Large area measurement

[123Cat]

Have got a room size vacuum system with inside parts that need accurate alignment relative to one another
Height wise too
Is there a large laser or similar system that will resolve about 10 thou in 3D
The aero people must have this down pat with their big structures
Thanks

 

[CoryPad]

Try vision systems from gom. Here is a link that shows a NASA vehicle application:

http://www.gom.com/En/Applications/Digitizing/qual/x38.html

Regards,

Cory

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

 

[aviat]

What you are referring to is still done with theodolites in some places, although it is being replaced with lasers and indoor GPS. On aircraft, basically what they do is put targets on known points on aircraft and shoot them with the theodolites, which is then feed into a computer, which has software for a particular aircraft. As they measure in the hundred thousand of an inch ranges, these systems are very expensive.

The site below is for a manufacture of these systems. Although it is probably more than you need, they maybe could help you or suggest a company in your area that could be contracted.

http://www.attinc.com/basics.htm

http://www.attinc.com/index.htm

 

[BrianR]

You could look at the Kern 3D measurement system.

http://web547.gsfc.nasa.gov/amb/Metrology_/kern2/kern2.html

We have used it for airframe geometry measurements and it is very accurate, like 0.02mm

 

[WhiteRabbit]

At our fabrication facility we use a theodolite laser system. We had hard orientation targets on our assembly jigs to align the actual model to the laser.

The system works by tracking a "target ball" that has a set of mirrors in it to reflect the laser back to the unit. The target ball also has fixtures that can be used to track surfaces, edges and holes.

It has a frequency pulse sweep through the laser that it uses to measure distance.

You can track in real time if you have a theoretical model. We've actually located complicated parts using this system.

There is a range to it due to the light dispersal. We've always oriented the laser unit fairly close to the aircraft. We were able to acheive a tolerance as tight as 5 ten thousandths.

However, you will need a direct line of site for this system. The theodolite machine cannot be moved during a shoot. The machine is very sensitive.

Someone walking close to the machine or dropping a tool near the machine will throw it off due to the floor vibration (even through concrete floors).