JP2904803B2 - Surface processing method - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for processing a flat surface. INDUSTRIAL APPLICABILITY The present invention is used for planar processing of a near net shape product having a planar surface by, for example, powder metallurgy.

[Prior Art] Near net shape molding using powder metallurgy has been performed mainly on ceramic products. As a typical process, there is a die press molding method in which powder is subjected to die press molding, and then fired to be solidified into a product. The obtained baked product has dimensions and shapes close to those of the final product, and there is a great merit if applied to parts having complicated shapes and parts made of difficult-to-process materials.

A relatively difficult product obtained by applying this process is a grooved disk shown in FIG. FIG. 4 shows an AA cross section of FIG. The intermediate product 21 shown in FIG. 3 is manufactured by die press molding, and the upper and lower surfaces of the disk are ground 25, 26 as shown in FIG.
And the product 21 indicated by oblique lines is removed. The depth from the upper grinding surface of the inner and outer groove bottoms 23 is determined respectively,
Here, the description will be made assuming the same.

In order to make the groove bottom depth uniform in each groove 22, it is necessary to form the groove bottom 23 of the intermediate product 21 of FIG. 3 on the same plane. However, when making a plate-shaped product by die press molding,
As shown in FIG. 5, warpage and distortion are likely to occur, and in mass production, the degree generally varies from product to product. Therefore, in principle, it is necessary to measure the planar shape of each product, select only good-shaped products, and then process the products.

Conventionally, as a flat surface processing method, as shown in FIG.
The work piece 8 is set on a mounting table having a flat surface, and the tool 6
There is a widespread use of a processing method in which the target is moved in a plane at a target height in parallel with the plane. However, in this method, when the workpiece 8 having a relatively poor shape is placed on the mounting table, the seating is poor, so that it is apt to perform double surface processing due to backlash, which causes a decrease in the accuracy of the finished dimension of the plane. It has become.

The workpiece 8 is a grooved intermediate product 21 shown in FIG.
In such a case, even if the upper and lower surfaces are processed well and parallelism is achieved, in order for the groove bottom depth to be the same on the inner and outer circumferences, the surface passing through the groove bottom and the upper and lower surfaces must be parallel. Must. In an intermediate product having a bad shape and a loose shape, the surface passing through the groove bottom is not horizontal, and if the upper and lower surfaces are machined in this state, the groove bottom depth differs between the inner and outer peripheries. From the above, even if the inner and outer groove bottoms of the intermediate product are on the same plane with the target accuracy and a theoretically good product can be obtained, the inner and outer groove bottom depth dimensions due to shape defects during surface processing It is out of specification, resulting in lower yield.

[Problems to be Solved by the Invention] The present invention solves the above-mentioned problems in the prior art when performing flat processing of a product having a flat surface, and prevents the product dimensions from being out of specification due to the flat processing. The aim was to improve yield and provide an efficient manufacturing process.

[Means for Solving the Problems] A planar machining method of the present invention for achieving the above object is a planar machining method for a product having a flat surface, comprising a cutting device, a grinding device, or a polishing device, and a product attached to the device. A jig having a driving device for fixing and changing the direction and position of the product, a position sensor for measuring at least three or more arbitrary points on the plane of the product, and processing the measured values to obtain a virtual plane Processing is performed using an arithmetic unit that transmits a control signal for moving and fixing a plane to a target processing plane position.

 Hereinafter, the present invention will be described in detail.

The present inventor has proposed a ceramic intermediate product shown in FIG.
In the measurement of the planar shape of No. 21, it was found that although the shape was a little bad, but the surface processing was good, the ones that could well enter the standard dimensions would be out of specification after the surface processing. Therefore, the mechanism for causing the dimension deviation has been theoretically elucidated, and a countermeasure has been invented to establish the processing method of the present invention.

First, before the description of the processing method of the present invention, a method capable of accurately measuring the planar shape of a workpiece without a measurement error will be described. As shown in FIG. 1, the platen surface 7b of the jig 7 is placed so as to match the platen surface 1b of the stand 1 with a platen, and the DUT 3 is firmly fixed to the mounting device 4 of the jig 7. In the measurement, the jig 7 is slid on the surface 1b of the stand 1 so that the measurement point of the DUT 3 is just below the contact 2a, and then the contact 2a is brought into contact with the measurement point to record the indicated value. . When a non-contact measurement device is used, the probe position is measured according to the same method as the measurement point. In order to obtain surface information, three or more points may be measured.

By the way, in the above-described measuring method, an error occurs in the measured value due to a variation in the installation state of the DUT 3 on the mounting device 4. FIG. 7 is a diagram showing a mechanism in which a measurement error occurs when the DUT 3 is inclined with respect to the surface of the platen of the stand 1, and is represented in a two-dimensional space for simplicity. With the point O as the origin, the x coordinate is taken in the horizontal direction and the z coordinate is taken in the vertical direction. It is assumed that the object to be measured is a flat plate, and its width is b, and the difference between the z-coordinates of both width ends due to the inclination is h. Arbitrary measurement point P on the upper surface
Assuming that the coordinates of (x _P , z _P1 ), z _P1 = h · x _P / b (1) Assuming that the DUT 3 is completely horizontal, z _P2 = 0 (2). Therefore, when the measurer recognizes that the object to be measured has been placed horizontally and is actually inclined as shown in FIG. 7, the measurement error ε _P becomes ε _P = h · x _P / b (3) ). That is, the measurer recognizes that the point P is out of the plane by ε _{P based on} the information from the measured value z _P1 . To eliminate error due to the inclination determines a virtual plane O-Q as a reference to measure the positions of both points O and the point Q of the plate, less the position z _P3 of the virtual plane from the position z _P1 any point Correction value z _P4
May be used instead of the measured value. For Figure 7, if the coordinates of any point P on the virtual plane O-Q and _{(x P, z P3),} z P3 = h · x P / b ... (4) , and the formula (1) equal to the measured values z _P1. Therefore, correction values z _P4 is _{z P4 = z P1 -z P3 =} 0 = z P2 ... (5) , and the correction value are equal error is eliminated in true value z _P2.

