Nissei Plastic Industrial Co., Ltd.

Makoto Nakazawa

Toshiyasu Koda

Masahiko Miyajima

Nobuyuki Nakamura

Tsuyoshi Arai

Kazutoshi Takayama

Minoru Yamazaki

Kazuki Miyairi

Tyuyoshi Arai

Toshiyuki Kanai

Shuji Aiba

The present invention has an object of eliminating the holding pin trace of a composite-molding of the dichromatic molding by refilling with resin by the pushing pin and preventing the lateral-shift of the primary molding during the refilling. It is made possible to fill closed recess and cavity with resin through a communicating hole formed in the primary molding by the pushing pin. A primary cavity moldand a secondary cavity moldare juxtaposed at symmetrical positions of a fixed plate. Core moldsclosing alternately with both thereof are juxtaposed on a rotary tableinstalled on a movable platen. Holding pinsof the primary moldingand a resin pushing pinare installed in the core moldin a way to appear and disappear in respect to a cavity. The primary moldingis held in contact with the surface of the secondary cavity mold by the holding pin. A pin holefor refilling resin is formed to be opened on a surface of the core mold by retracting the pushing pin. A secondary cavity including the pin holeis refilled with a different material resin by injection. The holding pinis retracted and sunk in the surface of the cavity mold. The pushing pinis moved forward to force the resin for refilling the pin holeinto the resin in the cavity. The regions not filled with resin due to the holding pinare refilled up.

Composite-molding method and injection-molding machine of different material resin

An injection molding method for an injection molding machine in which molten resin in an injection barrel is injected and charged into a cavity of a mold through advancement of a screw in order to form a thin molding product. When the screw reaches a first set point that is set in advance and corresponds to completion of charge during the advancement of the screw, the screw is immediately and forcibly retracted to a second set point that is set in advance. With is operation, when the screw reaches the first set point X1 corresponding to completion of charge during the advancement of the screw, the internal pressure of the cavity is relieved quickly. Therefore, the cavity, which has deformed due to high pressure resin, is restored to its designed shape before the resin solidifies.

Injection molding method for an injection molding machine

A method of operation for an injection molding machine is disclosed. The injection molding machine includes an injector having an advancable screw and a barrel cylinder, and a mold clamp for holding a mold with a controllable pressure and for allowing the mold to open a controllable amount. In performing the method, preset values are established for a stop position of the advancable screw, a clamping pressure of the mold clamp, and an opening amount for the mold. The screw is advanced up to the preset stop position and stopped thereat. The screw is controlled so as to ensure the location of the screw at the preset stop position for a preset time. Resin is injected from the barrel cylinder into the mold. The mold is clamped with the preset clamping pressure, during the preset time, by operating the mold clamp while maintaining the positioning of the screw at the preset stop position. Further, the mold clamp is operated to controllably allow for opening of the mold during the injecting step, so that the mold is allowed to open to the preset opening amount when the injecting step is completed.

Molding method of injection molding machine

An injection pressure is detected as a pressure detection value Dp during injection and filling, and the thus obtained pressure detection value Dp is multiplied by a preset predetermined coefficient so as to be converted into a desired mold clamping force Fc with which the mold clamping force is controlled. The desired mold clamping force Fc is set to a minimum value which a mold does not open, that is, the desired mold clamping force Fc is calculated with the use of Fc=(.alpha.*S*.beta.)Dp, where .alpha. is a charging rate of resin in a mold cavity, S is an entire projected area of a molding article, .beta. is a safety factor, and Dp is a pressure detection value Dp. With this arrangement, in a section where the injection pressure gradually increases from zero during injection and filling, the profile (variation curve) of mold clamping force gradually increases as the injection pressure varies. At this stage, the mold clamping force during injection and filling is set to a minimum value with which the mold does not open so that the power consumption can be minimized.

Method of controlling mold clamping force for injection molding machine

A control method of an injection molding machine includes the steps of advancing a screw 2, injecting and filling the resin in a barrel cylinder 3 into a mold 4 to fill the mold, and then applying a predetermined holding pressure to the resin in the mold 4. The control method further includes the steps of performing an injecting and filling by using an injection cylinder 5 having a double-rod piston 6 which can advance and retreat the screw 2, and then controlling the injection cylinder 5 by a controlling signal Dc including a predetermined alternating current signal in such a manner that the screw 2 is reciprocated in a longitudinal direction as a center with an advance finish and. stop position Xs and a position at which the screw is moved so as to retreat by a predetermined distance from the advanced finish and stop position Xs. Thereby, the mold failure such an overpack and a burr is eliminated.

Control method of injection molding machine

A die assembly for molding a disc such as a compact disc, a video disc or the like by employing an injection molding process. The die assembly comprises a stationary die half including as essential components a stationary platen, a base die half, and an insert die half received on the stationary platen, and a movable die half. The insert die half includes a first insert for fixing the insert die half on the stationary platen, and a first mirror surface board removably received in a cavity of the first insert. The insert die half can be easily installed and removed into/from an installation space defined by a pair of retaining members and a die receiving member and when installed, it can be certainly and easily fixed by a pair of retaining members.

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Nagano, Japan

Makoto Nakazawa