What is the accuracy of a ZEISS CMM- duramax?

[[An...]]

Hello all,

What is the accuracy of a ZEISS CMM -duramax?


Thank you in advance

[[Is...]]

[[An...]]

Thanks for answering
But what does 2.4 + L/300 mean?

[[Da...]]

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It means, that for every 300mm you add another micrometer.

For example:
2,4μm+300mm/300mm=3,4μm

[[An...]]

I don't get it =(((

2.4μm+300mm/300mm=3.4μm?????????? how??

Example) Vernier scales are usually used to measure objects up to a few centimetres across and to an accuracy of +/- 0.1mm.

What is the accuracy of a CMM machine (Duramax)? Is it +/-0.00005 inch? OR +/- 0.0003937 inch? OR +/- 0.00013386 inch?

Accuracy.JPG

[[To...]]

Here's something from our dear colleague and friend Ryan Stauffer

CMM Accuracy Statements.ppt

[[To...]]

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CMM accuracies are not stated in this fashion. Unlike vernier scales, the stated accuracy of a CMM decreases as the measured feature becomes larger. The formula above states the base accuracy of the machine is 2.4um. Then, when measuring something 300mm in distance, you take that number and divide it by 300, which equal 1um. 2.4um + 1um = 3.4um or just over .±.0001"

So, let's work on something 30mm in size 30/300 is 0.1. 2.4um + 0.1um = 2.5um. This means the accuracy of the machine measuring something 30mm is within 2.5um.

Most of the time, Zeiss machines are often well within their stated tolerance. Hope this helps.

[[An...]]

Let's work on something 30mm in size 30/300 is 0.1. 2.4um + 0.1um = 2.5um.????????
I still dont get it

Should be same unit why changed the unit?

30mm/300mm -> 0.1mm not 0.1 um

if it is 30um/300 um, it is 0.1 um. we use only "inch" what if it is "inch" not "mm"?

[[Er...]]

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Andrew, When you multiply/divide the same unit in math the units disappear also. 300mm/300mm=1 and represents just a value to add to the rest of the formula.
It's the same way it's used if you are in a car driving 60 miles per hour, and you want to know how far you go in 2 hours, 60 m/h * 2 hours gives you 120 miles. Dimensionally it is (miles/ hr) * hr = miles*hrs/hrs but the hours cancel, and left with miles only.

You can look up unit canellation in math to see more examples of this.

So now with our accuracy equation, 2.4um + L/300 or 2.4um + 300mm/300mm = 2.4um + 1 = 3.4um. Again, the L/300 becomes a value to add to the 2.4um starting accuracy of the machine and become less accurate as the part becomes larger.
I hope this helps make more sense of the equation.

[[Er...]]

Page 53 covers this.

Metrology introduction a.pdf

[[An...]]

Then If it is inch can i do this way below?

2.4μm+L/300mm = 0.00009449+L/11.8110236

(2.4 Micron = 0.00009449inch)
(300mm = 11.8110236inch)

[[Ma...]]

Now you are trolling right?

[[Ri...]]

The length expansion constant is a unitless number. The formula only works when working with lengths in millimeters.

I would convert the measured length to mm and use the uncertainty formula to calculate your uncertainty.

[[Er...]]

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To Richard's point I believe the formula would be written correctly as +/-(2.4 + L/300)um where L is measured in mm. So once you do have your value the final value is in microns and should only be converted to inches after calculating. 2.4+300/300 or 1=3.4um or 0.000133858 inches.