sensors to measure thickness and width of moving steel strip.

hello all, is anyone aware of sensor devices which may be able to accurately measure width and thickness of a steel strip. i am currently working on a cut by weight project here at our tube mill. the steel strips come off of a large coil into an uncoiler followed by a Floop. it is then sent through a forming mill where it is formed into a tube. it is then welded and sent through a sizing mill (turk heads). the tube is then cut by a flying cut-off. the reason we need to measure the strip thickness and width is so that we can make the neccessary conversions to measure the weight of the tube before it is cut. after the cut the tube is drawn out to a certain length, outside diameter, and inside diameter. the weight is the only way to know what length a certain tube will draw out to. load cells are not an option for several reasons. x-ray is cost prohibitive, and the environment is awfully nasty for a light curtain. if anyone has any suggestions, they would be welcome. thanks.

I would use an LVDT (linear variable displacement transducer). You can buy units from LVDT vendors that take the input and either condition it to your desired output (4-20mA, etc.) or relay contacts for pass or fail. Or put the signal into a PLC, depending on the signal out of the LVDT.

You probably need to "capture" the strip with spring loaded rollers so the movement doesn't enter the equation.

Good luck! Hope this helps.

By the way, years ago I built panels for the company that made Floops. I worked with the engineer who co-held a patent on the accumulation calculation electronics process. Back then, we built PC (printed circuit) boards to house the electronics. Yeeezzz, have I forgotten a ton of that old stuff.

Hi Skunkcat,

From my experience you could consider using MTS Temposonic Sensors: http://www.mtssensors.com/index.html

Or you could consider MEL Laser Sensors: http://www.melsensor.com/

We use Vollmer gauges at our plant to measure the thickness of strip. They are not cheap. I have looked into a few others to get away from the cost of Vollmer, Marh Federal or Marh Poss i think?

Note that this is a very old thread

Bernie do you think he figured something out after 3+ years?

Jeff,

We may never know