Investigation of the laser ablation threshold for optimizing Laser Direct Structuring in the 3D-MID technology

This paper is aimed at investigating the laser ablation threshold for optimizing Laser Direct Structuring (LDS) and minimizing laser energy demand. Two different methods are used to identify the ablation threshold of LDS material for single pulse irradiation. The results show the good agreement with the value of 2.2 J/cm ² and 1.7 J/cm ² respectively. Furthermore, a new approach is developed for indirect investigation of the ablation threshold of LDS material for multiple pulse irradiation. This new approach is based on changing in roughness or metallization thickness in laser fluence demand. The ablation threshold of 0.4 J/cm ² is identified from these investigations. At the laser fluence of 0.8 J/cm ² , the activation process and the roughening reach a saturation, which corresponds to a reduced laser ablation efficiency. The optical estimation with respect to an indication of the activated additive verifies these conclusions.