Amada 1-288-01, Operation Manual, Page: 131 / 144

APPENDIX F: DEFINING THE OPTIMUM PROCESS
HF28 DC RESISTANCE WELDING SYSTEM
990-372 F-7
Weld Profiles
The basic welding profile (or schedule) consists of a controlled application of energy and force over
time. Precision power supplies control the energy and time and therefore heating rate of the parts. The
weld head applies force from the start to finish of the welding process.
The figure on the right
shows a typical welding
sequence where the force is
applied to the parts; a
squeeze time is initiated
which allows the force to
stabilize before the current
is fired. Squeeze time also
allows time for the contact
resistances to reduce as the
materials start to come into
closer contact at their interface. A hold time is initiated after current flows to allow the parts to cool
under pressure before the electrodes are retracted from the parts. Hold time is important as weld
strength develops in this period. This basic form of weld profile is sufficient for the majority of small
part resistance welding applications.
Power supply technology selection is based on the requirements of both the application and process. In
general, closed loop power supply technologies are the best choice for consistent, controlled output and
fast response to changes in resistance during the weld (for further details comparison see the Miyachi
Unitek “slide rule” tool).
Squeeze Heat Hold
Welding Force
Trigger Force
Current