JPH0423617Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an injection molding device for molding a thin plate-shaped molded product, such as a compact disk, and in particular, the invention relates to an injection molding device for molding a thin disk-shaped molded product, such as a compact disk. The present invention relates to an injection molding device equipped with a punching mechanism.

[Prior Art] For example, when molding a compact disc, the unnecessary part at the center of the molded disc is punched out together with a sprue in a mold to remove it, thereby obtaining the disc as a product.

FIG. 2 shows a mold of a conventional compact disk molding apparatus. In the figure, 1 is a fixed mold, 2 is a movable mold, and inside the fixed mold 1, a sprue bush 3 is provided so as to be movable in the axial direction with its tip facing the cavity C, and the movable mold 2 Inside the
A punching cutter 4 is provided opposite the sprue bush 3 so as to be freely movable in the axial direction. The punching cutter 4 has a cylindrical shape, and inside thereof is an ejector pin 5 for removing the punched piece and sprue after being punched out by the punching cutter 4 from the tip of the punching cutter 4. It is provided so as to be freely movable in the axial direction.

These punching cutters 4 and ejector pins 5 are each extruded with a strong force in the left direction in the figure by shifting the process, and in order to extrude them, the molding device is equipped with an independent extrusion operating mechanism. It is being Usually, one operating mechanism is an ejector rod provided on the side of the molding apparatus body that does not include the mold, and the other operating mechanism is a cylinder mechanism provided inside the mold.

In the example shown in FIG. 2, the ejector pin 5 is operated by an ejector rod 6 on the molding apparatus main body side, and the punching cutter 4 is operated by a hydraulic cylinder mechanism 7 inside the movable mold 2.

That is, a piston 8 is connected to the rear part of the ejector pin 5, and the rear end surface of the piston 8 is exposed to the mounting surface 2A of the movable mold 2. The ejector pin 5 can be operated by pushing with the tip of the ejector pin 6. Regarding the operating mechanism on the punching cutter 4 side, a hydraulic cylinder mechanism 7 is provided inside the movable mold 2, and the tip of the piston 9 of this hydraulic cylinder mechanism 7 is connected to the rear end of the punching cutter 4. By introducing pressure oil into the oil chamber 10 of the hydraulic cylinder 7, the punching cutter 4 can be pushed out and moved.

In addition, as another conventionally known example of the above example,
There is one shown in Publication No. 62-42773. This product operates an ejector pin (protruding pin) with a cylinder mechanism built inside the mold, and a cutter (punch) is operated by an ejector rod (punch operating member).
I am trying to get it to work.

In any case, in this type of conventional molding apparatus, one of the two operating mechanisms is built into the mold as a cylinder mechanism.

[Problems to be solved by the invention] Therefore, there was a problem that the internal structure of the mold was complicated and maintenance was troublesome. Also,
If the hydraulic cylinder mechanism is built into the mold, there is a risk of oil leakage due to the longevity of the packing due to the temperature rise during molding, which is a problem especially when molding compact discs where oil contamination is averse. Furthermore, when the gaskets are replaced during maintenance, oil must be completely removed, making the work complicated.

[Means for Solving the Problems] The injection molding apparatus of the present invention was provided in order to solve the above problems, and the injection molding apparatus of the present invention is provided with a movable mold so as to face a sprue bush on the fixed mold side. A cylindrical punching cutter with its tip facing the cavity is provided inside the punching cutter so as to be movable in the axial direction, and a punched piece and sprue produced by the punching cutter are removed from the tip of the punching cutter. An ejector pin is inserted through the die so as to be movable in the axial direction, and the rear end of the punching cutter and the rear end of the ejector pin are respectively faced directly or via an indirect member to the mold mounting surface of the movable mold mounting plate. On the other hand, the movable platen is provided with an ejector rod for pushing out the ejector pin at a position facing the rear end of the ejector pin with its tip exposed on the mold mounting surface, and at the rear of the punching cutter. A cylindrical cutter extrusion sleeve for pushing out the punching cutter is provided at a position facing the end with its tip exposed to the mold mounting surface.

[Function] In the present invention, the punched cutter is extruded by moving the cutter extrusion sleeve toward the mold side. Then, unnecessary portions of the molded product are punched out using the tip of the punching cutter. Furthermore, by moving the ejector rod toward the mold side, the ejector pin is projected from the tip of the punching cutter, and the punched piece and sprue punched with the punching cutter are removed from the tip of the punching cutter.

[Example] Hereinafter, an example of the present invention will be described with reference to FIG.

