Toshiba Kikai Kabushiki Kaisha

Toshiba Machine Co., Ltd.

Haruyuki Matsubayashi

Takashi Yamazaki

Yutaka Yamaguchi

Yukio Iimura

Makoto Nishizawa

Masamitsu Suzuki

Takamitsu Yamashita

Akira Kanda

Jun Koike

Takaki Miyauchi

Nobuyuki Muroi

Takeshi Abe

Mitsunori Kokubo

Kazuhito Kobayashi

Kiyoshi Sasaki

Nobuyuki Asanuma

Yasumasa Sugiyama

Motoyuki Miyauchi

Keisuke Mori

Kazunori Urushibata

Shigehiro Saitou

Used in a method of this invention is a die clamping unit, which comprises a tie bar movably attached to a stationary platen, a halfnut positioning servomotor which advances and retreats to the tie bar, a halfnut which is provided on a movable platen and fixes the movable platen and the tie bar together by engaging the tie bar, an engaging mechanism which engages the halfnut with the tie bar, a hydraulic die clamping cylinder which presses the stationary platen and the movable platen, and a control device which controls the halfnut positioning servomotor and the hydraulic cylinder. The control device drives the halfnut positioning servomotor to remove a clearance between the halfnut and an engaging groove of the tie bar before a die clamping process carried out by the hydraulic cylinder.

Die clamping method

Used in a method of this invention is a die clamping unit, which comprises a tie bar movably attached to a stationary platen, a halfnut positioning servomotor which advances and retreats the tie bar, a halfnut which is provided on a movable platen and fixes the movable platen and the tie bar together by engaging the tie bar, an engaging mechanism which engages the halfnut with the tie bar, a hydraulic die clamping cylinder which presses the stationary platen and the movable platen, and a control device which controls the halfnut positioning servomotor and the hydraulic cylinder. The control device drives the halfnut positioning servomotor to remove a clearance between the halfnut and an engaging groove of the tie bar before a die clamping process carried out by the hydraulic cylinder.

Die clamping unit and die clamping method

A transcript apparatus has a vacuum-forming chamberin which a transcription dieand a forming producttranscribed from the dieare disposed face to face with each other, a movable bodysupporting one of the dieand the productto allow the dieand the productto be movable closer to or away from each other, a balance cylinderplaced in parallel to a moving direction of the movable bodyand connected to the movable bodyvia a piston rod, a pressure detectordetecting a pressure inside the chamber, and a pressure control sectionoperative to control a pressure of working fluid supplied to the chamberdepending on an output from the pressure detectorto cancel fluctuation in load acting on the movable bodyin the moving direction thereof.

Transcript apparatus

A screw tip is provided in front of a screw with a shaft interposed therebetween, and a check ring is fitted around the shaft. The check ring is separated from a front end portion of the screw when the screw is rotated in a forward direction. The check ring contacts the front end portion of the screw when the screw is advanced. A front end surface of the check ring is provided with teeth, and a rear end surface of the screw tip is provided with grooves with which the respective teeth are engaged. Respective one side surfaces of the grooves and the teeth which are pressed against each other when the screw is rotated in the forward direction are formed vertical to the front end surface of the check ring, and side surfaces thereof located on the reverse sides of the above respective one side surfaces are inclined.

Backflow prevention device for in-line screw injection molding machine

An electric injection molding machine capable of maintaining a quality of molded articles and capable of suppressing a variation of weight of articles molded by a mold having a plurality of cavities when transferring molding conditions in a hydraulic injection molding machine as they are to the electric injection molding machine. This electric injection molding machine has an electric injection mechanism for injecting a molding material into a mold by a drive force of an electric motor, an injection control unit and a servo driver for controlling the injection motor so as to follow the injection speed reference, and an reference compensation unit for compensating the injection speed reference based on the characteristics of the hydraulic drive system so that fluctuation characteristics of the injection speed with respect to the injection pressure when controlling the electric injection mechanism approximate the fluctuation characteristics of the injection speed with respect to the injection pressure in the hydraulic injection mechanism performing the injection of the molding material to the mold by the hydraulic drive system.

