Development of low‐cost imaging system for laser metal deposition processes

Abstract

Purpose

The melt pool created by a laser is one of the most important factors affecting the quality of the deposit in a laser metal deposition (LMD) process. The high‐intensity infrared (IR) radiation emitted by the melt pool saturates a conventional camera sensor preventing useful data acquisition. The purpose of this paper is to discuss the development of a low‐cost vision system to monitor the size of the melt pool for in‐process quality control of the deposit.

Design/methodology/approach

According to the black body radiation theory, there is no radiation emitted in the ultraviolet (UV) region from the melt pool created in the LMD process. IR radiation and visible light are the only radiations inherent to the LMD process. UV illumination is utilized along with narrow band pass filters on a USB camera to achieve a clear image of the melt pool while IR radiation of the process is blocked out. The melt pool size and shape were closely monitored during the deposition process.

Findings

A clear image of the melt pool was obtained using a relatively low‐cost imaging system during laser deposition process.

Originality/value

Traditional approaches to vision systems in high‐intensity processes use a high‐speed video camera fitted with IR filters to prevent saturation of the camera sensor. Such systems are usually complex and expensive to run and maintain. This paper demonstrates an alternative and lower cost method to achieve in process monitoring in an LMD process.

Citation

Barua, S., Sparks, T. and Liou, F. (2011), "Development of low‐cost imaging system for laser metal deposition processes", Rapid Prototyping Journal, Vol. 17 No. 3, pp. 203-210. https://doi.org/10.1108/13552541111124789