JPH0649313B2 - Injection compression molding equipment - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an injection compression molding apparatus capable of obtaining a precision molded product such as an optical disk, and more particularly to a molded product simultaneously with molding by a direct spool method. The present invention relates to an injection compression molding device capable of making a hole in a predetermined portion.

[Conventional technology]

As this injection compression molding, when the molten resin is injected into the mold, the fixed mold and the movable mold are separated from each other by a predetermined distance so that the molten resin does not leak outside. After injecting and filling, the above-mentioned parting surfaces are joined by various known means, and the resin in the mold is compressed.

Compared with normal injection molding, this injection compression molding method has better transferability to the mold, the influence of the injection flow line and the residual stress are relatively small, and a molded product that is uniform throughout can be obtained. Moreover, it has the feature that the "sink" of the molded product can be reduced, and it is often used for precision molding of optical discs, for example.

FIG. 8 is a partial sectional view of a conventional injection compression molding device.

In the figure, 1 is a fixed die plate, 2 is a fixed die attached to the fixed die plate 1, 3 is a movable die plate, 4 is a movable die attached to the movable die plate 3, and 5 is a heating cylinder. , 6 is a nozzle attached to the tip of the heating cylinder 5, 7 is a sprue bush provided in the fixed mold 2, 8 is a molten resin, and 9 is movably arranged in the movable mold 4. Punch for punching and gate sealing, 10 is a punch driving hydraulic cylinder, 11 is an injection device main body, 12 is a nozzle touch / back hydraulic cylinder,
Reference numeral 13 is a nozzle touch / back hydraulic circuit, and 14 is a punch drive hydraulic circuit.

In injection compression molding, first, the fixed mold 2 and the movable mold 4 are not leaked to the outside even if the molten resin 8 is injected into the cavity formed by the fixed mold 2 and the movable mold 4. Keep the patenting surface of the specified distance apart,
The punch 9 is arranged at the standby position as shown in the figure. By driving the nozzle touch / back hydraulic cylinder 12, the apparatus main body 11, the heating cylinder 5, the nozzle 6 and the like advance integrally by a predetermined stroke, and the tip end of the nozzle 6 is in contact with the sprue bush 7 (nozzle touch).

Then, the molten resin 8 is injected and filled into the cavity from the heating cylinder 5 through the nozzle 6 at a relatively low pressure. When this filling is completed, the punch driving hydraulic cylinder 10 is driven to move the punch 9 forward (to move to the fixed mold 2 side), and at the same time, to drive the nozzle touch / back hydraulic cylinder 12 to heat the apparatus main body 11 and The cylinder 5, the nozzle 6, and the like are retracted by the stroke by which the punch 9 advances (nozzle back). The sprue bush 7 is moved by the forward movement of the punch 9 and the backward movement of the nozzle 6.

As a result of the advance of the punch 9, as a result, a hole is opened in the center of the molded product, and along with that, the advance of the punch 9 causes a gate seal, and then the movable die plate 3 is fixed to the mold clamping mechanism (not shown). (2) is moved slightly to join the parting surfaces to each other, whereby the filling resin is compressed. By this compression operation, the pattern of the movable mold surface is precisely transferred to the surface of the molded product. Then, it is cooled for a fixed time and the molded product is taken out.

This direct sprue mold has little flow resistance in the sprue part when filling the cavity with molten resin, and can quickly and evenly fill the cavity, and a hole is opened in the center of the molded product before opening the mold. If the sprue is cut by cutting the sprue, the step of cutting the sprue runner from the gate portion after molding is not necessary, and the molding process can be shortened.

[Problems to be Solved by the Invention]

In this direct spool system, the heating cylinder 5 and the nozzle 6 must be retracted in synchronism with the forward movement of the punch 9, and the sprue bush 7 and the nozzle 6 must be kept in contact with each other during the backward movement and at the end of the backward movement. I don't know. This is because the resin at the tip of the nozzle is in a semi-molten state in preparation for the next shot even when the nozzle is backed up. This will cause a phenomenon.

However, in this conventional injection compression molding apparatus, the nozzle touch / back hydraulic cylinder 12 retracts the nozzle as the punch 9 moves forward.

For example, when molding a compact disk, punch 9
The stroke of the (punch drive hydraulic cylinder 10) is extremely short, which is equal to or larger than the thickness of the compact disk, for example, about 1.5 to 2.5 mm. On the other hand, the stroke of the nozzle touch / back cylinder 12 varies depending on the model, but it is a long stroke of, for example, 200 to 1300 mm, and there is a considerable difference in stroke. Therefore, it is very difficult to accurately synchronize the operation of the nozzle touch and back hydraulic cylinders 12 with the instantaneous operation of the small punch drive hydraulic cylinders 10. The nozzle 6 has a drawback that it is separated from the sprue bushing 7 and punching cannot be performed.

The object of the present invention is to eliminate such drawbacks of the prior art,
An object of the present invention is to provide an injection compression molding apparatus having high operation reliability.

