JPH02279273A - Device and method for polishing - Google Patents

Abstract

PURPOSE:To easily set the accuracy of a polishing work face to a desired value with good accuracy without performing the secondary work of the upper face of a polishing surface plate by providing a passage where a fluid is fed from a controller between the controller controlling and feeding the temperature of the fluid and polishing surface plate. CONSTITUTION:A work is worked by pressing it to the upper face of a polishing surface plate 11 located on a base plate 9. In this case a fluid is fed from a controller 8 to the passage provided between the base plate 9 and polishing surface plate 11, the lower face of the polishing surface plate 11 is cooled or heated to a specific temperature, a temperature difference is provided on the upper and lower faces of the polishing surface plate 11, the upper face of the polishing surface plate 11 is deformed in a specific shape and the work is subjected to polishing at a desired accuracy.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a polishing device, and more particularly, to a polishing device for polishing an optical element,
The present invention also relates to an apparatus and a polishing method for polishing electronic components such as magnetic heads with high precision.

[Conventional technology]

In the contact polishing method, in which the surface to be polished is pressed against a polishing surface plate for processing, the polishing accuracy of the surface to be polished largely depends on the accuracy of the polishing work surface of the polishing surface plate, and is In order to obtain the desired processing accuracy, it is necessary to create a polishing work surface of the polishing surface plate that is commensurate with the processing accuracy.

FIG. 4 is a perspective view showing a conventional polishing apparatus, in which 1 is a main body, 1 is a polishing surface plate, and a continuously variable speed motor (not shown) installed in the main body 1 is the drive source, and a spindle (not shown).

The material can be soft metal such as tin or copper, resin, or iron-based.
Copper casting etc. are used. Further, the polishing work surface is provided with grooves in a spiral shape, a twill shape, a concentric circle shape, etc. 17 is a work plate, which has a circular shape, and the work is adhered to the bottom surface (
(glue, water adhesive) fixed. 18 is a carrier arm fastened to the pillar 20, and two rollers 19
is attached, and serves to position the work plate 17 on the polishing surface plate 11 via the roller 19, and at the same time, to smoothly rotate the work plate 17 during processing.

A processing liquid nozzle 26 supplies a polishing liquid onto the polishing surface plate 11 during processing.

Figure 5 (al, (bl K) shows a concrete outline of the conventional method of creating a polishing work surface for a polishing surface plate, and Figure 5 (a
) is a longitudinal sectional view, and FIG. 5(b) is a plan view.

In FIG. 5(a), the polishing surface plate 11 is placed on the base plate 9 fixed to the rotating shaft 60 at the loose fitting portion of the guide bin 11b. A surface plate correction ring 25 is placed on the polishing surface plate 11 in place of the work plate 17, and a correction ring 25 has hard particles such as diamond embedded in the lower surface of the surface plate correction ring 250 to promote correction efficiency. A plurality of pellets 26 are adhesively fixed.

In Figure 5 (bl), the surface plate correction ring 25 is
The polishing surface plate 11 is placed at a predetermined position by a carrier arm 18 via a carrier arm 9 . When the polishing surface plate 11 rotates, the surface plate correction ring 25 rotates along with it. At this time, the sprayer (
(not shown) intermittently sprays water to smooth the rotation of the surface plate correction ring 250. The surface plate correction ring 25 is positioned and fixed by the carrier arm 18 so that it is at an optimal position within a distance of 1% m from the center of the polishing surface plate 11 according to the amount of correction and the shape of the surface plate. Ru. When the polishing surface plate 11 is corrected at a distance l, the polishing surface plate 11 is as shown in Fig. 5 (a
) is modified to an intermediate shape as shown in A. Similarly m
When the polishing surface plate 11 is corrected as shown in Fig. 5 (
It is corrected into a convex shape as shown in B of a). This is an effective application of the change in the wear amount of the surface plate due to the movement of the center of gravity of the surface plate correction ring 250, and the management of the position of the surface plate correction ring 25 and the machining time currently relies on the operator's intuition.

[Problem to be solved by the invention]

However, in the conventional method described above, the correction work takes time and the correction accuracy is poor. Furthermore, due to the large amount of wear on the top surface of the polishing surface plate due to correction, the grooves formed become shallow, significantly shortening the life of the polishing surface plate.

In order to solve this problem, an object of the present invention is to provide an apparatus that can easily bring the accuracy of the polishing surface plate within the required range without adding any processing to correct the accuracy.

