The Famous Ford Study of Mazda Transmissions - Can the characteristic be measured?
- Thread starter Marc
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blast from the past...I think this was actually my first 'post'! 1999. wow!
S
statdoug
Re: The Famous Ford Study of Mazda Transmissions - Can the characteristic be measured
I was working for a major Ford supplier at the time. They (Ford) brought the tape in and had us watch it. We also were required to sign a non-disclosure agreement. I have also seen boot-legged copies. That was back in the mid 80's. without knowing if the non-disclosure agreement is still binding, I don't know if I can say any more.
I was working for a major Ford supplier at the time. They (Ford) brought the tape in and had us watch it. We also were required to sign a non-disclosure agreement. I have also seen boot-legged copies. That was back in the mid 80's. without knowing if the non-disclosure agreement is still binding, I don't know if I can say any more.
Re: The Famous Ford Study of Mazda Transmissions - Can the characteristic be measured
It is interesting that they interpreted what they found as "continuous improvement", and back in the day I guess they did not know any better.
I interpret it as not understanding their true tolerancing requirements in relation to their performance. They all but admitted that. If you have evidence that performance is a function of tighter tolerancing, then properly tolerancing to the correct "tightness" is the starting point. The competition was not 27% of the tolerance....they were 75% of the correct tolerance!
You can control precision machining as tight as you want - once you understand how. But, it requires more adjustment. So balancing the amount of adjustment to the true need is critical to total economic success - quality and performance.
It is interesting that they interpreted what they found as "continuous improvement", and back in the day I guess they did not know any better.
I interpret it as not understanding their true tolerancing requirements in relation to their performance. They all but admitted that. If you have evidence that performance is a function of tighter tolerancing, then properly tolerancing to the correct "tightness" is the starting point. The competition was not 27% of the tolerance....they were 75% of the correct tolerance!
You can control precision machining as tight as you want - once you understand how. But, it requires more adjustment. So balancing the amount of adjustment to the true need is critical to total economic success - quality and performance.
Re: The Famous Ford Study of Mazda Transmissions - Can the characteristic be measured
I think a lot of people are further polluted with a perception of the "quadratic loss function" model that indicates the closer you are to the target the less "loss" there is. It is an interesting broad brush model, but you have to be careful. It does not accommodate the cost of always being just at the target. That includes (as Ford found) measurement systems that can discern that closely, as well as process controls capable of better discerning adjustment. It also assumes one facet of functionality - there are many, so the true function will be multi-modal.
If you get back to the core of variation - the total variance equation - you will see that the output is always multi-modal. Always. But, you can make many of the factors statistically insignificant - often at more of a cost (again, see Ford's dilemma with their air gages). So, real decisions need to overlay these factors to determine specifications: loss (functional), risk, impact on how to control factors of variance in the total variance equation and cost.
One other nice detail...did you see how Ford measured those bores? Did they take one diameter, as one would do with traditional X-bar R charting, to describe them accurately? No. They took the diameter and roundness, as you would do in X hi/lo-R charting. That is how you correctly control precision machining! Thanks Ford!
I think a lot of people are further polluted with a perception of the "quadratic loss function" model that indicates the closer you are to the target the less "loss" there is. It is an interesting broad brush model, but you have to be careful. It does not accommodate the cost of always being just at the target. That includes (as Ford found) measurement systems that can discern that closely, as well as process controls capable of better discerning adjustment. It also assumes one facet of functionality - there are many, so the true function will be multi-modal.
If you get back to the core of variation - the total variance equation - you will see that the output is always multi-modal. Always. But, you can make many of the factors statistically insignificant - often at more of a cost (again, see Ford's dilemma with their air gages). So, real decisions need to overlay these factors to determine specifications: loss (functional), risk, impact on how to control factors of variance in the total variance equation and cost.
One other nice detail...did you see how Ford measured those bores? Did they take one diameter, as one would do with traditional X-bar R charting, to describe them accurately? No. They took the diameter and roundness, as you would do in X hi/lo-R charting. That is how you correctly control precision machining! Thanks Ford!
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