Fast Runs - Four lots, one day each, every month - What chart to use?



Look next:

We have a product that runs four lots every month
But this run happens in one day of labor
This means one run with four lots but they have same part number

Every lot has 2400 sheets
Our process makes one punch by sheet and we obtain 5 pieces
Every piece has same number of variables to control

How can I take samples to measure them if we have one run per day every month?
And after this our process time is 5 seconds per sheet. This means (2400 * 5 =12,000 pieces in one lot but 2400 sheet x 5 sec = 3 Hours and 20 minutes by Lot)

Should we use a XR Bar Chart in this case?
If this is correct,
How we can see if we are in control if there is a fast time to take those samples when that run is made? Or
Should I use another type of chart?

Smile is good for your health!

:bigwave: :bigwave:

Rick Goodson


The speed of your process does not make it easy to take samples in a reasonable time frame. Never the less, the X-bar and R chart seems appropriate given you want to do charting. The question you might want to ask relates to the appropriateness of charting. there are other techniques that might be better suited for this type of production. Have you calculated process capability on the process?


Al Dyer

If you are doing a punch in the material maybe a go/nogo gage and a P-Chart!:)
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