JPH0116648B2 - - Google Patents

Description

[Detailed Description of the Invention] (a) Technical Field of the Invention The present invention relates to audio discs and video discs used to reproduce sounds, images, etc. The present invention relates to a method of manufacturing a disk that can be used.

(B) Background of the Invention In recent years, optical disks and magnetic disks have been the mainstream of disks such as those described above, and as is well known, these disks have light reflecting grooves (pits) carved on the surface of the disk, or It is provided to be reproducible based on the application of a required magnetism, and will be explained below using an optical disk as an example.

As is well known, the raw materials used for conventional optical disks are aluminum or glass fiber materials, which have excellent deformation resistance and durability.

However, the surface of an optical disk requires high flatness precision in order to form highly sensitive light reflection grooves, and for this reason, currently, in the disk manufacturing process,
Special polishing of the disk surface is required, which increases the cost and makes the disk expensive.

(c) Purpose of the Invention Therefore, the object of the present invention is to provide a method for manufacturing a disk that can be manufactured efficiently without requiring special polishing.

(D) Summary of the Invention This invention provides a fixed nozzle having an outer diameter equal to the disk diameter on the front end surface, and a fixed nozzle having an outer diameter equivalent to the disk thickness at the center of the front end surface of the first movable mold having the fixed nozzle on the axis. A recessed portion is formed by retracting the front end surface of the fixed nozzle, and the fixed nozzle pours heated and softened resin into the recessed portion with the flat end surface of the second movable mold in planar contact with the front end surface of the first movable mold. The disk manufacturing method is characterized in that the first movable mold is retracted by a slight movement amount after the injection is completed.

(E) Effects of the Invention According to the present invention, a disk can be easily molded by injecting and solidifying a heat-softened resin raw material into a recess formed at the disk diameter and disk thickness.

In addition, after injecting the resin raw material during this molding, by moving the first movable mold backward by a slight amount, the two molds are separated, and the flat end surface of the opposing second movable mold is injected into the recess. Only the resin materials that have been molded are brought into plane contact intensively, and a resin disk with high flatness precision and extremely small surface roughness is molded without warping of the resin materials due to thermal contraction.

Therefore, since the obtained resin disk can be molded without special polishing, the number of man-hours required for manufacturing it is reduced, and it is possible to provide a disk that is both cost-effective and cost-effective.

(F) Embodiment of the Invention An embodiment of the invention will be described in detail below based on the drawings.

The drawing shows an example of manufacturing an optical disk. In FIG. 1, an optical disk manufacturing apparatus 1 includes a first movable device 2.
and a second movable device 3.

The first movable device 2 includes a fixed nozzle 4, a first movable mold 5, a first advancement/retraction device 6, and a first support body 7 that supports these.

The fixed nozzle 4 described above has an outer diameter that is the same as the disk diameter, and has a flat front end surface for molding the disk surface, and a resin raw material for the disk is formed in the center of the nozzle on the front end surface. An injection hole 8 for injecting to the side is bored in the axial direction, and with the rear end of this nozzle fixed to the first support 7, the front end protrudes forward horizontally to form the first nozzle, which will be described later. It is inserted into the center hole of the movable mold 5.

The above-mentioned first movable mold 5 is formed into a large-diameter disk, and has a center hole 9 bored in its center through which the front end shaft of the above-mentioned fixed nozzle 4 is inserted. A recess 10 corresponding to the thickness of the disk is formed on the front end surface of the fixed nozzle by retreating the front end surface of the fixed nozzle, and this recess 10 is provided in a mold portion for forming the disk, which will be described later. Further, the front end surface of the first movable mold 5 is formed as a first flat end surface 11 so as to be in planar contact with a second movable mold, which will be described later. A first advancing/retracting device 6, which will be described later, is installed so that the upper portion thereof can be slightly advanced and retracted in the front-rear direction (axial direction).

