选择性激光烧结翘曲变形模拟

Warping simulation of selective laser sintering

建立了烧结过程的温度场、弹性应力应变场的有限元计算模型,开发了C++模拟软件,模拟了选择性激光烧结(SLS)过程的温度、残余热应力的演化,以及最终的翘曲变形。提出的改进移动热源加载算法提高了计算速度。研究结果表明:激光烧结过程中温度场不均匀,导致了热应力的产生,进而使制件变形,制件的上下部分收缩不一致,从而向.上翘曲。随着烧结制件增厚,其弯曲所需的应力增大,翘曲变形减小;选择合理的扫描方式可以使温度场更加均匀,从而减少制件的翘曲变形;随着激光功率增大,温度场更不均匀,热应力增大,翘曲变形增大。

The finite element model of selective laser sintering(SLS)process was built.The corresponding C++software was developed which involving temperature,elastic stress and strain fields.Then the temperature,the thermal residual stress,and the warping in the SLS process were simulated.An improved loading algorithm of moving heat source was presented,which reduced the time consumption and accelerates the computation greatly.It is found that in the process of laser sintering,the temperature field is not uniform,which leads to thermal.stress and warping deformation.The upward warping of a workpiece is caused by inconsistent shrinkage of the upper and lower parts of the work piece.As the thickness of the sintered parts increases,the required bending stress will increase,leading to reduced warping.Selecting a reasonable scanning mode can make the temperature field more uniform and reduce the warping of the parts.As the laser power increases,the unevenness of the temperature field increases,leading to greater thermal stress and warping.