JP2019013998A - Workpiece processing system and shape data acquisition device for grindstone - Google Patents

Abstract

To provide a workpiece processing system which precisely measures a shape of a grindstone and processes a workpiece using the shape data, and thereby can process the workpiece having a target processing shape without repeating a trial-and-error, and a shape data acquisition device for grindstone.SOLUTION: A workpiece processing system 1 including a machine tool 2 that processes a workpiece W with a grindstone S includes: a shape data acquisition device 10 which acquires shape data of the grindstone S; a calculation device 3 which calculates a contact point of the grindstone S to the workpiece W based on the shape data of the grindstone S obtained by the shape data acquisition device 10 and target processing shape data of the workpiece W; and a control device 4 which adjusts arrangement of the grindstone S to the workpiece W based on the calculation result of the contact point obtained by the calculation device 3.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a workpiece processing system and a shape data acquisition device for a grindstone, and more specifically, by accurately measuring the shape of a grindstone and machining the workpiece using the shape data, target machining without repeating trial and error The present invention relates to a workpiece machining system and a grindstone shape data acquisition device that can machine a workpiece having a shape.

  In a lens processing machine, a cup-type grindstone or a disk-type grindstone is used to perform curved surface processing on a workpiece having a curved surface such as a spherical lens or an aspherical lens (for example, Patent Document 1). For example, in the case of a cup-type grindstone, based on the inner diameter, outer diameter, grindstone length, and the curvature to be created, the grindstone tilt angle and lateral movement amount are calculated to position the grindstone during processing. In the case of a cup-type grindstone, the positioning of the grindstone is calculated on the assumption that the shape of the tip of the grindstone is an ideal semicircular shape.

  However, even if the actual cup type grindstone is new, the shape of the tip of the grindstone is not an ideal semicircular shape, or the shape of the tip of the grindstone has already been used in other processing. Many things are changing. When a workpiece is machined using such a cup-type grindstone, a large curvature error and uncut portion of the central portion (so-called velvet) occur, so it is necessary to repeat trial machining until it reaches the reference value while applying correction. . Therefore, there is a problem that a great deal of time and materials are required for trial processing.

  In the case of a cup-type grindstone, it is necessary to measure the grindstone length with a measuring tool such as a vernier caliper after being mounted on a lens processing machine. While such a measurement takes a lot of time, it can measure three points of the inner diameter, the outer diameter, and the length of the grindstone, but there is a problem that the tip shape of the cup-type grindstone cannot be measured. .

JP 2003-150216 A

  An object of the present invention is to accurately measure the shape of a grindstone and machine the workpiece using the shape data, thereby enabling workpiece machining that can be machined into a workpiece having a target machining shape without repeating trial and error. It is providing a shape data acquisition device for a system and a grindstone.

  In order to achieve the above object, a workpiece machining system according to the present invention is a workpiece machining system including a machine tool for machining a workpiece with a grindstone. The shape data obtaining device for obtaining the shape data of the grindstone, and the shape data obtaining device. An arithmetic device that calculates a contact point of the grindstone with respect to the workpiece based on the obtained shape data of the grindstone and target machining shape data of the workpiece, and the workpiece based on a calculation result of the contact point obtained by the arithmetic device And a control device for adjusting the arrangement of the grindstone with respect to.

  Further, the shape data acquisition device for a grindstone of the present invention is a shape data acquisition device for obtaining shape data of a grindstone used for processing a workpiece, and includes a mounting base for holding the grindstone and a measurement device for measuring the shape of the grindstone. And a transfer unit that transfers the measuring device along the cross-sectional direction of the grindstone at a position facing the tip of the grindstone held on the mounting base.

  In the present invention, a shape data acquisition device that acquires shape data of a grindstone, and an arithmetic device that calculates a contact point of the grindstone with respect to the workpiece based on the shape data of the grindstone obtained by the shape data acquisition device and the target machining shape data of the workpiece And a control device that adjusts the arrangement of the grindstone with respect to the workpiece based on the calculation result of the contact point obtained by the arithmetic device, so that the shape of the grindstone can be measured accurately and efficiently, and trial and error are repeated. And can be machined into a workpiece having a target machining shape. As a result, the time required for trial machining can be greatly reduced. Further, by previously obtaining the correlation between the grinding wheel lengths on the shape data acquisition device, it is not necessary to measure the grinding wheel length after the grinding wheel is attached to the machine tool. Further, it is possible to grasp the shape change of the grindstone, and in particular, in aspherical processing, the point of contact with the grindstone changes with time, which is significant. As a result, the wear rate of the grindstone can be grasped over time, and the life and performance of the grindstone can be evaluated.

