JPS6350146B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an apparatus for polishing disks such as coding magnetic disks used as external storage devices for computers.

Conventionally, this type of polishing apparatus has used a method in which polishing is performed using a polishing head that is the same as or slightly longer than the polishing width of the disk, or by a cup-shaped grindstone containing abrasive grains. The disadvantages of the former are that the long polishing width makes it difficult to follow minute irregularities on the disk surface, and the heavy polishing head is also disadvantageous to fluctuations in the disk surface.
Although the latter type of cup-shaped grindstone has excellent abrasiveness, it is difficult to remove minute protrusions, and it has become difficult to meet the recent demands for improved surface roughness. Furthermore, in any of the methods, when the surface roughness of a magnetic disk is improved and the coating thickness of the magnetic medium applied to the disk surface becomes non-linear, shaping polishing to make the thickness of the magnetic medium have a constant slope is necessary. There were also drawbacks to not being able to do so.

In order to eliminate these drawbacks, the present invention is designed to move the polishing head in a direction perpendicular to the circumference of the disk (expressed as the radial direction of the disk) while pressing the polishing head against the disk and at the same time increasing the speed of its radial movement. It is an object of the present invention to provide a polishing device that can be controlled arbitrarily to obtain a desired polishing profile.

According to the invention, there is provided a polishing head movement drive for moving the polishing head in the radial direction of the disk to be polished;
a speed control section that controls the moving speed of the polishing head movement drive section; a speed change rate setting section that changes the speed at a required rate of change when the speed control signal to the speed control section changes; a speed setting output section that sequentially supplies a speed control signal to the speed change rate setting section; and a polishing head position detection sensor whose setting position is variable and is made up of a plurality of sensors corresponding to the plurality of speed control signals set by the speed setting output section. Accordingly, it is possible to realize a disk polishing apparatus having a speed position detection section that detects the position of the polishing head and provides an output trigger of a speed control signal set corresponding to the polishing head position detection sensor to the speed setting output section. .

Next, embodiments of the present invention will be described in detail using the drawings.

FIG. 1 shows a polished state of a magnetic disk as an example, FIG. 2 is a block diagram showing the configuration of an embodiment, and FIG. 3 shows a polishing profile. In FIG. 1, the polishing head 1 is shown moving from the inner circumference to the outer circumference while applying the abrasive tape 2 to the surface of the magnetic disk 3 with a predetermined pressure. It shows the condition. In this diagram, the polishing head 1 is the polishing tape 2.
However, polishing is also possible by embedding abrasive grains in the polishing head 1 itself to restrict its rotation.

Prior to polishing, in order to shape a magnetic disk having a non-uniform magnetic medium thickness distribution 4 as shown in FIG. The detection positions of the speed change position detection units 6, which are composed of a plurality of units shown in Fig. 1, are determined. The positions are determined at equal intervals if the amount of polishing is linear, and if it is non-linear, the positions are set densely at locations where the degree of change in the amount of polishing is large. Set the required speed to 7.

Simultaneously with the start of polishing, a speed control signal is output from the speed setting speed unit 7 corresponding to the speed change position detection unit 6 to the speed control unit 9 via the speed change rate setting unit 8, and the speed is adjusted according to the speed control signal. The polishing head movement drive 10 is activated. The speed change rate setting section 8 described above is configured to output a signal that follows the speed control signal with a preset time constant in response to changes in the speed control signal of the speed setting output section 7, so that the speed change is large. A smooth speed transition is achieved even in the case of In the figure, 11 is a pressurizing mechanism for the magnetic disk 3 of the polishing head 1, 12 is a rotary table, 13 is a motor for driving the rotary table, 1
Reference numeral 4 indicates the rotation direction of the magnetic disk 3, and reference numeral 15 indicates the movement stroke of the polishing head 1.

With the above structure, the amount of polishing in the radial direction of the disk can be freely set and the amount of polishing can be easily controlled. Furthermore, even if there is non-linear unevenness in the thickness of the magnetic medium in the radial direction of a magnetic disk, it is possible to shape it into the desired profile by replacing the amount of polishing with the speed of movement of the polishing head, which solves the problem of the conventional method. It is also possible to improve polishing defects caused by radial nonlinearity of the magnetic medium. Furthermore, since the polishing head can be made smaller than the polishing width, the weight of the head can be reduced and the ability to follow changes in the disk surface can be improved.

In this embodiment, the speed change rate setting section 8 is inserted before the speed control section 9, but the same effect can be obtained even if it is inserted after the speed control section 9. Furthermore, although this example mainly shows a coated magnetic disk coated with a magnetic medium, the plate thickness can be easily controlled in the same way even when applied to polishing the surface of a general disk such as a raw plate before applying a magnetic medium. be able to.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the polishing state of a magnetic disk, FIG. 2 is a block diagram showing the configuration of an embodiment, and FIG. 3 is a diagram showing a polishing profile. In the figure, 1 is a polishing head, 2 is a polishing tape, 3 is a magnetic disk, 4 is a film thickness distribution of a magnetic medium, 5 is a film having a uniform inclination angle and thickness, 6 is a speed change position detection unit, and 7 is a speed A setting output section, 8 a speed change rate setting section, 9 a speed control section, 10 a polishing head movement drive section, 11 a polishing head pressurizing mechanism,
12 is a rotary table, 13 is a motor for driving the rotary table, 14 is the direction of rotation of the magnetic disk, and 15 is the movement stroke of the polishing head.

Claims (1)

[Claims] 1. A polishing head movement drive unit that presses the polishing head against the disk surface to be polished and moves the polishing head in the radial direction of the disk, a speed control unit that controls the moving speed of the polishing head movement drive unit, and a speed control unit that controls the speed control unit. A speed change rate setting section that changes the speed at a required rate of change when a signal changes, a speed setting output section that sequentially supplies a plurality of set speed control signals to the speed change rate setting section, and this speed setting output section. The position of the polishing head is detected by a plurality of polishing head position detection sensors whose positions are variable and which correspond to the plurality of speed control signals set in and a speed position detection section for providing an output trigger of a control signal to a speed setting output section.