[Means for Solving the Problems]

In order to achieve the above-mentioned object, the present invention includes a fixed die attached to a fixed die plate and having a sprue bush arranged therein so that the sprue bush can be moved forward and backward, and a movable die plate attached to a position facing the sprue bush inside. A movable die in which a punch for punching is arranged so as to be able to move forward and backward, a driving means for the punch for punching, such as a hydraulic cylinder, a heating cylinder having a nozzle abutting against the sprue bushing attached to a tip thereof, and heating thereof. A support member such as an apparatus main body for supporting the cylinder, and a nozzle touch / back drive means such as a motor with a brake or a hydraulic cylinder for moving the nozzle forward and backward by moving the support member forward and backward, and fixed to the support member. For example, a connecting bar such as a ball screw or cylinder rod that connects with the die plate, and And a hydraulic cylinder for punching back which operates when the punch for punching advances and lengthens the distance between the fixed die plate and the support member by the stroll of the punch. is there.

〔Example〕

 Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a partial cross-sectional view of an injection compression molding apparatus according to the first embodiment, and FIG. 2 is an explanatory view showing power transmission.

In the case of this embodiment, a motor with a brake 15 is used in place of the nozzle touch / back hydraulic cylinder 10 and the nozzle touch / back hydraulic circuit 13 of the conventional apparatus shown in FIG. Then, as shown in FIG. 2, the rotational force is transmitted from the drive side gear 16a connected to the motor 15 to the gear 16c and the gear 16d via the idler 16b. The gear 16c is screwed with the ball screw 17a, and the gear 16d is screwed with the ball screw 17b. The ball screws 17a and 17b are arranged diagonally as shown in FIG. When nozzle backing is performed at times other than the nozzle touch and the nozzle back at the time of drilling, the motor 15 is driven to perform the nozzle touch or the nozzle back.

The tip of each of the ball screws 17a and 17b has a first
As shown in the figure, it is connected to the fixed die plate 1 through a hydraulic cylinder 18 for punching back. The drilling back hydraulic cylinder 18 is connected to a drilling back hydraulic circuit 19.

The punching hydraulic cylinder 18 is a relatively small hydraulic cylinder that can be adjusted to the same stroke as the punch driving hydraulic cylinder 10. Further, the punching hydraulic circuit 19 can use the same hydraulic source as the punch driving hydraulic circuit 14.

The fixed mold 2 side of the movable mold 4 is composed of a stamper 4a and a stamper holder 4b. On the surface of the stamper 4a, a recording pattern 2 on an optical disk 20 described later is formed.
The reverse pattern 1 (fine unevenness) is previously formed.

3 and 4 are a plan view and an enlarged sectional view of the optical disk 20. As shown in FIG. 3, a hole 22 for driving the disk is provided in the center of the optical disk 20, and this hole 22 is formed by the punch 9 when the optical disk 20 is molded. On the outer periphery of the hole 22, a recording pattern 21 having fine irregularities such as grooves and pits is formed. As described above, the reverse pattern of the recording pattern 21 is formed on the stamper 4a. Reference numeral 23 in FIG. 4 is a transparent substrate made of, for example, polycarbonate or the like, which is molded by injection compression. Reference numeral 24 is a protective layer formed on the recording pattern 21.

Prior to the molding of the optical disc 20, the motor 15 is driven so that the gear 16a connected to the motor 15 drives the idler 16
The gear 16c and the gear 16d are simultaneously rotated via b, the heating cylinder 5 and the nozzle 6 are advanced by a predetermined stroke, the tip end of the nozzle 6 is brought into contact with the sprue bush 7, and the rotation of the motor 15 is stopped in this state. The nozzle touch force can be expressed by the braking force.

In the punch driving hydraulic circuit 14, hydraulic pressure is supplied from the B port side, so that the punch driving hydraulic cylinder 10 is in the retracted position and the punch 9 is held in the standby position.
In the hydraulic circuit 19 for punching back, hydraulic pressure is supplied from the A port side, and the hydraulic cylinder 18 for punching back is in a standby state. Although not shown, the partitioning surfaces of the fixed mold 2 and the stamper 4a of the movable mold 4 are separated by the compression margin.

In this state, the molten resin is filled into the cavity at a relatively low pressure, and at the same time as the end of filling, the hydraulic pressure on the A port side in the hydraulic circuit 19 for punching back is released and the hydraulic pressure on the B port side is supplied. Further, the hydraulic pressure is supplied to the port A side of the punch driving hydraulic circuit 14. By doing so, the punch 9 advances by a predetermined stroke (for example, 2.5 mm), and in this forward movement, the nozzle 6 and the heating cylinder 5 are retracted by the same stroke through the sprue bush 7, and the hole 22 (the third (See the figure) and the gate seal is formed. When the punch 9 moves forward, the punching back hydraulic cylinder 18 simply moves to the right in the drawing by the same amount as the punch forward stroke.
The motor 15 still remains in the stopped state and holds the nozzle touch force.

