Intelligent detection method for in-place finishing contour of grinding wheel

Abstract

The invention belongs to the technical field of grinding wheel dressing, and provides a grinding wheel in-place dressing contour intelligent detection method, which comprises a grinding wheel dressing wheel, a grinding wheel dressing shaft, a dressing linear shaft and a dressing rotating shaft, the grinding wheel dressing wheel is connected to the grinding wheel dressing shaft, and the grinding wheel dressing shaft is connected to a dressing shaft shell; the bottom end of the dressing shaft shell is fixedly connected to the dressing linear shaft, the bottom end of the dressing linear shaft is rotationally connected to the dressing rotating shaft, a dressing shaft controller of the numerical control system controls the grinding wheel dressing shaft to rotate, and a linear shaft controller of the numerical control system controls the dressing linear shaft to linearly move. A rotary shaft controller of the numerical control system controls the dressing rotary shaft to rotate, and online dressing of the grinding wheel with the complex molded surface is achieved through movement of the three. All the components are connected through high-strength bolts, and mounting and dismounting are convenient. The whole structure is simple and convenient, the requirement for a control system is low, and the device is suitable for various finishing working conditions and facilitates industrialization.

Description

Technical Field

[0001] The invention belongs to the technical field of grinding wheel dressing, and in particular relates to an intelligent detection method for an in-situ dressing profile of a grinding wheel for a numerically controlled grinder. Background Art

[0002] The surface profile of complex curved parts is determined by the shape of the grinding wheel, and the grinding wheel dressing accuracy directly affects the shape accuracy of the grinding wheel. The grinding wheel of the CNC grinder will wear out after a period of use during the grinding process, and the surface shape of the grinding wheel can be maintained by using the grinding wheel dressing method.

[0003] Existing grinding wheels often need to be tested offline after dressing. If the test results do not meet the use requirements, they need to be re-grinded. Repeated clamping will cause installation errors and verification errors. Conventional online detection methods can only effectively detect simple geometric profile grinding wheels such as common cylindrical grinding wheels and spherical grinding wheels. It is impossible to effectively monitor complex curvature and special-shaped grinding wheels. In addition, the online detection technology of grinding wheels is relatively simple, the detection cost is high, and it takes a long time. The existing grinding wheel profile detection technology cannot meet the needs of grinding wheels in precision grinding. Summary of the invention

[0004] The present invention aims to overcome the technical defects and shortcomings of the existing grinding wheel detection device, such as single applicability, low detection efficiency, and poor detection accuracy, and provides an intelligent detection method for the in-situ dressing contour of the grinding wheel for a CNC grinder. The in-situ monitoring of the dressing process is achieved through the real-time power feedback of the machine tool guide rail signal, and the detection requirements of grinding wheels of different shapes can be met at the same time. The technical means adopted by the present invention are as follows:

[0005] The invention discloses an intelligent detection method for the in-situ dressing contour of a grinding wheel, comprising a grinding wheel dressing wheel, a grinding wheel dressing shaft, a dressing linear shaft and a dressing rotary shaft, wherein the grinding wheel dressing wheel is detachably connected to the grinding wheel dressing shaft, the grinding wheel dressing shaft is connected to a dressing shaft housing, the bottom end of the dressing shaft housing is fixedly connected to the dressing linear shaft, the bottom end of the dressing linear shaft is rotatably connected to the dressing rotary shaft, the grinding wheel dressing shaft is controlled to perform rotational motion by a dressing shaft controller of a numerical control system, the dressing linear shaft is controlled to perform linear motion by a linear shaft controller of the numerical control system, and the dressing rotary shaft is controlled to perform rotational motion by a rotary shaft controller of the numerical control system, online dressing of a grinding wheel with a complex profile is achieved through the motion of the three, tool setting operation and error compensation of dressing are achieved through the power of a machine tool guide rail motor without the need for additional sensors, on-site real-time monitoring of the dressing process and contour detection of the grinding wheel after dressing are achieved by obtaining the real-time power consumption of the dressing process, and constant power dressing can be achieved by adjusting the real-time power consumption of the dressing process.

[0006] Furthermore, the dressing rotary axis is connected to the X-axis of the machine tool guide rail through the guide rail adapter plate. In addition to driving the movement of the X-axis itself, the power change of the X-axis of the machine tool guide rail also reflects the change of the X-axis load. During the dressing process, the dressing axis drives the dressing wheel to dress the grinding wheel. The grinding wheel and the dressing wheel rotate at high speed together, which is a high-frequency signal; while the X-axis itself and other loads move at low speed, which is a low-frequency signal. Based on this, the power consumed in the dressing process can be extracted in real time through the PMAC numerical control system to achieve real-time monitoring of the dressing process in situ, and the real-time tool setting can be achieved through the change of the X-axis power of the machine tool guide rail during the dressing process: when the dressing wheel contacts the grinding wheel, the X-axis of the machine tool guide rail is subject to resistance. In order to make the guide rail move normally, the output power of the X-axis of the machine tool guide rail increases at this time, which is reflected in the output power of the machine tool guide rail as a mutation point, which is the tool setting point of the grinding wheel; when the dressing wheel is out of contact with the grinding wheel, the X-axis of the machine tool guide rail has no additional load at this time, and the output power is reduced. The dressing process and dressing point of the grinding wheel can be determined accordingly.

[0007] Furthermore, the dressing device is installed beside the spindle of the CNC machine tool, and the coordinates of each position of the dressing device are determined in the workpiece coordinate system. On the basis of the aforementioned obtained grinding wheel dressing points, when dressing the complex contour grinding wheel, the machine tool X-axis output power is matched one by one with the current grinding wheel contact point (dressing point), so as to achieve high-precision grinding wheel contour dressing and detection.

