1mm accuracy

Please post any tips or advice you have in general relating to laser scanning either whilst onsite or office based.
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Joon
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Re: 1mm accuracy

Post by Joon »

With coordinate metrology, the relative accuracy to the range of measurement is more practical than the nominal one. E.g., a measurement accuracy of 1 nm is too low for 10 nm pattern of semiconductor circuit. In contrast, a measurement accuracy of 1 mm is too high for 1 km long bridge.

The range of relative measurement accuracy for industrial applications:
1. The lower bound: 1/100, i.e. 1 cm for 1 m
2. Usual requirement: 1/1,000 ~ 1/100,000
2. The upper bound: 1/1,000,000, i.e. 1 mm for 1 km.

There are a variety of measurement methods and tools available for industrial applications.

For moon observation, a telescope.
For cell investigation, a microscope.

Joon
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Re: 1mm accuracy

Post by Dave Andrews »

landmeterbeuckx wrote: Sat Mar 07, 2020 5:07 am
Dave Andrews wrote: Fri Mar 06, 2020 5:51 pm
landmeterbeuckx wrote: Fri Mar 06, 2020 3:05 pm

What price range are these trackers actually? I knwo Leica and Faro have them but have never used or seen one irl.
We have a little over $140k in 1 tracker and everything to do what we need. Now, we also do high precision alignment so the tooling needs a huge expense.
wow, you got to have some decent jobs for this gear to earn it back. I suppose the rates aren't as conventional surveying?
Haha yeah it’s a touch pricey. Our tracker rate is 4 times the survey rate.
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stevenramsey
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Re: 1mm accuracy

Post by stevenramsey »

Usual question has anyone bothered asking the client what they are using the data for and helping them understand what level of Accuracy/precision they really actually need
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Jamesrye
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Re: 1mm accuracy

Post by Jamesrye »

Yes, we've asked the client - they are looking at a subsidence issue. The trouble is that when a client reads something like the article below, why wouldn't they want the best possible accuracy?
https://www.spar3d.com/news/lidar/faro- ... -accuracy/

We get over-specced tenders all the time! Clients asking for 2mm point spacing on a building facade and then when you deliver, they cannot work with the point cloud and so we have to reduce it.
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Re: 1mm accuracy

Post by jcoco3 »

That's a shame :| I wish you luck in educating your client...if you can.

There is a saying that I have heard that is a good representation of this ignorance problem.

"Measure it with a micrometer, mark it with caulk, cut it with a chainsaw."

How is the contractor going to ensure they hit that mark even if you can? This is why I also suggested supplying tracker services during construction.

Edit: Sounds like the project is still over-specified, but at least you might get a chance to use a tracker, and possibly charge 4x what you would normally due to their ignorance. I think that it would be better to educate them and get the specified accuracy reduced, but in the event that fails you will still be giving them excellent data.
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Re: 1mm accuracy

Post by Scott »

jcoco3 wrote: Mon Mar 09, 2020 1:25 pm "Measure it with a micrometer, mark it with caulk, cut it with a chainsaw."
That tat would give the surgeon a laugh, too :D
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