[Means to solve the problem]

In order to achieve the above object, the present invention is constructed by controlling the temperature of the bottom surface of the polishing surface plate so as to maintain the amount of thermal deformation at a target value based on the thermal deformation caused by the temperature difference between the top and bottom surfaces of the polishing surface plate. be done.

[Effect]

When one side of a surface plate, which remains flat at a constant temperature, is cooled or heated, and the other side is kept at a constant temperature, a temperature difference will occur between the two sides, and the resulting difference in thermal expansion will cause polishing to be difficult. It can cause the board to warp.

When the lower surface of the polishing platen is cooled, the upper surface deforms into a medium convex shape, and when the lower surface of the polishing platen is heated, the upper surface deforms into an intermediate shape.

Therefore, in the contact polishing method in which the surface to be polished is pressed against the polishing surface plate for processing, when modifying the polishing surface plate to obtain the desired processing accuracy, the cooling or heating temperature of the polishing surface plate must be adjusted. By controlling this, the desired surface plate accuracy can be obtained.

〔Example〕 Embodiments of the present invention will be described below based on the drawings.

FIG. 1 is a partially cutaway sectional view showing a polishing apparatus according to an embodiment of the present invention.

In FIG. 1, a continuously variable speed motor 2 is mounted on a main body 1, and a bearing portion 6 is attached to the main body 1. A pulley 5 connected to the continuously variable speed motor 2 is attached to the center of the bearing portion 3. A hollow rotating shaft 4 is loosely connected to the hollow rotating shaft 4, and a rotating joint 6 is fitted into the lower end of the hollow rotating shaft 4. Further, a circulating fluid supply pipe 7 is connected via this rotation joint 6, and the other end of the circulating fluid supply pipe 7 is connected to a circulating fluid controller 8. A base plate 9 is attached to the upper end of the hollow rotating shaft 4. The base plate 9 is provided with a center hole 9a through which the circulating fluid 8a flows, and a circulating fluid groove 10 connected to the center hole 9a. The circulating fluid groove 10 is formed, for example, in a shape in which concentric grooves are connected by a radial groove, or in a helical shape so that the circulating fluid 8a flows over the entire polishing surface plate 11 at the supply ports at the two locations. .

A circulating fluid return hole 9b is provided at the outermost part of the circulating fluid groove 10, and a circulating fluid return pipe 9C is press-fitted into the circulating fluid return hole 9b. Further, an 01J groove 9e is provided near the outer periphery of the joint surface with the polishing surface plate 11, and this OIJ groove 9e
An O-ring 13 is attached to the. Base plate 9
A surface plate guide 9d in the form of a donut-shaped disc is fastened to the center of the polishing surface plate 11.
is being positioned.

A circulating fluid receiver 14 is attached to the upper surface of the main body 1 over the circumference, and circulating fluid discharge ports 15 are fixed to the circulating fluid receivers 1401. One end of the discharge pipe 15a is connected, and the other end is connected to the circulating fluid controller 8.

The workpiece 16 is adhesively fixed to a workpiece plate 17 and positioned and placed on the polishing surface plate 11 via a roller 19 attached to a carrier arm 18 . The carrier arm 18 is fastened to a column 20 fixed to the main body.

The cover 21 is attached to the main body 11C, and has a machining liquid return pipe 22 attached to one end thereof, and discharges the machining liquid supplied from the machining liquid nozzle 26 to the outside.

Next, the operation of the polishing apparatus configured as described above will be explained. In this polishing device, a circulating fluid 8a cooled or heated to a predetermined temperature is supplied from a circulating fluid controller 8 through a circulating fluid supply pipe 7, a rotating cylinder intro, a hollow rotating shaft 4, and a base plate center hole 9a, which is installed in a base plate 9. When flowing into the circulating fluid groove 10, the lower surface of the polishing surface plate 11 is cooled or heated to a predetermined temperature. A constant amount of machining fluid at a constant temperature is supplied to the upper surface of the polishing surface plate 11. However, polishing surface plate 11
A temperature difference occurs between the upper and lower surfaces of the polishing surface plate 11, and the polishing surface plate 11 is thermally deformed.

Figure 2 shows data obtained by actually measuring thermal deformation.

The amount of deformation ΔI of the top surface of the polishing surface plate 11 (at room temperature (23°C),
Measurements were taken during cooling (22°C) and heating (24°C). The polishing surface plate 11 is made of tin, has a thickness of approximately 30 mrn, and an outer diameter of approximately 460 mrn.