[0008] Furthermore, the dressing parameters (dressing wheel speed, grinding wheel speed, rotary feed speed, dressing depth, etc.) are adjusted according to the output power signal of the machine tool guide X-axis. By dressing the linear feed motion of the linear axis, the worn dressing wheel end face is continuously put into the dressing motion, so that the power of the machine tool guide X-axis is output steadily, constant power dressing is achieved, the dressing process is smooth, the grinding wheel dressing accuracy is improved, and the loss of the dressing wheel is reduced.

[0009] Furthermore, a method for intelligently detecting the contour of an in-situ dressing of a grinding wheel comprises the following steps:

[0010] Step 1: Select a grinding wheel dressing wheel based on the complex surface grinding wheel to be dressed, and install the grinding wheel dressing wheel on the grinding wheel dressing shaft;

[0011] Step 2: Install the grinding wheel with complex surface to be dressed on the grinding machine, and move the guide rail of the grinding machine during dressing so that the center of the arc part of the grinding wheel is approximately coincident with the rotation center of the dressing rotary axis;

[0012] Step 3: Adjust and dress the linear axis, and observe the real-time power consumption curve of the X-axis of the machine tool guide rail at the same time. The end face of the wheel to be dressed is tangent to the contour surface of the complex-shaped grinding wheel to be dressed. At this time, a significant peak is observed on the real-time power consumption curve of the X-axis of the machine tool guide rail, and then the position of the linear axis to be dressed is fixed;

[0013] Step 4: Run the NC code compiled according to the grinding wheel contour shape, control the rotary motion of the dressing rotary axis within the motion range to preliminarily realize the dressing of the complex surface grinding wheel to be dressed, and observe the real-time power consumption curve of the X-axis of the machine tool guide rail. If there is an error between the center of the arc part of the grinding wheel and the rotation center of the dressing rotary axis, the real-time power consumption curve of the X-axis of the machine tool guide rail will have a significant mutation value. The real-time power consumption curve of the X-axis of the machine tool guide rail is drawn in the machine tool coordinate system of the CNC system, and the size of the coincidence error and position deviation between the center of the arc part of the grinding wheel and the rotation center of the dressing rotary axis are judged accordingly, and the grinding wheel is moved to the corresponding position in the machine tool system. Repeat the steps until the real-time power of the X-axis of the machine tool guide rail has no significant mutation and is continuously output.

[0014] Step 5. According to the dressing needs, adjust the dressing parameters (dressing wheel speed, grinding wheel speed, rotary feed speed, dressing depth, etc.) by real-time monitoring the output power signal of the machine tool guide X-axis, select specific dressing parameters, and continuously put the worn dressing wheel end face into the dressing movement through the linear feed motion of the dressing linear axis, so that the relative value of the machine tool guide X-axis power maintains a stable output to achieve constant power grinding wheel dressing.

[0015] Step 6: After the preliminary dressing is completed, that is, after the grinding wheel contour surface is completely dressed, a feedless dressing is performed, and the output power signal of the machine tool guide X axis and the real-time motion position of the rotary axis are obtained at the same time. The real-time power consumption curve of the machine tool guide X axis is filtered and drawn in the CNC system machine tool coordinate system. At the same time, the real-time motion position curve of the rotary axis is fitted with a perfect circle, and the fitting center position (Xmean, Ymean) and the fitting radius value Rmean are obtained. This radius value Rmean is compared with the distance between the real-time motion position of the rotary axis and the center position. If the error between the two exceeds the limit value, step 5 is repeated for dressing until the error between the two approaches the limit value. Within a certain accuracy range, it can be approximately considered that the secondary fitting center position (Xmean, Ymean) and the fitting radius value Rmean are the grinding wheel contour measurement values. The complex contour surface grinding wheel can also refer to the above method to obtain the segmented center position, that is, the corresponding arc radius, and then obtain the complex contour surface grinding wheel generatrix measurement value.

[0016] The present invention has the following advantages: the present invention can realize the dressing of grinding wheels of different materials by replacing the grinding wheel dressing wheel; the dressing of rotary surfaces such as spherical and disc-shaped grinding wheels can be realized by the movement of the dressing linear axis and the dressing rotary axis; the tool setting operation and error compensation of the dressing can be realized by the real-time power consumption of the machine tool guide motor without the need for additional sensors; the real-time power consumption of the dressing process can be obtained to realize the on-site monitoring of the dressing process; the real-time power consumption of the dressing process can be adjusted to realize constant power dressing; the dressing of irregular and complex surface grinding wheels can be further realized by linkage with the numerical control system. The on-site dressing device has the characteristics of versatility, small size, multiple functions, high dressing efficiency, etc. It can be adapted to various models of numerical control grinders, and then meet different grinding processing requirements for different processing materials and application occasions. All components of the present invention are connected by high-strength bolts, which are convenient for installation and disassembly. The overall structure is simple, the control system requirements are low, it is suitable for various dressing conditions, and it is conducive to industrialization. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a system diagram of the numerical control system of the present invention.

[0018] Figure 2 This is a schematic diagram of the state in which the present invention is installed on a grinding machine.

[0019] Figure 3 It is a schematic diagram of the structure of the present invention.

[0020] Figure 4 It is a schematic diagram of the dressing movement of the present invention, wherein the rotary axis is in the original position.

[0021] Figure 5 Schematic diagram of the dressing motion of the present invention, wherein the rotary axis rotates 90 degrees.

[0022] Figure 6 The real-time output power curve of the X-axis of the machine tool guide rail, where (a) is the case where the dressing wheel is not in contact with the grinding wheel, (b) is the case where the dressing wheel is partially in contact with the grinding wheel, and (c) is the case where the dressing wheel is in full contact with the grinding wheel.

