Abstract: Taking the part deformation in SL process as the objective of study, the source of shrinkage force and its acting principle is analyzed in detail. Some new concepts as shrinkage force and surface-distributed loads are proposed according to the resin shrinkage while curing and the adhesive characteristics between adjacent layers. Furthermore, the time-varied stiffness is presented based on the change of part structure during layer incress. Based on the FEA method, the deformation trend of part is demonstrated. Hence the nature of part deformation in SL process is exposed. The experiment results show that they are consistent with the theoretical analysis. Therefore, a new hatching pattern called separate area scanning is proposed, which can improve the part accuracy by reducing the deformation.

Key words: Deformation, FEM, Rapid prototyping, Shrinkage force