Influence of laser marking parameters on data matrix code quality on polybutylene terephthalate/glass fiber composite surface using microscopy and spectroscopy techniques

Abstract

Laser marking on polymer composite surfaces can be difficult to read and cause readability problems for electronic decoding equipment on production lines due to poor interaction between the laser and the fibers used to reinforce these materials. This problem can be solved with the right choice of marking parameters, resulting in savings for companies by avoiding production problems such as rejection, scrap and customer complaints. The present work uses the polybutylene terephthalate/glass fiber (PBT/GF) composite used in the manufacture of instrument panels for motorcycles. The tests were carried out with different laser marking parameters using a neodymium:yttrium-aluminum-garnet (Nd:YAG) laser. Subsequently, the laser-marked data matrix codes (DMC) were analyzed using a microscope verifier to evaluate the quality according to the ISO/IEC 29158:2020 standard. A detailed analysis of these surfaces was also carried out to observe some physical and chemical changes using scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). The optical analysis showed that lower radiation power and pulse frequency and higher marking speed corresponded to weaker laser marking and therefore poorer DMC code quality, which was confirmed by the SEM. EDS showed that the laser marking process did not cause the chemical changes on the sample surface.

Keywords

• laser marking quality
• marking parameters
• dmc
• pbt composite
• sem analysis