An Alternative to Minitab™; Cpk Calculation Made Easy, this Lean/Six Sigma app allows you to calculate:
- Cp, Cpk, Pp, Ppk, PPM Defects & Confidence Interval
- Fully exportable data and Histogram
This app allows you to calculate process capability (Cpk) on the manufacturing shop floor ( Gemba ). No longer do you need to scribble down manufacturing data on a note pad, then go back to your continuous improvement office to input data into an expensive subscription based software such as Minitab ™.
Why buy this App? The creation of this app has been a long and winding road. It all started when two Lean, Six Sigma, Continuous Improvement professionals found that they had used to same data to calculate process capability index, but ended up with different results. This led us down an Alice in Wonderland like path of Google searching, Wikipedia, blogosphere searching, and found that there is no real consensus in how to properly calculate Estimated Standard Deviation and Confidence Interval. Knowing that it should be a logic discussion, not a philosophical question we decided to do extensive research and found the logical solution was actually very simple, but seemed murky due to all of the incorrect information out there on the interweb. At the end of this journey we decided that there was a need for a simple lean/six sigma tool that anyone could afford in order to break the economic and educational chains restraining the tool that is Process capability studies. Our goal is to provide this tool to anyone that can gain value from understanding their actual process capability and use it for continuous improvement.
This app automatically calculates standard deviation in 1 of 3 ways depending on data set characteristics:
1. If data is in one large group we use the regular sample standard deviation calculation (n-1). If you collect your data in sub groups there are (2) preferred methods of estimating standard deviation using unbiasing constants:
2. Rbar /D2
This App. Allows you to measure your process capability index, or how good your process is compared to your internal, or customer requirements (specifications).
Six Sigma is a methodology for collecting and analyzing data in order to develop a continuous improvement strategy in manufacturing and many other industries. The Cpk Calculator app allows you to fully utilize the Six Sigma principals in the field, and gives the Lean Manufacturing approach that is to do the work on the shop floor (Gemba) in real time.
Process capability studies are essential in any comprehensive lean, DMAIC, PDCA, continuous improvement strategy.
The results page and histogram in this app is fully exportable and unique. At the top of the page it calculates Mean, Standard Deviation and Estimated Standard Deviation. Below that, the Histogram displays the relative frequency of where your data falls in relation to your specification limits. Below the Histogram is a summary of your capability data and process performance: Pp, Ppk, Cp, Cpk, Confidence Interval and Defects per million observations (DPMO).
The Cpk Calculator App is a onetime purchase and is an inexpensive, user friendly alternative to the subscription based software such as Minitab™ for capability studies. Minitab ™ is a great tool for statistical process control (SPC), but in many cases software such as Minitab™ are too expensive to purchase and require extensive training to become proficient. For example, Minitab requires you to select which method to use when calculating estimated standard deviation (Rbar/D2 vs. Sbar/C4). This app evaluates the characteristic of you data and sub grouping and auto selects the most appropriate method.
A true six sigma manufacturing process has 3.4 DPMO. Confidence interval is based on your sample size, so more data = narrower confidence interval. Histogram..