Intelligent system for prediction and control: Application in plasma spray process

Parametric drifts and fluctuations occur during plasma spraying. These drifts and fluctuations originate primarily from electrode wear and intrinsic plasma jet instabilities. One challenge is to control the manufacturing process by identifying the parameter interdependencies, correlations and individual effects on the in-flight particle characteristics. Such control is needed through methods that (i) consider the interdependencies that influence process variability and that also (ii) quantify the processing parameter-process response relationships. Due to the large amplitudes of the drifts and fluctuations, the strategy to adopt would depend on the required corrections to apply to the in-flight particle characteristics. Artificial intelligence is a pertinent tool to reach this objective. The system is flexible in order to permit a full control based on pre-defined rules aiming at maintaining at constant values in-flight particle characteristics (average surface temperature and velocity) by adjusting in real time the arc current intensity, the total plasma gas flow and the hydrogen content whatever the fluctuations.