  In the present invention, the shape data acquisition device includes a mounting base for holding the grindstone, a measuring device for measuring the shape of the grindstone, and a measuring device at a position facing the tip of the grindstone held on the mounting base. It is preferable to provide a transfer unit for transferring along the line. Thereby, the shape of the grindstone can be accurately and efficiently measured.

  In this invention, it is preferable that a measuring apparatus is a laser measuring device which measures the shape of a grindstone by irradiating a strip | belt-shaped laser beam or scanning the cross-sectional direction of the said grindstone, irradiating a point-like laser beam. Thereby, the shape of the grindstone can be accurately and efficiently measured.

It is explanatory drawing which shows roughly the workpiece processing system which consists of embodiment of this invention. It is a perspective view which shows an example of the shape data acquisition apparatus which consists of embodiment of this invention. It is sectional drawing for demonstrating the calculation method of a contact in this invention. It is sectional drawing for demonstrating the shape measurement of the conventional grindstone. It is explanatory drawing which shows the curvature error on a measuring machine.

  Hereinafter, the configuration of the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 schematically shows a workpiece machining system according to an embodiment of the present invention.

  As shown in FIG. 1, a workpiece processing system 1 according to an embodiment of the present invention includes a machine tool 2 that processes a workpiece W with a grindstone S, and a shape data acquisition device 10 for a grindstone that acquires shape data of the grindstone S. The calculation device 3 that calculates the contact point of the grindstone S with respect to the workpiece W based on the shape data of the grindstone S obtained by the shape data acquisition device 10 and the target machining shape data of the workpiece W, and the contact point obtained by the calculation device 3 And a control device 4 that adjusts the arrangement of the grindstone S with respect to the workpiece W based on the calculation result.

  The machine tool 2 has a curved surface with respect to the workpiece W by mounting and rotating the grindstone S on a rotatable main spindle, rotating the workpiece W, and relatively moving and swinging the grindstone S and the workpiece W. (Spherical or aspherical) processing can be applied. For example, when a cylindrical cup-type grindstone is used as the grindstone S, curve generator machining (CG machining) in which one end of the cup-type grindstone is brought into contact with a part of the workpiece W can be performed. In the case of a curve generator processing machine using a cup-type grindstone, the arrangement of the grindstone S is appropriately adjusted based on the spherical surface creation principle.

  The arithmetic device 3 calculates the contact point of the grindstone S with respect to the workpiece W based on the shape data of the grindstone S measured by the shape data acquisition device 10 and the target machining shape data that is the final shape of the workpiece W. The arithmetic device 3 may be provided outside the machine tool 2 as shown in FIG. 1 or may be incorporated inside the control device 4. In addition, the arithmetic device 3 is connected to the machine tool 2 and the shape data acquisition device 10 to manage the shape data of the grindstone S obtained by the measuring device 12, and to process data related to the life and performance of the grindstone S. It is also useful to manage. As the arithmetic device 3, for example, a personal computer can be used.

  The control device 4 is provided in the machine tool 2. The control device 4 adjusts the arrangement of the grindstone S with respect to the workpiece W based on the contact calculated by the arithmetic device 3. More specifically, the position of the grindstone S with respect to the workpiece W is corrected based on the contact calculated by the arithmetic device 3, and adjustment is performed so that the contact is positioned on the central axis of the workpiece W. In this way, by performing processing while being positioned at the contact point of the grindstone S and the center axis of the workpiece W, it is possible to eliminate the occurrence of kinks.

  FIG. 2 shows a shape data acquisition apparatus according to an embodiment of the present invention. As shown in FIG. 2, the shape data acquisition device 10 includes a mounting base 11 that holds the grindstone S, a measurement device 12 that measures the shape of the grindstone S, and a transfer unit 13 that transports the measurement device 12. . When measuring the shape of the grindstone S, the grindstone S is fixed to the mounting base 11, and the measuring device 12 scans the grindstone S so that the shape data of the grindstone S can be acquired. Yes.

  The mounting base 11 has an attachment portion 11a for holding the grindstone S at one end thereof, and the grindstone S is detachable from the attachment portion 11a. The attachment portion 11a can also be configured to hold the grindstone S rotatably and rotate around the central axis of the grindstone S when measuring the shape of the grindstone S.

