From May to August 2022, the airtightness qualified rate of a certain project product of MINTH was 81.6%~87.6%, which could not meet the target of 95% airtightness qualified rate of mass production. The main problem was the end cover welding leakage, which accounted for more than 50%. The main defects of end cover welding leakage were notch welding defects, notch too shallow, and poor fusion at the overlap. By applying the Six Sigma method combined with JMP software to investigate and analyze the problem points, and successfully found the root cause, the countermeasures recommended by the JMP software were implemented, and finally the goal of improving the airtightness performance qualified rate was achieved.
