Selective laser sintering（SLS）technology has been widely used in precision casting due to its ability to form complex investment patterns especially in the formation of complex parts of aerospace.The forming of investment pattern is an important part of investment casting

and the forming dimensional accuracy is especially important.In order to understand effect of the structure on the forming dimensional accuracy of SLS

the thin wall

circular hole and flange structure were analyzed in the investment castings.Firstly

polystyrene samples were prepared by SLS technology

and three-dimensional scanning techniques were used to obtain the deformation results of three sets of samples.Secondly

the scanning results were compared with the original geometric model

and the size deviation comparison and cylindricity comparison mean were used to analyze influence of structure on dimensional accuracy.It is concluded that the circular hole structure can change the radial contraction and reduce the dimensional accuracy.The flange structure can restrict the deformation of sintered parts and improve the dimension accuracy.