×

Method for controlling fluctuation in flow property of resin in injection molding machine

  • US 5,419,858 A
  • Filed: 11/30/1992
  • Issued: 05/30/1995
  • Est. Priority Date: 11/28/1991
  • Status: Expired due to Fees
First Claim
Patent Images

1. A method of judging a molding process for controlling a fluctuation in resin flow property in an injection molding machine, comprising the steps of:

  • (a) obtaining a signal representing injection pressure from a sensor provided in at least one of an injection cylinder of the injection molding machine and a hydraulic circuit for driving the injection molding machine;

    (b) sampling said signal from said sensor for a period of time beginning prior to a start of an injection stage of a molding cycle and extending for an amount of time which exceeds a likely injection time;

    (c) detecting a rise in injection-pressure data obtained by said step of sampling, and judging that a point in time corresponding to the rise is an injection starting time;

    (d) detecting a peak value of the injection-pressure data other than a peak of the injection-pressure data which may appear immediately after the injection starting time;

    (e) judging that a point in time corresponding to the peak value, determined by said step of detecting a peak value, is an injection end time;

    (f) calculating, as an injection time, a period of time from the injection starting time to the injection end time;

    (g) obtaining the peak value of the injection pressure and the injection time in a molding cycle of the injection molding machine over a plurality of molding cycles by repeating above steps (a) to (f);

    (h) examining whether a fluctuation in flow property of a resin material supplied to the injection molding machine appears as a fluctuation in the injection time or as a fluctuation in the peak value of the injection pressure; and

    (i) judging that a constant-pressure injection process is in effect when the fluctuation appears as a fluctuation in the injection time and a constant-speed injection process is in effect when the fluctuation appears as a fluctuation in the peak value of the injection pressure.

View all claims
  • 1 Assignment
Timeline View
Assignment View
    ×
    ×