Abstract
This article establishes a general thermal modeling and control methodology for ablative processing of layered materials for rapid prototyping technologies. An analytical multivariable model of lumped temperature outputs generated by heat inputs on a surface grid is developed, based on Green’s function and state-space descriptions. The few independent parameters needed in such a linearized formulation are experimentally identified, and their time-variability reflects the heat transfer nonlinearities and process disturbances. A robust controller with thermal feedback is designed by pole placement methods, to obtain a specified dynamic temperature field yielding the desired material structure and properties. The regulated thermal processing is optimized in real time by proper heat source power modulation and torch guidance through a simulated annealing strategy. Its performance is tested on both the computer model and a laboratory station in regulating the sensitized zone during blanking of an elementary contour pattern on stainless steel, using robotically guided plasma-arc cutting and infrared thermal sensing.
