I’m looking for a way to measure the width of a 38” sheet of aluminum as it is feed into a stamping press to a tolerance of .050”. The sheet does have about a half inch of movement side to side where we want to make the measurement before it enters the press. This can not be a new concept but I am having trouble finding a place to start so any help would be greatly appreciated.

Thanks in advance,
Steve

 

A pair of inexpensive cameras could easily provide this precision if the speed isn't too high. You could also correct for skew. One expensive camera could do it, but two with normal optics would be more cost effective. With a one inch FOV, each camera could resolve to within 3 or 4 thousandths with high certainty. If you're interested
I can flesh this out a bit.

Regards

cww

 

Hello Steve,

Take a look here for ideas, you can download lots of literature.

http://www.keyence.com

Roddy

 

With the accuracy you want, mounting of sensors and control of the sheet will be major concerns. Generally you can do this with two sensors one on each side that measure the location of the edge and software that calculates the width from these measurements and the distance between the sensors. If the edge of your sheet flutters you may find that the flutter exceeds your accuracy requirement. Also things like vibration from the press may cause problems. Try people like Banner, Cognex, STI for solutions.

James Bouchard

 

Sorry by my bad english...

I use two inductive sensors for non ferrous material, with a controller with mathematical functions...
More resolution in sensor is much better...
I applied sensors with 1 micron in resolution.

Best regards

Manny

 

Hi Steve,

One of fiber photoelectric Keyence sensors maybe used for edge detection (only one sensor is enough for detection of both sheet edges). The focusing lens maybe strongly suggested for your application.

Also modern motion controllers with Position Capture feature allows precise synchronize of both edge positions for accurate measurement of sheet length.

best wishes,
Leonid

 

Sunx has a "GD" series sensor which uses 2 sensor heads to verify thickness or single vs double sheet feed.

Sunx also has the HL lasers to measure thickness with 2 sensor heads with 12 controller for about 2/3 the price of Keyence.

If you are worried about cost, Balluff has a line of Ultralinear Inductive prox sensors that give a 0-10 V output and up to 2 micron accuracy for a low $150 list price.

Thanks,
Christian Dow