Welding process selection through a double criteria: Operational costs and non-quality costs

This paper presents a methodology to compare two welding processes, namely SAW (submerged arc welding) and GMAW (gas metal arc welding) and to select the best one for a given application. The selection was based on double criteria: operational costs and non-quality costs. The former is related to the normal costs evaluated in such kind of decision, like consumable cost, labor cost, etc. The latter is the financial loss suffered by the client every time response variable drifts away from its target value or presents variability. The non-quality costs reduction is fulfilled through the proper adjustment of the process variables, in such a way that deviations from the target are minimized while robustness to noise and to process variable fluctuations is maximized. Since this a multi-response, multi-objective problem, the optimum solution is a compromise. Prior to comparison, the two welding processes were optimized. The results indicated that the non-quality costs for the SAW process are slightly higher, but these are compensated by its lower operational costs. Therefore, the SAW process has the lowest total cost and, consequently, it is the best process for the given application.