[0023] Figure 7 is the curve of the X-axis output power of the machine tool guide rail changing with the grinding wheel contour point in the machine tool coordinate system, where: Figure 7a Because the dressing wheel does not contact the grinding wheel, Figure 7b The dressing wheel is in partial contact with the grinding wheel. Figure 7c Because the dressing wheel is in excessive contact with the grinding wheel, Figure 7d The dressing wheel is in even contact with the grinding wheel.

[0024] Figure 8 shows the process of measuring the grinding wheel profile based on the real-time output power of the X-axis of the machine tool guide rail, where: Figure 8a This is a schematic diagram of the grinding wheel profile fitting process (1 / 2 arc fitting). Figure 8bThe fitting process is measured for the actual profile of the grinding wheel.

[0025] In the figure: 1. In-situ dressing device for grinding wheel; 2. Grinding machine spindle; 3. Chip groove; 4. Grinding machine guide rail; 5. Grinding wheel dressing wheel; 6. Grinding wheel dressing axis; 7. Dressing linear axis; 8. Dressing rotary axis; 9. Linear axis controller; 10. Rotary axis controller; 11. Dressing axis housing; 12. Rotary axis adapter plate; 13. Rotary axis rotation center; 14. Grinding wheel dressing axis axis; 15. Hemispherical grinding wheel; 16. Grinding wheel dressing point; 20. Contact point between dressing wheel and grinding wheel; 21. Theoretical contour center of grinding wheel; 22. Dressing rotary axis Center of rotation; 23. Grinding wheel profile fitting curve; 24. Grinding wheel profile measurement radius minimum point rmin; 25. Minimum grinding wheel profile Rmin determined by the minimum grinding wheel profile measurement radius point; 26. Grinding wheel profile measurement radius minimum point rmax; 27. Minimum grinding wheel profile Rmax determined by the minimum grinding wheel profile measurement radius point; 30. X-axis output power of machine tool guide rail; 31. Actual contour of grinding wheel; 32. Ideal arc surface contour of grinding wheel; 33. Peak output power of X-axis of machine tool guide rail; 34. Overcut point between dressing wheel and grinding wheel. DETAILED DESCRIPTION

[0026] The specific implementation of the present invention is further described below in conjunction with the accompanying drawings and technical solutions.

[0027] like Figure 3 As shown, an in-situ dressing device for a grinding wheel of a CNC grinding machine comprises a grinding wheel dressing wheel, a grinding wheel dressing shaft, a dressing linear shaft and a dressing rotary shaft. The grinding wheel dressing wheel 5 is detachably connected to the grinding wheel dressing shaft 6. In this embodiment, the grinding wheel dressing wheel is fixedly connected to the grinding wheel dressing shaft by a thread, and the grinding wheel dressing shaft is connected to the dressing shaft housing 11. In this embodiment, the grinding wheel dressing shaft is clamped on the dressing shaft housing, and the parallelism of the dressing shaft axis is ensured by tolerance matching. The bottom end of the dressing shaft housing is fixedly connected to the dressing linear shaft, and the bottom end of the dressing linear shaft 7 is rotatably connected to the dressing rotary shaft 8. The grinding wheel dressing shaft is controlled to perform rotational motion by the dressing shaft controller of the CNC system, the dressing linear shaft is controlled to perform linear motion by the linear shaft controller 9 of the CNC system, and the dressing rotary shaft is controlled to perform rotational motion by the rotary shaft controller 10 of the CNC system. The online dressing of complex surface grinding wheels is achieved through the movements of the three. The grinding wheel dressing wheel is installed on the grinding wheel dressing shaft axis 14. The present invention can realize the dressing of various irregular complex surface contour grinding wheels by linking the dressing linear shaft 7 and the dressing rotary shaft 8 in the machine tool coordinate system, thereby meeting different grinding processing requirements for different processing materials and application occasions.

[0028] Specifically, Figure 1As shown, the grinding wheel dressing shaft is connected to the dressing linear shaft through a dressing shaft housing. The dressing linear shaft is directly controlled by a CNC grinder through a servo driver, and the control of the grinding wheel profile rotation diameter is achieved through micron-level precision feeding.

[0029] The dressing linear axis is connected to the dressing rotary axis through a rotary axis adapter plate 12. The dressing rotary axis is directly controlled by the CNC grinder through a servo driver. The rotation range of the grinding wheel profile is controlled by the rotary motion and the limit function of the CNC system, while avoiding the dressing error caused by the interpolation motion of the ordinary grinding wheel in-situ dressing device.

[0030] The grinding wheel dressing axis, the dressing linear axis and the dressing rotary axis can further realize the dressing of the irregular and complex surface grinding wheel by linkage with the numerical control system, and can also be directly controlled externally separately through the industrial control computer.

[0031] The motion form of an in-situ dressing device for a grinding wheel of a CNC grinder of the present invention is realized by the motion of a dressing linear axis 7 and a dressing rotary axis 8. The coordinates of the rotation center 13 of the rotary axis have been input into the CNC system of the grinder in advance. When the grinding wheel is dressed, the rotation center of the grinding wheel contour to be dressed is moved to the rotation center 13 of the rotary axis through the guide rail movement of the CNC grinder so that the two coincide with each other; then the dressing of the grinding wheel is realized by adjusting the dressing linear axis 7 and the dressing rotary axis 8. The dressing linear axis 7 can adjust the rotation radius, that is, the radius of the grinding wheel to be dressed, and the dressing rotary axis 8 can adjust the rotation range, that is, the arc length of the grinding wheel; during the dressing process, the dressing linear axis 7 is locked and does not move, and the dressing of the grinding wheel contour to be dressed is realized by controlling the rotation of the dressing rotary axis 8, such as Figure 4 , Figure 5 As shown, since no interpolation error is introduced, the grinding wheel dressing accuracy of the device is higher than that of the conventional grinding wheel dressing device.

