(Cpk > 1.33 is desirable) Cp and Cpk useSigma Estimator σ̂ Pp, Ppk Formula & Calculations (Ppk > 1.33 is desirable) Pp, Ppk usestandard deviation σ Sigma Estimator Calculation - Three Different Methods Pooled Standard Deviation Use when n > 2 ...
CP与CPK的计算方法IntegratedprocesscapabilityindexCpk:simultaneousoffsetandconsistencyareconsidered.Cpk=xCporMIN(1-k){CPU,CPL}Ppk=xPporMIN(1-k){PPU,PPL}(X-mu)K=|Ca|=---(T/2)PS.processcharacteristicsdefineunilateralspecifications(designspecifications)becausethereisnospecificationupperorlowerlimit,nospecifi...
Since CP is merely a calculation, there aren’t a lot of best practices but more of a series of hints that allow you to get the maximum value out of the calculation. 1. Do Both CP and Cpk Calculations By comparing the potential capability with the actual capability, you will understand...
Pp and Ppk to the SPC Chart. 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 displ...
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...
in Figure 2, then the percentage of the normal curve area that spills over the upper and/or lower tolerance limits calculates to .27%, or 2700 PPM. For Cpk = 1.33, seen in Figure 2, the PPM is 64. When Cpk = 2, also seen in Figure 2, the calculation works out to be 0.002...
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...
They had run the QI Macros histogram on two columns of data, one measured at 0 degrees and one measured at 90 degrees. Looking at the histogram you can see that there are two “humps” or distributions. Cp and Cpk are both below 1.0 so you can understand why they were concerned: I’...
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
variability The Cpk Index accounts for process variability and centering of the process mean to the design nominal Therefore, Cp Cpk NOTE: Same applies also for Pp and Ppk Cp = Cpk (both low) LSL USL Mean = Nominal Reject parts Reject parts Cp high, Cpk low Process should be ...