Process Capability Analysis of Worm Gearbox Manufacturing Process

Abstract

In worm gearbox manufacturing it is found that variability present in the output of the process of manufacturing of worm shaft and worm wheel which is the two main components of worm gearbox. The process is operating in the presence of assignable causes that resulting in a shift to an out-of-control state where the process output does not conform to requirements which directly affect the quality and cost of the gearbox.

In this project, analysis is carried out in Worm gearbox manufacturing unit to bring manufacturing process of worm shaft and worm wheel under statistical control by eliminating assignable causes, rejection, rework, cycle time, scrap, etc. A major objective of this project is to standardize the process for improving the quality of worm gearbox. To acquire the design specification of the main two component worm shaft and worm wheel to reduce non-conformities in its manufacturing process, a process capability analysis is carried out in this project. To obtain the manufacturing process of worm gearbox under statistical control the quality control tools like Pareto charts, cause and effect (Fishbone) diagrams are used to get target quality characteristics and the root cause of the assignable cause. Quality tools like Why-Why analysis, 4M (Man, Material, Method, Machine), 6W2H (What, Why, Who, When, Where, Whom, How and How much) Action Plan are used to optimize the quality. By implementing the quality control tools and revising the 4M Condition using a 6W2H action plan, the worm gearbox unit has significantly reduced non-conformities and get the process under statistical control from last year statistical data.