward pressure N of the grinding and polishing disc 16 is adjusted and maintained within an ideal range, thereby ensuring the processing quality and accuracy of the grinding and polishing machine tool.

[0094] For purposes of the description hereinafter, spatial

[0095] In addition, it should be noted that the terms "first", "second", and so on can be used herein to describe various elements, but the elements should not be construed as being limited to the above terms. Singular forms "a", "an" and "the" can be used herein to describe one or more than one element, but the use of the singular forms is not intended to limit the meaning of the phrase used in the context to the singular. The terms "comprises", "comprising", "includes", "including", "contains", "containing" or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises, includes or contains a list of elements does not include only those elements but can include other elements not expressly listed or inherent to such process, method, article, or apparatus. An element proceeded by "comprises... a", "has... a", "includes... a", "contains... a" does not, without more constraints, preclude the existence of additional identical elements other than the one specified in the clause. The terms "a" and "one" are defined as including one or more than one, unless specified otherwise or clear from the context to be directed to a singular element.

[0096] The preferred embodiments of the present application have been described above with the aid of drawing figures, and are not limited to those embodiments per se, but can be modified in various ways. It should be noted that specific terms are used in this description for the purpose of description only and are not intended to limit the scope of protection of the present application, which is limited only by the appended claims.

Claims

1. A control method of a lapping polishing machine, characterized by, The method comprises: a judging step of judging whether the thickness T of a workpiece to be processed is greater than the thickness T0 of a finished workpiece, and if the thickness T of the workpiece to be processed is not greater than the thickness T0 of the finished workpiece, the processing is completed, otherwise, a processing step is performed; the processing step of detecting the current working current I and the current working voltage U of a spindle motor (10) of the lapping and polishing machine tool, and calculating the current pressing force N of a lapping and polishing disc (16) according to the current working current I and the current working voltage U; judging whether the current pressing force N is within a pressing force allowable fluctuation range X, and if the current pressing force N is within the pressing force allowable fluctuation range X, the judging step is performed; if the current pressing force N exceeds the pressing force allowable fluctuation range X, judging whether the difference between the current pressing force N and a pressing force standard value N0 is greater than zero, and if the difference between the current pressing force N and the pressing force standard value N0 is greater than zero, controlling the lapping and polishing disc (16) to move a single-cycle feeding amount δ away from a worktable (30) of the lapping and polishing machine tool, and re-performing the processing step, and if the difference between the current pressing force N and the pressing force standard value N0 is less than or equal to zero, controlling the lapping and polishing disc (16) to move the single-cycle feeding amount δ towards the worktable (30), and re-performing the judging step; the step of calculating the current pressing force N of the lapping and polishing disc (16) comprises: calculating the output power P of the spindle motor (10) according to the current working current I and the current working voltage U; calculating the load torque M of a spindle (12) of the lapping and polishing machine tool according to the output power P of the spindle motor (10) and the rotating speed n of the spindle motor (10); calculating the load force F of the spindle (12) according to the load torque M of the spindle (12) and the radius r of the lapping and polishing disc; calculating the current pressing force N of the lapping and polishing disc (16) according to the friction coefficient μ between the lapping and polishing disc (16) and the workpiece to be processed and the load force F of the spindle (12).

2. The control method of the polishing machine according to claim 1, wherein The output power P of the spindle motor is calculated by the following formula: wherein A represents a constant; I represents the current working current of the spindle motor (10); U represents the current working voltage of the spindle motor (10).

3. The control method of the polishing machine according to claim 2, wherein The load torque M of the spindle (12) is calculated by the following formula: wherein B represents a constant; n represents the rotating speed of the spindle motor (10).

4. The control method of the polishing machine according to claim 3, wherein The load force F of the spindle (12) is calculated by the following formula: wherein M represents the load torque of the spindle (12); r represents the radius of the lapping and polishing disc.

5. The control method of the polishing machine according to claim 4, wherein The current pressing force N of the lapping and polishing disc (16) is calculated by the following formula: wherein f represents the friction force between the lapping and polishing disc (16) and the workpiece; μ represents the friction coefficient between the lapping and polishing disc (16) and the workpiece.

6. The control method of the polishing machine according to claim 1, wherein In the processing step, the current pressing force N of the polishing disc (16) is calculated by the following formula: wherein C represents a constant; μ represents a friction factor between the polishing disc (16) and the workpiece; r represents a radius of the polishing disc; n represents a rotating speed of the spindle motor (10); I represents a current working current of the spindle motor (10); U represents a current working voltage of the spindle motor (10).

7. A control system for a lapping / polishing machine, characterized by The control system comprises a control module for performing the control method of the polishing machine tool according to any one of claims 1 to 6.

8. The control system for a lapping / polishing machine according to claim 7, wherein The control module comprises: a current detecting element (21) electrically connected with the control module and the spindle motor (10) respectively, for detecting the current working current I of the spindle motor (10) and transmitting the current working current I of the spindle motor (10) to the control module; a voltage detecting element (22) electrically connected with the control module and the spindle motor (10) respectively, for detecting the current working voltage U of the spindle motor (10) and transmitting the current working voltage U of the spindle motor (10) to the control module; a first signal converting unit (23) electrically connected with the current detecting element (21), the voltage detecting element (22) and the control module, for converting the current working current I and the current working voltage U into digital signals; a second signal converting unit (25) electrically connected with the control module and a lifting motor (14) of the polishing machine tool, for converting a value of a difference between the current pressing force N and the standard pressing force N0 into an electric signal; a control unit (26) electrically connected with the second signal converting unit (25) and the lifting motor (14) and for controlling the lifting motor (14); a data processing unit (24) electrically connected with the first signal converting unit (23) and the second signal converting unit (25) for data processing.

9. The control system for a lapping / polishing machine according to claim 8, wherein The first signal converting unit (23) and the second signal converting unit (25) each comprise an RS485 communication interface.

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