Shielding gas is important to keep steady reaction of melting and resolidification in arc welding.
An explanation of right-hand figure is writen in Japanese. Please click this sentence, or right picture.
Capturing ultra-high-speed video is easy. It takes only a short moment. However, captured data size is quite large. It is troublesome to watch whole video to understand what was actualy occured. I usually make time-chart image from captured image sequnce as shown in right image.
You can watch ultra high-speed video to click images in right-hand side. Left three images are the same condition but for video rate.
Right three images are in different video. these are the same for right-up image.
You had better to watch an arc ignition situation in nitrogen shield to click this sentence.
The cathode keeps clean in nitrogen shield. However, nitrogen reacts surface oxide of stainless steel.
Right images were captured by monochrome video which attached narrow band-pass filter of 950nm. I had forgotten to open shielding gas valve in these cases. A cathode and anode was shielded in helum or argon at starting situation. But, air came into the arc region soon. I usually make pseudo color video to understand what is going on in monochrome video.
A "2kfps" is shortend into 10% from "20kfps" video. This means an information of 9 images are lost. "2kdif" and "2kmax" are used to know what was actually occured in the original video. The "2kdif" videro shows difference in 10 images. The "2kmax" video pickup the macimum value on each pixels of 10 images.
2016.09.15作成 2016.09.29改定
