A mechatronics approach to laser powder deposition process
This paper introduces a mechatronics approach for the development of a closed-loop control system utilized in laser powder deposition. The laser powder deposition process, as a manufacturing technique, is combined with a feedback control system to increase the quality of the final formed parts. The interconnections between the technologies involved in this complex mechatronics system along with the development of a CCD-based optical detector are explained. The optical CCD-based detector monitors the process zone to provide a series of single pass band images of the near-locus region. A pattern recognition algorithm is incorporated into the feedback device to obtain the clad's height and angle of solid/liquid interface in real-time. This feedback device is blended in a PID-based controller, which is designed using a knowledge-based model, to adjust the laser pulse energy for enhancing the output of the process. The experimental assessments of the developed system are also presented at different process conditions and disturbances when Fe-20%Al was deposited on mild steel. It is shown that the PID-based controller can effectively improve the geometrical characteristics of the clad around the operating point by overcoming the effects of various disturbances. (C) 2006 Elsevier Ltd. All rights reserved.
laser powder deposition ccd-based optical detector rapid prototyping vision-based feedback device image processing