Process capability is related to the variation in part dimension from shot to shot and therefore in the complete set of parts, such as in a production run. Shrinkage determines the final dimensions of the part. Minitab Cookbook Capability, Process Variation, and Specifications Introduction A capability and control chart report using the capability analysis sixpack. Shrinkage is the reduction in volume and is therefore reflected in the PVT diagram. All terms and concepts used in Capability Analysis. It consists of the following tools with practical examples for easy understanding and better clarity. As the melt is being transformed into the final molded product, the pressure, volume and temperature of the melt are all continuously changing, and the final contour in the PVT graph is a combination of the curves in Fig. This is a complete & detailed course in Process Capability Analysis with an illustration of practical examples in Minitab. During this process-and after the plastic is inside the mold-the melt is cooling. The molten plastic is then injected with high pressure into a cold mold. There is some compression of the melt because of the back pressure during the shot buildup process. Process Capability Report for Observations LSL Process Data USL Overall. The melt is collected as a shot in front of the screw. (Let me know if you would like me to expand that answer for you.In injection molding, a combination of these factors is involved as the melt is transformed into the product.
I'm not sure exactly were your problems are, but there do seem to be some calculation errors in your analysis (although the $C_$ calculated based upon the average process fallouts. The results reveal a Cpk of 0.35 with a corresponding DPMO (defects per million opportunities) of more than 140,000. I have no previous Six Sigma/DMAIC/statistical analysis experience so have only learnt what I could online. Suppose we collect some data and run a capability analysis using Minitab Statistical Software. Sorry for the essay but any help would be appreciated.
PROCESS CAPABILITY MINITAB SOFTWARE
Now my question is, is there a way that I can calculate the same cpk in Minitab just to check that my software is performing correctly?Īlso, to do a complete capability analysis for the laser marker do I just need to calculate cpk for X and Y for each and every point and as long as the smallest cpk is > 2.0 the process is six sigma compliant or is there an overall cpk that I should be calculating? The problem seems to be that I am getting crazy high accuracy (a cpk of between 20-100) Here is a sample of my data: I'm only using 4 samples here for simplicities sake, also ignore the Y Cpk. I have written a small program for a cPK calculator, that I can confirm the results with in excel using the cpk formula cpk = Min(cpU,cpL). Now, the trouble that I am having is calculating the capability of the laser marker (cPK). With this in mind I have calculated the Standard Deviation of each X,Y coordinate and used this to calculate the sigma value of the measurement system which is well within the Six Sigma spec. The laser marker can have a maximum variance of 0.7mm, therefore the measurement system is allowed a maximum of 0.07mm.
I've conducted the GR&R by measuring the same points(77 in total) a total of ten times and I've ensured that the variance within the measurements is within 10% of the maximum allowed variance. Just as a little background info, I have started off by conducting a GR&R for the measurement system that I'll be using. As the title states I'm conducting a statistical analysis for the variation within a machine (a laser marker).