Computer Control of Float Glass at Ford

The float glass process at Ford is a continuous process running 7 days a week, 24 hours a day. Like most of the continuous processes, it is pretty well automated and operates continuously, with manual intervention on exceptions basis. It consists of three major areas using three different types of automatic control equipment. The first section is called "batch house," in which predetermined amounts of raw materials are weighed, mixed, and conveyed to the second step. The control logic here is all prewired and uses relays and stepping switches. The second stage is melting and forming where the batch is converted into molten glass and finally into a flat ribbon of float glass. The control system for this portion is a real-time process control computer using direct-digital control philosophy for control. The third stage is cutting and unloading of brackets. This system is driven by a General Electric hard-wired numerical-control cutting machine using transistor technology and hydraulic as well as electric power to drive the equipment. Thus Ford has automated its float process using all three generations of control equipment.