Statistical evaluation of welding quality in production

Other conference contribution, 2010

In this study the change in pre-conditions for quality/inspection are studied when the performance of an existing robotised welding process is improved using parameter design from robust design methodology. The findings are several. First, it was found that it is possible to build empirical response surface models of the key performance indicators measured that serves to improve the chances to find settings in the welding geometry that fulfil all requirements without increasing production cost. Secondly, it was also found that basic standard gauges and procedures for weld quality inspection easily are out-dated if not care is taken to investigate and improve all measurement systems used relative the actual variations occurring in the production. Thirdly, it was showed that improved welding performance will change pre-conditions for both product development and quality/inspection. Fourthly, ultrasonic P-scan has the potential to monitor penetration depth, but lower detection limits need to be further explored. Ultrasonic time-of-flight deflections his problems to monitor welding penetration depth less than 5mm on the present fillet weld set-up.