A method is presented for applying a microcomputer to the control of a hydraulic plastic injection molding machine. A servovalve and appropriate transducers are attached to the injection cylinder of the original machine, and a process control program which is composed of assembly language and which takes charge of the function of controller is developed for the purpose of controlling the injection speed, packing and holding pressure, and back pressure of the machine. Also, the sequential control program is developed in order to make the machine execute the fundamental processes automatically according to its sequential logic.
To reduce the amount of trial-error which may occurs during the development of the process control program, theoretical analyses in the frequency domain are tried, based upon the linearized system equations, and also, the digital simulations are executed by using the MIMIC program language, where the whole system equations are adapted with several nonlinear ones included.
The experimental results of the microcomputer application lead to the conclusion that it is possible to achieve not only the automatic sequential control but also the aforementioned process controls. And finally, the effect of cost-down is estimated which can be obtained by substituting the software for the analogue-type controller developed already for the injection molding machine.
마이크로컴퓨터를 응용하여서 플라스틱유압성형사출기를 제어하는 방법을 규명했다. injection speed, packing and holding pressure, 그리고 back pressure 를 제어하기 위해서, 기본유압 사출기의 injection cylinder 에 servovalve 와 적합한 transducer 들을 부착하고 assembly language 로 구성된 과정제어 프로그램을 개발하여 controller 의 기능을 담당하도록 했다.
또한 유압사출기가 순서적인 논리에 따라서 자동적으로 기본작동 과정을 수행하도록 제어하기 위한 연속제어프로그램을 개발했다.
과정제어프로그램을 개발할 때 발생될 수 있는 시행오차를 줄이기 위해서, 선형화된 system equation 들을 바탕으로, frequency domain 에서 이론적해석을 시도하였고, 비선형식들을 포함한 전체 system equation 들을 사용하여, MIMIC 컴퓨터언어에 의한 digital simulation 을 수행했다.
마이크로컴퓨터를 응용한 실험결과, 연속제어의 자동화뿐만 아니라 앞에서 말한 과정제어들이 가능하다는 결론을 얻었다. 그리고 마지막으로 이미 유압사출기를 위해 개발된 analogue-type controller를 software 로 대체하여 사용할 때 얻을 수 있는 가격절감효과를 추정했다.
