【摘要】 选区激光烧结成型过程中,激光束扫描时反复的加热、冷却带来不均匀的热应力,影响烧结过程和烧结件的质量。基于弹性变形原理,利用单轴应力作用下的变形梁的挠曲和应变与应力之间的关系,来分析烧结过程中的应力以及不同烧结层之间的相互影响,结果表明,在每个单层烧结时,烧结应力主要集中在烧结层的上表面和下表面的两端,且呈现为拉应力;在多层烧结时,烧结的热载荷对紧邻已熔接层的应力有直接影响,随着烧结层数增加,新烧结层对已熔接层的热影响逐渐减小,对应的随着温度变化较小,已熔接层的应力也较小且保持较低水平。更多还原

【Abstract】 In selective laser sintering process,the uneven thermal stresses caused by repeated heating and cooling during laser beam scanning affect the sintering process and the quality of sintered parts. The sintering stress and the interaction of different sintered layers are analyzed based on the principle of elastic deformation and the relation between the flexure of beam under uniaxial stress and its strain and stress,so we get the sintered stress through the deformation of sintered slender beam. The result shows that the sintering stress is mainly concentrated on the edge of upper and under surface of the sintered layer,and presents to the tensile stress. Further more,the thermal load has a direct influence on the stress of adjacent sintered layer,the influence of new layer to the old layers reduced as the increase of number of sintered layers,and stress of old layers stays a low level since the corresponding temperature remains stable.更多还原