In this figure, 1 is a fixed mold, and 20 is a movable mold. The fixed mold 1 has the same structure as the fixed mold shown in FIG. 2 described above, and is provided with a sprue bush 3 inside thereof so as to be movable in the axial direction with its tip facing the cavity C. In addition, the movable mold 20
A cylindrical ejector sleeve 21 is provided inside the ejector sleeve 21 so as to be movable in the axial direction, and a cylindrical shaft-like punching cutter 22 is provided inside the ejector sleeve 21.
is provided opposite the sprue bush 3 so as to be freely slidable in the axial direction.

The punching cutter 22 punches out the center of the molded product with its tip (left end) outer periphery by being pushed to the left in the figure, and although the tip is formed to have a small diameter, the rear end has a large diameter. It is formed into a cup shape with a diameter, and the cup-shaped portion serves as a cutter piston 22A.
It is fitted into a cylinder hole 23 in the movable mold 20 so as to be slidable in the axial direction. The cylinder hole 23 is bored along the axial direction of the punching cutter 22 from the mounting surface 20A of the movable mold 20 to the movable mold mounting plate 40, and is connected to the bottom surface 23A of the cylinder hole 23 and the cutter piston 22A. An airtight space 24 secured between
By introducing high pressure air into the piston part 2
2A is moved to the right in the figure, thereby making it possible to return the punching cutter 22 that has protruded to the extrusion position to its original position.

A cooling sleeve 25 is housed inside the punching cutter 22, and the ejector pin 5 is inserted into the cooling sleeve 25 so as to be freely slidable in the axial direction. The ejector pin 5 is a punching cutter 22
After punching out unnecessary parts of the molded product, use the punching cutter 21
The punching piece and sprue that are fixed to the lock part (undercut part) 26 at the tip of the punching cutter 22
The purpose is to exclude it from the tip.

The rear end of this ejector pin 5 is connected to the cooling sleeve 2.
5, and its protruding rear end is connected to an ejector piston (indirect member) 27 that is slidably fitted into a cylinder hole 22B in a cutter piston 22A. .
Further, a ring-shaped rear end surface of the cutter piston 22A formed at the rear end of the punching cutter 22 is provided with a ring-shaped flange (indirect member) 28 in close contact with the cutter piston 22A. It also serves as a stopper for 27.

The ejector piston 27 and the ring-shaped flange 28 are arranged concentrically, and each rear end surface is connected to the movable mold mounting plate 40 of the movable mold 20.
It is exposed almost flush with the mounting surface 20A. By pressing the ring-shaped flange 28 to the left in the figure, the punching cutter 22 can be pushed out and moved.
By moving the ejector pin 5 to the left,
It is now possible to extrude and move. In addition, by introducing high pressure air into the airtight space 29 secured between the ejector piston 27 and the bottom surface of the cylinder hole 22B inside the cutter piston 22A, the ejector piston 27 is returned to the right in the figure, and the cutter piston By introducing high pressure air into the airtight space 24 between 22A and the bottom surface 23A of the cylinder hole 23 inside the movable mold 20, the cutter piston 22A is returned to the right in the figure. In reality, both airtight spaces 24 and 29 are filled with high-pressure air, and the return operation is performed by the action of an air spring.

Next, the structure of the movable mold mounting plate 40 will be described. In the center of the movable mold mounting plate 40, there is a ring-shaped flange 2 disposed behind the punching cutter 22.
A cylindrical cutter extrusion sleeve 41 for pushing out the punching cutter 22 is provided so as to face the punching cutter 8 with its tip exposed to the mold mounting surface 40A. This cutter extrusion sleeve 41 is formed to have an inner diameter slightly larger than the diameter of the rear end surface of the ejector piston 27 on the movable mold 20 side, and is used for cylinder members 42 and 43 embedded in the movable mold mounting plate 40. The piston portion 41A is fitted on the inner periphery so as to be slidable in the axial direction, and has a piston portion 41A in the center that is operated by hydraulic pressure.

The cutter extrusion sleeve 41 is pushed out to the left in the figure by introducing pressure oil into the oil chamber 44 on the right side in the figure adjacent to the piston part 41A.
By introducing pressure oil into the oil chamber 45 on the left side in the figure, it is returned to the right side, and a hydraulic cylinder mechanism 46 is constituted by the cutter push-out sleeve 41 and cylinder members 42 and 43. . Note that the symbol 47A is an oil passage leading to the oil chamber 44, and the symbol 47B is an oil passage leading to the oil chamber 4.
This is an oil road leading to No. 5. These communicate with oil passages 49 and 50 in a pressure oil supply block 48 fixed to the side surface of the cylinder member 43, respectively.

