Cathodie Jet Forces

By Aviatordave Date 11-01-2013 14:31

Hello,

I'm currently going to school for welding and I'm trying to learn a little more about a topic we recently covered in class.
We've moved from GMAW-S into Axial Spray transfer and talked only a little about Globular transfer. In our discussion about globular, we learned how there are some smaller and larger droplets that come off of the electrode. The smaller ones are still affected by the magnetic pinch effect but the larger ones that tend to fly away and cause all the spatter that globular exhibits are affected by "Cathodie Jet Forces".
The explanation of what exactly cathodie jet forces are and how they are formed was not gone into in depth.
Google searches and a search of this forum's topics yield nothing either.
Can anybody explain anything more to me about these forces?

Thanks in advance!
-Dave

By jwright650 (*****)

Date 11-01-2013 15:12 Edited 11-01-2013 15:20

Hi Dave

enter "cathode jet forces" into your search engines this will narrow your results alot more and point towards a better explanation than "cathodie jet forces".

Also take a look at Pages 7-10 in here(particularly the top right of page 8):
http://www.lincolnelectric.com/assets/en_US/Products/literature/C4200.pdf

By jwright650 (*****)

Date 11-01-2013 15:19

Oh, I just noticed this was your first post.....Welcome to the forum!

By Aviatordave Date 11-04-2013 21:45

Boy to I feel a little sillie! (or should I say silly? Or in this case, perhaps even sille?)

Thank you, jwright650. Amazing that Google didn't give me the "Did you mean to type . . . blah blah blah" and save you the trouble from pointing out a simple spelling error.

I did as you requested and modified my search. There's a pretty comprehensive paper on the subject published by S.T. Eickhoff and T.W. Eagar called "Characterization of Spatter in Low-Current GMAW of Titanium Alloy Plate" here on AWS's web site. It's 7 pages of great reading if you can't fall asleep but otherwise pretty informative if you want to wade through it and can keep your eyes open. I'm assuming that steel responds similarly. The only thing that the paper doesn't define that I'm still trying to wrap my brain around is what exactly a cathode jet is. Through some research, I'm starting to think it's an electromagnetic force.

http://www.aws.org/wj/supplement/WJ_1990_10_s382.pdf

The Lincoln Electric manual essentially contained what we learned in class.

Thanks for the welcome to the forum. Lots of interesting stuff here!