Resistance Welding Electrode Maintenance
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Resistance Welding Electrode Maintenance

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1) The electrode tips are the most important component in any spot welding system. 9 times out of 10 spot weld quality problems (Week Spot, Heavy Spatters Expulsion, and Burrs) can be traced to poor electrode tip dressing or maintenance.

2) The First & Most important thing is to place a thin film of cup (Copper) grease on the tip taper prior to inserting in the holder/Shank, to make it easier to remove.

3) Timely dress the Electrode to maintain the Tip diameter or profile of electrode, never use a coarse file to dress the electrode instead you can use a polish paper to clean the surface of electrode (Removal of oxidized black layer) between the 02 dressings defined.

4) Optimization of parameters (Current /Force) to the lowest possible, as excess current will produce more heat & excess force will help the tip to mushroom faster. Welded Spot should be stronger but energy efficient too.

5) Cooling of resistance welding electrodes is very important part to get maximum electrode life. Though temperature conditions vary in regions try to keep the temperature to the minimum best possible. eg inlet temperature 18-20 degrees.(There should be no condensation on water lines & in Control panel).

6) Water Flow rate should be maintained to minimum ½ gallon /min through each electrode.

7) To assure perfect alignment, both the faces and the axis of the electrodes must be parallel. This can be checked by inserting between the electrodes a piece of carbon and a piece of plain white paper and applying pressure. The resulting impression on the plain paper will indicate the extent and uniformity of the surface contact between the two faces.

8) Last & most important is selection of Electrode material, which should be according to RWMA Specification. For Sheet metals RWMA Class-2 i.e. CuCrZr/CuZr, again depends on to be used for Coated or noncoated sheets.

9) Even after maintaining above recommendations the problems like Burrs, Weld metal expulsion is occurring You can go for following changes:

You can divide the weld time to 2-3 impulses (Impulses mostly recommended for Spotting on edges) You can go for change in electrode profile, You can go for combination of 2 different profiles of electrode. (One flat electrode & another normal taper nose electrode)

Mangesh Borse

+919881689393 / 8983089393