Abstract Abstract. RP/M is an advance technology based on build-up and discrete idea, and Laser direct deposition by coaxially feeding the powders to laser melting pool is a RM technology in general use. It is a major attention problem in the researches on this technology that the distortion occurring in the depositing process, particularly in the substrate. The characteristics on the substrate distortion and “Christmas tree step” occurring in the depositing process of vertical thin wall samples of 316L stainless steel are analyzed by use of results simulating the thermal stress field in this paper. The analysis results have explained that varied temperature field and dissimilar temperature of melted pool at the position of the start point and end point of laser scanning paths cause the “Christmas tree step”. The distortion of the substrate only occur in the region on which 316L stainless steel have been deposited, and there is the rigidity displacement at the left end and right end. It has demonstrated the finite element models simulating the temperature field and the thermal stress field that the test results to measure the rigidity displacement are agreement with simulating results of finite element.
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