JP5883581B2 - Form grinding machine and control method thereof - Google Patents

Description

  The present invention relates to a forming grinder and a control method thereof, and more particularly to a CNC forming grinder that automatically performs a correction dress on a grindstone for grinding a product workpiece in the forming grinder and a control method thereof.

  The CNC mold grinding machine that has been widely used in the precision mold market has advanced the precision and miniaturization of mold components, and has realized automation of processing. And since grinding is often required to have a higher quality than other machine tools, especially in terms of dimensional accuracy, in actual work, not only the final result of machining but also measurement work in various situations. Is intervening.

  In the forming grinding process, manual operations for forming a grinding wheel shape in accordance with the shape of the product workpiece, measuring the shape, and feeding back to the correction dress are performed at any time.

JP-A-8-192358 JP 2008-105119 A

  However, the dimension (shape) measurement technique is very important for forming grinding, and higher-precision measurement realizes higher-precision processing. Since the work is generally a human work, there is a problem that the quality varies as a result of the skill level of the worker. In addition, there is a problem that the number of skilled workers is gradually decreasing.

  Particularly, when performing the grinding wheel forming process, the accuracy of the forming shape is important. The molding shape accuracy is confirmed by the operator manually processing the dummy workpiece after dressing, transferring the shape of the grindstone, and checking it with an external measuring instrument such as a projector. Since the process is repeated until the machining accuracy is satisfied, there are many operations that require human intervention, and it takes time for setup.

  Under these circumstances, the need for on-machine molding shape measurement technology is increasing year by year. It is an object of the present invention to mount an image processing technique using a CCD camera on a CNC forming grinder and automatically perform automatic measurement feedback processing, grinding wheel forming, forming accuracy confirmation, and correction dressing in forming grinding.

The present invention is for solving the above-described problem, and the invention according to claim 1 is a molding grinder for performing molding grinding on a product workpiece by automatic control of a control unit.
The control unit includes: a dresser control unit that controls a dresser unit; a shape measuring unit that measures a shape of a forming grindstone that is molded based on a predetermined target value by the dresser unit ; and a result of the measurement and a preset value. Difference information generating means for generating difference information with the target grinding wheel shape made,
Comparing the difference information with an allowable tolerance to determine a tolerance, and if the difference information is outside the range of the allowable tolerance, obtaining a redress amount based on the difference information, correcting the dresser position and the dresser tip R, A correction dress for the forming grindstone is executed.

  According to a second aspect of the present invention, the shape of the forming grindstone is as follows: (a) a shape obtained by processing the product workpiece with the forming grindstone with a CCD camera and image processing; and (b) the shaping grindstone. Any one of a shape measured and recognized by means capable of direct measurement and (c) a shape of a dummy workpiece processed by the forming grindstone is captured by a CCD camera and obtained by image processing. And

  In the invention according to claim 3, the control unit performs control to shift to product workpiece processing if the difference information is within the range of the dimensional tolerance, and shifts to a correction dress if the difference information is outside the range of the dimensional tolerance. The shift control is performed, and the correction dress is repeatedly executed until it falls within a dimensional tolerance.

The invention according to claim 4 is a molding grinder control method for performing molding grinding on a product workpiece by automatic control of a control unit.
A dresser control step for controlling the dresser means , a shape measuring step for measuring the shape of the forming grindstone formed by the dresser means based on a predetermined target value, and a result of this measurement and a preset target shaping grindstone A difference information generation step for generating difference information with the shape,
Comparing the difference information with an allowable tolerance to determine a tolerance, and if the difference information is outside the range of the allowable tolerance, obtaining a redress amount based on the difference information, correcting the dresser position and the dresser tip R, A correction dress for the forming grindstone is executed.
The invention according to claim 5 is characterized in that a processing amount of the processing before the correction dress by the dresser means is made minus with respect to a predetermined target value.

  According to the present invention, by automatically measuring the shape of the forming grindstone transferred to the dummy workpiece by image processing using a CCD camera, an automatic correction dress is possible, and further, the automatic correction dress is within a dimensional tolerance. By repeatedly executing the process until it enters, the quality does not vary and processing with a certain product accuracy can be performed in a short time.

