Hi,

could somebody please help me? I am looking for a
noncontact length measurement gauge for use on a process lines in the steel industry. I have to measure the steel shafts with the maximum lenght of 6m. On those steel shafts I have to find a determinated position (for example 500mm from the beginning of the shaft). The shafts are rotating and they have a speed in lenght direction.
The speed in lenght direction is about 2m/min and the rotation is about 70r/min. The diameter of the shafts are from 50mm till 100mm.

Thanks
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CONNECT THE ENCODER TO SHAFT DRIVING DEVICE SUCH AS GEAR MOTOR.
FOR TYPE OF ENCODER LET ME KNOW WHAT AUTOMATION YOU ARE USING .

FOR EXAMPLE WE HAVE ALUMINIUM BILLETS FOR ULTROSONIC INSPECTION FOR THE CRACKS .

HERE ALSO BILLETS WILL ROTATE AND WE ARE MEASURING THE WHAT LENGTH THE CRACK IS .

FOR THAT WE ARE USING GELMA MAKE ABSOLUTE ENCODERS

THANKS

CHAND PASHA

 

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What is the required accuracy?

what do you do with at the pre-determined measurement from the end?

Jocko Harmet
TAMTECH, Inc.
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Without seeing the configuration and geometry of the situation it is probably difficult for anyone to recommend sensors. However, the technologies that immediately spring to mind are laser distance measurement and image processing.

Vince

 

I would reccomend using encoders to be attached to the transport system who carries the rods.
REgards,

MBA Ing. Jimmy Saldivias
TECSIM
Phone: 591-4-4523438
Fax: 591-4-4523413
http://tecsim.trading.net

 

Encoders are not accurate when used in conjunction with the machine gearing.

You are right to use a non-contact system to accurately measure the length. The best system i have found for this is a laser guage which uses beam interferance , ie 2 beams are focused onto the moving surface and then the speed can be calculated.

We used a company called TSI, try www.tsi.com, we even managed to use this method on copper, which is highly reflective to the wavelength of laser light.

Good luck

 

I think, you can use interferometric sensor. There is no contact measurements.
It just needs a block or flange reflectrometer where is attached to the moved body. This reflectrometers has a function to reflect laser beam from or to interferometer part, so you will get a very accurate measurements of
displacement.
You can found a literature about this theory like
Precision Machine Dessign by Alexnder H. Slocum, Prentice-Hall.
Or you can contact Zygo Corp about the equipments.

Thanks

 

We've use TSI on Plates and Slabs, they work well and are very accurate; although the price is salty. You may want to keep in the back of your mind that the bar rotation may have some effect on your readings though.

Mike

 

Do a web search for "laser doppler velocimetry/velocimeter". That is the type of technology that TSI uses, and there are some completing products.

One thing to be aware of is your target must be able to reflect the laser. Second, the doppler frequency is proportional to the velocity of the target. As such, there will be a minimum velocity
that can be measured that is related to the minimum difference that the system can resolve between the doppler and reference frequency.

Anthony Kerstens P.Eng.