Lower Confidence Bound and Acceptance Sampling for Cpk with Multiple Lines
|關鍵字:||允收抽樣計劃;信賴下界;製程能力指標;多條生產線;acceptance sampling plans;lower confidence bound;process capability index;multiple independent lines|
Process capability indices (PCIs) have been proposed in the manufacturing industry to provide numerical measures in process capability, which are effective tools for quality assurance and guidance for process improvement. Methods for measuring yield for processes with single manufacturing line have been investigated extensively, but comparatively neglected for processes with multiple independent manufacturing lines. Therefore, in this thesis, we consider the process capability index CpkM with multiple independent manufacturing lines. We explore the approximate normal distribution of CpkMhat by Taylor expansion approximate and lower confidence bound. We verify the accuracy between the Taylor expansion approximate normal distribution and the simulated distribution through simulation data. The lower confidence bound is calculated, and make corrections. In addition, we consider the product acceptance sampling plan based on CpkM to deal with product acceptance determination for processes with multiple independent manufacturing lines. We tabulate the required sample size and the corresponding critical acceptance value for various vendor’s risks with the capability requirement average requirement average quality level (AQL) and lot tolerance percent defective (LTPD). The computational results are useful to the practitioners for their in-plant applications.
|Appears in Collections:||Thesis|