JPS6362335B2 - - Google Patents

Description

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

[Prior art]

Figure 1a shows a cross-sectional view of shape processing by conventional polishing.
~b. In the figure, 1 is the workpiece, 2 is the work holder, and 3 is the wax. A of the workpiece 1 is the polished surface, and B is the surface that is bonded to the work holder 2 in the pre-processed state. It is.

The conventional polishing process is configured as described above, and by polishing the A side, the surface shape and surface roughness of the A side are corrected. This is illustrated in Figure 1a.
It is. Thereafter, the wax 3 is melted and gradually removed, and the workpiece 1 is separated from the work holder 2. This is illustrated in Figure 1b.

However, due to the difference in residual stress between the pre-processed surface B and the polished surface A, even though the workpiece 1 has good shape accuracy when it is adhesively fixed to the workpiece holder 2 after polishing, the workpiece After separating from holder 2,
Due to the Twyman effect, the polishing surface A is greatly curved, resulting in a significant deterioration in shape accuracy.

[Summary of the invention]

This invention was made in order to eliminate the above-mentioned drawbacks, and after polishing a workpiece bonded to a work holder via wax once, the workpiece is bonded to the work holder. By heating and slowly cooling the workpiece to release stress, and then polishing the workpiece, the polished surface of the workpiece will not be curved after the workpiece is separated from the workholder. First, it is an object of the present invention to provide a method of polishing a thin plate in which the shape can be maintained with high precision.

[Embodiments of the invention]

FIG. 2 is a sectional view showing changes in shape of a thin plate in the order of steps in a polishing method according to an embodiment of the present invention.
In this embodiment, the workpiece 1 is germanium that has been ground as a pre-process.

In the polishing method configured as described above, first, the A side of the workpiece 1 is polished to correct the surface shape and surface roughness of the A side. This is shown in a.Next, with the workpiece 1 and work holder 2 fixed, the wax 3 is heated on a hot plate to a temperature of 150°C, at which point it melts, left for several minutes, and then slowly cooled. The workpiece 1 and work holder 2 are bonded and fixed again with wax 3. At that time,
As the stress is released, the workpiece 1 is largely curved and fixed, and b represents this state.
Next, the shape of the A side is corrected by polishing the A side again. c represents this state.
After that, even if the wax 3 is melted and removed and the workpiece 1 is separated from the work holder 2, the polished surface A will not curve and its shape will be maintained with high accuracy because the stress has already been released. become.

In the above embodiment, the workpiece 1 and work holder 2 were heated to 150°C for several minutes.
Similar effects can be expected as long as the temperature and time range is such that the wax 3 is melted and residual stress is released.

In addition, the workpiece 1 was made of pre-processed germanium, but the same effect can be expected with not only germanium but also tungsten, molybdenum, silicon, etc., and the pre-processing conditions can be used not only with grinding but also with cutting, lapping, etc. Similar effects can be expected with those treated with

By the way, in the above explanation, the present invention was described for the case of plane correction, but it can also be used to correct the shape of other curved surfaces such as spherical and aspherical surfaces, and by applying this method to both sides, the shape of both sides can be corrected. It goes without saying that it can be done.

As a reference, the same effect can be expected by applying the same treatment to the grinding process.

〔Effect of the invention〕

As explained above, in this invention, a workpiece bonded to a work holder via wax is once polished, and then the workpiece is heated and slowly cooled while being bonded to the work holder. Since the workpiece is polished, the stress of the workpiece is released, the curvature of the polished surface upon separation from the workholder is effectively suppressed, and the shape accuracy is easily maintained.

[Brief explanation of drawings]

Figures 1a and b are cross-sectional views showing changes in the shape of a thin plate in the order of steps in a conventional polishing method, Figures 2a and b,
c and d are cross-sectional views showing changes in shape of a thin plate in the order of steps in an embodiment of the present invention. In the figure, 1 is a workpiece, 2 is a work holder, and 3 is wax. A of the workpiece 1 is a polished surface, and B is a surface bonded to the work holder 2 in a pre-processed state. In each figure, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Claims] 1 After polishing the workpiece bonded to the work holder via wax, the workpiece is heated and slowly cooled while it is bonded to the work holder to release the stress of the workpiece, and then the workpiece is A thin plate polishing method for polishing the workpiece.