Utilização de ferramentas da qualidade para a análise de refugo em uma fundição

Abstract

This research presents an analysis of identification and proof of possible causes, which are leading to the high percentage of scrap in two engine blocks in a foundry company. A practical approach is presented where through the PDCA methodology and quality tools it is possible to analyze and prioritize defects. It is identified that the 6-cylinder block has 34% of its rejects due to a leak in its final inspection, revealed through the non-destructive liquid penetrant test. After material analysis, the inclusion of oxide as the cause of the leak is confirmed. With the aid of the process map, all factors related to the processes of molding, melting, casting and molding are verified. The prioritization matrix is used to determine the most impacting factors on oxide generation. After an individual study was carried out for each factor, causes without actions taken were found, where one can act to reduce the defect and experimentally proven causes where we have effective actions that can be replicated for other processes.