电子束选区熔化过程中基于背散射电子成像系统的优化

Optimization of an Imaging System Based on Backscattered Electrons in Electron Beam Selective Melting

摘要: 电子束选区熔化(Electron beam selective melting, EBSM)具有能量利用率高、真空环境无污染等优点，然而目前相关技术设备的成像清晰度和分辨率难以达到实际应用的需求。基于背散射电子成像原理，应用本课题组研制的EBSM过程中背散射电子成像系统，进行了背散射电子传感器极板个数及单极板面积的优化实验，确定了四极板大面积的背散射电子传感器。同时进行放大电路中滤波电容的优化实验，减小了滤波电容的容值，使高频扫描的成像形貌更清晰。解决了传统光学成像监测技术由强光、高温、金属蒸气造成的限制。最终得到的监测系统可以实现360 × 360 mm的大范围监测，1200 × 1200像素的高分辨率成像。

Abstract: Electron beam selective melting (EBSM) has the advantages of high energy efficiency and no pollution in the vacuum environment. However, the imaging clarity and resolution of related technical equipment cannot meet the needs of practical applications. Based on the principle of backscattered electron imaging, the backscattered electron imaging system in the EBSM process developed by our research group was used to optimize the number of backscattered electron sensor plates and the area of the single plate. A large-area backscattered electron sensor on a quadrupole plate was identified. At the same time, the optimization experiment of the filter capacitor in the amplifying circuit was carried out. The capacitance value of the filter capacitor was reduced, so the imaging morphology of high-frequency scanning was clearer. It solves the limitations of traditional optical imaging monitoring technology caused by strong light, high temperature, and metal vapor. The final monitoring system can realize large-scale monitoring of 360 × 360 mm and high-resolution imaging of 1200 × 1200 pixels.