The product quality determination apparatus in an injection molding machine

摘要

PROBLEM TO BE SOLVED: To make it possible to decide the propriety of a product in the state of metered molten resin immediately before the injection is started irrespective of the irregularity of a metering completing position or predetermined metering time by outputting a non-defective product signal if the resin pressure falls within an allowable range immediately before the start of the injection or outputting a defective product signal if it falls out of the allowable range. ;SOLUTION: A pressure detector 4 is provided at the base of a screw 2, and the resin pressure operating in the axial direction of the screw, i.e., the injection dwell pressure in an injection dwelling step or the resin pressure in a metering and kneading steps is detected via an A-D converter 16. A CPU 18 for a PMC (programmable machine control) regards a molded product as being a non-defective product and outputs a non-defective product signal if the value of the pressure P immediately before the start of injection falls within an allowable range previously set to a nonvolatile memory 24 through the CPU 17 and the detector 4. If the pressure P falls out of the set allowable range, i.e., is smaller than the lower limit value or larger than the upper limit value, it regards the molded product as being defective product, and outputs a defective product signal.;COPYRIGHT: (C)1997,JPO