A control system for creating, modifying, initiating and controlling a manufacturing process is provided using computer on-screen icons as metaphors for actual process steps. The icons are selected on-screen from a library of icons, and are selectively inserted in, appended to, edited or deleted from the manufacturing process. Each icon represents a discrete process step including associated default-value physical parameters, which may be modified (edited) within predetermined boundary limits. Using the icons, the physical manufacturing process is symbolically assembled on-screen and saved to a storage medium from which it is accessed for use. During actual operation, the manufacturing process is displayed on-screen in an animated graphic representation, with real-time presentation of instantaneous parameter values. The control system also selectively provides on-screen trend graphs showing in strip-chart form the recent history of selected process variables. Other features provide on-screen execution and control of start-up, operation, alternative operation, suspended operation (park), shut-down, and servicing functions.