Unitec Peco HF25A, Руководство пользователя

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APPENDIX G: DEFINING THE OPTIMUM PROCESS
HF25D LINEAR DC RESISTANCE WELDING CONTROL
990-333 G-8
At this stage, it is good practice to document the welding set up so that it can be referred to later (request
Unitek Equipment “Process Audit Worksheet” for an example). 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?