Rbar / D2 is an easier way to estimate the value of Sigma (standard variation), where D2 is a function of n (sample size). I've deliberately skipped this formula since it may become pretty difficult to explain D2 which is a result of extremely difficult mathematical calculations. Just remember, as the sample size increases, the value of D2 increases and the value of standard deviation decreases for the same Rbar. That means with bigger sample size we can have better estimate of Standard Deviation. Coming back to your point, whether you calculate Sigma with Rbar/D2 or using the standard formula, your result will be the same. or most likely to be the same :)
Think of Cp (Process Capability) as a measurement unit to identify if the process qualifies to make the product. If it doesn't, it's normally an engineer's job to 'IMPROVE' the process by modifying the machine, using different tools/dies or reducing the clearance between moving parts, etc. Once the Cp is qualified, then in the next step Cpk (the process index) is a measurement unit to identify if a process is set at the mean position. If it isn't, like the diameter is on the higher side or the length is on the lower side, then it's normally an operator's job to 'ADJUST' some machine's setting and bring it back to the mean position. Hope I'm able to answer; if you're asking something else, please elaborate a little. For example, what exactly is not clear? -Amit Gupta
Nicely explained... Thanks a lot
This is the best video I have seen on process capability video. Thanks a lot.
Agree with past comments. Other videos are good, but this one is most simple & straight forward. No extra fluff. The visual is very helpful too.
Simplified to the core. Amazing 😍
This was very helpful. Thank you!
by far the best video....
Well explained! Thank you for your efforts in making this video. You definitely deserve more than 5.7k view. I'll do my part.
Thank You for your support.
Much appreciated 😊
Perfect explanation! Thank you!
You're welcome!
Super explanation.
Amazing 👋🏾
I need one clarification, i have not seen Rbar/D2 in your sigma calculation for Cp. Please clarify
Rbar / D2 is an easier way to estimate the value of Sigma (standard variation), where D2 is a function of n (sample size). I've deliberately skipped this formula since it may become pretty difficult to explain D2 which is a result of extremely difficult mathematical calculations.
Just remember, as the sample size increases, the value of D2 increases and the value of standard deviation decreases for the same Rbar. That means with bigger sample size we can have better estimate of Standard Deviation.
Coming back to your point, whether you calculate Sigma with Rbar/D2 or using the standard formula, your result will be the same. or most likely to be the same :)
thanks a lot
Happy to help
subscribed!
Cpk and ppk not cleared properly,Can u give some more examples and explanation?
Think of Cp (Process Capability) as a measurement unit to identify if the process qualifies to make the product. If it doesn't, it's normally an engineer's job to 'IMPROVE' the process by modifying the machine, using different tools/dies or reducing the clearance between moving parts, etc.
Once the Cp is qualified, then in the next step Cpk (the process index) is a measurement unit to identify if a process is set at the mean position. If it isn't, like the diameter is on the higher side or the length is on the lower side, then it's normally an operator's job to 'ADJUST' some machine's setting and bring it back to the mean position.
Hope I'm able to answer; if you're asking something else, please elaborate a little. For example, what exactly is not clear?
-Amit Gupta
My freind Thomas asks if u are from India?
100% 😊