[0032] The grinding wheel dressing wheel is a slotted electroplated diamond grinding wheel, which increases the chip space and improves the dressing efficiency, while increasing the service life of the dressing wheel. When the grinding wheel dressing wheel is greatly worn during the dressing process and the dressing accuracy is reduced, the dressing accuracy can be improved by replacing the grinding wheel dressing wheel. A dressing wheel matching the grinding wheel material can also be selected.

[0033] The complex profile grinding wheels include spherical grinding wheels, arc grinding wheels, V-shaped grinding wheels and cup / cylindrical grinding wheels.

[0034] like Figure 2 As shown, the grinding wheel in-situ dressing device 1 can be installed on a CNC grinding machine. The bottom end of the dressing rotary shaft is installed on the CNC grinding machine, specifically, it is connected to the grinding machine guide rail connecting plate by fastening bolts, and the grinding wheel in-situ dressing device 1 and the grinding machine spindle 2 are placed on the same side of the grinding machine guide rail 4.

[0035] When the grinding wheel is dressed, the rotation center of the grinding wheel contour to be dressed moves to the rotation center of the rotary axis.

[0036] The trimming linear shaft includes a main body and a sliding part. The main body is provided with a track. The sliding part can slide in the track. The top end of the sliding part is fixedly connected to the trimming shaft housing. The bottom end of the main body is fixed to the trimming rotary shaft by bolts and a rotary shaft adapter plate.

[0037] In addition, in addition to the rotary type surface contour, the present invention also realizes the dressing of grinding wheels with complex surfaces and irregular contours through the linkage of the CNC grinder and the dressing device, and achieves good dressing effects. For typical cup-shaped grinding wheel dressing, the dressing rotary shaft 8 can be fixed during the dressing process, the dressing wheel can be replaced with a cup-shaped grinding wheel to dress the end face of the cup-shaped grinding wheel to be dressed, and the dressing wheel can be replaced with a disc grinding wheel to dress the circumferential surface of the grinding wheel to be dressed; for the dressing of V-shaped or butterfly-shaped grinding wheels, the dressing rotary shaft 8 can be fixed to a half angle of the V-shaped butterfly-shaped grinding wheel during the dressing process, and the single-sided dressing of the V-shaped or butterfly-shaped grinding wheel can be achieved through the unidirectional feeding of the CNC grinder, and the fixing angle of the dressing rotary shaft 8 can be adjusted to achieve the dressing of the grinding wheel on the other side; and the grinding wheel in-situ dressing device of the present invention also has a certain dressing ability for general special-shaped grinding wheels, and is very flexible to use.

[0038] In addition, the grinding wheel in-situ dressing device of the present invention can not only be linked controlled within the numerical control system of the grinding machine, but can also be connected to an industrial computer to be directly controlled outside the numerical control system, which greatly improves the versatility of the device.

[0039] The present invention realizes the dressing of complex-surface grinding wheels such as spherical grinding wheels, arc grinding wheels, V-shaped grinding wheels and cup-shaped / cylindrical grinding wheels through the rotational motion of the grinding wheel dressing shaft, the linear motion of the dressing linear shaft and the rotational motion of the dressing rotary shaft, and realizes tool setting, constant-power dressing and grinding wheel profile detection through the detection and adjustment of the X-axis output power of the machine tool guide rail. The tool setting, dressing and detection principles are as follows:

[0040] The tool setting process is as follows Figure 6 As shown in the figure, when the dressing wheel is not in contact with the grinding wheel, the X-axis of the machine tool guide rail has no additional power consumption. The power consumed is the power of the X-axis guide rail and the movement of the machine tool. At this time, the real-time output power of the X-axis of the machine tool guide rail is obtained after filtering and subtracting the no-load power consumption. Figure 6 As shown in a, the amplitude basically fluctuates around zero; when the dressing wheel contacts the grinding wheel at a certain point during the dressing process, the real-time output power of the X-axis of the machine tool guide rail will undergo a significant mutation at this point. At this time, the real-time output power of the X-axis of the machine tool guide rail needs to bear the additional dressing load. At this time, the real-time output power of the X-axis of the machine tool guide rail is obtained after filtering and subtracting the no-load power consumption. Figure 6As shown in b, the amplitude increases to about 1.8W. At this time, the mutation point 20 can be clearly observed in the real-time output power curve of the machine tool guide rail X axis, which is the contact point between the dressing wheel and the grinding wheel. The machine tool coordinate value corresponding to this point can be captured in the machine tool CNC system to determine the specific position of the point. By selecting the set dressing parameters and entering the steady-state / constant power dressing, the real-time output power of the machine tool guide rail X axis will be stable in a continuous output range. At this time, the real-time output power of the machine tool guide rail X axis has been further improved, such as Figure 6 The amplitude shown in c increases to about 2.2 W. Observing the real-time output power of the X-axis of the machine tool guide rail, it can be found that its curve is pulse-shaped, corresponding to the slotted diamond dressing wheel selected during the dressing process. The slotted part does not participate in the dressing. When the unslotted part of the dressing wheel contacts the contour surface of the grinding wheel, the load changes and forms a peak.

