CPK的计算方法 热度: CP与CPK的计算方法 IntegratedprocesscapabilityindexCpk:simultaneousoffset andconsistencyareconsidered. Cpk=xCporMIN(1-k){CPU,CPL} Ppk=xPporMIN(1-k){PPU,PPL} (X-mu) K=|Ca|=--- (T/2) PS.processcharacteristicsdefineunilateralspecifications (...
The difference between Cp and Pp lies in the method for calculating s, and whether or not the existence of rational subgroups is considered. Calculating Ppk presents similarities with the calculation of Cpk. The capability rate for Ppk is calculated using the formula: Once more it becomes cl...
Cpk is used more often than Cp because it accounts for both the standard deviation and the mean in its calculation. A difference between Cp and Cpk values indicates how far the average production will be from the target specification. The closer production is to the target specification, the c...
The difference between Cp and Pp lies in the method for calculating s, and whether or not the existence of rational subgroups is considered. Calculating Ppk presents similarities with the calculation of Cpk. The capability rate for Ppk is calculated using the formula: , Once more it becomes cle...
Cp, Cpk Formula Cp=(USL-LSL/6SIGMA) -> USL-LSL/6*RBAR/d2 Cpk=min(USL-XBAR/3Sigma,LSL-XBAR/3Sigma) Pp and Ppk -> Process Performance Pp- measures how well the datafits withinthe spec limits (USL, LSL) Ppk -measures how centered the data is between the spec limits ...
Caution:Only after a process is under statistical control, can one safely assume that the mean and standard deviation to have a stable values over time. Cpk is more widely used than Cp, since it takes into account the mean and the standard deviation in its calculation. Please note that the...
There is a specific equation for the calculation of Cpk. The equation for the process capability index includes [Minimum (mean– LSL, USL – mean)] / (0.5*NT). NT stands for natural tolerance here, and LSL is for the lower specification limits. On the other side, USL stands for upper...
Using this information I have created **UCL **and **LCL **by Standard formula .for details about UCL and LCL calculation kindly check the above links. After all the values are calculated I will draw the SPC chart in PictureBox using GDI+ and display the result to the end user....
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processcapability(cp,cpk,ppk)资料.ppt,Two Types of Processes All processes have: Natural (random) variability = due to common causes The Two Causes of Variation Common Causes: Causes that are implemented in the process due to the design of the process, a