Process Capability Estimation with Non-Normal Distribution Case Study: Resonance of Pivot

Abstract

This paper present about Pivot resonance which dynamic data and non-normal distribution basis and must be transform data to be normal distribution before estimate Ppk. The study on Pivot resonance characteristics that is dynamics data while measuring resonance frequency and it has non-normal distribution. The FEM (Finite Element Method) was use to analysis the data on two pivots with different ball bearing position to represent ball movement while measuring the resonance frequency of Pivot to be used data for Ppk estimation. FEM was used to gather 32 modes to verify the resonance frequency. Result shows that there is dynamic data which difference in resonance frequency on mode 1-19. And there become to be static data which no difference was observed on mode 20. Based on the data and analysis, this paper demonstrates the proposal of setting the measuring mode of resonance frequency at a minimum of mode 20 to get static data for Pivot size 3.138 x 8.9 mm. With this methodology, the data would be normally distributed and no need to transform data for estimates Ppk.