[0041] Corresponding to the dressing process, when the end face of the wheel 5 to be dressed is tangent to the grinding wheel contour surface, a significant peak is observed on the real-time power consumption curve of the machine tool guide rail X-axis. Then, the position of the dressing linear axis 7 is fixed and does not move. This is the grinding wheel dressing point 16. The rotary motion of the dressing rotary axis 8 within the motion range is controlled to achieve preliminary dressing of the grinding wheel contour. The dressed waste falls into the chip groove 3 of the grinder. After the preliminary dressing is completed, the real-time power consumption curve of the machine tool guide rail X-axis is observed. If there is an error between the center of the arc part of the grinding wheel and the rotation center of the dressing rotary axis, the real-time power consumption curve of the machine tool guide rail X-axis will have a significant mutation value. The real-time power consumption curve of the machine tool guide rail X-axis is plotted in the machine tool coordinate system of the CNC system, and the size of the coincidence error and the position deviation between the center of the arc part of the grinding wheel and the rotation center of the dressing rotary axis are judged accordingly.

[0042] The specific steps of tool setting, trimming and inspection are as follows:

[0043] Step 1: Select a grinding wheel dressing wheel based on the complex surface grinding wheel to be dressed, and install the grinding wheel dressing wheel on the grinding wheel dressing shaft;

[0044] Step 2: Install the grinding wheel with complex surface to be dressed on the grinding machine, and move the guide rail of the grinding machine during dressing so that the center of the arc part of the grinding wheel is approximately coincident with the rotation center of the dressing rotary axis;

[0045] Step 3: Adjust and dress the linear axis, and observe the real-time power consumption curve of the X-axis of the machine tool guide rail at the same time. The end face of the wheel to be dressed is tangent to the contour surface of the complex-shaped grinding wheel to be dressed. At this time, a significant peak is observed on the real-time power consumption curve of the X-axis of the machine tool guide rail, and then the position of the linear axis to be dressed is fixed;

[0046] Step 4: Run the NC code compiled according to the grinding wheel contour shape, control the rotary motion of the dressing rotary axis within the motion range to initially realize the dressing of the complex surface grinding wheel to be dressed, and observe the real-time power consumption curve of the X-axis of the machine tool guide rail. If there is an error between the center of the arc part of the grinding wheel and the rotation center of the dressing rotary axis, the real-time power consumption curve of the X-axis of the machine tool guide rail will have a significant mutation value. The real-time power consumption curve of the X-axis of the machine tool guide rail is drawn in the machine tool coordinate system of the CNC system, and the size of the coincidence error and position deviation between the center of the arc part of the grinding wheel and the rotation center of the dressing rotary axis are judged accordingly, and the grinding wheel is moved to the corresponding position in the machine tool system. Repeat the steps until the real-time power of the X-axis of the machine tool guide rail has no significant mutation and is continuously output.

[0047] Step 5. According to the dressing needs, adjust the dressing parameters (dressing wheel speed, grinding wheel speed, rotary feed speed, dressing depth, etc.) by real-time monitoring the output power signal of the machine tool guide X-axis, select specific dressing parameters, and continuously put the worn dressing wheel end face into the dressing movement through the linear feed motion of the dressing linear axis, so that the relative value of the machine tool guide X-axis power maintains a stable output to achieve constant power grinding wheel dressing.

[0048] Step 6: After the initial dressing is completed, that is, after the grinding wheel contour surface is completely dressed, a feedless dressing is performed, and the output power signal of the X-axis of the machine tool guide rail and the real-time motion position of the rotary axis are obtained at the same time. The real-time power consumption curve of the X-axis of the machine tool guide rail is filtered and plotted in the machine tool coordinate system of the CNC system. At the same time, the real-time motion position curve of the rotary axis is fitted with a perfect circle, and the fitting circle center position (X mean ,Y mean ) and the fitting radius value R mean . Set this radius value R mean Compare the real-time motion position of the rotary axis with the distance between the center of the circle. If the error between the two exceeds the limit, repeat step 5 for trimming until the error between the two approaches the limit. Within a certain accuracy range, it can be considered that the secondary fitting center of the circle (X mean ,Y mean ) and the fitting radius value Rmean are the grinding wheel profile measurement values. The complex profile surface grinding wheel can also refer to the above method to obtain the segment center position, that is, the corresponding arc radius, and then obtain the complex profile surface grinding wheel generatrix measurement value.

[0049] Specifically, the dressing of the super hemispherical grinding wheel 15 is taken as an example to illustrate the tool setting, dressing and detection methods in the dressing process:

[0050] When setting the tool, the dressing wheel 5 uses a disc or cup-shaped dressing wheel, adjusts the movement length of the dressing linear axis 7 according to the grinding wheel radius, and determines the movement range of the dressing rotary axis 8 according to the arc range of the spherical grinding wheel. When dressing, move the grinding machine guide rail 4 so that the center of the spherical grinding wheel and the rotation center 13 of the dressing rotary axis are approximately coincident; then adjust the dressing linear axis 7, and observe the real-time power consumption curve of the machine tool guide rail X axis at the same time. When the dressing wheel is not in contact with the grinding wheel, the real-time output power of the machine tool guide rail X axis is as follows: Figure 6 As shown in a, the real-time output power of the X-axis of the machine tool guide rail is plotted on the grinding wheel contour surface. Figure 7a As shown, at this time, the real-time power consumption curve 30 of the X-axis of the machine tool guide rail is close to the ideal contour 32 of the grinding wheel; by further adjusting the grinding wheel position so that when the dressing wheel contacts a certain point of the grinding wheel contour, the real-time output power of the X-axis of the machine tool guide rail is as follows: Figure 6 As shown in b, the real-time output power of the X-axis of the machine tool guide rail is plotted on the contour surface of the grinding wheel. Figure 7b As shown, at this time, the real-time power consumption curve 30 of the X-axis of the machine tool guide rail is obviously divided into two sections, one of which is P min , and closely adheres to the ideal contour 32 of the grinding wheel, and the continuous range is within θ0; a part of the contour 33 takes the value of P max , and there is a certain distance ΔP from the ideal contour 32 of the grinding wheel; the connection point 20 of the two parts is the contact point between the dressing wheel and the grinding wheel. Analysis shows that the dressing wheel and the grinding wheel are in full contact on the left side of the contact point 20 between the dressing wheel and the grinding wheel, and the dressing wheel and the grinding wheel are not in contact on the right side of the contact point 20 between the dressing wheel and the grinding wheel. According to the coordinate value of the contact point 20 between the dressing wheel and the grinding wheel in the CNC system, the angle θ0 of the non-contact range between the dressing wheel and the grinding wheel can be obtained; and the grinding wheel can be controlled to θ 0 / 2 Move around, such as Figure 7b As shown by the dotted line, it can eliminate the tool under-cutting error.

