Research On MCCB Thermal Trip Adjustment And Testing Workstation Quality Control Of H Company

Moulded Case Circuit Break (MCCB) is used to protect the equipment, lines etc. in case of overload or short circuit happen. Thermal tripping, as one of the most important functional character of MCCB, has been obtained a lot of research resources. The target of this research is to improve the production bottleneck by quality yield improvement.Several quality control methodologies has been used in this paper, such as Pareto method, Cause and Effect method, PFMEA, GR&R analysis, DOE, Process capability analysis, SPC etc. Three main causes which impact the quality yield were found: Equipment parameter not properly setting, Cpk of cimetal original position lower than requiremenet, Cpk of welding subset dimension lower than requiremenet. Related improvement actions were taken to treat the causes, the target was almost achieved after the implementation of the improvement action, the right first time quality yield is improved from 92.58% to 97.70%.The study result of this paper can provide a reference for the national low voltage circuit break manufacturing industry to improve their thermal tripping quality level.