JP2912850B2 - Injection mold for disk molding - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mold used for injection-molding information recording disks such as compact disks and video disks.

[0002]

2. Description of the Prior Art FIG. 4 schematically shows an example of a fixed side of an injection mold for disk molding. A circular board 2 is inserted into a recess formed in a closed surface of a base mold 1 in which a die 3 is inserted. It is fitted over. The surface to be the mold surface of the board 2 is mirror-finished,
For this reason, it is generally called a mirror surface disk.

A central portion of the disk body 2 is formed in a hole, and a cylindrical body 6 having an opening edge on one side formed in a ring 5 for suppressing the inner peripheral edge of a donut-shaped stamper 4 is inserted from the front side into the hole. It can be fastened with screws. A ring 7 for holding the outer peripheral edge of the stamper 4 is detachably attached to the outer periphery of the base mold 1 using a screw 8 or the like.

[0004] In the drawing, reference numeral 9 denotes a receiving member of a cylindrical body 6 protruding from the insert 3 into the hole of the board body 2, and a sprue bush 10 is inserted through the seat body 1 a of the base mold 1 at the center thereof. is there.

In the injection mold having the above structure, the stamper 4 is in contact with the mirror surface of the board 2 with the cylindrical body 6 and the outer ring 7 removed. In this contact, the mirror surface is cleaned, and the contact is performed by inserting the center of the stamper 4 into the cylinder 6 and inserting the cylinder 6 into the center of the panel.
As a result, the stamper 4 is brought into contact with the board using the cylindrical body 6 as a guide, and the inner periphery is suppressed by the inner peripheral ring 5. Thereafter, the outer peripheral ring 7 is attached to the base mold 1, thereby suppressing the outer periphery of the stamper 4 and bringing the back surface of the stamper 4 into close contact with the mirror surface.

[0006]

When the back surface of the stamper 4 is directly contacted with the front surface (mirror surface) of the disk body 2 as described above, if the mirror surface is damaged, the stamper 4 is also damaged. Since the influence appears to cause a bump failure, the board 2 needs to be replaced or repaired. This replacement requires disassembly and reassembly of the mold, and has disadvantages such as the need to rebuild the board 2 when there is no spare.

When the stamper is replaced on site while the mold is mounted on the molding machine, dust easily enters between the mirror surface and the stamper, and it is difficult to clean the mirror surface before the stamper abuts.
For this reason, it is necessary to remove the mold and replace the stamper in a clean room, etc.However, in the production of a large variety of small disks, the mold is frequently attached and detached, so even small molds are troublesome. In addition, the mold structure becomes complicated to facilitate attachment and detachment, resulting in an increase in cost.

Usually, a clearance for gas escape is formed in the stamper holding portion of the inner ring 5 and the outer ring 7 so that molten resin does not enter.
If there is a variation in the thickness of the disc, the clearance changes, causing poor gas release and affecting the quality of the disc.

The present invention has been conceived in order to solve the above-mentioned conventional problems, and an object of the present invention is to change the structure of a conventional injection mold by using a combination of a stamper and a thin disk. It is another object of the present invention to provide a new disk molding injection mold that can prevent the adhesion of dust when exchanging a stamper on site and eliminate the necessity of exchanging a mirror surface disk.

[0010]

Means for Solving the Problems A thin disk having the same shape as a donut-shaped stamper and a mirror-finished surface is provided on the back surface of the stamper in close contact with the mirror surface, and the stamper is connected to the base mold closing surface via the thin disk. The stamper is fixed to the above-mentioned board by the outer ring attached to the surface of the circular board fitted inside and the outer ring attached to the outer periphery of the base mold closed surface, and the inner ring fitted to the center of the board. In the injection mold for disk molding,
The thin disk is formed of a hard disk thicker than a stamper made of a cemented carbide or ceramic disk having a thickness of 0.3 to 1.0 mm.

Further, the stamper of the present invention is mounted on the disk body via the thin disk by the inner peripheral ring fitted at the center of the disk body and the outer peripheral ring mounted on the outer periphery of the surface of the disk body. It is configured to be detachable from the base mold together with the board.

[0012]

[Operation] The surface of a thin-walled disc that has been mirror-finished in advance on the back of the stamper can be brought into close contact with the stamper so that the stamper can be transported or mounted, thereby preventing dust from adhering to the mirror surface when the stamper is replaced. . In addition, since the hard disk is hardly deformed even if it is thin, the stamper can be easily replaced while the mold is mounted on the molding machine, and the total thickness of the stamper and the thin disk can be mounted on the disk body. Accordingly, even if the thickness varies among the stampers, the total thickness is always constant, so that a change in the clearance for gas escape due to the variation in thickness is also prevented.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the embodiments shown in FIGS. In the drawing, reference numeral 11 denotes a base type, and 12 denotes a board body which is fitted over a nest 13 in a recess provided in a base closed surface of the base type, and the surface serving as a die surface is finished to a flat surface.

A cylindrical body 16 having an opening edge on one side formed on an inner peripheral ring 15 for suppressing an inner peripheral edge of a donut-shaped stamper 14 is inserted into the hole formed in the center of the board 12 from the front side. Although not shown in the figure, it can be fixed with screws or the like. Although not shown in the drawing, a sprue bush is inserted through the center of the receiving member 19 located inside the cylindrical body 16 as in FIG.

Reference numeral 17 denotes a screw 1 on the outer periphery of the closed surface of the base die 11.
8 is an outer peripheral ring which is detachably attached to the outer peripheral ring.