With the gate sealed in this way, the stamper holder 4b and the stamper 4a are advanced by a compression mechanism (not shown) in a preset pressure pattern and speed pattern, the resin in the cavity is compressed, and the pattern of the sternper 4a is transferred to it. To do. After that, cooling is performed for a predetermined time in accordance with a conventional method, and the optical disk 20 that has been molded and punched is taken out.

FIG. 5 is a partial sectional view of an injection compression molding apparatus according to the second embodiment of the present invention. This embodiment differs from the first embodiment in that the motor 15 and the gear groups 16a to 16d are different.
Instead of the above, a nozzle touch / back hydraulic cylinder 12 and a nozzle touch / back hydraulic circuit 13 are used. As shown in the figure, a hydraulic cylinder 18 for punching back is provided in the middle of the cylinder rod of the cylinder 12 for nozzle touch / back.

In the case of this embodiment, when the punch 9 is moved forward, hydraulic pressure is sent to the A port side to the nozzle touch / back hydraulic circuit 13 in the same manner as when the molten resin 8 is filled, and the nozzle touch force is applied. It is held in a closed state.

Other operations and the like are the same as those in the first embodiment, and therefore their explanations are omitted.

In the above-mentioned embodiment, the case where the disk-shaped molded product is injection-compression-molded has been described, but the present invention is not limited to this. For example, a plurality of runners 30 and gates 31 are provided in the direct sprue as shown in FIG. The present invention is also applicable to a case in which a ring-shaped gate portion is punched out with a punch and then the mold is opened after a molded article having the above is injected by normal injection molding.

〔The invention's effect〕

As described above, the present invention is provided with the hydraulic cylinder for punching back and the hydraulic circuit for punching back, and when the hole is opened by advancing the punch, the original nozzle touch / back drive means is stopped and the nozzle tarch is driven. With the force still applied,
Since it suffices to operate the hydraulic cylinder for punching back with a short stroke, it is possible to accurately match the operation timing of the punch driving cylinder and the hydraulic cylinder for punching back. Therefore, the nozzle can always be kept in contact with the sprue bush while pressurizing it while the punch is moving forward or after moving forward, so that a high-quality molded product can be obtained, and an injection compression molding apparatus with high operation reliability is provided. be able to.

[Brief description of drawings]

FIG. 1 is a partial sectional view of an injection compression molding apparatus according to a first embodiment of the present invention, FIG. 2 is an explanatory view showing power transmission of the molding apparatus, FIG. 3 is a plan view of an optical disk, and FIG. FIG. 4 is an enlarged sectional view of an optical disk, FIG. 5 is a partial sectional view of an injection compression molding apparatus according to the second embodiment of the present invention, and FIG. 6 is another molded article that can be molded according to the present invention. 7 is a timing chart of the injection compression molding apparatus according to the first and second embodiments of the present invention, and FIG. 8 is a partial sectional view of the conventional injection compression molding apparatus. 1 ... Fixed die plate, 2 ... Fixed die, movable die plate, 4 ... Movable die, 4a ... Stamper, 4b ...
Stamper holder, 5 ... Heating cylinder, 6 ... Nozzle, 7 ...
Sprue bush, 8 ... Molten resin, 9 ... Punch, 10
...... Punch drive hydraulic cylinder, 11 …… Device body, 1
2 …… Nozzle touch / back hydraulic cylinder, 13 ……
Hydraulic circuit for nozzle touch / back, 14 …… Punch drive hydraulic circuit, 15 …… Brake motor, 16 …… Gear, 17 …… Ball screw, 18 …… Hole drilling hydraulic cylinder, 19 …… Hole punching hydraulic circuit Hydraulic circuit, 22 ...
hole.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Seiichi Tsuchiya No. 523 Nishinoyama, Futari-cho, Futami-cho, Akashi-shi, Hyogo Toyo Kikai Metal Co., Ltd. (72) Hiroshi Kamei Fukusato, Futami-cho, Akashi-shi, Hyogo Nishinoyama No. 523 No. 1 Toyo Kikai Metal Co., Ltd.

Claims (1)

[Claims] 1. A fixed die attached to a fixed die plate and having a sprue bush arranged therein so as to be able to move forward and backward, and a punch for advancing forward and backward at a position attached to a movable die plate and opposed to the sprue bush inside. A movable die that is arranged so that it can be driven, a driving means for the punch for punching, a heating cylinder with a nozzle that abuts the sprue bushing attached to the tip, a support member that supports the heating cylinder, and the support member By advancing, the nozzle touch / back drive means for moving the nozzle forwards and backwards, a connecting bar for connecting the supporting member and the fixed die plate, and the connecting punch provided in the middle of the connecting bar, the punch for punching advances. And a hydraulic cylinder for punching back, which is operated occasionally to lengthen the distance between the fixed die plate and the supporting member by the stroke of the punch. An injection compression molding device characterized in that