Quality Improvement for Spline Manufacturing Through Attribute Control Chart (NP) in a Northern India Industry

摘要

Attribute control chart (np) has been applied on gear manufacturing industry in North India. The objectives behind this work are to monitor the ongoing process and eliminate assignable causes of variation in the existing process. A total of three critical parameters have been selected for spline manufacturing i.e blank inspection, spline hobbing at two junctures, Spline shaping. Hence a total of four (4) np charts have been developed in this work. In addition, one overall np chart also has been developed to see mainly the number of defects. A total of 20 samples were collected with each of sample size 50. Each day one sample was collected. It was found that assignable causes of variations were present in Spline blank, and two types of spline hobbing stations, however no assiganable causes of variation is present in spline shaping. Suggestion was conveyed to industry about presence of assignable causes of variation for a particular day.