电子束熔丝成形随行退火系统设计及其仿真

Programming and Simulation of Real Time Annealing Technology for Electron Beam Rapid Manufacturing System

控制电子束偏转扫描对成形件进行局部实时退火热处理,可降低大型金属工件在电子束熔丝成形过程中产生的热应力,减少热应力累积而超过材料屈服强度产生的变形。采用工控机、波形发生卡、驱动电路及偏转扫描线圈搭建了电子束偏转扫描控制试验平台;使用LabVIEW开发了扫描控制程序,合成了X、Y两路输出波形,实现了矩形折线扫描及圆形偏置扫描。针对电子束扫描加热对成形件局部温度分布的影响,建立了随行退火扫描的有限元模型,分析了随行退火偏转扫描对100mm×100mm区域内温度场分布的影响。仿真结果表明,在束流30mA、束斑直径4mm、束斑搭接1mm的条件下,电子束以25m/s的速度扫描加热0.6323s,区域内温度差值由初始的94℃减小到11℃,有效改善了100mm×100mm区域内温度场分布均匀程度。

During the electron beam rapid manufacturing procedure of large metal work piece, the electron beam is used for scanning and heating in order to implement real-time annealing treatment which can eliminate the residual stress in the electron beam freedom fabrication process and reduce the deformation caused by the stress accumulation.In this paper, an electron beam high-frequency deflection scan control experiment platform, which consists of industrial computer, waveform generation card, drive circuit, and deflection scanning coil, is built to generate X, Y output waveform, do rectangular scan and circular offset scan. LabVIEW is used to develop the software interface.A real time annealing finite element model is built to analyze the influence of scanning on temperature distribution difference in a range of 100 mm×100 mm. The conclusion is the temperature difference in the area is reduced from94℃ to 11℃ which improves the uniformity of the temperature distribution when the beam current is 30 mA, beam spot radius is 4 mm, beam spot overlap is 1 mm, and using the electron beam to scan for 0.6323 s with a speed of 25 m/s.