Welding is often considered an art form and sometimes black magic, especially when the results are difficult to control and seem to vary with the phase of the moon. Fortunately, welding science has progressed far enough that most unexplainable phenomena can be explained. However, getting to the root cause of the problem often requires patience and meticulous experimentation.
A good place to start is to collect information from experiments (or production runs), evaluate the data, and plan for changes. Key is to ask lots and lots of questions.
Questions about specifications
What is the definition of a good weld (strength, visual, porosity, etc.) ?
Do the specifications correlate well with the performance requirements of the weld
Is there is specification for Cpk of the welding process?
What is the expected nature of the metallurgical bond that will meet the requirements of the specifications?
Questions about materials and part design
Are the materials suitable for the welding process selected?
Is the part design suitable for the selected process (similar question on process selection)?
Can the materials (part and fillers) be modified to improve the process
How will the surface condition (roughness, cleanliness, plating, etc.) affect the process?
Questions about the process
Is the selected welding/joining process suited to the part design?
Will the process be robust enough to account for day-to-day variations?
Are there enough outputs from the process that can be related to weld quality (so as to avoid expensive destructive testing)?
Answers to the above questions will set you in the right direction to find a suitable solution. If you would like to have us help you with your welding process, please send us as much information on the above questions as possible and we can start the discussions. Our contact information is on the home page.
Good luck with your welds.
Girish P. Kelkar, Ph.D.