Moreover, inside the cutter extrusion sleeve 41,
An ejector rod 6 provided in the molding apparatus main body is inserted. This ejector rod 6 is moved to the cutter pushing sleeve 41 by a drive mechanism (not shown).
It is moved in the axial direction independently of the movement of the ejector piston 27, and its tip is exposed to the mold mounting surface 40A so as to face the rear end surface of the ejector piston 27.

Next, a case in which a compact desk is molded using the apparatus of the above embodiment will be described.

First, as in the case of normal injection molding, the movable mold 20 is brought into contact with the fixed mold 1 to close the mold, and a nozzle (not shown) is brought into pressure contact with the sprue bush 3.
After completing the mold closing and performing even stronger mold clamping, next, molten resin is injected into the cavity C formed by the fixed mold 1 and the movable mold 20 to mold a compact disk.

When the resin has solidified to some extent, the hydraulic cylinder mechanism 46 built into the movable mold mounting plate 40
Pressure oil is introduced into the oil chamber 44 to move the cutter push-out sleeve 41 to the left in the figure. Then,
The cutter piston 27 is pushed to the left by the tip of the cutter extrusion sleeve 41, thereby pushing out the punching cutter 22, thereby punching out the unnecessary part in the center of the hardening disk. At this time, the sprue bush 3 on the fixed mold 1 side is also pushed to the left.

After this punching is completed, the mold is opened and the disc is released from the mold. At this time, the sprue is attached to the punching cutter 22 together with the punched piece by the punching cutter 22.
It is fixed to the lock part 26 at the tip and comes out of the sprue bush 3. After the mold is released, the ejector rod 6 is moved to the left and the rear end of the ejector piston 27 is pushed. Then, as the ejector piston 27 is pushed, the ejector pin 5 is pushed to the left, and the sprue and punching piece are pushed out from the tip of the punching cutter 22. As a result of the above, a compact desk is obtained as a product. Note that the ejector pin 5 may be actuated and returned at any point in the mold opening process.

As described above, in the molding apparatus of the above embodiment, the operation of the punching cutter 22 and the ejector pin 5 are
Both operations are performed by mechanisms outside the mold. Therefore, the structure of the mold is simple,
In particular, since there is no need to introduce hydraulic oil into the mold, it is ideal for molding compact desks that are sensitive to oil.

Note that the present invention can of course be applied to molding devices other than compact disks.

[Effects of the invention] The invention has the following excellent effects.

(1) Since neither an operating mechanism for pushing out the punching cutter nor a drive mechanism for pushing out the ejector pin is provided inside the die, the structure of the die is simple and maintenance of the die can be performed easily.

(2) Since the mold does not have a built-in hydraulic cylinder mechanism, there is no risk of oil getting into the molded product, making it ideal for molding compact desks. Furthermore, since the mold is not provided with a hydraulic cylinder mechanism, the packing can be easily replaced during maintenance regardless of the mold.

[Brief explanation of the drawing]

FIG. 1 is a side sectional view of the main parts of an embodiment of the present invention, and FIG. 2 is a side sectional view of a conventional compact desk mold. 1...Fixed mold, 3...Sprue bush, 5
...Ijiektapine, 6...Ijiektarod,
20...Movable mold, 22...Punching cutter, 27...
...Ejector piston (indirect member), 28...Ring-shaped flange (indirect member), 40...Movable mold mounting plate, 41...Cut extrusion sleeve, C...
Cavity.

Claims (1)

[Scope of utility model registration request] A cylindrical punching cutter with its tip facing the cavity is provided inside the movable mold so as to face the sprue bush on the fixed mold side, and is movable in the axial direction.
An ejector pin for removing punched pieces and sprue from the punching cutter tip is inserted into the punching cutter so as to be movable in the axial direction, and the rear end of the punching cutter and the rear end of the ejector pin are inserted into the punching cutter. are made to face the movable mold mounting plate either directly or through an indirect member, and on the other hand, the movable mold mounting plate has an ejector rod for pushing out the ejector pin at a position facing the rear end of the ejector pin. is provided with its tip exposed to the mold mounting surface, and a cylindrical cutter extrusion sleeve for pushing out the punching cutter is provided at a position facing the rear end of the punching cutter with its tip exposed to the mold mounting surface. An injection molding device equipped with a punching mechanism, characterized in that the punching mechanism is provided in an exposed manner.