JPS63200951A - Duplex polishing method for sheet - Google Patents

Abstract

PURPOSE:To aim at improvement in parallelism and flatness, by applying a first polishing to both sides side by side of the sheet stuck to a work holder via wax, correcting each surface roughness and, after stress release by means of heating and annealing, applying a second polishing likewise. CONSTITUTION:A workpiece 1 of a germanium sheet or the like is stuck to a work holder 2 via wax 3, while a first polishing by diamond abrasive grains is applied to a polishing surface A, and surface from and surface roughness are corrected. Next, the surface A is turned down, and surface form and surface roughness of a polishing surface B are corrected likewise. Afterward, it is heated up to a temperature, for example, of 60-80 deg.C where the wax 3 is melted, annealed, stress is released, and the workpiece 1 is clamped in a curved state by a polishing strain difference, applying a second polishing to the A surface as well, then it is turned down, thus this second polishing is applied to the B surface as well, and both surfaces A and B are formed into a polished surface being high in from accuracy. Thus, parallelism and flatness is both surfaces of the sheet are polishable so favorably and, what is more, such a surface that is high in form accuracy is securable.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a method for polishing both sides of a thin plate in which shape finishing is performed by polishing.

〔Technical field〕

An example of applying the conventional method (Japanese Unexamined Patent Publication No. 61-33848) to a double-sided polishing method is shown in cross-sectional views of FIGS. ) is a thin plate of the workpiece, +21Vi workholder, (3) is wax, (A) is one side of the workpiece fil to be polished first, (Bi
is the other surface B that is polished following surface A.

In conventional polishing, the B side is bonded to the holder (2) via wax (3), and the A side of the workpiece fil is first polished to improve the surface shape and surface roughness of the A side. (8) expresses this.

Next, with the workpiece 11) and work holder (2) fixed, heat the wax (3) on a hot plate to a temperature that melts it, leave it for a few minutes, cool it slowly, and then fix the workpiece (2) again.
1) and work holder (2) are adhesively fixed with wax (3). At this time, due to the Twyman effect, it becomes thick (curved) and the stress is released and it is fixed. This state is shown in (b). Next, by polishing the A side again, the shape of the A side is fixed. The state is represented by fc). After that, wax (3) is melted and removed,
Separate the workpiece +11 from the work holder (2). Since the reaction force has already been released, it will not curve to the A side (the shape will be maintained with high accuracy, which is shown in (d)
The force of finishing one side with high precision in a manner similar to that of the previous method; (e) to (h) are the conventional method, and this method is also applied to the other side B of the workpiece, and the final (1) is obtained by polishing both sides and separating the workpiece (]) from the work holder (2).
It is.

[Problem that the invention seeks to solve]

However, although this method allows both sides to be machined with fairly high precision, when polishing the other polished surface B, even the first polished surface A finished with high precision in (d)
There was a problem in that the surface was slightly curved in the steps (f) to (g) due to the difference between the processing distortion caused by pre-processing and the processing distortion caused by final polishing.However, this invention has the same problem as above 9. The overall purpose is to obtain a method of polishing a thin plate in which both sides of the workpiece are not curved and the shape is maintained with high precision.

[Means for solving problems]

The method of polishing both sides of a thin plate according to the present invention is to perform first polishing on one side of a thin plate bonded to a work holder via wax to correct the surface roughness, and then heat and slowly cool the thin plate to relieve stress. [Operation] In this invention, the first polishing is applied to both surfaces of the thin plate, and the surface shape is corrected by applying second polishing to both sides of the thin plate that has been subjected to the first polishing. After that,
When the stress is released by heating and slow cooling, the thin plate is curved and fixed due to the difference between the processing strain caused by the pre-processing and the processing strain caused by the first polishing.

Since this stress-relieved thin plate is subjected to second polishing to modify the surface shape, it can be polished with good parallelism and flatness. [Example] Figure 1 (8) to (1) tfi In Figure 5, which shows the method for polishing both sides of a thin plate according to an embodiment in the order of steps using cross-sectional views showing changes in the shape of the thin plate, (1) is a thin plate workpiece, and in this case, green carbon carborundum ( (hereinafter abbreviated as GC) germanium polished with 14,000 abrasive grains, (2) is a work holder, +31
1d wax, in this case Electron wax (trade name Nippon Seiko Co., Ltd.).

Note that (A) represents one surface (A) of the workpiece (1) to be polished first, and (B) represents the other surface B.

First, the polished surface A of the workpiece (1) is polished with diamond abrasive grains to perform first polishing, thereby modifying the surface shape and surface roughness of the surface A. This is expressed in (a), which is 9
Next, the workpiece (1) is separated from the work holder (2), as shown in (b), and is greatly curved due to the Twyman effect. Next, the workpiece fil f: (C) is the workpiece turned over and bonded to the work holder (2) with wax (3), and (d) is the state where the B side has been first polished with diamond abrasive grains. be. At this time, the B side has G of the pre-processing.
Since machining distortion that is different in size from the machining distortion caused by C#4000 abrasive grains remains, the work holder (2) is heated to the temperature at which the wax (3) melts, in this case 60 to 80°C, for several minutes. When the workpiece is allowed to stand and then slowly cooled, the workpiece is curved and fixed due to the difference in processing strain. (e) shows this state.

Next, the B side is polished again and second polishing is performed to correct the shape of the B side. This state is expressed by ff). Finally, the workpiece (1) was turned over and bonded to the work holder (2) with wax (3), as shown in (g), and the A side was polished again and the shape of the A side was corrected. Noga(h)
It is. Then, place the workpiece (1) on the work holder (2).
(1) is separated from

By performing the above polishing process, a machined surface with high shape accuracy on both surfaces can be obtained.

In the above example, the workpiece fl) was made of germanium subjected to GO silanking, but germanium is not the only material to be used (the same effect can be expected with any thin plate that bends due to processing strain). The same effect can be expected even if the pre-processing condition is not only ramping (but also other polishing, cutting, grinding, etc.).

In addition, in the above explanation, one side is studied once, and both sides are combined.
After polishing, perform stress relief.

Furthermore, although a method of polishing both sides by polishing one side at a time has been shown, the same effect can be expected if stress is released in each polishing step and polishing is performed two or more times.

By the way, in the above description, the present invention can also be used to correct the curved shape of both planes and aspherical surfaces.

〔Effect of the invention〕

This invention has been explained above two times, and the first grinding M? After the surface roughness has been corrected, the thin plate is heated and slowly cooled to release stress.

Furthermore, by applying a second polishing to both surfaces of the thin plate that has been subjected to the first polishing, the surface shape is modified.

Both sides of thin plates can be polished to good parallelism and flatness.

This has the effect that a surface with high shape accuracy can be obtained.

[Brief explanation of the drawing]

Figures 1 (a) to (1) are cross-sectional views showing the opening of the shape of a thin plate in the double-sided polishing method for a thin plate according to an embodiment of the present invention, and Figures 2) to (1) are sectional views showing the conventional method. The steps are shown in the order of steps using cross-sectional views showing changes in the shape of the thin plate. In the figure, flll is a thin plate, (2) is a work holder,
(3) is wax, (A) is one side, IBm is the other side. In addition, in FIG. 1, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Claims] A thin plate bonded to a work holder via wax is subjected to first polishing on one side and both sides to correct the surface roughness, and then the thin plate is heated and slowly cooled to release stress, and then first polishing is applied. A method for polishing both sides of a thin plate, in which second polishing is applied to both sides of the thin plate to modify the surface shape.