JPH0418834Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention relates to a mold for multiple molding of disk-shaped molded products having a center hole such as optical disk substrates.

[Conventional technology and its problems]

In general, in the molding of optical disk substrates such as CDs, the mold clamping force is applied evenly, the flow of the resin when injecting and filling the cavity is a radial flow spreading from the center in the radial direction, and the molded body is It is necessary that the center part can be punched out in a mold to form a center hole.

Conventionally, there is a single-cavity mold that satisfies these molding requirements (Tokuko Kokko 1986-
(See Publication No. 23970). However, conventional molds have poor production efficiency, so in order to increase production efficiency, it is necessary to install multiple molding machines, which increases operating costs and
It was disadvantageous in terms of the area occupied by the molding machine, equipment costs, etc.

Therefore, one possibility is to arrange many cavities on the same plane, but since a runner is required to flow the resin in a direction perpendicular to the injection direction, if a center hole punching mechanism is provided, it is necessary to avoid interference with the mechanism. The second sprue extending from the runner section to the gate of the cavity must be retractable, and it is extremely difficult to provide a center hole punching mechanism due to the structure. Furthermore, as a mold for multiple molding that does not require a runner, a mold in which a cavity plate is provided with a hot runner mechanism that movably extends through the stationary core plate has been known (Special Publication No. 59).
In this case, although it is easy to incorporate the center hole punching mechanism, it is extremely difficult to maintain the same gate balance for each cavity, and in the unlikely event that the hot runner chip is damaged and the gate is blocked. In such cases, excessive resin pressure is applied to other cavities, and there is a high risk of damage to the stamper such as generation of burrs.

[Purpose of invention]

The present invention was made in order to solve the above-mentioned conventional problems, and its purpose is to enable efficient molding of a disk-shaped molded product having a central hole while satisfying the above-mentioned molding requirements. .

[Means for solving problems]

The multi-molding mold for disc-shaped molded products of the present invention has a carrier movable relative to both core plates between a fixed core plate and a movable core plate that can move forward and backward with respect to the core plate. In a multi-molding mold in which a cavity plate is interposed and a cavity is formed between the cavity plate and both core plates, a connecting hole is provided in the cavity plate to connect the cavities on both sides to each other, and the fixed side The sprue bushing attached to the core plate and the movable bushing attached to the movable core plate are inserted into the connection hole through the cavity, and the sprue bushing and movable bushing are movable toward and away from the cavity. It is characterized in that a sleeve-shaped gate cutter is fitted so that the outer peripheral edge of the tip of the gate cutter and the end of the connecting hole provided in the cavity plate can be brought into contact with and separated from each other.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings.

In the figure, reference numeral 1 denotes a stationary side core plate, which is attached to a stationary platen 2.

Reference numeral 3 denotes a movable core plate, which is attached to the movable platen 4 and can be moved forward and backward relative to the fixed core plate 1 by a mold clamping device.

A cavity plate 5 is interposed between the fixed core plate 1 and the movable core plate 3, and is movable relative to both core plates 1 and 3.

6A and 6B are cavities for disc-shaped molded products, which are formed between the fixed side core plate 1 and the cavity plate 5 and between the movable side core plate 3 and the cavity plate 5.

Reference numeral 7 denotes a connection hole, which is provided in the center of the cavity plate 5, and allows the centers of the cavities 6A and 6B on both sides of the cavity plate 5 to be connected to each other.

A sprue bush 8 is attached to the stationary core plate 1 and inserted into the connection hole 7 through the center of the cavity 6A.

9 is the movable side bushing, and the movable side core plate 3
The connecting hole 7 is inserted into the connecting hole 7 through the center of the cavity 6B.

A runner 10 runs between the end of the sprue bush 8 and the end of the movable bush 9, the inner peripheral surface of the connecting hole 7 of the cavity plate 5, and the outer peripheral surface of the sprue bush 8 and the movable bush 9. The street leads to cavities 6A and 6B.

11 is a fixed side gate cutter that is formed in a sleeve shape and also serves as a center hole insert;
The sprue bushing 8 can be moved forward and backward by a hydraulic cylinder 12 built into the stationary core plate 1.

Reference numeral 13 denotes a sleeve-shaped movable gate cutter, which is fitted into the movable bush 9 and can be moved forward and backward toward the tip of the movable bush 9 by a hydraulic cylinder 14 built into the movable core plate 3. .

Reference numerals 15A and 15B are annular gates provided on the inner surface of the center hole of the molded product, and between the edge of one connecting hole 7 of the cavity plate 5 and the inner peripheral edge of the tip of the fixed side gate cutter 11, and the other side of the cavity plate 5. are formed between the edge of the connecting hole 7 and the outer peripheral edge of the tip of the movable gate cutter 13, respectively.

Reference numeral 16 denotes a fixed-side floating punch formed in the shape of a sleeve, which faces the cavity 6A and is fitted into the fixed-side gate cutter 11, and is pushed to the cavity 6A side by a pneumatic cylinder 17 built into the fixed-side core plate 1. It is now possible to advance and retreat.