It is the schematic which shows the outline of a CNC forming grinder. It is explanatory drawing explaining the structure of a CNC shaping grinder. It is explanatory drawing explaining the structure of a CNC shaping grinder. It is a flowchart which shows operation | movement of a CNC shaping grinder. It is explanatory drawing explaining a process shape. It is explanatory drawing explaining the test | inspection of a dummy workpiece | work. It is explanatory drawing explaining the test result of a dummy workpiece.

  DESCRIPTION OF EMBODIMENTS Embodiments for carrying out the present invention will be described with reference to the drawings.

  Please refer to FIGS. 1 shows a CNC (Computer Numerical Control) forming grinder 1 according to the present invention.

  Referring to FIG. 1, the CNC forming grinder 1 includes a main body portion 3, a processing portion 5, and an NC device 7. The main body 3 is a portion serving as a base for mounting the processing unit 5 and the NC device 7. The processing portion 5 is a portion that performs processing.

  The NC device 7 includes a display unit 7A, an operation unit 7B, and a control unit 7C. That is, it is configured by a computer, and includes a CPU (Central Processing Unit), a RAM (Random Access Memory), a ROM (Read Only Memory), a storage unit such as an external memory, an input / output unit (screen as the display unit 7A, Etc. (including buttons and the like as the operation unit 7B) and the like, and operate as the control unit 7C by a computer program to perform numerical control and the like.

  In the present embodiment, as shown by the coordinate axis Dim (see FIG. 1-3), the left-right direction of the CNC forming grinder 1 is the W-axis direction, the front-rear direction is the X-axis direction, and the vertical height direction is Y. It is defined as the axial direction.

  Please refer to FIG. The processing unit 5 includes a grindstone cover 9, a forming grindstone 11, and a table 17, which function as means for processing the product workpiece W. Specifically, the product workpiece W is fixed on the table 17 mounted on the base board 19 and reciprocates together with the table 17 in the W-axis direction, while it can be moved and positioned in the X-axis, Y-axis, and W-axis directions. After the grindstone 11 is positioned at a predetermined position, the grindstone 11 is gradually moved downward in the Y-axis direction while rotating and brought into contact with the product workpiece W for grinding.

  The processing unit 5 includes a dress grindstone 21 and a dress cover 23 and is mounted on a base board 19. These function as dresser means for cutting the grindstone. Specifically, the grindstone cover 9, the forming grindstone 11, and the like move close to the dress grindstone 21. In FIG. 2, the moved position is shown as a grindstone cover 9 </ b> A and a shaping grindstone 11 </ b> A.

  Then, the molding grindstone 11 and the dress grindstone 21 are rotated, and the molding grindstone 11 is brought into contact with the dress grindstone 21 to be molded. In this example, the shape is gradually formed by moving the shaping grindstone 11 in the X-axis and Y-axis directions along the outer shape of the target shaping shape. In this dresser, there is no movement (movement other than rotation) of the tip R portion of the dressing grindstone 21, but it is inclined with respect to the tip R portion so as to always contact the contact surface of the forming grindstone 11 perpendicularly. It is configured.

  Please refer to FIG. The processing unit 5 includes a CCD (Charge Coupled Device) camera 13 and a transmission illumination device 15, which function as a part of the shape measuring means. The CCD camera 15 is normally stored and moves from the storage location to the imaging position at the time of imaging.

  The schematic configuration of the CNC forming grinder 1 is as described above, and the features that characterize the present invention will be described in more detail.

  The control unit 7C includes a dresser control unit that controls a dresser unit that molds a grindstone, a shape measuring unit that measures the shape of the shaped grindstone 11 that is a shaped grindstone, and the shape of the measured shaping grindstone 11 in advance. Difference information generating means for generating difference information with the set target shaping grindstone shape.

  Then, the control unit 7C further performs control to correct the dressing stone 11 according to the difference information. Here, the shape related to the forming grindstone 11 is: (a) the shape obtained by processing and transferring the product workpiece W by the forming grindstone 11 with the CCD camera 13 and obtained by image processing; (b) the shaping grindstone 11; The shape measured and recognized by means that can be directly measured, (c) the shape of the dummy workpiece DW processed by the forming grindstone 11 and captured by the CCD camera 13 and obtained by image processing. That is, the means which can specify the shape of the shaping grindstone 11 belongs to the technical scope of the present invention.