The measurement was carried out by rotating the polishing surface plate 11 for a certain period of time (preliminary experiments confirmed that it reached a steady state in about 30 minutes), and after stopping the rotation, the processing liquid on the polishing surface plate 11 was removed, and the electrostatic charge was immediately removed. The measurement was carried out by moving a capacitive non-contact displacement meter over an area of 35 to 225 mm in the radial direction (excluding the 70 mm center hole). The circulating fluid 8a was controlled to a room temperature of ±0.1°C, and the processing fluid was controlled to an accuracy of 23°C±0.2°C. According to this graph, it can be seen that the values during cooling and heating are nearly symmetrical with respect to room temperature, and a stable shape can be obtained. The amount of change ΔH can be controlled by changing the temperature of the circulating fluid 8a, and further by changing the material and shape of the polishing surface plate. In addition, in this embodiment, the deformation of the base plate 9 during cooling and heating is suppressed, and the polishing surface plate 11 has better reproducibility.
In order to obtain the amount of deformation on the upper surface of the , amber, a metal with a low coefficient of thermal expansion, was used.

In this measurement, the gap between the displacement meter and the polishing surface plate 11 is measured, so that the larger the amount of deformation ΔH, the more the polishing surface plate 11
The upper surface of will be deformed downward.

Figure 3 (a) and (l) show the heating of the circulating fluid 8a and the
FIG. 3 is a cross-sectional view showing the top surface shape of the polishing surface plate 11 when it is cooled in FIG.

The arrow shown inside the polishing surface plate 11 indicates the direction of thermal deformation. Figure 3 (In the case of al, the lower surface of the polishing surface plate 11 is heated and expands outward, and the upper surface shape becomes intermediate. Generally, when polishing is performed in this state, the shape of the workpiece after processing is shown on the right) As shown in FIG. 3(b), the processed surface 16a has a convex shape.
As the lower surface of the polishing surface plate 11 is cooled, it contracts inward, and the upper surface becomes convex. If polishing is performed in this state, the shape of the workpiece after machining will be the same as the machined surface 1, as shown on the right.
6a has a concave shape.

In this embodiment, a liquid is used to control the temperature of the polishing surface plate 11, but if air is used, it will take time to achieve a steady state, but the only mechanism for discharging will be the discharge port.

Further, although it is better to form the circulating fluid grooves 10 on the base plate 9 because it will not be affected by the replacement of the polishing surface plate 11, it is of course possible to form them on the polishing surface plate 11.

〔Effect of the invention〕

Since the polishing apparatus according to the present invention utilizes thermal deformation of the polishing surface plate as a means of creating the polishing work surface of the polishing surface plate, the accuracy of the polishing work surface can be adjusted to a desired value without performing secondary processing on the top surface of the polishing surface plate. It can be easily and accurately inserted into the image.

[Brief explanation of drawings]

FIG. 1 is a partially cutaway sectional view showing a polishing apparatus according to an embodiment of the present invention, FIG. 2 is a graph showing the amount of deformation of the top surface during cooling or heating of the bottom surface of the polishing surface plate, and FIGS. b) is a sectional view showing the relationship between the top surface shape of the surface plate and the shape of the workpiece after processing; FIG. 4 is a perspective view showing a conventional polishing device; and FIG. 5 is a diagram showing the creation of the polishing work surface of a conventional polishing surface plate. The method is shown in Figure 5 (at
is a sectional view, and FIG. 5(b) is a plan view. 1...Main body, 8...Circulating fluid controller 9...Pace plate, 10...
Circulating fluid groove, 11... Polishing surface plate. Figure 1 Figure 2 Figure 3 (Q) (b) Figure 4

Claims (4)

[Claims] (1) In a contact polishing device that has a base plate pivotally supported by the main body and a polishing surface plate placed on the base plate, and processes a workpiece by pressing it against the top surface of the polishing surface plate, the temperature of the fluid provided between a controller for controlling and supplying the base plate and the polishing surface plate,
and a flow path through which fluid is supplied from the controller. (2) The polishing apparatus according to claim 1, wherein the base plate is made of a low thermal expansion material. (3) The polishing apparatus according to claim 1 or 2, wherein the flow path is formed in the base plate. (4) In a contact polishing method that includes a base plate pivotally supported by a main body and a polishing surface plate placed on the base plate, and in which a workpiece is pressed against the upper surface of the polishing surface plate for processing, the polishing surface plate is The top surface of the polishing surface plate is kept at a constant temperature, the bottom surface of the polishing surface plate is cooled or heated to a predetermined temperature, a temperature difference is created between the top surface and the bottom surface of the polishing surface plate, and the top surface of the polishing surface plate is shaped into a predetermined shape. A polishing method characterized by processing a workpiece by deforming it into a shape.