Process Quality Study of Laser Machining and Water Jet Assisted Laser Machining of SiC
S. Huang and Y-X. Zhang
To study the effect of water jet assisted laser machining and waterless auxiliary laser machining of SiC on the processing results, the effects of water jets with different jet velocities on the impact force and convective heat transfer of water jet assisted laser processing are simulated by finite element (FE) modelling. During the experiment the laser parameters were kept unchanged while the jet velocity was changed. A comparison experiment of water jet assisted laser machining and water jet assisted laser machining of SiC was carried out. The results show that with the increased water jet velocity, the impact pressure and convective heat transfer of water jet impact material are gradually enhanced. When there is no water jet assisted laser machining of SiC material, there are more slag and recondensation layers on both sides and notches of the tank body, the heat affected zone (HAZ) is larger, and the surface processing quality is poor. Compared with water jet assisted laser machining, there are fewer almost no slag and re-condensation layers on both sides and notches of the tank, the HAZ is reduced, and the quality of the processing groove is better. In the 45° water jet assisted laser machining, the processing effect is better when the water jet velocity reaches 20 m/s. Water jet assisted laser machining can obtain better processing quality than waterless auxiliary laser machining.
Keywords: Nd:YAG laser, SiC, laser machining, water jet assisted laser machining, water jet velocity, impact, convective heat transfer, heat affected zone (HAZ), quality