This is the third entry in our multi-part series exploring micro pulse arc welding welding. Today we will cover troubleshooting – tips for improving your results when you’ve followed all the recommended setup tips and you’re still getting spurious results, inconsistencies, or part shrinkage.
- Ground not connected
- Electrode tip too far from work piece to create start arc
- Electrode damaged and cannot fire
- No cover gas to aid arc formation
Firing, but not welding
There are several reasons that a pulsed Micro TIG power supply may fire but not achieve a good weld. Most common are:
- Material selection – Are the materials suitable for welding according to the weldability table?
- Part fit up – Parts should be in close proximity. Tooling is a key aspect in TIG welding because the electrode does not clamp the parts together while firing.
- Worn/damaged electrode – If weld is weak and shot count is high, it is possible that the electrode has worn out.
If the part has too much shrinkage, the pulse energy is too high. This can be corrected by lowering the current and/or shortening the weld time. For every weld, some material will be consumed.
Uneven welding is a common issue in the welding process. To help minimize the unevenness:
- Ensure that the part is straight with respect to electrode tip.
- Ensure that the electrode tip is centered on the workpiece.
Oxidation is a common issue in welding. It typically happens when there is too little (or non-existent) cover gas used or if there is turbulence in the gas. It can also happen when there is plating or coating (like for magnet wires). A rule of thumb starting value for the cover gas is 20 cubic feet per minute (cfm.) Also, if weld area is larger than the gas nozzle, select a larger nozzle.
Porosity in the weld indicates that the contaminants were not able to escape. Using pulsation to rapidly turn the arc off and on, will allow for the contaminants to boil off. Operators must optimize the frequency. This will depend on material and weld parameters.
For more information on improving your MicroTIG pulse arc welding results, visit our previous blogs: