APPENDIX D: DEFINING THE OPTIMUM PROCESS
UB25 LINEAR DC RESISTANCE WELDING CONTROL
D-8 990-665
At this stage, it is good practice to document the welding set up so that it can be referred to later. Once
the equipment set up has been documented the next stage is to fix as many of the process and material
variables as possible to reduce variation in the subsequent welding trials. The main welding parameters
such as energy, force, and time cannot be fixed at this stage but many of the other variables such as
repeatable part positioning should be fixed.
Initial Welding Trials -- The “Look See” Tests
“Look see” welding tests are a series of mini welding experiments designed to provide a starting point for
further statistical development of the welding parameters. The user should adjust the key welding
variables (energy, force, time) in order to identify the likely good “weld window”.
The mini experiments should also be used to understand the weld characteristics from both application
and process perspective. Key factors in this understanding are listed on the next page.
Application Perspective
• Materials: Resistivity, melting point, thermal mass
• Shape, hardness
• Heat balance: Electrode materials, shape
• Polarity, heating rate (upslope)
• Observation: visual criteria, cross section, and impact of variables on heat balance
Process Perspective
• What are the likely variables in a production process?
• How will operators handle and align the parts?
• What tooling or automation will be required?
• How will operators maintain and change the electrodes?
• What other parameters will operators are able to adjust?
• What are the quality and inspection requirements?
• What are the relevant production testing methods and test equipment?
• Do we have adequate control over the quality of the materials?
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