Defect Reduction in the Welding Process of Motorcycle STAY R-L Parts

Thanida Sunarak



The case study company runs the business of automotive and motorcycle
parts manufacturing. In the past, the company faced the main problem of a lot of
defects of the STAY R-L part welding process. This research aims to reduce these
defects by applying Pareto Chart, Cause-and-Effect Diagram to identify and classify
defect types, and also analyze the cause of defects. It was revealed that the number
of defects from welds without full penetration was the most. The main cause is that
the previous welding fixture wasn’t locked firmly and angular fixture hid welding
alignment. Therefore, the improvement was performed by designing and developing
new fixture in order to reduce the defects in the welding process. The results show
that the defects from welds without full penetration decreased from 2.04 percent to
0.34 percent or decreased by 1.70 percent, representing 83.33 percent decrease of the


Defect reduction, Fixture, Welding process, Motorcycle STAY R- L parts

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