Tolerance Stackup?
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Posted by: SIVA_KOVAI ® 11/04/2009, 04:14:26 Author Profile eMail author Edit

What is Tolerance Stackup & Tolerance Stackup analysis? How it is important? Where can I get the informations related to this?

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: Tolerance Stackup?
: Tolerance Stackup? -- SIVA_KOVAI	Post Reply	Top of thread	Engineering Forum

Posted by: traingdt ® 11/04/2009, 21:17:09 Author Profile eMail author Edit

Tolerance stacks, stack-ups, and stack analysis are three phrases for the same thing: a numerical study of the effects of two or more dimensions and their tolerances, and calculating how a total overall dimension may vary due to these. It sometimes involves one part (such as finding the worst-case distance between two holes on a plate that each have a position tolerance) or it may involve many parts in an assembly (such as finding the maximum amount of looseness or "play" at the end of a gearbox shaft if all the components within are at their smallest). Doing the stack involves three things -- identifying the unknown gap/distance that you seek, finding a path of known dimensions that you can string together to find that gap/distance, and then performing the math. There is no technical standard that prescribes how to do stacks, so to perform the math it could be as simple as writing down a few numbers and doing some quick arithmetic, but it usually requires a more methodical approach that uses an Excel spreadsheet or customized software. Finally, be aware that stacks can be done based on a pure arithmetic adding-up of numbers (called a worst-case assumption), but many times a statistical formula called root-sum-square is used to find a more realistic answer. John-Paul Belanger Modified by traingdt at Wed, Nov 04, 2009, 21:24:48

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: : Tolerance Stackup?
: : Tolerance Stackup? -- traingdt	Post Reply	Top of thread	Engineering Forum

Posted by: SIVA_KOVAI ® 11/04/2009, 22:10:30 Author Profile eMail author Edit

Thank you very much John.

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