[perlmonkey]

Hello All.
I'm making a frame for an industrial robot to sit in and I have a 1/2" steel plate where this robot is mounted and the plate will sit on 0.065" A513 square tubing.
My questions are:
1. Is it better to weld or bolt the plate to the tubing (warpage is not that critical as the robot has leveling feet)
2. I have a lincoln 120v MIG welder with flux core setup. Can I stitch-weld the plate to this thin wall tubing without issue?

I realize that this isn't the best setup, but hey, I'm just getting started. I figured I'd ask the forum instead of just going at it, because the plate cost me about $80 and I don't want to screw it up on my first try. I realize that I'd probably have to pre-heat the plate and keep the puddle on the plate more than on the tubing - I guess I'm just asking for the best solution. I had a hell of a time drilling 3/4" holes in the plate to mount the robot and am dreading drilling holes around the perimeter to mount the plate to the tubing. I'm sure someone here has an idea, because I'm sure many of you have mounted plate to the top of a welding table... same situation I have here. I just need to know if welding is possible with my setup before I make a mess of it all - I'd rather weld than have to drill and burn up a bunch of bits.
Thanks again!

[Otto Nobedder]

Welding shouldn't be a problem, even with a light-duty rig. Consider the loads the welds will see. With the weight of the plate plus the robot, it's unlikely the welds would be loaded in tension. They will likely only see shear, so a number of stitches around the perimeter should do nicely. You won't need all that much penetration in the plate.

If your tube frame is the same size as the plate, there should already be a slight "bevel" where the corner of the tube meets the edge of the plate, and that 90* plate edge will melt in just fine. If the frame is larger than the plate, you could bevel the underside of the plate to present a sharp corner to the weld zone.

Steve S.

[Tombstone]

How heavy is this robot that's sitting on top of its base structure your trying to make? It it's big and heavy, I'd definitely recommend you using a bigger machine, such as a Lincoln 180c or miller 211 or Ironman 210. If you can get your hands on a stick welder and know how to use it, that may also be a better route for that thick steel? This is only my opinion based on the fact that I weld on 1/2" mild steel, daily. I fabricate off road roll cages and hydraulic lift gate hinged hardware that is really thick. A 120v mig wouldn't cut it.