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This topic contains 3 replies, has 4 voices, and was last updated by ali 2 months, 2 weeks ago.

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Hello.I do my thesis in 6sigma and have some data from a ceramic tiles company.This company has 1 production line where (according to the production plan) something like 70 product lines are being produced.I did a pareto and most of the lines contribute the same to the overall defectives.In the end of the line, there is an optical then a dimensional and then a control of the even surface.The product is either categorised as defective by the first second or third control.U cannot know if a product is defective by more than one controls.So lets sau i have overal 100.000 ceramic tiles being prodiced (not categorized by product line) and have something like 6.000 defectives from optical control,3.000 from dimensional 3.000 from even control.How do i calculate the sigma level?

1. Yield=88%-Sigma=1,5 (the classical way)

2. a) DPU=Yield (since i cannot categorize defects and for me 1 defective=1 defect?)and therefore sigma level=2,7? Or i convert yield to dpu RTY=e^(-DPU) and then from Sigma level = 0.8406 +sqrt(29.37-2.221 * ln (ppm) formula sigma=2,7?

3.Its is a compound product so i dont think i have to use DPMO.Anyway,as an opportunity i consider 3 and DPMO=(120000/3(13.0000))*1000000 Sigma level almost 3,2!!!

Moreover the distribution of the average defects per month (N=11 months) has ?=0,87 but StDev=0,03!!Is there any connection with the above sigma levels (although i know they conclude the supposed 1,5? drift)??plz Help!!Which one of them should i useAdditionaly, I am trying to evaluate the indices of the specific weight in pulp mills used in athe ceramic tiles company. The mills are used randomly and the company keeps data of the specific weight in not fixed time but when a mill is going to empty.Is that safe to use Capability indices when my process in not inherently normal?And after i transform it to normal shouldnt Pp almost equal to Cp and even Cp

Huge post but ypur answer would be more than helpful.Thank youAdditionaly, I am trying to evaluate the indices of the specific weight in pulp mills used in athe ceramic tiles company

Do you understand the difference between defects and defectives?

alihi, i work in qc ceramic tile whit 4 line product. more important defect in our company is Superficial defect like pinhoul in product. planning is second and liner is last because of chamfering.

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