尼龙6粉末选区激光烧结试件平面尺度对应力和变形的影响分析

Influence analysis of stress and deformation for parts plane scale of PA6 powders by selective laser sintering

针对选区激光烧结的局部加热和冷却过程,试件平面尺度变化对温度场、应力和变形都有着直接影响。通过建立烧结过程的瞬时温度场和应力应变模型,结合不同面能量密度,对试件平面尺度与应力和变形的关系进行分析。结果表明,对于正方形试件,不同面能量密度下,当平面尺度由5 mm×5 mm增至30 mm×30 mm时,试件端部表面应力增幅为20.5%~36.2%,且变形量也从0.11 mm增大到2.95 mm;而试件中部的应力变化量较小。不同平面尺度的烧结实验结果显示,当烧结试件平面尺度由5 mm×5 mm增大到30 mm×30 mm时,其变形量由0.14 mm增至1.74 mm;平面尺度较小(5 mm×5 mm、10 mm×10 mm)时,烧结试件为四边翘曲变形,较大平面尺度下多呈现为中凸变形形态。

For the partial heating and cooling process in selective laser sintering,changes in the parts plane scale have a direct effect on the temperature field and its stress and deformation.By establishing the instantaneous temperature field and stress-strain model of the sintering process,combined with different surface energy densities,the relationship between the part's plane scale and its stress and deformation was analyzed.The results show that for the square part,when its plane scale increases from 5 mm×5 mm to 30 mm×30 mm at different surface energy densities,the surface stress at the end of the part increases by 20.5%~36.2% and the deformation also increases from 0.11 mm to 2.95 mm,while the stress of the part'middle part makes smaller change.The sintering experiments'results of parts in different plane scales show that the deformation increases from 0.14 mm to 1.74 mm when the part's plane scale increases from 5 mm×5 mm to 30 mm×30 mm.And the part is four-sided warping when the plane scale is small(5 mm×5 mm,10 mm×10 mm),while it is mostly convex for larger plane scales.