Six Sigma

[[Da...]]

So I have always been told that Six Sigma was 3.4 defects per millions parts made. Different company's but the same interpretation. Has anyone else been told this?

I found out in my MBA program that the correct statement is not parts made but per opportunities. That makes things a lot different when calculating Six Sigma.

"The objective of Six Sigma quality is to reduce process output variation so that on a long term basis, which is the customer's aggregate experience with our process over time, this will result in no more than 3.4 defect parts per million (PPM) opportunities (or 3.4 defects per million opportunities – DPMO)."

[[Da...]]

The Pivot table that puts all data in to one excel document.
Just select the part number on the Left, The Points you want to look at, and The Order,
Up top is the Days that you want to look at.
In seconds it updates all the data to one excel sheet from every CMM
Select the data set and copy it to a new excel work sheet

With a couple of excel formulas you can
Get the Average, Mean, Max, Min, and Difference
Formulas_______=Average(Cell(A3):Cell(A25))
______________=Median(Cell:Cell)
______________=Max(Cell:Cell)
______________=Min(Cell:Cell)
Difference is____=Max-Min

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[[SH...]]

I have been told that six Sigma is invented by Japan's Motorola company for the purpose of zero defect...

[[Ri...]]

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The whole point of statistics is to be able to measure a sample set that shows what the calculated probability/capability of the whole population would be. It is a best guess. That's why there are things called alpha levels and confidence intervals.

You are correct, it is a probability that you could POTENTIALLY make parts that fit into a particular distribution. What it doesn't account for is whoops.

Capability analysis is fun, and also it is a nightmare.

[[Ro...]]

I think that most of the theories behind lean and 6sigma and statistics in general are made with the idea that a machine is going to be setup and run the same ball joint or stamped widget or machine screw for the next 15 years. Auto if you will. dedicated machines.
Where i work at and where i have worked at for the past 20 years are job shops, where machines are setup and run 5 to 200 parts then tore down and something else setup. nothing about the next setup has anything to do with the setup we ran back in january, often times the same part will be run on different machines with different tools and operators, so how is anything going to fit within a single chart?
And that's why i never got into the numbers side of Quality.......

Boss: you want to go for your CQE cert?
Me: Nope.

soapbox-ive-got-two-pull-up-a-chair-for-the-rant.jpg

[[Ri...]]

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Being certified by ASQ as a CQE is great if you are looking to grow your resume.

Capability cannot be first achieved without stability. If you do not have a stable process, you cannot expect to measure your capability accurately. Part of stability is also being able to reproduce those same results over multiple setups. It is a difficult thing to achieve, but people have to actually care about the process, and unfortunately it's difficult to get people to care the same about a manufacturing process as they do their Facebook News Feed.

[[Me...]]

I heard the Motorola story also. I've also heard that company's like Toyota are moving to 7sigma, I believe.
We were approached by a Co. that we make parts for wanting us to move into 6sigma. As a small co. like Roberto stated it didn't make sense. Though it goes that when you make only 200, 300 parts then brake down you're supposed to then track that when you run it again, and again AND again until you trend for the better. Cpk if you will. But we don't and won't. We just couldn't be sold on it.
It takes time though a lot of our parts run into the thousands.

[[Da...]]

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In Six Sigma methodology, the target is to limit product defects to six standard deviations,( i.e. six “sigmas.”)The Upper Specification Limit is three standard deviations above the mean, and the Lower Specification Limit is three standard deviations below the mean

It was invented by Motorola Cell Phone Company. It was also the reason that you don't here much about Motorola anymore. Six Sigma works until you take it to fare rather then saving the company money it starts costing money. Motorola keep pushing Six Sigma until there phones cost 3 times as much as there competitors

Six Sigma (6σ) is a set of techniques and tools for process improvement. It was introduced by American engineer Bill Smith while working at Motorola in 1986. Jack Welch made it central to his business strategy at General Electric in 1995.

New Razor
Only 1499.99

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[[Da...]]

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I would totally agree with you Until my Job with Autoliv the numbers never made sense. Autoliv facility that I work at makes over a 1,000,000 parts a week with 400 workers (Or we did until Covid)
When I worked for Triumph Gear Systems (Rolls Royce Gear Systems before it changed hands) They thought that going from making 12 parts once a year to making one part once a month to become a lean manufacture would be a good idea. The only problem is there is a lots of steps to make an aerospace Gear but someone always at some point did something wrong. So we went from one bad part per year to 12 bad parts per year. It was very lean we had no parts to make anything with. 🤣 🤣

[[Ri...]]

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If producing near zero scrap costs you money, you might have a problem.

[[Ch...]]

Six Sigma can totally cost you money if you over apply it. The first 98% is always the easiest, Pareto principal. Then when companies should stop and call it good, they spend 1000's of manhours trying to get the last 2%. These resources would be better spent elsewhere.

Also, Six Sigma can't innovate. It knows only knows how to drive in one direction and can't slow down. That is great is you have a good product that won't change. If the market changes and you need to change your product, then Six Sigma can't change fast enough. It will drive you right off of the cliff.

[[Da...]]

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My Company has tried Zero Scrap but pulled away after it stated cost more then it was saving.
It all about the math!!!!
The Point that people implementing miss both Lean and Six Sigma cost money to do. When the cost Implement exceeds the savings Stop.

[[SH...]]

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It will not work in india and China for a twenty years...