Monday, March 2, 2009

What are the negative effects of whipping or weaving?

“We Mig weld carbon steel materials 1/8” thick and greater. Our Welders use a whipping technique that you have described as a bad work habit. What are the negative effects of whipping or weaving?

Whipping and Weaving.
As with many welding techniques, there is a time and place for everything. Watch most robotic applications and you’ll see a constant weaving motion (side to side). Observe as a Fitter puts a 6010 root pass in a pipe and you’ll notice a distinct whipping action (fore and aft). This movement is perfectly acceptable for these applications. The robot uses the motion to find its way. The Pipe Fitter uses the “fast freeze” characteristic to burn away the land and place the root perfectly at each whip.

In production GMA (Mig) welding those same techniques can have negative affects on your finished product. Weaving with the Mig process is a common technique when welding vertical up. It can be difficult to carry the puddle up without the weave technique. A slight weave is common when Mig welding in other positions, but slight should be defined as 2-1/2 x the electrode (wire) diameter. With an 0.035 diameter wire that is about 1/8” of movement. Exceeding that can lead to overlap, undercut and other undesired conditions. Multiple stringer passes should be considered when additional bead width is needed.

As for whipping when Mig welding… There are times when whipping is used to bridge a gap, but often the Welder would be far better off turning the welder down to a short circuit transfer and applying that root. Again, a slight whip is common but slight in this case should be defined as 1-1/2 x the wire diameter. If the key to quality Mig welding is keeping the arc on the leading edge of the puddle, then the whip technique goes against that.

When a whip is excessive weld throats can be undersized and weld spatter is increased. Each time the Welder backs the arc up away from the leading edge the wire is driven into the molten metal and spatter increases. This will require removal and increases the cost of your product.
Good technique is important to improving weld quality. The internet is loaded with great resources for improving our welding skills. Check out this Mig Handbook for additional information. (