초록 ▼

An injection molding machine uses a summed, multi-term control law to control ram velocity during the injection stroke of a molding cycle to emulate a user set velocity profile. An automatic calibration method sets no load ram speeds to duplicate user set ram speeds. Finite impulse response filters

An injection molding machine uses a summed, multi-term control law to control ram velocity during the injection stroke of a molding cycle to emulate a user set velocity profile. An automatic calibration method sets no load ram speeds to duplicate user set ram speeds. Finite impulse response filters produce open loop, no load control signals at advanced positions on the velocity profile to account for lag in system response. An adaptive, error term indicative of load disturbance, observed from a preceding cycle is added at the advanced travel position predicted by the finite impulse response filter to produce a predictive open loop, load compensated control signal. Finally, an auto tuned PID controller develops a real time, feedback load disturbance signal summed with the open loop control signal to produce a drive signal for the machine's proportioning valve.

대표청구항 ▼

[ Having thus defined the invention, it is claimed:] [1.] A method for controlling the speed of a ram in an injection molding machine during the injection step of the molding cycle after the operator has set a plurality of velocity set points, said method comprising the steps of:a. machine generatin

[ Having thus defined the invention, it is claimed:] [1.] A method for controlling the speed of a ram in an injection molding machine during the injection step of the molding cycle after the operator has set a plurality of velocity set points, said method comprising the steps of:a. machine generating a second, larger plurality of set point signals from said operator set points, each set point signal indicative of a set ram velocity at a set ram travel position in a sequence defining a velocity profile said ram is to emulate during said injection step;b. automatically adjusting selected set point signals for processing by a machine generated calibrated factor so that any selected set point signal of a given speed will cause said ram to move at approximately the same speed when the machine is not under load;c. modifying the selected set point signals to account for the load imposed on the machine by the molding material being injected to produce velocity control signals at set ram positions corresponding to said velocity profile; andd. applying said control signals as a drive signal to the machine for controlling the speed of the ram.