Development Of An Auto-Control Unit For The Direct-Control Optimizing System Of Green Sand Quality

The quality of Green Sand is one of the key factors to the casting quality. This project aims to develop an auto-control unit of a direct-control optimizing system of green sand quality for a sand mixer. The system controls the ingredients of Green Sand directly by testing the ingredients. It consists of auto-control unit, auto-testing unit and a master. Followed the instructions from the master, the auto-control unit, as an essential part for the system, controls the feeding of the returned sand, new sand, clay, water and coal powder precisely. The auto-control unit consists of an automatic feeding device and a control slave. The feeding device involves four feeders, two weighting-discharging sub-units and a water tank. By designing an 80C196KC-centered circuit, the control slave controls external memory, I/O interfaces, weight sensors, air cylinders, electric-magnetic switchers, water tank and motors. The unit receives the data from the master and starts the motors and switchers while sampling and recording the data from the sensors and the tank. Based on the results from PID algorithm, the slave controls rough feeding and starts the first sand mixing. The auto-testing unit tests the sand ingredients and sends related data to the master. The master decided whether to start a more precise feeding or not.