Effect of substrate on temperature field in selective laser sintering of metal powders

Abstract

Selective laser sintering (SLS) of metal powders is an attractive Rapid Prototyping and Manufacturing (RPM) technology which can be used to produce three-dimensional metal parts directly from a CAD model. In the process, the substrates are commonly used for avoiding the balling effect in powder melting and dislocation of sintered part. A three-dimensional finite element thermal model in SLS of metal powder including the effect of powder-to-solid transition has been established. Element-dependent material properties in SLS are determined according to the history maximum temperature. The thermal conductivity and heat capacity of the compounds is calculated using the weighted average approach. Experiments and simulations have been carried out using multi-component Cu-based metal powder. Some conclusions related to the simulation results are reached: When using substrate, the maximum temperature in powder bed becomes lower and sintered zone is reduced, which is mainly caused by the higher consistent thermal conductivity of substrate. Measures of employing moderate thermal conductivity substrate and preheating substrate should be taken lest input-heat mainly transfers to substrate.Selective laser sintering (SLS) of metal powders is an attractive Rapid Prototyping and Manufacturing (RPM) technology which can be used to produce three-dimensional metal parts directly from a CAD model. In the process, the substrates are commonly used for avoiding the balling effect in powder melting and dislocation of sintered part. A three-dimensional finite element thermal model in SLS of metal powder including the effect of powder-to-solid transition has been established. Element-dependent material properties in SLS are determined according to the history maximum temperature. The thermal conductivity and heat capacity of the compounds is calculated using the weighted average approach. Experiments and simulations have been carried out using multi-component Cu-based metal powder. Some conclusions related to the simulation results are reached: When using substrate, the maximum temperature in powder bed becomes lower and sintered zone is reduced, which is mainly caused by the higher consistent thermal c...