JPH036583B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION BACKGROUND OF THE INVENTION The present invention relates to a method and apparatus for providing large storage capacities to floppy disks of magnetic media for computer storage, and more particularly to methods and apparatus for providing large storage capacity to floppy disks of magnetic media for computer storage. The present invention relates to a method and apparatus for increasing concentricity with the parts.

With the spread of various OA (office automation) devices including word processors (document editing machines) and personal computers, the need for magneto-optical recording media such as floppy disks has expanded dramatically. The development of magnetic recording media with higher density, ie, larger storage capacity, is highly desired.

There are computer storage aluminum disks, floppy disks, etc. The former is made of an aluminum base (plate) coated with magnetic powder (about 1 to 2 μm thick), while the floppy disk is made of polyester film or acrylic. Magnetic powder is applied to a substrate made of resin or the like. Furthermore, in recent years, magneto-optical disks that utilize laser beams (including semiconductor laser beams) have been considered.

An example of a magneto-optical recording disk using laser beams is one in which a barium ferrite oxide magnetic film is coated on a glass substrate and a light reflective layer.
The reason for using a glass substrate is as follows: In order to increase the storage capacity, strict flatness and parallelism are required on both sides of the Dix substrate, which is not the case when conventional glass substrates are used. It is clear that glass substrates are far superior to those made of aluminum or plastic, but unlike aluminum or plastic, glass is difficult to process, and requires precise roundness and
Because it is very difficult to obtain concentricity, it is difficult to use it, unlike the materials other than glass mentioned above.

An object of the present invention is to solve these difficult problems and provide a method and apparatus for obtaining accurate concentricity and roundness in a glass substrate for a magneto-optical disk using a laser beam. be.

(Improvements to solve the problem) As mentioned above, glass has excellent properties as a substrate material for computer storage magneto-optical media, but it is difficult to obtain conventional concentricity and roundness. The processing and cutting method is to first cut, process, and drill either the center hole (inner diameter part) or the outer peripheral part (outer diameter part), and then process other parts. Because this was a two-step process: cutting the center hole (inner diameter) and then chamfering the outer periphery, vibrations and impacts during machining caused the inner periphery (center hole diameter) and outer periphery to Since it was impossible to obtain accurate concentricity and roundness between the This is to give roundness.

(Embodiments) The present invention will be described below with reference to preferred embodiments with reference to the accompanying drawings.

In FIG. 1, 1 is a glass plate with a low expansion degree, 2 is its center hole (inner circumference), and 3 is its outer circumference (outer diameter). The glass plate No. 1 is intended to be processed as a substrate material for a floppy disk, which is a magneto-optical medium for computer storage.

The following processing conditions () and disk conditions () are required for a substrate for a floppy disk.
must be satisfied at the same time. That is, conditions () 1. Outer diameter m/m is ±0.1 or less; 2. Girdle portion m/m is ±0.05 or less; 3. Inner diameter m/m is ±0.05 or less; 4. Thread face m/m is ±0.1 Below 5 Roundness, inner diameter m/m is 0.03 or less 6 Concentricity m/m is 0.03 or less () 1 Inner thickness (plate thickness) m/m is ±0.03 or less 2 Parallelism m/m is, ±0.03 or less 3 Flatness ±0.03 or less 4 Surface roughness Rmax (Å) 200 or less However, as mentioned above, glass has conditions () such as parallelism (2), flatness (3), and surface roughness (4). It has far superior properties to plastics, etc., which are the materials used for floppy discs, so the problem is to meet the processing conditions in ().
In the present invention, by machining the center hole (inner diameter part) and the outer diameter part at the same time, we succeeded in dramatically increasing concentricity. Roundness is not a problem unless the concentricity is out of order.

Referring to FIGS. 1 to 3, a method of simultaneously machining a center hole and an outer diameter portion to obtain accurate concentricity according to the present invention, and the structure and operation of the apparatus will be described. Note that the dimensions of the drawings are slightly enlarged or reduced for the sake of explanation.

5 in FIG. 1 is a girdle portion of the processed glass substrate, and 4 is a thread surface portion.

Fig. 2 is an explanatory diagram illustrating the state in which the method of the present invention is carried out, and 6 is a precision lathe usually used for processing and cutting (chamfering) glass, but it is different from the conventional one. The point is that the outer diameter part and the center hole (inner diameter part) can be machined at the same time with a diamond blade. The glass plate 7 is processed appropriately to become a floppy disk substrate. 8 is a diamond jig (blade) for processing the center part (inner diameter part) of the glass substrate. Reference numeral 9 denotes a diamond jig similar to the diamond jig 8 for machining and cutting the outer peripheral part of a glass substrate, and in the apparatus of the present invention, like the diamond jig 8 which is rotationally driven by a drive motor 10, It is operated and rotated by a drive motor 11. These diamond jigs 8 and 9 are electrodeposited diamonds, and are capable of processing, cutting, thread chamfering, etc. on the glass substrate 7 at the same time.

