Process capability is the ability of processedproducts when process is in a normal state (steadystatecontrolled)B = 602007.4Process Capability:Concept11
2007.4 Process Capability: Concept 11 Process capability is the ability of processed products when process is in a normal state (steady state controlled). B = 6σ
3e criterionIn the production process, when thereexsists only accidental error, the qualitycharacteristics of X obey normal distributionN( μu,o? ) , and according to the nature of thenormal distribution of probability, there isP(μ-3 c< X<u+3) =99.73%that （μ-3, μ+ 3ε） is the actualvaluerange of X.2007.46Process Capability12
2007.4 12 Process Capability 3σ criterion In the production process, when there exsists only accidental error, the quality characteristics of X obey normal distribution N( µ， ) , and according to the nature of the normal distribution of probability, there is that（ µ － 3 σ ， µ＋ 3 σ ） is the actual value range of X . P｛µ － 3 σ ＜ Ｘ＜ µ ＋ 3 σ ｝＝99.73 % 2
The reason why the provisions boundaries of controlchart is 3g mainly due to economic considerations.Type I error : Normal viewed as abnormal, vain alert.QProbabilityisType II error : Abnormal viewed normal, omission alertBProbabilityis1BQ andcan not be reduced at the same time,they can only be controlled within a certain range.2007.4ProcessCapability13
2007.4 13 Process Capability The reason why the provisions boundaries of control chart is 3σ mainly due to economic considerations. Type I error : Normal viewed as abnormal, vain alert. Probability is Type II error : Abnormal viewed normal , omission alert. Probability is and can not be reduced at the same time, they can only be controlled within a certain range .
dM-30+302009.6.6Process Capability14
2007.4 14 Process Capability 2003.6.6
The reason why the provisions boundaries of controlchart is 3 mainly due to economic considerations.LossesLossescausedcausedby βα2 g3g4g5gO2007.4ProcessCapability15
2007.4 15 Process Capability The reason why the provisions boundaries of control chart is 3σ mainly due to economic considerations. Losses caused by Losses caused by σ 2σ 3σ 4σ 5σ