Method for controlling injection of electric injection molding machine

The present invention relates to a method of detecting a malfunction during a die clamping step in an injection molding machine. A reference pattern is taken which shows a relation between a die clamping force and a position of a movable platen when die clamping is normally carried out. One or more monitoring sections are set in advance with respect to that position on the basis of the reference pattern and an allowable limit value of a die clamping force in the respective monitoring sections is also set in advance in a form of a linear function of the position. The die clamping force is monitored in the respective monitoring section during a respective die clamping step and, when its value exceeds the allowable limit value, it is decided that a malfunction occurs and an alarm is issued.

Malfunction-detection method during die clamping step in injection molding machines

A stationary die is held on the front surface of a stationary platen and a movable die is held on the front surface of a movable platen. A plurality of monitoring sections are set in advance within a moving range of the movable platen and an upper limit of forward thrust of the movable platen is set for each of the monitoring sections. When the forward thrust of the movable platen reaches the upper limit set in one of the monitoring sections during a die closing operation, it is determined that abnormality occurs to stop the movable platen from moving forward. If a die closing mechanism is of a toggle link type, the forward thrust of the movable platen is calculated based on the thrust of a crosshead which drives a toggle link mechanism, the moving speed of the crosshead, and the moving speed of the movable platen.

Method for protecting dies in an injection molding machine

An electric injection molding machine capable of maintaining a quality of molded articles and capable of minimizing weight variation of molded articles. An electric injection mechanism injects molding material into a mold using an electric motor. An injection control unit and a servo driver control the motor so as to follow an injection speed reference. A compensation unit compensates the injection speed reference based on characteristics of a hydraulic drive system so that fluctuation of injection speed with respect to the injection pressure approximate the fluctuation characteristics of a hydraulic injection mechanism.

Electric injection molding machine for controlling injection of electric injection molding machine

This invention provides a method which makes it possible to reliably detect malfunctions during the ejecting step without rendering the injection molding machine more complicated. An ejector pin is incorporated in the movable die. This ejector pin is connected, via an ejector plate, a connecting rod, a connecting plate and a feed screw, with a servo motor. The force for ejecting the ejector pin pushing a molded product is measured from the driving torque of a servo motor. In this invention, the relationship between driving torque and elapsed time from the initiation of ejection of the molded product is stored as a reference pattern. The tolerance limit and monitoring interval of driving torque are preset relative to the reference pattern. When the value of driving torque falls outside the tolerance limit during the ejecting step, it is judged as a malfunction, and an alarm is generated to stop the machine in a safe state.

Malfunction-detecting method in injection molding machines

A filling step control method of an injection molding machine for filling a molten resin into a die cavity is provided. The control method has the steps of: sampling in initiating the filling step for filling the molten resin into the die cavity by controlling an injection speed and, thereafter, by controlling a filling pressure while not exceeding a predetermined value; storing the injection speed over an entire filling process when a quality product can be stably obtained during the sampling step into a storage medium as a reference waveform; and after storing the reference waveform, molding for filling the molten resin into the die cavity by controlling the injection speed to follow the reference waveform over the entire filling step.

Filling step control method of injection molding machine

The retreat completion position of the screw in the charging step in actual production is controlled based on the result in pilot production as follows. In pilot production, the measurement value Ts of the screw driving torque is integrated with respect to the screw position P from the forward limit to the retreat completion position Ps. When conforming item is produced in the pilot production, the value &Sgr;Ts&middot;dP obtained as a result of the integration is stored as a reference value. After actual production begins, the measurement value Tx of the screw driving torque is integrated in real time with respect to the screw position P from the forward limit to the screw position at each time. The obtained value &Sgr;Tx&middot;dP is monitored. When this value &Sgr;Tx&middot;dP coincides with the reference value &Sgr;Ts&middot;dP, it is determined that the charging step has been completed, and the retreat operation of the screw is stopped.

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Numazu, Japan

Haruyuki Matsubayashi