[0051] If the grinding wheel position is adjusted so that the dressing wheel is in contact with the grinding wheel profile, the real-time output power of the X-axis of the machine tool guide rail is plotted on the grinding wheel profile surface. Figure 7c As shown, at this time, the real-time power consumption curve 30 of the X-axis of the machine tool guide rail is divided into two sections, one of which is P mid The output curve is relatively stable and has a certain distance ΔP1 from the ideal profile 32 of the grinding wheel; let a part be P max , significantly higher than P mid , the continuous range is within θ1, and the distance ΔP from the ideal profile 32 of the grinding wheel is large, including P mid The distance ΔP1 from the ideal grinding wheel profile 32 and the distance P mid The distance between the dressing wheel and the grinding wheel is ΔP2. Analysis shows that the dressing wheel and the grinding wheel are overcut within the range of θ1, the overcut point is 34, and the unnecessary power loss caused by overcut is ΔP2. According to the coordinate values ​​of the two overcut points 34 in the CNC system, the overcut angle range θ1 of the dressing wheel and the grinding wheel can be obtained; and the grinding wheel can be controlled to θ 1 / 2Move around, such as Figure 7c As shown by the dotted line, it can eliminate the overcutting error.

[0052] Through the above steps, the X-axis output power of the machine tool guide rail can be used to detect whether undercutting and overcutting occur during the tool setting process, and thus eliminate the undercutting and overcutting errors until the center of the grinding wheel and the center of rotation of the rotary axis completely coincide. At this time, the X-axis output power of the machine tool guide rail is a stable value, such as Figure 6 c, the real-time output power of the X-axis of the machine tool guide rail is plotted on the grinding wheel contour surface. Figure 7d As shown, the peak value of the X-axis output power of the machine tool guide rail is a perfect circle, and its envelope 33 is completely concentric with the ideal arc surface contour of the grinding wheel. The radius difference ΔP is the dressing power consumed in the process of dressing the super-hemispherical grinding wheel at this time.

[0053] It should be noted that the above tool setting process takes the super-hemispherical grinding wheel as an example, and the tool setting process of other simple-shaped grinding wheels is simpler. If the dressing of the complex contour surface grinding wheel is taken into consideration, the complex contour surface can be decomposed into multiple arcs, and the center position of each segment and the corresponding arc radius can also be obtained respectively by referring to the above method, and the tool setting error is determined and eliminated based on the X-axis output power curve of the machine tool guide rail, which will not be elaborated here.

[0054] After the tool setting is completed, various types of grinding wheels can be dressed. According to the dressing needs, the dressing parameters (dressing wheel speed, grinding wheel speed, rotary feed speed, dressing depth, etc.) are adjusted by real-time monitoring of the X-axis output power signal of the machine tool guide rail. Specific dressing parameters are selected, and the worn dressing wheel end face is continuously put into the dressing movement through the linear feed movement of the dressing linear axis, so that the relative value of the X-axis power of the machine tool guide rail is maintained at a stable output to achieve constant power grinding wheel dressing. The following describes the dressing methods of various types of grinding wheels:

[0055] Dressing of arc grinding wheel: The dressing wheel 5 adopts a disc-shaped or cup-shaped dressing wheel. The movement length of the dressing linear axis 7 is adjusted according to the radius of the arc grinding wheel corner, and the movement range of the dressing rotary axis 8 is determined according to the range of the arc grinding wheel corner. During dressing, the grinding machine guide rail 4 is moved to make the arc center of the arc grinding wheel coincide with the rotation center of the dressing rotary axis 8; then the dressing linear axis 7 is adjusted, and the dressing linear axis 7 is fixed in place after the end face of the dressing wheel 5 is tangent to the contour surface of the spherical grinding wheel, and the rotary motion of the dressing rotary axis 8 within the movement range is controlled to achieve the dressing of the arc grinding wheel.

[0056] Dressing of V-type grinding wheel: the dressing wheel 5 adopts a disc-shaped or spherical dressing wheel, and the rotation angle of the dressing rotary axis 8 is determined according to the contour of the V-shaped grinding wheel. During the dressing process, the rotation angle of the dressing rotary axis 8 is fixed, and the grinding machine guide rail 4 is moved to make the contour of the V-shaped grinding wheel tangent to the edge of the dressing wheel 5. The V-shaped grinding wheel is controlled to move along a line parallel to the contour through the interpolation motion of the grinding machine guide rail to achieve the dressing of one side of the contour of the V-shaped grinding wheel; then, the rotation angle of the dressing rotary axis 8 is determined according to the contour of the second side of the V-shaped grinding wheel, and the rotation angle of the rotary axis 8 is adjusted again, and the grinding machine guide rail 4 is moved to make the contour of the other side of the V-shaped grinding wheel tangent to the edge of the dressing wheel 5. The V-shaped grinding wheel is controlled to move along a line parallel to the other side of the contour through the interpolation motion of the grinding machine guide rail to achieve the dressing of the other side of the contour of the V-shaped grinding wheel, and finally the dressing of the V-shaped grinding wheel is achieved.