Generally, in order to measure the shape of a plane, it is necessary to think in a three-dimensional space. FIG. 8 shows a case where the DUT 3 placed on the mounting device 4 is viewed from directly above, where x-coordinates and y-coordinates are taken in a horizontal plane, and z-coordinates are taken in a vertical direction. Coordinate by measurement of any point P in the plane (x _P, y _P,
z _P1 ). Further, the coordinates of an arbitrary point P of the virtual plane to be introduced in order to correct the error due to the inclination _{(x P, y P, z} P3) as shape amount to determine the use of the correction value z _P4 follows.

z _P4 = z _P1 −z _P3 (6) Here, as a correction value, as shown in FIG. 8, at least three or more measured values are taken in a plane without bias, and a plane passing as close as possible to this measurement point is used. And the following equation is obtained.

z _P3 = a ₁ · x _P + a ₂ · y _P + a ₃ (7) The coefficients a ₁ , a ₂ , and a _{3 on} the right side of the equation (7) can be determined by an arbitrary method. For example, each measured value is used. From the least squares method. The above calculation is input to a computer and automatically performed.

FIG. 2 shows an embodiment of a plane processing apparatus for carrying out the method of the present invention. In FIG. 2, reference numeral 8 denotes a workpiece to be subjected to planar processing, 9 denotes a mounting device for fixing the workpiece 8, 10 denotes a driving device for moving the mounting device 9, and 11 denotes a measuring device for measuring the position of the workpiece. , 12 is a processing tool, 13 is a reference virtual surface of a workpiece, 14 is a processing surface of the processing tool 12, and 15 is a calculation / control device.

As shown in FIG. 2, the workpiece 8 is fixed to the mounting device 9 with the processing surface of the workpiece 8 facing upward. Next, the measuring device 11 takes at least three or more measurement points on the surface to be processed to determine the position. The measured value is input to the arithmetic and control unit 15, and the reference virtual plane 13 of the workpiece is obtained by the method of the above equation (7). At this time, if the shape of the surface is measured at the same time, non-standard products can be sorted out without going to the subsequent process.

In the case where the plane passing through the groove bottom 23 shown in FIG. 4 must be parallel to the processing surface, the equation (7) may be obtained from the measured value of the groove bottom position. Once the reference virtual plane 13 is obtained,
A control command is transmitted from the arithmetic / control device 15 to the drive device 10 to move the workpiece 8 so that the reference virtual surface 13 and the processing surface 14 are optimally arranged. In the case of FIG. 4, the reference virtual surface of the groove bottom 23 is kept parallel to the processing surface 14, and the distance between the reference virtual surface and the processing surface is adjusted so that the groove depth is optimized. In this state, the workpiece is strongly fixed and the surface is machined by the machining tool 12.

As described above, according to the present invention, when there is a reference surface that must be satisfied as a product standard when processing a conventional flat surface, a deviation from the standard occurs because the positional relationship between the processed surface and the reference surface cannot be controlled. However, this control has been made possible to prevent out-of-specification, to improve the quality of the product, and to improve the yield significantly.

Embodiment An embodiment of the present invention will be described with reference to FIG. 2, FIG. 4, and Table 1. The structure and arrangement of the implemented device are based on FIG. 2, and the conditions are as shown in Table 1.

Comparison between the conventional method and the method of the present invention was performed under the conditions shown in Table 1.
As shown in FIG. 6, the conventional method refers to a method in which the workpiece mounting base is an electromagnetic surface plate, and the position of the workpiece is manually determined and processed. In the conventional method, the change in the outer groove depth of the processed product is 0.4 mm, whereas in the method of the present invention,
It is halved to 0.2mm. From this, it became clear that the method of the present invention is effective for improving the accuracy of planar processing.

[Effects of the Invention] The present invention is configured and operated as described above, thereby enabling control of the positional relationship between a processed surface and a reference surface during processing of a flat surface to prevent deviation from the standard. There is a remarkable effect that allows for an improvement in the quality and yield of the steel.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a planar shape measuring device, FIG. 2 is a configuration diagram of an example of a planar processing device for carrying out the present invention, and FIG. FIG. 4, FIG. 4 is a sectional view taken along line AA of FIG. 3, FIG. 5 is a perspective view showing an example of a defective shape, FIG.
The figure is a drawing for explaining an example of mounting failure of the workpiece, and FIG.
The figure is a plan view of a disk-shaped flat plate as an object to be measured. 1 ... stand with surface plate, 2 ... contact of measuring device, 3
... Workpiece to be measured, 4... Mounting device, 5...
8 Workpiece, 9 Mounting device, 10 Drive device, 11 Measuring device, 12 Processing tool, 13 Reference virtual surface, 14 Processing surface, 15 Calculation / control apparatus.

Claims (1)

(57) [Claims] In a method for processing a product having a flat surface, a jig having a cutting device, a grinding device, or a polishing device, a driving device for fixing the product to the device and changing the orientation and position of the product, and A position sensor for measuring at least three or more arbitrary points on the plane and an arithmetic unit for processing the measured values to obtain a virtual plane and transmitting a control signal for moving and fixing the virtual plane to a target processing plane position. A method for processing a flat surface, characterized in that the flat surface is processed.