The semi-automatic operation of the injection molding machine is to open the safety door, close the travel switch, send a signal to the machine to start the semi-automatic action, and then close the mold. After touching the SQ4 travel switch, the mold closing ends. Injection starts at the same time, and the injection time relay starts timing. After the injection time is up, pre-molding starts. After touching the travel switch for the end of pre-molding, flow prevention starts. After touching the flow-proof travel switch, the cooling time relay starts timing, and the time is up. Then perform the mold opening action, and then open the mold. After touching the mold opening end stroke switch, perform the ejection action. After touching the ejection end stroke switch, perform the ejection retraction action. After touching the ejection end stroke switch, wait for the safety door to open. In this way, Work that starts over and over again.