APPENDIX D: DEFINING THE OPTIMUM PROCESS
UB25 LINEAR DC RESISTANCE WELDING CONTROL
990-665
D-9
Common Problems
During this stage of process development it is important to understand that the majority of process
problems are related to either materials variation, or part to electrode positioning. Some examples are
shown below.
The changes detailed above generally result in a change in contact resistance and always affect the heat
balance of the weld. During weld development these common problems must be carefully monitored so
as not to mislead the course and productivity of the welding experiments.
In summary the “look see” welding experiments should be used to fix further variables from an application
and process perspective and also to establish a “weld window” for energy, time and force. This part of
weld development is critical in order to proceed to a statistical (Design of Experiments) method of
evaluation. Random explosions or unexpected variables will skew statistical data and waste valuable time.
The figure above shows common welding problems that can often be identified in the basic set up of the
force, energy and time welding profile. These problems can lead to weld splash and inconsistency and
variation (contact AMADA WELD TECH for further information and support).
Part-To-Part Positioning
Electrode-To-Part Positioning
Material Control
Poor Follow-up
(Sparks)
T
F
<< W
F
(Variation sparks)
No Squeeze
(Sparks)
Insufficient Force
(Sparks)
Impact Force
(Variation)
No Hold
(Variation)
Hold
Squeeze
Heat