Reference numeral 20 denotes a thin disk having the same shape as the stamper 14,
The stamper 14 is made of a hard disk having a thickness of 0.3 to 1.0 mm and made of a thicker hard disk than a stamper 14 made of a ceramic disk or the like, and its surface is mirror-finished. The thin disk 20 is used by being superimposed on the stamper 14 with its front surface in close contact with the back surface of the stamper. The stamper 14 is transported to a die together with the thin disk 20, and the thin disk 20
It is provided through.

The stamper 14 via the thin disk 20
Is performed with the cylindrical body 16 having the inner peripheral ring 15 and the outer peripheral ring 17 removed. First, the stamper 14 and the thin disk 20 are overlapped and inserted into the cylinder 6 in a clean room or the like, and brought together with the cylinder 6 to a mold. As in the conventional case, the thin disk 20 is brought into contact with the disk 12 by inserting the cylindrical body 16 into the center of the disk, and the stamper 1 is attached to the disk 12.
4 is pressed against the inner periphery of the stamper by the inner peripheral ring 15. Thereafter, the outer peripheral ring 17 is attached to suppress the outer periphery of the stamper. As a result, the stamper 14 comes into close contact with the surface of the mirror-finished board 12 and is provided against the board 12.

The embodiment shown in FIG.
Is mounted on the outer circumference of the surface. In such a disk body 12, after the disk body 12 is removed from the base die 11, the stamper 14 is moved together with the thin disk 20 by the outer peripheral ring 17. It can be carried as it is.

The stamper 14 can be held down by the inner ring 15 and the outer ring 17 by opening the necessary gas escape clearances 21 and 22 as in the conventional case.

[0020]

According to the present invention, as described above, the thin disk 20 is used.
Is formed by a hard disk thicker than the stamper 14 made of a cemented carbide disk or a ceramic disk having a thickness of 0.3 to 1.0 mm.

Since a thin disk made of a hard disk is hardly deformed, the back surface of the stamper and the mirror surface of the thin disk can be brought into close contact with each other in a clean room or the like and transported to a molding machine. Since the stamper can be attached to the mold body together with the thin disk in the mounted state, the stamper can be replaced more easily than before, and when the stamper is replaced on site, dust easily enters between the mirror surface and the stamper. The problem was also solved, and even in the frequent stamper replacement in the production of various kinds of small-quantity discs, the molds can be kept as they are, so there is no trouble and the replacement time is significantly reduced,
A structure for facilitating attachment and detachment of the mold is not required.

The abutment between the stamper and the mirror surface is not the mirror surface of the disk in the base die, but the mirror surface of the thin-walled disk that is superimposed and abutted on the back side of the stamper. It is not necessary to disassemble and reassemble the mold as before,
Maintenance of the mirror surface is also facilitated.

Since the total thickness of the stamper and the thin disk can be applied to the disk body, if a plurality of thin disks having different wall thicknesses are prepared, the thickness varies for each stamper. However, it is possible to apply a thin disk that conforms to the thickness of the stamper in view of the total amount, and as a result, the total amount is constant regardless of the type of stamper. Can be prevented.

The thin disk has a simpler structure and is less expensive than a disk configured to withstand the injection pressure, and since it is a plate, the processing required for mirror finish can be easier and cheaper than mass production. It also has an advantage that it can be immediately applied to a conventional mold.

In the case where the outer peripheral ring is provided on the outer periphery of the surface of the disk body, even after being removed from the base mold, the stamper is attached to the disk body together with the thin disk by the outer peripheral ring, so that the stamper is easy to carry. Since the ring prevents the stamper from being turned or displaced, the dust does not enter between the stamper and the thin-walled disk during transfer, and the board can be easily fitted into the base mold.

[Brief description of the drawings]

FIG. 1 is a perspective view of a stamper and a thin disk used in an injection mold for disk molding according to the present invention.

FIG. 2 is a partial sectional view of an injection mold for disk molding according to the present invention.

FIG. 3 is a partial cross-sectional view of another embodiment of the present invention.

FIG. 4 is a schematic sectional view of a fixed side of a conventional injection mold for disk molding.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Base type 12 Board body 14 Stamper 15 Inner peripheral ring 16 Cylindrical body 17 Outer peripheral ring 20 Mirror-finished thin disk 21 Clearance for gas escape 22 Clearance for gas escape

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-63-303713 (JP, A) JP-A-63-188021 (JP, A) JP-A-6-218770 (JP, A) JP-A-2- 295716 (JP, A) JP-A-5-347033 (JP, A) JP-A-3-79321 (JP, A) JP-A-6-270207 (JP, A) JP-A-6-285922 (JP, A) JP-A-2-295718 (JP, A) JP-A-2-134220 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) B29C 45/26-45/44 G11B 7/26

Claims (2)

(57) [Claims] 1. A thin-walled disk having the same shape as a donut-shaped stamper and a mirror-finished surface is provided on the back surface of the stamper so that the mirror surface is in close contact with the back surface of the stamper. A stamper is fixed to the board by an outer peripheral ring attached to the surface of the fitted circular board and attached to the outer periphery of the base mold closed surface and an inner peripheral ring fitted to the center of the board. Wherein the thin disk is formed of a hard disk thicker than a stamper made of a cemented carbide disk or a ceramic disk having a thickness of 0.3 to 1.0 mm. Injection mold for disk molding. 2. The stamper is attached to the board via the thin disk by the inner ring fitted to the center of the board and the outer ring attached to the outer periphery of the surface of the board. The injection mold for disk molding according to claim 1, wherein the injection mold is configured to be detachable from the base mold together with the board.