[0057] Dressing of S4 cup-type / cylindrical grinding wheel: The dressing wheel 5 adopts a disc-shaped dressing wheel. During dressing, the dressing rotary axis 8 is fixed in place, and the grinding machine guide rail 4 is moved to control the cylindrical surface of the cup-type grinding wheel to contact with the cylindrical surface of the disc-shaped dressing wheel, and the cylindrical surface of the cup-type grinding wheel is dressed in a straight line along the cylindrical surface of the disc-shaped dressing wheel; after the dressing of the cylindrical surface of the cup-type grinding wheel is completed, the cup-type grinding wheel is moved backward, the dressing rotary axis 8 in place 8 is rotated 90° and fixed, and the grinding machine guide rail 4 is moved to control the end face of the cup-type grinding wheel to contact with the cylindrical surface of the disc-shaped dressing wheel, and the end face of the cup-type grinding wheel is controlled to move in a straight line along the cylindrical surface of the disc-shaped dressing wheel to dress the end face of the cup-type grinding wheel to achieve the dressing of the cup-type grinding wheel.

[0058] After the dressing is completed, it is necessary to judge the dressing effect and measure the contour of the dressed grinding wheel so that the dressed grinding wheel can be put into grinding use. The present invention can also realize the in-situ measurement of the dressed grinding wheel. Here, the detailed steps are described by taking a hemispherical grinding wheel as an example: Figure 8a As shown in the figure, when the grinding wheel contour surface is completely dressed, a feedless dressing is performed, and the output power signal of the X-axis of the machine tool guide and the real-time motion position of the rotary axis are obtained at the same time. The real-time power consumption curve of the X-axis of the machine tool guide is filtered and plotted in the machine tool coordinate system of the CNC system. At the same time, the real-time motion position curve of the rotary axis is fitted with a perfect circle, and the fitting circle center position (X mean ,Y mean ) and the fitting radius value R mean , and thus obtain the fitted grinding wheel profile 23. Compare the real-time motion position of the rotary axis with the distance between the center of the circle to determine the maximum distance R max and the minimum distance R min If the error Δd between the two exceeds the limit value, the above adjustment process is repeated until the error between the two approaches the limit value. Within a certain accuracy range, it can be approximately considered that the secondary fitting center position (X mean ,Y mean ) and the fitting radius value R mean This is the grinding wheel profile measurement value. In this example, the limit value is 20μm. After repeating the dressing process twice, the grinding wheel profile measurement result is as follows: Figure 8b As shown, the grinding wheel profile value R mean =19.895mm, error Δd=15.675μm, repeated trimming can continuously reduce the error value until it reaches a stable value.

[0059] It should be noted that the above grinding wheel profile measurement process takes a hemispherical grinding wheel as an example, and the measurement process of other simple shape grinding wheels is simpler. If the dressing of the complex contour surface grinding wheel is taken into consideration, the complex contour surface can be decomposed into multiple arcs. The segment center position, that is, the corresponding arc radius, can be obtained by referring to the above method, and then the generatrix measurement value of the complex contour surface grinding wheel can be obtained, which will not be repeated here.

[0060] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements 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.

Claims

1. An in-situ dressing device for a grinding wheel of a CNC grinding machine, characterized in that: The grinding wheel in-situ dressing device comprises a grinding wheel dressing wheel (5), a grinding wheel dressing shaft (6), a dressing linear shaft (7) and a dressing rotary shaft (8); the grinding wheel dressing wheel (5) is movably connected to the grinding wheel dressing shaft (6); the grinding wheel dressing shaft (6) is connected to a dressing shaft housing (11); the bottom end of the dressing shaft housing (11) is fixedly connected to the dressing linear shaft (7); the bottom end of the dressing linear shaft (7) is rotatably connected to the dressing rotary shaft (8) via a rotary shaft adapter plate (12); the grinding wheel dressing shaft (6) is controlled to perform rotational motion by a dressing shaft controller of a numerical control system; the dressing linear shaft (9) is controlled to perform rotational motion by a linear shaft controller (9) of the numerical control system. The axis (7) performs linear motion, and the rotary axis controller (10) of the numerical control system controls the dressing rotary axis (8) to perform rotational motion, and the online dressing of the grinding wheel is realized by the movement of the grinding wheel dressing axis (6), the dressing linear axis (7) and the dressing rotary axis (8); the dressing rotary axis (8) is connected to the X-axis of the machine tool guide rail, and the tool setting operation and error compensation of the dressing are realized by adjusting the power of the motor of the X-axis of the machine tool guide rail, without the need for additional sensors, and by obtaining the real-time power consumption of the dressing process, the on-site real-time monitoring of the dressing process and the contour detection of the grinding wheel after dressing are realized, and by adjusting the real-time power consumption of the dressing process, constant power dressing is realized.

