Gage Repeatability and Reproducibility (R&R) is the measure of the amount of variation in a measurement system that is introduced by the measurement device (Repeatability) and the operator using the instrument (Reproducibility). “Gage R&R’s are important elements of any continuous development program in Six Sigma projects. Still, many companies avoid using it because of the perceived complexity and a lack of time and knowledge of their benefit.” – Tahira Bhasin, Business Analyst.
Benefits of Gage (R&R)
Measurement system variation is usually a major reason behind the observed process variation. This variation should be assessed and amended at the earliest to avoid the team the trouble of looking for variation causes beyond the measurement system.
“Measurement variation can come inherently into the values whenever a measuring instrument is used. A high-variation measurement system can drastically distort the quality of process capability study.” -Pallavi Sharma, Six Sigma Specialist.
A gage R&R tool offers 4 benefits:
- Benefit#1: It tells the amount of variation in the measurement system due to the measurement device.
- Benefit#2: It tells the amount of variation in the measurement system due to the differences between operators.
- Benefit#3: It tells whether the measurement system variation is small in comparison to the process variability.
- Benefit#4: It tells whether the measurement system can distinguish between different parts.
When you perform the Gage R&R, you can check if there is an issue with the measuring device or the operator in your measurement system. If the measuring device is not working as desired, you have to calibrate it.
All you need to do is follow the simple steps:
- Click Here to Download the FREE Excel spreadsheet template
- Add your company logo to the footer
- Conduct the gage study and fill the relevant data in the blue boxes
- Review the pie chart and your results to enhance your process!
How to use Gage (R&R)
Gage R&R template has 3 worksheets:
- Calculations – This is the place where all the calculations will take place. You have to enter your data here.
- d2 – Depending on the number of trials, parts, and operators, enter the lookup values required for the calculation page. You can enter values for 3 different trials and 3 different operators for each part and for up to 10 different parts.
- R&R Pie Chart – This pie chart compares the repeatability, reproducibility and part variation.
Use this example to understand how the template works:
- Step#1: Choose the size of your Gage R&R tool. You can pick 2or3 operators, 2or3 trials per part, and 2to10parts. For instance, you choose 2 operators, 2 trials and 5 parts, you will be working on 20 points study. Fill these values at the top of the template.
- Step#2: Type the operator’s name or ID in the blue box. Fill appropriate sections of the template with the collected data.
- Step#3: Add the specification limits of the parts that you are using. This will help in determining the percentage of Gage R&R variation in comparison to the tolerance width. You will get a warning message if the variation exceeds 10%. Depending on your company needs, you can customize this variation limit.
- Step#4: Check the calculations that the template provides and see whether your measurement process is satisfactory for these parts.
“Gage R&R template presents a simple solution to prevent false rejects and false accepts in a process. You can edit and customize the template to suit your needs.” – Gautam Jain, Henry Harvin Education.
Gauge repeatability and reproducibility is a measurement systems analysis technique that uses an analysis of variance random-effects model to assess a measurement system. “Gage R&R’s are important elements of any continuous development program in Six Sigma projects.
If the Total Gage R&R contribution in the %Study Var column (% Tolerance, %Process) is: Less than 10% – the measurement system is acceptable. Between 10% and 30% – the measurement system is acceptable depending on the application, the cost of the measuring device, cost of repair, or other factors.
It tells the amount of variation in the measurement system due to the measurement device, as well as due to the differences between operators. Whether the system can distinguish between different parts, It also tells if the measurement system variation is small in comparison to the process variability.
Step#1: Choose the size of your Gage R&R tool.
Step#2: Type the operator’s name or ID in the blue box.
Step#3: Add the specification limits of the parts that you are using.
Step#4: Check the calculations that the template provides and see whether your measurement process is satisfactory.