Laser Direct-Part Marking of Data Matrix Symbols on Carbon Steel Substrates

Certain applications have recently appeared in industry where a traditional bar code printed on a label will not survive because the item to be tracked has to be exposed to harsh environments. Laser direct-part marking is a manufacturing process used to create permanent marks on a substrate that could help to alleviate this problem. In this research, a 532 nm Nd:YAG laser was utilized to produce Data Matrix symbols onto carbon steel substrates. The quality of the laser marked Data Matrix symbol was then evaluated according to the ISO/IEC 16022 bar code technology specification for Data Matrix. Several experiments were conducted to explore the effects that different parameters have on the quality of the laser direct-part marked symbols. Parameters such as type of carbon steel, percent of laser tool path overlap, profile speed, average power, and frequency were found to have significant effects on the quality of the Data Matrix symbols produced with the laser. The analysis of the results indicated that contrast and print growth were the critical ISO/IEC 16022 standard performance measures that limited the laser marked Data Matrix symbols from achieving a higher final grade.