等离子熔积直接制造容积式送粉系统设计

Design of dosing powder feeding system for plasma deposition manufacturing

针对现有送粉系统粉末均匀性差、难以准确计量、不能输送超细合金粉末的缺点以及等离子熔积直接制造需要送粉气流量小的特点,研制了一种容积式送粉系统.采用双电机传动,粉末的计量与输送分开.定量机构精确计量送粉流量,高速柔性刷将送粉腔中团聚的粉末打散并在送粉气作用下输送到熔池中.采用89S52单片机为控制核心,LED数码管显示送粉速率和粉末余量等状态信息,送粉参数既可通过人工设定,又可以由上位机控制.送粉测试和等离子熔积试验表明:送粉误差小于2%,送粉气流量小于0.15 m3/h.单道焊的熔积层高度与送粉速率存在线性关系.

Aiming at the disadvantages of the present powder feeding systems and the characteristics of plasma deposition manufacturing （PDM）, a powder feeder based on dosing constancy and control system based on microcontroller 89S52 have been developed. The system has two motors and the measuring and transportation mechanisms are divided. The powder feeding rate is measured accurately by measuring mechanism. Then the powder is dispersed by the high speed flexible scraper and transported by carrying gas into melting pool. The status messages are displayed on the LED and each feeding status is given solely by operator or by computer. The experiments indicate that the error is within 2 %and the rate of powder carry gas is under 0.15 m^3/h. The thicknesses of welding paths by PDM are linear with powder feeding rate.