Effect of the properties of the polymer materials on the quality of selective laser sintering parts

The effect of the properties of the polymer materials, such as molecular weight, molten viscosity, crystallization rate and the particle size of the powder, on the quality of selective laser sintering (SLS) parts is researched. The results indicate that the molecular weight affects the quality of the SLS parts through the melting viscosity. SLS parts of higher density can be fabricated with polymer materials of lower melting viscosity. Crystallinity largely affects the precision of the SLS part-shrinkage is more serious with increasing crystallinity. SLS parts sintered with polymer powder materials, whose melting peak and crystalline peak differ greatly, have high dimensional precision. The particle size of the powder affects not only the precision but also the density of the SLS part. The appropriate particle size is about 75-100 mum.