Research On Metal Powder Making Based On Plasma Arc Flame Length Detection

With the rapid development of metal 3D printing technology,the demand for spherical metal powder for 3D printing materials is increasing day by day.The technology of high-quality spherical metal powder has become the focus of research by many companies and research institutions in various countries.The metal powder produced by the plasma rotary electrode method has the advantages of high purity,high sphericity,and narrow particle size distribution,which is an ideal material for metal 3D printing.At present,the most widely used methods for preparing metal powder in China are also the plasma rotating electrode method.The feed rate of the servo feed mechanism in the traditional plasma rotary electrode method is artificially set.It cannot guarantee a constant distance between the end surface of the bar and the plasma gun during the milling process,which not only affects the quality of the metal powder prepared,but also causes some security risks.Therefore,this paper designs a metal milling device based on the detection of plasma arc flame length.In the milling device,the feed speed of the servo feed mechanism was controlled according to the plasma arc flame length detected in real time to ensure a constant distance between the end face of the bar and the plasma gun.The content of this article mainly includes two aspects,the control of the servo feed mechanism and the detection of the plasma arc flame length.The control of the servo feed mechanism was mainly to control the feed speed of the servo feed mechanism to ensure that the distance between the end surface of the bar and the plasma gun is constant.The length detection of the plasma arc flame was to meet the control needs of the servo feed mechanism.In this paper,a servo feed controller based on fuzzy PID was designed to control the servo feed mechanism based on the length of the plasma arc flame.In order to meet the control needs of the servo feed mechanism,a plasma arc length detection system based on image processing was designed.Real-time detection of the plasma arc flame;Designed image detection based on the region of interest and arc flame length correction function,which could improve the real-time detection and detection accuracy;Designed the kingview displayed interface based on DDE communication could communicate with the detection system to achieve real-time monitoring of the detection site.The experimental results show that the target region of the image after plasma arc flame detection has smooth edges,clear brightness and no noise,which can meet the subsequent processing and monitoring requirements of the image.The corrected detection accuracy of the plasma arc flame length is high,and the error is less than 1mm compared with the actual length of the plasma arc flame,which meets the actual industrial requirements.The control of the servo feed mechanism can ensure that the distance between the rod and the plasma gun is constant during the milling process,which achieves the control requirements.