电子束快速成形温度场模拟

Temperature field simulation of electron beam rapid prototyping

关键词:  电子束快速成形  生死单元  温度场模拟

Key words:  electron beam rapid prototyping  element birth & death  temperature field simulation

摘要:

利用ANSYS软件模拟电子束快速成形过程的温度场分布情况,电子束能量输入用高斯面热源表示,由于快速成形过程在真空室中进行,因此只考虑热辐射散热。同时模拟了单圆扫描、多个圆同时扫描和多个圆依次扫描的温度场分布.结果表明,对于成形一定宽度的圆筒,多个圆从外到里依次扫描的方式比较理想,用较小的束流就可以达到熔点以上温度,扫描范围与成形范围趋于一致,得到的成形件表面均匀平整,成形精度较多个圆同时扫描时容易控制.利用"生死单元"技术模拟了层层堆积快速成形的过程,从中可以了解快速成形过程的温度场变化情况,以优化工艺参数。

Abstract:

The temperature field of electron-beam rapid prototyping is simulated by ANSYS.In this study, heat distribution is expressed as Gaussian equation.The heat loss just includes heat radiation as the process is carried out in the vacuum chamber.Temperature distributions of different scanning modes are studied and analyzed.Based on the experimental and simulation results circle scanning orderly with degressive radius from outer to inner is suitable to produce a certain width cylinder, while small electron beam current can reach temperature above the melting point.And the scanning range is consistent with the melting scope, melted powder in the depth is almost the same for the entire scanning area, so the prototyping result is uniform and the surface is flat.The temperature field of multi-layered scanning with element birth and death is predicted by simulation, and the simulation result is useful to instruct practical prototyping.