Process and Gage R&R Simulation

Using the Process and Gage R&R Simulation

This calculator simulates a Process and a Gage by taking a sample of 100 values and plotting them on a scatter chart (or X-Y plot).

Process – You can play with the Capability of the True Value Process using the ‘ Change Underlying Process Capability Index ‘ Slider.

Gage R&R – You can change the Gage R&R Variation using the ‘ Change Gage R&R (as % of Tolerance) ‘ Slider.

Process Output – True Value + Gage Error = Observed Value, so these two values combine to give you the Observed Process – i.e. the Measured Process.

What the simulation tells you

The Scatter chart plots the Underlying Process on the horizontal axis, and the Observed Process on the vertical axis. The Tolerance Limits are shown by the black dots on the chart.

The amount of Gage Variation determines how close the Observed Process is to the True Value Process. If Gage Variation is very low, then you will get a very clear picture of the real process, but if Gage Variation is high, then you will get an a very obscured picture of the real process.
Try playing with the simulator, by changing the sliders – The simulation will re-sample another 100 values every time a slider is moved

The Process Output shows how many parts are out of specification according to your measurement system (‘ As Measured‘), compared to how many parts are really out of specification – If you could measure with a perfect Gage – ‘ True Value‘)

Producer’s Risk and Consumer’s Risk

Another way of understanding the Process Output is in terms of Producer’s and Consumer’s Risk.
If good parts are classified by the measurement system as bad this is the Producer’s Risk
If bad parts are classified by the measurement system as good this is the Consumer’s Risk

As stated, the table on the right hand side updates to show how the measurement system is mis-classifying good parts as bad (the producer’s risk), and bad parts as good (the consumer’s risk).

Related Pages

This model is based on the model detailed in the book: Design and Analysis of Gauge R&R Studies

You can see an alternative Process and Gage Simulation at: Interactive Calculator – Impact of Gage R&R on Process Capability – This online calculator allows you to enter your own specification limits (must be a two sided tolerance), and draws the normal distribution curves for the True Process, and the Observed Process, on the same chart

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