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阐述了电子束快速成型机聚焦及偏扫系统在工程上所遇到的几个问题及解决方法。主要有:制造工艺引起s、t轴偏扫不垂直,通过斜角坐标和直角坐标数据互换算来解决此问题;电子束偏转后束斑散焦,采用以电子束偏转位置为因变量校正聚焦励磁电流来解决此问题;电子束聚焦校正励磁电流与反映位置的s、t轴偏扫励磁电流之间存在非线性,采用偏扫场按扇形分区,试验获取特征点参数数据,区域内每点参数按线性近似处理;磁路动态损耗影响聚焦补偿精度和偏扫精度,励磁电源指令电压采用比例-微分输入方式加以解决。试验结果表明电子束斑的均匀性和偏扫精度均明显优于无补偿系统。
Elaborated several problems and solutions in the engineering of electron beam rapid prototyping machine focusing and partial sweeping system. Mainly include: Manufacturing process caused by s, t-axis deflection is not vertical, through the bevel coordinates and Cartesian coordinate data interchange to solve this problem; electron beam deflection spot beam defocusing, the electron beam deflection position as the dependent variable to adjust the focus Excitation current to solve this problem; Electron beam focusing correction of excitation current and reflected position of the s, t-axis bias excitation current between the non-linear, the use of bias field sector by sector, the test feature points to obtain the parameter data, the region for each point The parameters are processed by linear approximation. The dynamic loss of the magnetic circuit affects the focus compensation accuracy and the deflection accuracy. The excitation power supply command voltage is solved by the proportional-differential input method. The experimental results show that the uniformity and deflection of the electron beam spot are better than the non-compensated system.