By Doug Longenecker

Doug is the president of DPLongenecker L.L.C. and serves on the Program Advisory Committee for the Hobart Institute of Welding Technology.

Production welding is a fast-paced, lucrative business that is often plagued with quality defects.  One such defect is porosity.  Porosity occurs due to a lack of shielding gas for one or more reasons.  The outcome is a weld that has pores similar to the look of a sponge.  This defect can be fixed off line, but in the world of lean manufacturing, this is very costly.

Troubleshooting porosity can be exhausting and finding the true root cause is not easy considering the matrix of probable causes.  Porosity can occur due to, but not limited to, the following conditions:

• Contact tip work distance (C.T.W.D. or electrode extension) too long or too short

• Voltage too high

• External air turbulences

• Clogged gas cups

• Worn out diffusers

• Improper torch angles

• Improper travel angles

• Improper gas nozzles size for travel speed

• Surface contaminates

• Dirty wire

• Flow rates too high or too low

• Leaks in the system

• Improper anti-spatter

A systematic approach to correcting the true root cause of the catalyst that is causing the defect is needed.  Too often, a technician will only correct the result of the problem and not correct the root cause.  This becomes evident when the same defect continues to surface repeatedly.  For example, a technician notices the gas cup is clogged, so (s)he proceeds to clean the cup and continue to run the operation.  This did not correct the problem.  It only addressed the result of the problem.  Ask yourself, “Why was the gas cup clogged?”  Review the list above.  Can an accounting be made for each one of those items?

Production welding is a dynamic process that has an infinite numbers of variables.  By using a systematic approach, DPLongenecker L.L.C. can help you to resolve your production issues and solve the problems you encounter.