  Further, the control unit 7C performs control to shift to product work machining if the difference information is within the range of the dimensional tolerance, and performs control to shift to the correction dress if the difference information is outside the range of the dimensional tolerance. Yes, the correction dress is repeatedly executed until it falls within the dimensional tolerance.

  The operation of the CNC forming grinder 1 will be described with reference to FIG.

  First, in step SA01, first, CAD (computer aided design) shape data (DXF (Drawing Exchange Format) format) of a product shape is read into the storage unit of the NC device 7.

  FIG. 5 shows an example of the shape of the read product. Concave shape combining taper and R. Note that grinding wheel-shaped CAD data (DXF data) is also generated from the shape of the product. In the present embodiment, the forming grindstone 11 for grinding the shape combining the taper and R is formed and dressed.

  In step SA03, the control unit 7C sets measurement conditions including measurement points necessary for measurement based on the CAD shape data. For example, each line segment or R shape constituting the shape is defined as the measurement shape. At this time, each line segment or R shape may be further divided to increase the number of measurement points.

  In step SA05, the positional relationship, the cut amount, and the number of spark-outs required when forming the grindstone by the dresser means (the dress grindstone 21 or the like) (the grindstone without giving a cut in the operation performed at the final stage of grinding) The control unit 7C performs processing, dress definition, and condition setting of the processing that is performed along the shape by rotating 11. The processing is performed for removing uncut portions and improving the finished surface.

  In Step SA07, the dresser control means of the control unit 7C performs control to form the grindstone shape using the dresser means (dress grindstone 21 or the like) attached to the processing unit 5. In step SA07, correction dressing is also performed, which will be described in detail later.

  In step SA09, the shape of the forming grindstone 11 is transferred to the dummy workpiece DM. That is, by grinding the dummy workpiece DW with the shaping grindstone 11, the dummy workpiece DW becomes substantially the same shape as the shaping grindstone (here, there are some errors but the accuracy can be ignored). The dummy workpiece DW is as thin as several millimeters so that it can be easily processed, and the material is optimally compatible with the forming grindstone 11 to be used.

  In step SA11, the shape measuring means of the control unit 7C images the shape transferred (processed shape) on the dummy workpiece DW with the CCD camera 13 and automatically measures it. Please refer to FIG. As shown in the screens G1 and G2, the measurement is performed for each point SP of the actual dummy workpiece DW (dummy workpiece DW after processing) corresponding to a plurality of predetermined measurement points. Get the coordinate position. And a difference information production | generation means produces | generates difference information with a target shaping grindstone shape (for example, CAD shape data).

  In step SA13, the control unit 7C performs tolerance determination (assuming that the tolerance is set by inputting a numerical value in advance). If the measurement result is within the tolerance, the dress is terminated in step SA15. Then, in step SA17, the measurement result is output, and the process proceeds to processing of the product workpiece W in step SA19. If it is determined that the measurement result is out of the tolerance, the process proceeds to a correction dress at step SA07. The correction dress is repeated until it falls within the dimensional tolerance.

  Please refer to FIG. An example of measurement results before correction dressing is shown on the screen G3. That is, the measurement results for the measurement points P1 to P18 defined on the molded shape are shown.

  The position of the measurement point P1 is −0.0024 (mm), which is negative by this amount with respect to the target value (CAD graphic data). The position of the measurement point P2 is -0.0020 (mm), which is negative by this amount with respect to the target value (CAD graphic data). The position of the measurement point P3 is -0.0020 (mm), which is negative by this amount with respect to the target value (CAD graphic data).

  Further, the position of the measurement point P4 is -0.0073 (mm), which is negative by this amount with respect to the target value (CAD graphic data). The position of the measurement point P5 is -0.0073 (mm), which is negative by this amount with respect to the target value (CAD graphic data). The position of the measurement point P6 is -0.0071 (mm), which is negative by this amount with respect to the target value (CAD graphic data). The position of the measurement point P7 is -0.0071 (mm), which is negative by this amount with respect to the target value (CAD graphic data).