The precision lathe 5 rotates the glass plate 7 for the substrate toward the diamond jigs 8 and 9 which are rotating in a fixed state while moving from arrow a to b shown in FIGS. 2 and 3. It is designed to proceed in the order of →c→d.

FIG. 3 is an enlarged explanatory view of the blade of the diamond jig (diamond hole) 9 in FIG. 2, with parts A, B, C, and D.
The ranges of and E indicate processing stages, respectively. In part A, the thread surface of the front part of the glass plate is formed, and in part B, the girdle part is processed (diameter correction).
It consists of a gently sloping part and a straight (horizontal) part in the C part, where the outer periphery (outer diameter) is cut while sliding sideways, and the D and E parts are This is the part that forms the rear thread surface.

Note that the D portion is intended to prevent the electrodeposited diamond corner portion from easily falling off and to improve the precision of the workpiece.

The glass plate is slowly advanced through the above sections A, B, C, D and E in that order. In this case, it is an essential requirement for the axes of each diamond wheel to be placed on the same table in order to obtain accurate concentricity.
In addition, make a rough round eye in the A part. Further, it is desirable to drill a rough hole in the center hole (inner diameter portion) prior to performing the above-mentioned machining operation. As mentioned above, if the shafts of each diamond wheel are installed on the same table or the same stand or floor, even if the wheels vibrate violently, they will move completely relative to each other, so there will be no deviation in concentricity.

FIG. 4 is a diagram when the motors 10 and 11 serving as the drive sources for the diamond jigs 8 and 9 are the same. Its operation and function are exactly the same as described above.

As described above, according to the present invention, the center hole and the outer periphery are simultaneously rotated and driven using a diamond wheel for machining, using a conventional precision machining lathe. It is possible to greatly increase the concentricity of the glass substrate required to increase the recording capacity of the disk.

Further, in the embodiment of the present invention, the glass plate to be processed is brought into contact with the rotating diamond jigs provided on a stationary stand or table, and the a→b→c The outer periphery (outer diameter part) and center hole (inner periphery) are machined and cut while changing direction in the order of →d, but of course, in contrast to this, a diamond jig that is rotationally driven is used. The traveling direction is a → b → c → d → so that it comes into contact with the glass plate rotating on a fixed axis.
In other words, the relationship between the glass plate to be processed and the diamond wheel (jig) that performs the processing and cutting work may be changed in the opposite direction of a.

Furthermore, if higher precision is required for the girdle and thread surface, a mixture of polishing sand, such as carborundum, and water may be applied to the inner and outer periphery of the glass plate to be cut using low-speed machining. By finishing while pouring and rotating the jig and glass substrate, the accuracy of concentricity and roundness can be further improved.

[Brief explanation of drawings]

FIG. 1 is a partially enlarged explanatory diagram showing a glass plate, which is a substrate of a floppy disk for magneto-optical recording, processed into a desired shape using the method and apparatus of the present invention; FIG. FIG. 3 is a partially enlarged explanatory diagram of the apparatus for implementing the method of the present invention; FIG.
The figure is a schematic explanatory diagram of another embodiment. DESCRIPTION OF SYMBOLS 1, 7... Glass plate, 2... Center hole (inner diameter part) of glass plate, 3... Outer periphery part, 4... Thread face part, 5... Girdle part, 6... Precision lathe, 8... Diamond wheel for processing the center hole, 9... Diamond wheels for machining and cutting the outer periphery, 10, 11... drive motors.

Claims (1)

[Claims] 1. A method for increasing the concentricity between the center hole and the outer periphery of a glass substrate for a floppy disk of a magneto-optical medium for computer recording. A step of attaching it to the processing part of the lathe and moving it toward the processing diamond wheel while rotating it; and the diamond wheel 8 rotating the center part 2 of the glass substrate and the diamond wheel 9 rotating the outer peripheral part 3. and a step of rotating the two diamond wheels against the glass substrate and moving them from top to right to bottom to left while in contact to finish the girdle part, thread surface, and the like. A method for increasing the concentricity of a glass substrate, characterized by: 2. The method of increasing the concentricity of a glass substrate according to claim 1, characterized in that, before finishing the center hole of the glass substrate, a rough hole is made in advance. 3. Claim 1, characterized in that the center hole and the outer periphery of the glass substrate are cut at the same time.
A method for increasing the concentricity of a glass substrate according to item 1 or 2. 4 A device for cutting a glass plate, including a device that rotates the glass plate and advances it in a fixed direction, and a device that is installed on the same stand or table and that rotates and advances the glass plate in the center hole and outer periphery of the glass plate. and a device having a blade that comes into contact with the glass substrate, and the device that moves the glass substrate contacts the blade and then moves the glass substrate in the order of top → right → bottom → left with the glass plates in contact with each other. ,
An apparatus characterized by increasing the concentricity of a glass substrate of a floppy disk for a magneto-optical medium, which simultaneously performs desired machining and cutting. 5 The blade of the device that cuts the glass plate is
5. The device for increasing the concentricity of a glass substrate according to claim 4, which is an electroplated diamond wheel.