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Abstract

A system of injection-molding a super-precision product by an injection machine with a mold comprises conventional fundamental steps including a material plasticizing and metering step, an injection step and a material pressure-holding step, with additional features in that a nozzle passage, enlarged in volume, extending from a machine body to a cavity gate is interrupted midway therealong by a valve from communication with the interior of the body, after the injection step but while the pressure-holding step is being carried out. The pressure-holding step is carried out at least using the valve for exerting an internal pressure on a forward portion of the injected material separated due to the passage interruption, and compacted in a fixed closed space limited by the valve including a mold cavity, during which step a next plasticizing and metering step is commenced. An instantaneous remetering step is carried out such that the material in the fixed closed space is adjusted to a predetermined value in amount in every shot by regulating its internal pressure to a corresponding value with a possible excess part of the material being discharged out of the machine system.

First Claim