点阵结构压气机叶轮3D打印过程设计及打印性能分析

3D Printing Process Design and Printing Performance Analysis of Lattice Structure Compressor Impeller

关键词:  3D打印  点阵结构  压气机叶轮  数值模拟  曲面拟合

Key words:  3D printing  Lattice structure  Compressor impeller  Numerical simulation  Surface fitting

摘要:

基于八角桁架点阵结构，提出了一种新的涡轮压气机叶轮轻量化设计方法。在保证点阵轮具有可加工性的同时，为了提高打印成功率，基于有限单元法，对点阵轮不同激光功率、激光走速、激光宽度、铺粉层厚和支撑切割高度下的增材制造过程进行模拟，分析了不同打印参数下点阵轮打印过程的最大残余变形及最大残余应力。结果表明，激光打印参数（如激光功率、激光走速和激光宽度）对叶轮残余变形和残余应力幅值有较大影响，而铺粉层厚对残余变形和残余应力幅值的影响相对较小，通过降低激光功率、提高激光速度和增加激光宽度，可以降低叶轮的残余应力。对于填充率为11.4%的晶格单元，点阵轮相对于原始轮质量可降低23.5%。加工完成后点阵轮的残余变形和残余应力均小于原始轮，本文工况下，点阵轮加工完成后的最大残余应力和变形可分别比设计轮最大降低8.72%和20.19%。这意味着采用点阵轮的设计方式在降低叶轮质量的同时，还将具有更接近于原始设计且更不容易在加工中损坏的优良加工性。

Abstract:

Based on the octagonal truss lattice structure， a new lightweight design method for compressor impeller was proposed. In order to ensure the machinability of the lattice impeller and improve the printing success rate， based on the finite element method， the additive manufacturing process of the lattice impeller under different laser power， laser speed， laser width， powder layer thickness and support cutting height was simulated， and the maximum residual deformation and stress of the lattice impeller printing process under different printing parameters were analyzed. The results show that the laser printing parameters （such as laser power， laser speed and laser width） have a great influence on the residual deformation and residual stress amplitude of the impeller， while the thickness of the powder layer has a relatively small influence on the residual deformation and residual stress amplitude. By reducing the laser power， increasing the laser speed and laser width， the residual stress of the impeller can be reduced. For the lattice element with 11.4% filling rate， the mass of lattice impeller can be reduced by 23.5% compared with the original impeller. After machining， the residual deformation and stress of lattice impeller are smaller than those of the original impeller. In this paper， the maximum residual stress and deformation of the lattice impeller can be reduced by 8.72% and 20.19% respectively compared with the design impeller. This means that the design method of lattice impeller will not only reduce the mass of impeller， but also have the excellent machinability which is closer to the original design and less likely to be damaged in machining.