JPS608187B2 - Donut-shaped disk processing equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION A magnetic disk used in a magnetic disk storage device is manufactured by coating the surface of a donut-shaped aluminum alloy disk with magnetic powder or plating with a magnetic material.

As memory density has improved dramatically in recent years, a high degree of processing precision has come to be required of the aluminum alloy discs.

Lapping or polishing has replaced traditional turning to achieve a high degree of flatness and smoothness of the disk surface.

FIG. 1 is a diagram schematically showing the lapping process of an aluminum alloy disk for a magnetic disk.

An aluminum alloy disk 2 is placed on a lapping machine 1 and lapping is performed by applying uniform pressure. Figure 2 is A-A of Figure 1.
This is a cross section at .

An aluminum alloy disk 2 is placed on the surface 11 of the lapping machine 1, a pressure plate 3 is placed thereon, and a pressure rod 4 is pressed with a air cylinder (not shown) to apply pressure. Pressure plate 3 and pressure rod 4
An automatic steel D mechanism 5 consisting of a ball and a spherical seat is provided between the lapping plate 1 and the automatic steel D mechanism 5, which follows the surface runout when the lapping machine 1 rotates. The aluminum alloy disk 2 for magnetic disks is usually a donut-shaped disk with an outer diameter of 36 m, an inner ridge of about 17 m, and a thickness of about 2 m. The diameter of board 1 reaches approximately 1 desk. Therefore, it is unavoidable that the surface 11 of the lapping plate 1 oscillates several hundred times during rotation.

As mentioned above, the processing mechanism of conventional lapping machines is equipped with a self-aligning machine to follow the surface runout of the lapping machine 1, but when high accuracy is required such as with magnetic disks, However, problems still arise.

FIGS. 3 and 4 are diagrams for explaining such problems.

The surface runout of the surface 11 of the lapping machine 1 is a combination of pure vertical motion and angular change, that is, rotational motion, but the vertical motion is particularly problematic because it can be escaped by the vertical motion of the piston of the processing shear cylinder. Must not be. However, the rotational motion component causes serious problems. In Figure 3,
It is assumed that the surface 11 of the lapping machine 1 has been rotated from its normal position 11 to 11' around point P.

Then, the pressure plate 3, which was initially in the state shown by the dotted line, changes to the position 3' shown by the solid line. In the first attitude, the center of the aluminum alloy disk 2 was in contact with the surface 11 of the lapping machine 1 at point P, but in the new attitude, it is in contact with the surface 11 at point P'.

Therefore, the aluminum alloy disk 2 has moved laterally by d on the lapping plate 1. However, since there is no force to move the aluminum alloy disk 2 and the lapping plate 1 in the lateral direction, it actually does not become as shown in FIG. 3, but as shown in FIG. 4. That is, the aluminum alloy disk 2 and the pressure plate 3
does not move on the lapping plate 1, but rotates around point P to assume the postures 2' and 3'. Therefore, the pressurizing rod 4 is inclined 4
'become that way. As a result, an unnatural force is applied to the pressure rod 4', and uniform processing cannot be performed over the entire surface of the real aluminum alloy disk 2.

If uniform processing is not performed, the plate thickness will become non-uniform, warpage will increase due to non-uniform processing strain, and the flatness will deteriorate significantly, making it impossible to use as a magnetic disk substrate. The present invention aims to solve these problems.

FIG. 5 is a diagram schematically showing an embodiment of a wrapping device using the present invention.

The lapping machine 21 has two processing surfaces 31 arranged concentrically.
and has 32. A groove 33 is provided between these two processed surfaces 31 and 32. Further, the aluminum alloy disk 22 is placed on a lapping machine and lapped as shown in the figure. FIG. 6 is a sectional view taken along line BB in FIG. 5.

An aluminum alloy disk 22 is placed on the processing surfaces 31 and 32 of the lapping machine 21, and a pressure plate 23 is placed on top of the aluminum alloy disk 22.

