红外激光烧结瞬态温度场的模拟和测量

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

针对在利用红外激光烧结快速成型的过程中瞬态温度场直接影响成型质量的问题.在充分考虑热物性参数的变化和材料固、液态间的转化的实际情况下,采用有限元方法,利用ANSYS软件对CO2红外激光束与Al2O3覆膜陶瓷粉末的瞬态温度场进行了三维数值模拟.利用高速CCD成像测温系统对瞬态烧结温度进行了测量,实现了烧结瞬态温度场的三维重建.数值模拟和实测结果显示,两者吻合较好.结果表明:Al2O3覆膜陶瓷粉末的烧结温度远小于Al2O3的熔点(1 500℃),当光束折返后多次经过观测点附近时,出现利于成型质量的二次峰值温度,这与实际覆膜陶瓷粉末的烧结机理一致.

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（1 500℃）.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.