The above-mentioned first advancing/retracting device 6 includes a pair of vertically parallel first hydraulic cylinders 12, 12 and their guide rods 13, 13, and the first hydraulic cylinder 12 is connected to a first support body disposed at the rear. The tip of the piston rod 14 is connected to the rear end surface of the first movable mold 5 located at the front, and the first movable mold 5 is moved in the front-rear direction by driving the first hydraulic cylinder 12. Moved slightly forward and backward. At this time, the amount of advance and retraction is set depending on the amount of thermal contraction of the disk resin raw material, and for example, in the case of a resin disk having a thickness of several millimeters, it is appropriate to set it to about 0.05 mm.

Further, the guide rod 13 includes a first support 7 and a second support 1 disposed opposite to each other at a rear position and a front position.
The guide rods 13, 13 have corresponding guide holes 17 of the first movable mold 5 and the second movable mold 16 (described later).
... are supported and guided in common.

A disk mold 18 is formed between the opposing surfaces of the first movable device 2 configured in this way and the second movable device 3, which will be described later.

The second movable device 3 described above includes a second movable mold 16
, a second advancing/retracting device 19 , and a second support body 15 .

The second movable mold 16 is formed into a disk having the same outer diameter as the first movable mold 5, and faces the first flat end surface 11 of the first movable mold 5. A flat end face opposite to the end face 11 is set as a second flat end face 20, and a contact space, that is, a sealed recess 1, is formed by making these flat end faces 11 and 20 face each other.
0 is provided as a mold 18 for forming the disk.
The second movable mold 16 is equipped with a second advancing/retracting device 19, which will be described later, for forming and opening the sealed molding mold 18 section.

The above-mentioned second advancing/retracting device 19 includes a pair of vertically parallel second hydraulic cylinders 21, 21 and a common guide rod 13, 13 supported by the second support body 15. The piston rods 22 are fixedly installed on the rear end surface of the second support body 15, and the tips of the piston rods 22 are connected to the back surface of the second movable mold 16, and the second movable mold 16 is guided by driving the second hydraulic cylinder 21. The holes 17 are guided by the guide rods 13 and moved forward and backward in the front and rear directions.

When manufacturing an optical disk using the optical disk manufacturing apparatus configured as described above, first, the first movable mold 5 is set to a predetermined forward position for molding the disk via the first advancement/retraction device 6, Next, drive the second advancement/retraction device 19 to advance the second movable mold 16,
After forming the disk mold 18 by bringing the opposed first and second flat end surfaces 11 and 20 of these molds 5 and 16 into contact with each other, the resin 23 is heated and softened and injected from the fixed nozzle 4. This resin 23 is injected into the disk mold 18, and after the injection is completed, the injection operation is stopped, and after waiting for the resin 23 to solidify to some extent, the first movable mold 5 is moved back by a slight movement amount. After high-plane molding is performed on the end face of the resin in the mold 5 and the resin 23 is completely solidified in the mold 18, the second movable mold 16 is moved back and the resin disk is taken out from inside the mold 18. By post-processing this in a subsequent press molding process, an optical disk 24 is manufactured as shown in FIG.

In the above embodiment, an optical disk was described, but the present invention can also be applied to a magnetic disk by using a resin material that can be magnetized.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention, and FIG. 1 is a longitudinal cross-sectional view of essential parts showing the manufacturing state of an optical disk manufacturing apparatus. FIG. 2 is a perspective view of the optical disk. DESCRIPTION OF SYMBOLS 1... Optical disk manufacturing device, 4... Fixed nozzle, 5... First movable mold, 6, 19... Advancement/retraction device, 10... Recessed portion, 11, 20... Flat end surface, 16
...Second movable mold, 18... Disk molding mold.

Claims (1)

[Claims] 1. A fixed nozzle having an outer diameter equal to the disk diameter is provided on the front end surface, and a recess corresponding to the thickness of the disk is formed in the center of the front end surface of the first movable mold having this fixed nozzle at its axis. The resin is formed by retreating arrangement, and heated and softened resin is injected into the recessed portion from a fixed nozzle with the flat end surface of the second movable mold in planar contact with the front end surface of the first movable mold, and after the injection is completed. A method for manufacturing a disk, characterized by retracting a first movable mold by a slight amount of movement.