The pressure plate 23 is pressurized by a pressure rod 24 using an air cylinder (not shown). Self-aligning machine side 25 is pressure plate 2
3 protrudes from the lower part of the pressurizing surface, and the protruding portion is located in the groove 33 of the lapping plate 21. The center of rotation of the self-aligning machine 25 is the processing surface 31 and 3 of the lapping machine 21.
It is set to be the same height as 2. In the structure of the present invention, even if the lapping machine 21 runs out, the rotation center of the self-aligning machine side 25 is at the same height as the machined surfaces 31 and 32 of the lapping machine 21, so as shown in FIG. No problems occur. Therefore, by using the apparatus of the present invention, very uniform processing can be performed over the entire surface of an aluminum alloy disk.

Using the device shown in Figure 1, the outer diameter is 356 willow, the inner diameter is 168 sail,
When lapping aluminum alloy discs with a thickness of 2, the thickness of the discs was uneven to the extent of low depending on the location, and at the same time warpage of 100 mm or more occurred in more than 50% of the discs.

However, by using the apparatus of the present invention, it was possible to reduce the non-uniformity of the plate thickness to 2 or less, and to reduce the occurrence of warpage to 20 or less. Although the case where the present invention is applied to wrapping an aluminum alloy disk for magnetic disks has been described as an example of the present invention, the same effect can be obtained even if the present invention is applied to any donut-shaped disk other than aluminum alloy disks for magnetic disks. It is obvious that this method can be obtained, and it is also obvious that it can be applied not only to lapping but also to polishing performed by pasting a cloth to the processed surface.

It is also obvious that the features of the present invention are fully exhibited in grinding where the processing surface is a grindstone. Furthermore, although the embodiments have been described with respect to the case where the machined surface is horizontal and faces upward, it is clear that the effects of the present invention can be similarly obtained when the machined surface is horizontal and facing downward, or vertically. .

Further, although the case has been described in which an air cylinder is used as the source of the pressurizing force, the effects of the present invention are not impaired even when pressurizing by other means such as oil pressure, water pressure, a spring, a car weight, etc.

[Brief explanation of the drawing]

1 and 2 are views showing one embodiment of a lapping device for an aluminum alloy disk for a magnetic disk, and FIG. 2 shows a cross section taken along line AA in FIG. 1. In these figures, 1 is a lapping machine, 2 is a workpiece (aluminum alloy disk), 3 is a pressure plate, 4 is a pressure rod, 5 is an automatic steel core machine, and 11 is the processed surface of the lapping machine 1. Each is shown. 3 and 4 are diagrams for explaining problems that occur in the apparatus shown in FIGS. 1 and 2, and the numbers are the same as in FIGS. 1 and 2. 6 is a diagram showing an embodiment of the present invention, and FIG. 6 shows a cross section taken along line BB in FIG. 5. In these diagrams, 21 is a lapping machine, and 22 is a workpiece (aluminum alloy disk) , 23 is a pressure plate, 2
4 is a pressure rod, 25 is the side of the self-aligning machine, 31 and 32 are machined surfaces, and 33 is a groove. FIG. 7 is a diagram showing that the problem that occurs in FIGS. 3 and 4 does not occur with the apparatus of the present invention, and the number 5 is
It is the same as FIG. Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7

Claims (1)

[Claims] 1. A processing disk consisting of two ring-shaped processing surfaces arranged concentrically forming the same plane and a groove provided between the processing surfaces, and the surface of a donut-shaped disk to be processed. It has a pressure plate and a pressure mechanism for pressing against the processing surface, and a self-aligning mechanism provided between the pressure plate and the pressure mechanism to follow the surface runout of the processing plate. The center mechanism portion protrudes forward from the pressure surface of the pressure plate, passes through the hole in the center of the workpiece, is located within the groove of the processing plate, and is located at the center of rotation of the self-aligning mechanism. is located within a plane formed by the processing surface of the processing plate.