Product Code: ICAL06_1404

Camera Based Feedback Control of the Laser Cladding Process
Authors:
Johannes Hofman, University of Twente; Enschede Netherlands
D.F. de Lange, Netherlands Institute for Metals Research; Enschede Netherlands
J. Meijer, University of Twente; Netherlands
Presented at ICALEO 2006

A camera based feedback controller is designed and implemented to optimize the energy input during the process. This controller eliminates the need and effort to experimentally optimize the process. Moreover this controller automatically determines the required energy input to meet a well-defined criterion for a wide range of speeds, powder mass rates and material combinations. Also, it corrects the energy input for changes of geometry, absorptivity and heat accumulation in the product during the process. An important quality aspect of the cladding process is the burn-in depth. Unfortunately, the burn-in depth can not be measured during process. The meltpool width is directly related to the burn-in depth as well as the width of the produced clad layer, and is therefore used as feedback signal to adjust the laser power. The width, but also length and area of the meltpool are extracted from camera images of the process. The controller was proven successful for a wide range of cladding speeds and powder mass rates. The influence of the controlled meltpool width on the burn-in depth is investigated for several cladding speeds.