Research On Physical Mechanisms Of Laser Marking

Laser marking technology and its applications are developing rapidly in recent years, Due to their advantages of mature technology. Longer lifetime and higher processing efficiency for some materials, infrared (IR) Nd: YAG and CO₂ lasers occupy most of the laser marking markets. However for many materials especially metallic materials with low absorptivity of IR radiation, to get clear mark, it has to increase the output power and pulse repetition rate which would result serious thermal damage and heat diffusion, causing poor marking quality. These disadvantages are unacceptable in some applications. UV lasers are very good substitutes. Excimer and diode-pumped solid-state (DPSS) laser are important UV laser sources. Materials with high absorptivity of UV laser can be processed by shoot pulse-width with great precision and very little thermal effect.This thesis attempts to study the physical mechanism of laser marking and compare the marking effects of different laser wavelength. Quantitative results for some often used materials are given which great importance to the parameter optimization is in laser marking.