Laser marking on polyoxymethylene (POM) polymer substrate for a lean manufacturing application

Abstract

Laser marking is a critical production process step in most automated production systems. However, some materials such as polyoxymethylene (POM) can be quite challenging to laser to 80 kHz.mark, hence the need to develop new laser marking methods. By employing a wide range of marking parameters (marking speed 15–2000 mm/s, laser power from 10 to 100% of 30 W maximum, and frequencies mainly from 1 to 400 kHz) and characterization techniques, and with the use of marker inks as masking agents successful laser marking POM is demonstrated irrespective of its presentation (white or black coloured) using a new method akin to Laser Polymer Tattooing (LPT), and without prior modification of polymer composition (by addition of laser marking additives). Results indicate laser marking of acceptable quality can be obtained with black POM at marking speeds up to 2000 mm/s. For white POM, markings of acceptable quality were obtained at markings speeds up to 100 mm/s, with laser power ≥ 80% (of 30 W maximum), and with frequencies in the range of 20 kHz with the help of a masking agent. The effects of the laser marking parameters on marking quality and the changes induced in the material are presented and discussed. The wide range of marking parameters employed enabled the determination of feasible marking parameters for the development of a lean manufacturing-based automatic and self-evaluating and improving laser marking system with minimal human intervention.