JP3105072B2 - Manufacturing method of disk substrate - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to, for example, LD, CD, C
D-ROM, rewritable magneto-optical disk or M
The present invention relates to a method for manufacturing a disk substrate such as D.

[0002]

2. Description of the Related Art Generally, a disk substrate is manufactured by injection molding using an injection molding apparatus as shown in FIG. In FIG. 2, reference numeral 1 denotes a movable mold, 2 denotes a fixed mold, 3 denotes a sprue protruding piston for taking out a sprue from the mold, and 4 denotes a gate cut piston for forming a center hole of a disk. Reference numeral 5 denotes a product protruding piston for peeling and taking out a product (disk substrate) from the stamper 6, reference numeral 7 denotes a sprue bush, reference numeral 8 denotes a cavity, and reference numeral 9 denotes an injection nozzle. After the molten resin is injected and filled into
The gate cut piston 4 is protruded to form the center hole of the disk, the mold is opened, and the disk substrate and sprue attached to the movable mold 1 are removed from the mold. Have been.

By the way, in such a manufacturing cycle, after the cavity 8 is injected and filled with the molten resin,
When the gate cut piston 4 is protruded toward the sprue bush 7, the injection nozzle 9 is simultaneously retracted, and
The sprue bush 7 also moves backward while being pressed by the protruding pressure of the gate cut piston 4, and a center hole of the disk is formed. Then, as shown in FIG. 3, after the mold is opened, the robot is inserted into the mold, the disc substrate 10 is protruded by the product protruding piston 5, held by the suction pad 11, and the sprue 12 is It is protruded by the sprue protruding piston 3 and is respectively taken out of the mold by the sprue chucking finger 13.

[0004]

However, in the above-described manufacturing process, the disk substrate 10 is removed from the die.
When removing the sprue 12 and the disc substrate 1
Material handling such as vacuum suction mechanism for 0, sprue 1
A separate mechanism such as a mechanical chucking mechanism is required for the apparatus 2, and the manufacturing apparatus itself has a complicated structure and the cost is high accordingly.

Further, as the disk substrate 10 becomes smaller, the signal area formed on the disk substrate 10 becomes closer to the center hole, the holding area for the disk substrate 10 becomes narrower, and The work of sucking and taking out 10 becomes difficult. When the suction pad 11 is formed in a donut shape along the center hole of the disk, the suction pad 11 is made to approach the disk substrate 10 from the rear side (the right side in FIG. 3) of the sprue 12 which is protruded. In such a case, the operation in the mold becomes large, and it takes much time, so that the manufacturing cycle time becomes longer and the manufacturing cost becomes higher.

Accordingly, it is an object of the present invention to provide a disk substrate manufacturing technique in which the manufacturing cycle time is short and the manufacturing operation itself is simple.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to provide an injection molding step of injecting a disk substrate material into a mold, a center hole forming step of forming a central hole in the injection molded disk substrate, and a center hole forming step. A disc characterized by comprising: an integrating step of inserting a sprue into a center hole after a hole is formed to integrate the sprue; and a disk substrate extracting step of holding the sprue and extracting a disk substrate after the integrating step. This is achieved by a method of manufacturing a substrate.

With the above-described structure, the sprue once cut and formed in the mold is separated from the disk substrate, but is thereafter fitted into the center hole and restored to the original position. However, even if the two are to be separated, they are not separated due to a large frictional resistance between them. Therefore, the disk substrate having the center hole formed therein is held only by holding the sprue portion, and the disk substrate can be taken out of the mold without holding the disk substrate particularly.

As a result, when removing the disk substrate and the sprue from the mold, separate mechanisms such as a material handling device such as a vacuum suction mechanism on the disk substrate side and a mechanical chucking mechanism on the sprue side are not required. The structure itself is simple, and the cost is low. Even if the disk substrate becomes smaller and the signal area formed on the disk approaches the center hole, it does not directly hold the disk substrate. There is no difficulty.

In addition, since the removal operation is performed only by gripping the protruding sprue, the operation in the mold does not become large, the time is shortened accordingly, the manufacturing cycle time is short, and the manufacturing cost is low. It becomes something.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a schematic side view showing a part of a movable mold when a mold is opened for explaining a method of manufacturing a disk substrate according to the present invention. Also in this embodiment, it is basically manufactured by injection molding using an injection molding apparatus as shown in FIG. That is, similarly to the conventional case, the molten resin is injected and filled into the cavity 8 from the injection nozzle 9 through the sprue bush 7, and solidifies as time passes.

Thereafter, the gate cut piston 4 is protruded toward the sprue bush 7 to form a center hole of the disk. And after the center hole of the disc is formed,
Immediately, the gate cut piston 4 is returned to the original position (the position before the formation of the center hole), and the injection nozzle 9 is advanced (moved to the left in FIG. 2), so that the sprue bush 7 is advanced. One end of the sprue 12 once separated is pushed into the center hole of the disk substrate 10. At the time of this operation, since the resin is solidified, the disk substrate 10 and the sprue 12 do not fuse together.

Thereafter, the mold is opened. FIG. 1 is a schematic side view in this state. When the sprue ejecting piston 3 and the product ejecting piston 5 are simultaneously ejected (right side in FIG. 1), the disk substrate 10 and the sprue 12 are ejected.
Are separated from the movable mold 1 without being separated,
Therefore, by chucking the sprue 12 with the sprue chucking finger 13, the disk substrate 10 and the sprue 12 can be taken out from the mold.

Incidentally, a polycarbonate MD substrate of φ64 mm was prepared (resin temperature 320 ° C., mold temperature 110 ° C.).
C. and a cooling time of 3 seconds), the MD substrate is taken out with only the sprue chucking finger 13 as described above, and the total molding cycle time is 7
Seconds. On the other hand, as shown in FIG. 3, the MD substrate was taken out using both the suction pad 11 and the sprue chucking finger 13 and the time required for the removal was examined. The total molding cycle time was 8 seconds. .

[0015]

According to the present invention, the disk substrate can be quickly removed from the mold, and therefore the manufacturing cost can be reduced.

[Brief description of the drawings]

FIG. 1 is a schematic side view showing a part of a movable mold in a manufacturing process (at the time of mold opening) of a disk substrate according to the invention.

FIG. 2 is a schematic view of an injection molding apparatus for a disk substrate.

FIG. 3 shows a conventional disk substrate manufacturing process (when a mold is opened).
FIG. 4 is a schematic side view showing a part of a movable side mold of FIG.

[Explanation of symbols]

 Reference Signs List 1 Mold on movable side 3 Sprue protruding piston 4 Gate cut piston 5 Product protruding piston 10 Disk substrate 12 Sprue 13 Sprue chucking finger

Claims (1)

(57) [Claims] An injection molding step of injecting a disk substrate material into a mold; a center hole forming step of forming a center hole in the injection-molded disk substrate; 1. A method for manufacturing a disk substrate, comprising: an integration step of inserting a disk substrate into a disk substrate to integrate the disk substrate;