  Although the measuring apparatus 12 will not be specifically limited if the shape of the grindstone S can be measured, For example, a laser measuring device can be used. In particular, as a laser measuring device, the measurement is performed by irradiating the grinding wheel S with a belt-shaped laser beam, or while irradiating the grinding stone S with a point-like laser beam (in the case of a cup-type grinding wheel). Is preferably a laser measuring instrument that scans and measures in a direction perpendicular to the rotation axis of the grinding wheel S). Thereby, since the shape of the grindstone S can be grasped by one measurement and the time required for the measurement is short, the shape of the grindstone S can be measured accurately and efficiently. Moreover, the shape data of the grindstone S obtained by such a laser measuring machine is point cloud data that represents the shape of the tip of the grindstone S by a number of points.

  The transfer unit 13 is a measuring device at a position facing the tip of the grindstone S held on the mount 11 along the cross-sectional direction of the grindstone S (in the case of a cup-type grindstone, the direction orthogonal to the rotation axis of the grindstone S). 12 is transferred. In addition, the transfer unit 13 is configured to scan a position that passes through the rotation axis of the grindstone S, in other words, a position that is the diameter of the grindstone S.

  The process until the workpiece W is machined in the workpiece machining system will be described. First, the grindstone S is fixed to the mounting portion 11 a of the mount 11, and the shape of the grindstone S is measured by scanning the grindstone S with the measuring device 12. Based on the shape data of the grindstone S obtained in this way, as shown in FIG. 3, the circle Q of the curvature R of the target machining shape having the center O on the center line CL of the grindstone S and the grindstone S 2 Find two contacts P. There is one contact point P on each side of the center line CL. Based on this contact P, the grindstone diameter D and grindstone length H1 of the grindstone S are obtained. As shown in FIG. 3, the grindstone diameter D is the distance between the points P at the tip of the grindstone S, and the grindstone length H1 is the distance from the bottom surface in the measuring device 12 to the contact P. Then, the grindstone length H2 in the machine tool 2 is obtained in advance from the grindstone length H1 in the measuring device 12. The grindstone length H2 is calculated in consideration of the difference in the reference plane between the measuring device 12 and the machine tool 2.

  Based on the grindstone diameter D and grindstone length H2 of the grindstone S calculated as described above, the inclination angle θ and the lateral movement amount of the grindstone S are calculated, and the grindstone S is positioned with respect to the workpiece W. Based on the positioning calculation result, the machine tool 2 starts machining the workpiece W.

  Here, FIG. 4 is for demonstrating the shape measurement of the conventional grindstone. In the conventional measuring method, a caliper or the like is used when measuring the shape of the grindstone S. In this case, only three points of the outer diameter d1, the inner diameter d2 and the grindstone length of the grindstone S can be measured. is there. In the first trial machining, the actual curvature r1 (radius on the inner side in the radial direction) and the curvature r2 (curvature on the outer side in the radial direction) calculated from the dimensions of the grindstone S often do not match, and correction is performed several times. Needed. This is because, in the conventional positioning calculation, the calculation is based on the assumption that the shape of the tip of the grindstone S is a semicircle (diameter RL shown in FIG. 4) having the grindstone width as a diameter. Yes. Therefore, the position of the contact point between the workpiece W and the grindstone S is different from the actual contact point p1 and the calculated contact point p2. When the workpiece W is machined in such a state, a thigh k having a diameter t is formed at the center of the workpiece W due to a deviation between the contact point p1 and the contact point p2. At this time, the curvature r1 and the curvature r2 do not match, and the curvatures r1 and r2 are different. In FIG. 4, WL is the central axis of the workpiece W, and θ is the inclination angle of the grindstone S.

  On the other hand, in this invention, based on the shape data acquisition apparatus 10 which acquires the shape data of the grindstone S, the shape data of the grindstone S obtained by the shape data acquisition apparatus 10, and the target machining shape data of the workpiece W. Since it has the control device 4 that calculates the contact point P of the grindstone S with respect to the workpiece W and adjusts the arrangement of the grindstone S with respect to the workpiece W based on the calculation result of the contact point P, the shape of the grindstone S can be measured accurately and efficiently. The workpiece W having the target machining shape can be machined without repeating trial and error. As a result, the time required for trial machining can be greatly reduced. Further, by previously obtaining the correlation between the grinding wheel lengths on the shape data acquisition device 10, it is not necessary to measure the grinding wheel length after the grinding wheel S is attached to the machine tool 2. Furthermore, the shape change of the grindstone S can be grasped, and the point of contact with the grindstone S changes with time particularly in aspherical processing, which is significant. Thereby, the wear rate of the grindstone S can be grasped over time, and the life and performance of the grindstone S can be evaluated.

  In the work processing system 1 and the shape data acquisition device 10 described above, an example in which a convex lens is processed using a cup-type grindstone as the grindstone S is shown. The present invention may be applied to a spherical lens. Moreover, the kind of grindstone S is not specifically limited, A disk type grindstone can be employ | adopted for others.

