Pre- and postweld inspection using laser vision

The most widely utilized welding evaluation technique is visual testing (VT). Major limitations of visual inspection are the subjectivity of judgments of the acceptability of the weld and time required to perform the inspection. Machine vision technology can replace or augment VT to curtail these limitations. Pre-weld inspection is an effective and efficient means of determining size and fit-up problems as well as seam tracking. Post-weld inspection with machine vision is efficient in that it saves time, provides a record of the inspection, and establishes a quantitative standard for measurements. This paper discusses laser-based, structured- light machine vision technology and its application toward automated pre- and post-weld inspection. Practical industrial applications including small, laser-welded tailored blanks and larger fillet welds are discussed along with results of initial testing.