电子束选区熔化技术中可控振动落粉铺粉系统的研究

Study on Controllable Vibration Powder Spreading System in Electron Beam Selective Melting

分析了快速成形技术中常用供粉系统与铺粉系统的优缺点。结合电子束选区熔化成形技术在真空环境下人工无法干预、成形区域温度高、成形件刚度大等特点和接触式铺粉机构遇到凸起后经常无法越过而导致成形中断的实验情况,提出了一种可控振动落粉铺粉方案。设计了具有粉末结拱与振动破拱功能且不与成形件相接触的上置式铺粉筛及具有称重传感器反馈的铺粉系统,通过改变铺粉筛的运行速度和加速度实现粉末铺送功能。实验结果表明,该系统运行可靠,在铺粉筛中粉末量一定的情况下可实现均匀铺粉,铺粉厚度通过改变铺粉筛运行速度和加速度来获取,最小粉末层厚度可达0.1mm。

This paper analyzed the merits and faults of the existing powder supply and spread system.A new controllable vibrating powder spread system was proposed,considering the experimental conditions of EBSM：difficult to interfere in the vacuum chamber,high temperature in the melting zone,large stiffness of manufacturing parts,together with contacting powder spread system bringing down the whole process upon meeting bump unable to overcome.A new designation,non-contacting overhead sieve with feedback weighting sensor,capable of powder arching and arch vibrating elimination,realized powder spreading function by varying its speed and acceleration.The experimental results have verified the steadiness of the system,uniformly spreading can be achieved with certain a- mount of powder in the sieve,and the depth can be decided by moving speed and acceleration of the sieve,with 0.1mm the minimum.