Hitachi, Ltd.

Masayoshi Aoki

Aizo Kaneda

Hitoshi Yokono

Junichi Saeki

Hidemi Sato

Susumu Tsuzuku

Masaki Yoshii

Mitsunori Oka

A transfer molding machine for filling at least one cavity of a mold with a resin by means of a plunger including a resin pressure sensor for sensing the resin pressure in the mold, and a control device for controlling the pressure applied to the plunger to drive same in such a manner that an arbitrarily selected primary pressure higher than a holding pressure is applied to the plunger to drive same until the pressure of the resin charged into the mold which pressure is detected by the resin pressure sensor in the mold reaches a predetermined pressure level and a secondary pressure corresponding to the holding pressure is applied to the plunger to drive same after the predetermined pressure level has been exceeded by the pressure of the resin being charged into the mold sensed by the resin pressure sensor in the mold, and a warning device that issues a warning when the pressure applied to the plunger to drive has exceeded a predetermined pressure.

Transfer molding method and transfer molding machine

A method of and an apparatus for molding a plastic wherein the injection pressure (transfer pressure) is switched to a holding pressure when the internal pressure of the mold cavity sensed by a pressure sensor reaches a predetermined injection pressure (transfer pressure), to initiate holding of the pressure applied to the cavity. The holding pressure is removed when the internal pressure thereof becomes zero or in accordance with the detection of a predetermined inflection point in the internal pressure which is indicative of a gate sealing point in the mold cavity or is brought to a predetermined value close to zero. The molded articles are of high precision finishes, and conservation of energy and natural resources can be achieved.

Apparatus for molding plastic

Growing community of inventors

Kamakura, Japan

Masayoshi Aoki