Amada 1000ADP, Operation Manual

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APPENDIX F: DEFINING THE OPTIMUM PROCESS
125ADP/300ADP/1000ADP DUAL PULSE RESISTANCE WELDING POWER SUPPLY
990-922 F-11
Criteria for Success
Before running the series of experiments, the user must establish an acceptable window for energy, time,
and force, thus preventing voided results. It is common practice to include one or all of the above
variables in a Screening DOE. This is only recommended if sufficient understanding has been
established for the other application and process variables that can impact quality Users should first try
to screen out all common application and process variables that require further exploration from the
results of the “look see” mini experiments and then include the three key welding variables (energy,
force and time). Several Screening DOE’s may be required.
Results should be interpreted carefully. Typically, one would look for the highest result in terms of
quality with the least variation. A Screening DOE provides only a measurement that indicates the
relative importance of a parameter and not the ideal setting. Factorial DOE’s should be used to establish
the correct or best setting for a parameter once many of the other variables have been screened and
fixed. This is also the time to assess the measurement accuracy and consistency of the test method and
procedure. Variation in test method can invalidate the test and lead to misinterpretation of results.
What are Factorial DOE’s?
The purpose of a Factorial DOE is to narrow in on the optimal setting for a particular parameter. This
method is generally used when the critical or main key variables have been identified, and we need to
establish the best settings for the process. A factorial DOE may also give an indication as to how wide
the acceptable weld window is in relation to quality requirements. We recommend data be gathered
from a monitoring perspective so that this can provide a starting point for establishing a relationship
between quality and the monitored measurement parameter.
Criteria for Success
Critical parameters should be identified from the list of unfixed variables left from the Screening DOE’s.
A mini-experiment may be required establishing reasonable bounds for the combination of parameters to
be tested. This will prevent void data and wasted time. At this stage, it is useful to record multiple
relevant quality measurement or inspection criteria so that a balanced decision can be reached. For
example, if part marking and pull strength are the relevant criteria, a compromise in ideal setting may be
required.
As with all experiments, the test method should be carefully assessed as a potential source of variation
and inconsistency. Once the optimum parameters have been established in this series of experiments, a
validation study can be run which looks at the consistency of results over time. It is good practice to
build in variables such as electrode changes and cleaning, as well as equipment set up by different
personnel. This will ensure that the solution is one that can run in a real production environment.
Welded assemblies should be tested over time and under real use conditions to ensure that all functional
criteria will be met. Validation testing is usually required to prove the robustness of the process under
production conditions.