A Laser-Based Vision System for Weld Quality Inspection

Wei Huang,Radovan Kovacevic

doi:10.3390/s110100506

Abstract

Welding is a very complex process in which the final weld quality can be affected by many process parameters. In order to inspect the weld quality and detect the presence of various weld defects, different methods and systems are studied and developed. In this paper, a laser-based vision system is developed for non-destructive weld quality inspection. The vision sensor is designed based on the principle of laser triangulation. By processing the images acquired from the vision sensor, the geometrical features of the weld can be obtained. Through the visual analysis of the acquired 3D profiles of the weld, the presences as well as the positions and sizes of the weld defects can be accurately identified and therefore, the non-destructive weld quality inspection can be achieved.

Highlights

Welding, as the most commonly used process for joining metals and plastic, is vital to the economy of a country because up to 50% of the gross national product is related to welding in one way or another [1]
After the calibration of the laser-based vision system is performed, the vision system is ready to be used for weld quality inspection
In order to obtain the 3D profile of this weld with the developed laser-based vision system, the worktable moves along the longitudinal direction of the weld so that the vision sensor can scan the full length of the weld bead at a constant speed

Summary

Introduction

As the most commonly used process for joining metals and plastic, is vital to the economy of a country because up to 50% of the gross national product is related to welding in one way or another [1] Welding is such a complex process that the visually recognizable quality of the weld is affected by a number of process variables. There are two categories of methods that are applied for weld quality inspection: Sensors 2011, 11 on-line methods and off-line methods As welding is such a complex process, there are many different physical phenomena such as electromagnetic radiation, optical and acoustic emission and plasma generation that will occur. Different types of signals are generated during the welding process and usually these signals are closely associated with the weld quality

Objectives

Methods

Results

Conclusion