光固化快速成型中零件变形机理的研究

Investigation of the Part Deformation in Stereolithography

以光固化快速成型过程中的零件变形为研究对象 ,详细分析了收缩力产生的根源及其作用原理 .根据树脂固化时必然产生的收缩及层累加的特点 ,提出了收缩力、面分布载荷的概念 ;根据零件在成型过程中结构变化的特点 ,提出了时变刚度的概念 .基于此 ,建立了零件成型过程中的力学模型 ,揭示了成型过程中零件变形的本质问题 .通过实验研究了零件的变形问题 ,实验结果证明了理论分析的正确性 .由此提出了改进扫描工艺的分区域扫描策略 ,显著地减小了成型过程中零件的变形 ,提高了成型零件的精度 .

Taking the part deformation in SL process as the objective of study, principles are analyzed in detail. Some new concepts such as shrinkage force and surface-distributed loads are proposed according to the resin shrinkage while curing and the adhesive characteristics between adjacent layers. The time-varied stiffness is presented based on the change of part structure during layer increase. Hence, the nature of part deformation in SL process is exposed. The experiment results 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.