Reference numeral 18 denotes a movable-side floating punch formed in the shape of a sleeve, which faces the cavity 6B and is fitted into the movable-side gate cutter 13, and is moved to the cavity 6B side by a pneumatic cylinder 19 built in the movable-side core plate 3. It is now possible to advance and retreat.

Reference numeral 20 denotes an ejector pin for ejecting the sprue and runner, which is fitted into the movable bush 9 and can be moved to the tip side of the movable bush 9 by an ejector cylinder 21 (only the rod is shown).

Note that 22 is a plasticizing device (only the nozzle is shown).

[Effect]

As shown in FIG. 2, when molten resin is injected from the plasticizing device 22 with the molds 1, 3, and 5 clamped, the molten resin flows from the inside of the sprue bush 8 (sprue) to the middle part of the cavity plate 5. It reaches the gates 15A, 15B via the runner 10, and uniformly fills the cavities 6A, 6B with a radial flow that spreads in the radial direction from the center.

As shown in FIG. 3, the hydraulic cylinder 12,
14, the fixed side gate cutter 11 and the movable side gate cutter 13 are advanced toward each other individually or in conjunction with each other, the gate part is cut and a center hole of the molded product is formed in the mold. , the runner is compressed. The fixed side gate cutter 11 and the movable side gate cutter 13 are
Each is returned to its original position at an arbitrary timing during the cooling process or after the cooling process is finished.

As shown in FIG. 4, after opening the mold, when the ejector pin 20 is moved forward inside the movable bushing 9 by the ejector cylinder 21, the sprue runner attached to the movable side and released from the fixed side falls down by itself or is removed. Discharged by the machine. Further, when the fixed side floating punch 16 and the movable side floating punch 18 are advanced by the pneumatic cylinders 17 and 19, the molded product is formed by the fixed side core plate 1, the movable side core plate 3, and the fixed side gate cutter 1.
1 and the movable gate cutter 13 and are discharged by gravity or by a take-out machine. After the sprue runner and the molded product are discharged, the ejector cylinder 21 and the pneumatic cylinders 17 and 19 are returned, and the fixed side floating punch 16 and the movable side floating punch 18 are returned to their original positions before the mold is closed. The ejector pin 20 returns to its original position by the resin pressure during resin filling in the next molding cycle.

After the mold is closed, the next molding cycle is performed in the same manner as described above.

[Effect of idea]

As described above, the present invention involves inserting the sprue bushing protruding from the fixed side core plate and the movable side bushing protruding from the movable side core plate into the cavity plate (the connecting hole connecting the central part of the cavity). In addition to forming a runner in the middle of the plate, a gate was also formed between the outer periphery of the tip of the gate cutter fitted to the sprue bushing and the movable bushing, respectively, and the edge of the connection hole of the cavity plate. The resin can be uniformly filled into the cavity using radial flow that spreads from the center in the radial direction. Furthermore, the gate portion can be cut within the mold by advancing the gate cutter. Therefore, a molded product having a center hole can be molded accurately and efficiently by multiple molding, and the production efficiency per molding machine can be greatly improved.

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing one embodiment of the present invention;
Figures 3 and 4 show injection holding pressure, gate section cutting,
FIG. 3 is a cross-sectional view showing various situations in which the molded product and the molded sprue/runner are taken out. 1... Fixed side core plate, 3... Movable side core plate, 5... Cavity plate, 6A, 6
B... Cavity, 7... Connection hole, 8... Sprue bushing, 9... Movable side bushing, 10... Runner, 11... Fixed side gate cutter, 13...
...Movable side gate cutter, 12, 14...Hydraulic cylinder, 15A, 15B...Gate, 16...Fixed side floating punch, 18...Movable side floating punch, 17, 19...Pneumatic cylinder, 20... Ejector pin, 21... Ejector cylinder.

Claims (1)

[Claims for Utility Model Registration] (1) A cavity plate that is movable relative to both core plates is interposed between a fixed core plate and a movable core plate that can move forward and backward with respect to the core plate. and in the multi-molding mold in which a cavity is formed between the cavity plate and both core plates, a connection hole is provided in the cavity plate to connect the cavities on both sides to each other, and the cavity is attached to the fixed side core plate. The sprue bushing and the movable bushing attached to the movable core plate are inserted into the connection hole through the cavity, and a sleeve-shaped gate cutter that can move forward and backward with respect to the cavity is attached to the sprue bushing and the movable bushing. A mold for multiple molding of disc-shaped molded products, characterized in that the outer peripheral edge of the tip of the gate cutter and the end of the connecting hole provided in the cavity plate can be brought into contact with and separated from each other by fitting. (2) Utility model registration claim 1, characterized in that the fixed side core plate and the movable side core plate are provided with floating punches for discharging molded products that are movably fitted into gate cutters provided respectively. A mold for multiple molding of the disc-shaped molded product described in 2. (3) A mold for multiple molding of disc-shaped molded products according to claim 1 or 2 of the utility model registration claim, characterized in that an ejector mechanism for ejecting sprue and runners is provided by penetrating the interior of the movable bushing. Type.