Definition
Electrode dressing is a manual or automated operation to reshape electrodes
or resurface their uneven faces after they have become worn.
Description
With time, the electrode tip faces wear or become mushroomed
(see Fig. 1). This modifies current flow through the workpiece and therefore
the formation of the weld. Wear can be compensated for by periodically
increasing (stepping) the weld current, but once the tips have
reached a certain level of wear, they must be either replaced or dressed.
Dressing is normally carried out with a special rotating cutter, and
the process restores the electrodes to the nominal tip face diameter,
and usually removes the tips' pitted surfaces. (In certain cases the
process may not require the resurfacing of the tip face).
Incorrect dressing may result in a number of defective conditions (see
Fig. 2):
- wrong tip diameter
- nonparallelism of tip faces
- tips closing in the wrong plane
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| Fig. 1. Mushroomed and
pitted tip (left) compared with a new tip (right). |
Fig. 2. Examples of the
effects of incorrect dressing: dressed to wrong diameter (left),
nonparallelism (middle), wrong plane (right). |
Detection
Any of the following weld issues may indicate that tip dressing has
not been carried out properly:
Significance
Quality, Workplace Issues, Cost, Downtime, Maintenance and Throughput
(cycle time; PPH) are all potentially affected by this condition.
Subordinate Causes
- Incorrect robot programming
- Insufficient dresser operator training
- Blunt cutter
- Wrong cutter
- Tip dresser not working
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