Simulation and testing of the transient temperature field of infrared laser sintering

In the process of rapid laser prototyping, the transient sintering temperature affects molding quality directly. In considering the variation of thermal properties and transformation between solid and liquid states of powder, using the finite element method, a 3-D numerical simulation was conducted by using the analysis system (ANSYS) software for the transient sintering temprature of CO₂ infrared laser beams and Al₂O₃ coated ceramic powders. The 3-D temperature field was reconstructed according to the measured result of high-speed charge coupled device (CCD). Numerical simulation agreed well with experimental results. The result demonstrates that the sintering temperature of Al₂O₃ coated with ceramic powders is far less than the Al₂O₃ melting point temperature (1500°C). When the beam passes by the observation points several times after several returns, the second peak of temperature occurs which is beneficial to molding quality. This is consistent with a practical sintering mechanism.