2. The grinding wheel in-situ dressing device for a CNC grinding machine according to claim 1, characterized in that: The dressing rotary shaft (8) is connected to the machine tool guide rail X-axis through a guide rail adapter plate. In addition to driving the machine tool guide rail X-axis to move, its power change also reflects the load change of the machine tool guide rail X-axis. During the dressing process, the dressing rotary shaft (8) drives the grinding wheel dressing wheel (5) to dress the grinding wheel. The grinding wheel and the grinding wheel dressing wheel (5) rotate at high speed together, which is a high-frequency signal. The machine tool guide rail X-axis moves itself and other loads move at low speed, which is a low-frequency signal. Based on this, the power consumed in the dressing process is extracted in real time through the numerical control system to achieve The dressing process is monitored in real time, and real-time tool setting is achieved through the change of the machine tool guide rail X-axis power during the dressing process: when the grinding wheel dressing wheel (5) contacts the grinding wheel, the machine tool guide rail X-axis is subject to resistance. In order to make the machine tool guide rail move normally, the machine tool guide rail X-axis output power increases at this time, which is reflected in the machine tool guide rail output power as a mutation point, which is the grinding wheel tool setting point; when the grinding wheel dressing wheel (5) is out of contact with the grinding wheel, the machine tool guide rail X-axis has no additional load, and the output power decreases, thereby determining the grinding wheel dressing process and grinding wheel dressing point (16).

3. The grinding wheel in-situ dressing device for a CNC grinding machine according to claim 2, characterized in that: The grinding wheel in-situ dressing device is installed beside the main axis of the CNC machine tool. The coordinates of each position of the grinding wheel in-situ dressing device are determined in the workpiece coordinate system. On the basis of obtaining the grinding wheel dressing point (16), when dressing a grinding wheel with a complex contour, the output power of the X-axis of the machine tool guide rail is matched with the current grinding wheel dressing point (16) one by one, thereby realizing high-precision grinding wheel contour dressing detection.

4. The grinding wheel in-situ dressing device for a CNC grinding machine according to claim 2, characterized in that: The dressing parameters are adjusted according to the output power signal of the X-axis of the machine tool guide rail, and the end face of the worn grinding wheel dressing wheel (5) is continuously put into the dressing movement through the linear feed movement of the dressing linear axis (7), so that the power of the X-axis of the machine tool guide rail is output steadily, constant power dressing is achieved, the dressing process is smooth, the grinding wheel dressing accuracy is improved, and the loss of the grinding wheel dressing wheel (5) is reduced.

5. An in-situ dressing and detection method for an in-situ dressing device for a grinding wheel of a CNC grinding machine according to any one of claims 1 to 4, characterized in that: The steps include: Step 1: Select a grinding wheel dressing wheel (5) based on the grinding wheel to be dressed, and install the grinding wheel dressing wheel (5) on the grinding wheel dressing shaft (6); Step 2, installing the grinding wheel to be dressed on the grinding machine, and moving the grinding machine guide rail during dressing so that the center of the arc portion of the grinding wheel to be dressed coincides with the rotation center (22) of the dressing rotary shaft; Step 3, adjusting the dressing linear axis (7), while observing the real-time power consumption curve of the X-axis of the machine tool guide rail, until the end surface of the grinding wheel dressing wheel (5) is tangent to the contour surface of the grinding wheel to be dressed, at which time a significant peak is observed on the real-time power consumption curve of the X-axis of the machine tool guide rail, and then fixing the dressing linear axis (7) in position; Step 4: compile the running NC code according to the contour shape of the grinding wheel to be dressed, control the rotary motion of the dressing rotary axis (8) within the motion range to realize the preliminary dressing of the grinding wheel to be dressed, and observe the real-time power consumption curve of the X-axis of the machine tool guide rail at the same time. If there is an error between the center of the arc part of the grinding wheel to be dressed and the rotation center (22) of the dressing rotary axis, the real-time power consumption curve of the X-axis of the machine tool guide rail will have a significant mutation value. The real-time power consumption curve of the X-axis of the machine tool guide rail is plotted in the machine tool coordinate system of the numerical control system, and the size of the coincidence error and the position deviation between the center of the arc part of the grinding wheel to be dressed and the rotation center (22) of the dressing rotary axis are determined accordingly, and the grinding wheel to be dressed is moved to the corresponding position in the machine tool system; repeat the above steps until the real-time power of the X-axis of the machine tool guide rail has no significant mutation and is continuously output; Step 5, according to the dressing needs, the dressing parameters are adjusted by real-time monitoring of the output power signal of the X-axis of the machine tool guide rail, the dressing parameters are determined, and the end face of the worn grinding wheel dressing wheel (5) is continuously put into the dressing movement through the linear feed movement of the dressing linear axis (7), so that the relative value of the power of the X-axis of the machine tool guide rail is maintained at a stable output, so as to achieve the dressing of the constant power grinding wheel; The dressing parameters include the rotation speed of the grinding wheel dressing wheel (5), the rotation speed of the grinding wheel to be dressed, the rotary feed speed, and the dressing depth; Step 6: After the preliminary dressing is completed, that is, after the contour surface of the grinding wheel to be dressed is completely dressed, a feedless dressing is performed, and at the same time, the output power signal of the X-axis of the machine tool guide rail and the real-time motion position of the dressing rotary axis (8) are obtained, and the real-time power consumption curve of the X-axis of the machine tool guide rail is filtered and plotted in the machine tool coordinate system of the numerical control system. At the same time, the real-time motion position curve of the dressing rotary axis (8) is fitted with a perfect circle, and the fitting circle center position (X mean ,Y mean ) and the fitting radius value R mean ; Set this radius value R mean The real-time motion position of the trimmed rotary axis (8) is compared with the distance between the center position. If the error between the two exceeds the limit value, step 5 is repeated for trimming until the error between the two approaches the limit value. Within a certain accuracy range, the secondary fitting center position (X mean ,Y mean ) and the fitting radius value R mean That is the grinding wheel profile measurement value; the grinding wheel to be dressed obtains the segment center position corresponding to the arc radius according to the above method, and then obtains the complex profile surface grinding wheel generatrix measurement value.

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