  Further, the position of the measurement point P8 is -0.0012 (mm), which is negative by this amount with respect to the target value (CAD graphic data). The position of the measurement point P9 is -0.0012 (mm), which is negative by this amount with respect to the target value (CAD graphic data). The position of the measurement point P10 is -0.0014 (mm), which is negative by this amount with respect to the target value (CAD graphic data). The position of the measurement point P11 is -0.0014 (mm), which is negative by this amount with respect to the target value (CAD graphic data).

  The position of the measurement point P12 is -0.0022 (mm), which is negative by this amount with respect to the target value (CAD graphic data). The position of the measurement point P13 is -0.0022 (mm), which is negative by this amount with respect to the target value (CAD graphic data). The position of the measurement point P14 is -0.0017 (mm), which is negative by this amount with respect to the target value (CAD graphic data). The position of the measurement point P15 is -0.0017 (mm), which is negative by this amount with respect to the target value (CAD graphic data).

  Further, the position of the measurement point P16 is −0.0032 (mm), which is minus this amount with respect to the target value (CAD graphic data). The position of the measurement point P17 is -0.0032 (mm), which is negative by this amount with respect to the target value (CAD graphic data). The position of the measurement point P18 is -0.0028 (mm), which is negative by this amount with respect to the target value (CAD graphic data).

  If the allowable tolerance is set to ± 0.005 (mm), it is determined that the tolerance is out of the range, and the process proceeds to step SA07. Note that the processing before the correction dress can be gradually brought close to the target dimension by making the processing amount minus in this way (processing is insufficient).

  In step SA07, a molding dress, measurement, and correction are performed. Using the correction algorithm, when the measurement result is out of the tolerance, the redress amount is obtained based on the measurement results (difference information) at the measurement points P1 to P18, and the correction amount of the dresser position, the dresser R, etc. is obtained, Make a correction dress. Thereby, the setup time by the operator is significantly shortened.

  Subsequently, the dummy workpiece DW is processed in step SA09, the measurement by the CCD camera is performed in step SA11, and the measurement determination is performed in step SA13.

  A screen G4 in FIG. 7 shows an example of a measurement result after correction dressing. That is, the measurement results for the measurement points P1 to P18 defined on the molded shape are shown.

  The position of the measurement point P1 is −0.0014 (mm), which is negative by this amount with respect to the target value (CAD graphic data). The position of the measurement point P2 is -0.0012 (mm), which is negative by this amount with respect to the target value (CAD graphic data). The position of the measurement point P3 is -0.0012 (mm), which is negative by this amount with respect to the target value (CAD graphic data).

  Further, the position of the measurement point P4 is -0.0022 (mm), which is negative by this amount with respect to the target value (CAD graphic data). The position of the measurement point P5 is −0.0022 (mm), which is minus this amount with respect to the target value (CAD graphic data). The position of the measurement point P6 is -0.0021 (mm), which is negative by this amount with respect to the target value (CAD graphic data). The position of the measurement point P7 is -0.0021 (mm), which is negative by this amount with respect to the target value (CAD graphic data).

  Further, the position of the measurement point P8 is -0.0005 (mm), which is negative by this amount with respect to the target value (CAD graphic data). The position of the measurement point P9 is -0.0007 (mm), which is negative by this amount with respect to the target value (CAD graphic data). The position of the measurement point P10 is -0.0008 (mm), which is negative by this amount with respect to the target value (CAD graphic data). The position of the measurement point P11 is −0.0008 (mm), which is negative by this amount with respect to the target value (CAD graphic data).

  The position of the measurement point P12 is 0.0007 (mm), which is plus this amount with respect to the target value (CAD graphic data). The position of the measurement point P13 is 0.0007 (mm), which is plus this amount with respect to the target value (CAD graphic data). The position of the measurement point P14 is 0.0005 (mm), which is plus this amount with respect to the target value (CAD graphic data). The position of the measurement point P15 is 0.0005 (mm), which is plus this amount with respect to the target value (CAD graphic data).

  Further, the position of the measurement point P16 is -0.0006 (mm), which is minus this amount with respect to the target value (CAD graphic data). The position of the measurement point P17 is -0.0006 (mm), which is negative by this amount with respect to the target value (CAD graphic data). The position of the measurement point P18 is -0.0005 (mm), which is negative by this amount with respect to the target value (CAD graphic data).

