Weld Equipment Setup
The Weld Equipment Setup domain tests whether you can take a robotic arc cell from installed to repeatable: torch geometry, wire delivery, gas delivery, current return, and the validation run that proves all of it works together. Items usually describe a setup error and ask what happens to the arc, or ask you to order the steps of a pre-production check.
Torch and tool center point
- Mount the torch so it holds the work angle and travel angle the procedure calls for; most robotic GMAW runs at 0 to 15 degrees push or drag.
- Establish the TCP with the wire trimmed flush at the contact tip and the robot in the production tool frame.
- Contact tip to work distance is a process variable, not a preference. For 0.045 in wire, roughly 3/8 to 5/8 in is typical. Longer stickout adds resistance heating, lowers current at a given wire feed speed, and flattens the bead.
- Dress the whip so wrist rotation never pulls the cable, and re-teach points after any dress change.
Wire delivery
- Drive roll groove and tension match the wire size and type. Knurled rolls belong to flux-cored wire, not solid.
- Liner type and length follow the wire: steel liner for carbon steel, nylon or Teflon for aluminum and many stainless setups. A liner cut too long buckles; too short birdnests at the feed head.
- Set the spool brake so the spool stops without overrun.
Gas and current return
- Set flow with gas actually flowing through the solenoid, not static at the regulator. Most GMAW sits around 30 to 40 cfh; spray transfer and high current need more.
- Clamp the work lead to the part or fixture as close to the joint as practical. Never let the return path run through the robot arm, positioner bearings, or a sling.
Worked example
A cell runs 0.045 in ER70S-6 at 300 in/min and 26 V. To reach a deeper fillet, a technician swaps the 1/2 in contact tip for a 3/4 in tip. With a constant voltage source, the longer electrode extension raises resistance heating, so arc current falls, penetration drops, the bead widens and crowns, and the voltage needed for a stable arc length rises. The fix is to restore the original CTWD or re-trim wire feed speed and voltage together, not to turn up wire feed alone.
Traps
Setting gas flow with the solenoid closed; setting TCP with wire recessed inside the tip; clamping the work lead to a painted or insulated fixture; assuming a replacement torch arrives with the same TCP as the old one.