等离子焊接小孔效应的电弧电压信号检测

为在等离子焊接小孔效应下对焊缝的熔透质量进行实时控制 ,在不同类型的焊接电源和被焊材料条件下 ,研究了熔池小孔效应与等离子电弧电压信号的关系规律。根据电弧电压信号相对于其均值的偏差的大小及熔池穿孔和未穿孔状态下电弧电压幅频低频段信号的差异分别设计了两种算法 ,并对电弧电压信号的加工处理 ,分别得到了两种传感信号。设计了熔池穿孔与否双阈值判断准则 ,用以检测熔池小孔是否存在。该传感技术可适用于不同焊接电源和不同工件材质 ,为实时熔透质量自动控制提供了反馈信息

Keyhole detection by arc voltage signal processing during plasma welding

The welding quality of keyhole welds is controlled in real time during plasma welding processes to be detection of the keyhole status. Various sensing techniques were investigated with different types of welding sources and different materials. During the welding experiments, the arc voltage signal was monitored by a computer to find characteristics related to keyhole and non keyhole status. Analysis of the data yielded two sensing techniques used the deviations from the average arc voltage for different keyhole shapes and the characteristics of the low end in the arc voltage signal's frequency spectrum analyzed by FFT. These algorithms used two kinds of sensing signals extracted from the arc voltage signal. A 'double threshold' rule was suggested, by which the signals can be used to tell whether the keyhole is established and maintained. The techniques can provide feedback information necessary for the automatic penetration control system for various types of welding sources and materials.