  If the allowable tolerance is set to ± 0.005 (mm), it is determined that the tolerance is within the tolerance range after the correction dress, so the process ends the correction dress in step SA15. Then, in step SA17, the measurement result is output, and the process proceeds to processing of the product workpiece W in step SA19.

  In step SA19, the product workpiece W is processed. Before processing the product workpiece W, the workpiece reference position is automatically measured to correct the processing start position of the forming grindstone 11, and the product workpiece W is processed. In addition, product workpiece processing is performed by plunge grinding while weaving a processing dress that feeds back the results corrected by the forming dress.

  In step SA21, workpiece measurement is performed. After product work processing is completed, product accuracy is confirmed by automatic measurement. If error factors such as thermal displacement during processing do not occur, processing accuracy equivalent to the molding accuracy at the time of molding dress can be obtained. Calibration is equipped with a calibration function, and it is possible to reduce errors with the master measuring instrument outside the machine.

  In step SA23, the measurement result is output and the process ends.

  In the above description of Step SA01 to Step SA23, the shape related to the forming grindstone 11 has been described as the shape obtained by imaging the shape of the dummy workpiece DW processed by the forming grindstone 11 with the CCD camera 13.

  However, the shape related to the forming grindstone 11 is a shape obtained by processing the product workpiece W with the forming grindstone 11 and transferring it with the CCD camera 13 and obtained by image processing, or a means capable of directly measuring the forming grindstone 11. Of course, the shape measured and recognized may be used.

The present invention is not limited to the embodiments of the invention described above, and can be implemented in other modes by making appropriate modifications.

DESCRIPTION OF SYMBOLS 1 CNC molding grinder 3 Main body part 5 Processing part 7 NC apparatus 7A Display part 7B Operation part 7C Control part 9 Grinding wheel cover 11 Grinding wheel 13 CCD camera 15 Transmission illumination device 17 Table 19 Base board 21 Dresser grinding wheel 23 Dresser cover W Product work DW Dummy work Dim coordinate axis

Claims (3)

In a molding grinder that performs molding grinding using a grinding wheel on product workpieces by automatic control of the control unit,
The controller is
A dresser control means for controlling the dresser means for molding the molding grindstone, by the dresser unit, a shape measuring means for measuring the shape according to the forming grindstone molded based on a predetermined target value, and the result of this measurement Difference information generating means for generating difference information with a preset target grinding wheel shape,
If the difference information is within the range of dimensional tolerance, the process shifts to product workpiece processing.If the difference information is outside the range of the dimensional tolerance, the process shifts to a correction dress for forming the forming grindstone by the dresser means. Perform control to execute the correction dress repeatedly until it falls within the tolerance,
The amount of processing before the correction dress by the dresser means is set in a state where processing is insufficient with respect to a predetermined target value, and control is performed to gradually approach the target shaping grindstone shape by the repeated correction dress. Mold grinding machine featuring The shape related to the forming grindstone is:
(A) a shape obtained by imaging a shape obtained by processing the product workpiece with the shaping grindstone with a CCD camera and image processing;
(B) a shape measured and recognized by means capable of directly measuring the forming wheel,
(C) The shape of the dummy workpiece processed by the forming grindstone is captured by a CCD camera and obtained by image processing,
The shape grinding machine according to claim 1, wherein the shape grinding machine has any one shape. In the forming grinder control method for performing forming grinding using a forming grindstone on the product workpiece by automatic control of the control unit, the control process is:
  A dresser control step for controlling the dresser means for forming the forming grindstone, a shape measuring step for measuring the shape of the shaping grindstone formed by the dresser means based on a predetermined target value, and a result of this measurement and A difference information generating step for generating difference information with the set target shaping grindstone shape,
  If the difference information is within the range of dimensional tolerance, the process shifts to product workpiece processing.If the difference information is outside the range of the dimensional tolerance, the process shifts to a correction dress for forming the forming grindstone by the dresser means. Perform control to execute the correction dress repeatedly until it falls within the tolerance,
The amount of processing before the correction dress by the dresser means is set in a state where processing is insufficient with respect to a predetermined target value, and control is performed to gradually approach the target shaping grindstone shape by the repeated correction dress. A method of controlling a forming grinder characterized by the above.

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