  Eight types of lenses (Comparative Examples 1 to 4 and Examples 1 to 4) were processed by varying the dimensions of the grindstone for processing the workpiece (lens) as shown in Tables 1 and 2.

  Comparative Examples 1 to 4 were processed using only a curve generator processing machine (in-house product MZ1-30A). In Examples 1 to 4, after measuring the shape data of the grindstone using the shape data acquisition device and calculating the contact point of the grindstone with respect to the workpiece based on the shape data and the target machining shape data of the workpiece, the curve generator machining machine Was used to adjust the arrangement of the grindstones based on the contact calculation results.

  In Comparative Examples 1 to 3 and Examples 1 to 3, the workpiece curvature was processed to 60.225 mm, and in Comparative Example 4 and Example 4, the workpiece curvature was processed to 47.693 mm. Moreover, the same kind of grindstone was used in each set of Comparative Example 1 and Example 1, Comparative Example 2 and Example 2, Comparative Example 3 and Example 3, Comparative Example 4 and Example 4.

  Evaluation of each lens evaluated the curvature error (micrometer) and the thigh (mm) on a measuring machine, The result was combined with Table 1 and Table 2, and was shown. The evaluation result means that the smaller the numerical value is, the better the processing result of the lens is, and the evaluation is performed by comparing the above-described comparative examples and examples.

  The curvature error (μm) on the measuring machine is measured using a ring spherometer 20 as shown in FIG. 5, and the diameter of the reference delta ring 21 (0.8 to 0.9 times the diameter of the workpiece). This means the difference in height between the R master 22 and the center of the workpiece W. The curvature error e shown in FIG. 5 indicates that the ring spherometer 20 is moved onto the workpiece W after the ring spherometer 20 is aligned with the R prototype 22 having the curvature R of the target machining shape, and the dial gauge 23 is read. Is measured.

  As can be seen from Tables 1 and 2, the lenses of Examples 1 to 4 are compared with Comparative Examples 1 to 4 by precisely measuring the shape of the grindstone and processing the workpiece based on the measurement data. Curvature error and navel were improved. In general, the curvature error on the measuring machine has a tolerance of about ± 3 (μm), but in all of Examples 1 to 4, it was within the range of the tolerance. Moreover, about the navel, it became 0 mm by one process in all of Examples 1-4, and the outstanding improvement effect was acquired.

DESCRIPTION OF SYMBOLS 1 Work processing system 2 Machine tool 3 Arithmetic apparatus 4 Control apparatus 10 Shape data acquisition apparatus 11 Mounting base 11a Mounting part 12 Measuring apparatus 13 Transfer unit D Grinding wheel diameter d1 Outer diameter d2 Inner diameter k Navel H1 Grinding wheel length O Center P, p1, p2 Contact Q Circle R, r1, r2 Curvature S Grindstone t Diameter W Work CL Centerline RL Semicircle WL Center axis θ Inclination angle

Claims (5)

  In a workpiece processing system including a machine tool that processes a workpiece with a grindstone, a shape data acquisition device that acquires shape data of the grindstone, shape data of the grindstone obtained by the shape data acquisition device, and a target machining shape of the workpiece A calculation device that calculates a contact point of the grindstone with respect to the workpiece based on the data, and a control device that adjusts the arrangement of the grindstone with respect to the workpiece based on the calculation result of the contact point obtained by the calculation device. Characteristic workpiece machining system.   The shape data acquisition device includes a mounting base for holding the grindstone, a measuring device for measuring the shape of the grindstone, and the measuring device at a position facing the tip of the grindstone held by the mounting base. The workpiece processing system according to claim 1, further comprising a transfer unit that transfers along the cross-sectional direction.   The measuring apparatus is a laser measuring instrument that measures the shape of the grindstone by irradiating a belt-shaped laser beam or scanning a cross-sectional direction of the grindstone while irradiating a point-shaped laser beam. Item 2. The workpiece machining system according to Item 2.   A shape data acquisition device for acquiring shape data of a grindstone used for processing a workpiece, a mounting base for holding the grindstone, a measuring device for measuring the shape of the grindstone, and a tip of the grindstone held by the mounting base And a transfer unit for transferring the measuring device along a cross-sectional direction of the grindstone at a position opposite to the grindstone.   The measuring apparatus is a laser measuring instrument that measures the shape of the grindstone by irradiating a belt-shaped laser beam or scanning a cross-sectional direction of the grindstone while irradiating a point-shaped laser beam. Item 5. The shape data acquisition device for a grindstone according to Item 4.

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