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CHAPTER 5: OPERATING INSTRUCTIONS
875DP/500DP/500HV DUAL PULSE
RESISTANCE WELDING
POWER SUPPLIES
5-6
990-290
Evaluating the Weld
Use pliers to peel the welded materials apart. A satisfactory weld will show residual material pulled from
one material to the other. Tearing of base material around the weld nugget indicates a material failure, not a
weld failure. Electrode sticking and/or "spitting" should define a weld as unsatisfactory.
Weak Weld
If the parts pull apart easily, or there is little or no residual material pulled, the weld is weak. Increase
the %ENERGY in increments of 1% to 2%. The actual weld strength is a user defined specification.
Electrode Sticking
Electrode sticking includes burning, sparking, and "blown welds." These problems indicate that either
the %ENERGY is too high or the electrode force is too low. Refer to figure 5-1.
Examine the electrode face. Resurface it if it is pitted, contaminated or burned. See
Electrode
Maintenance
later in this chapter. Increase electrode force and/or decrease %ENERGY and save it to
the weld schedule you are using.
Causes of Imperfect Welds
Table 5-2 lists the effects of the basic welding parameters on weld quality.
Table 5-2. Causes of Imperfect Welds
Electrode
Problem Energy
Force Size
Time
Weak Weld
Too Low
Too High
Too Large
Too Short
Blow Holes
Expulsion
Too High
Too Low
Too Small
Too Long
Burned, Pitted
or Cracked
Electrodes
Too High
Too Low.
Requires
Maintenance
Poor
Maintenance
Too Short