Sensor for measuring web thickness?

[PLCRookie]

Hello all! This is my first post here, so please bear with me. I am a Manufacturing Engineer and I am looking fo a non-contact sensor to measure the thickness of a Web as it is fed into a machine. The material is a filter type media composed of basically paper fiber. The problem I am trying to solve is that the supplier of the paper is prone to "splice " the roll during production, and this causes us tremendous problems when we try to process it . The splice is almost always overlapped and then taped. This c auses my process to jam severly, resulting in about 20 minutes of downtime on each occurance. If I can detect the splice, and stop the machine, restarting takes about 1 minute. Until QC can resolve the problem with the vendor, I want to install some sensors to detect the thickness difference. The range is about 1mm for a correct piece, anything more than 1.5mm should be detectable. Anyone with experience with this kind of sensor?

All comments greatly appreciated!!!!

Thanks

 

[unclesyd]

There are several approaches that will do the job. Here are two that I’m familiar with. I think the Kaman is still in use.

http://www.kamansensors.com/html/products/appnotes/webthickness.htm

http://www.isravision.com/likecms.php?site=index.html&dir=isra&function=set_lang&lang=en

 

[bklauba]

Also take a look at Accuray:

http://www.abb.com/global/abbzh/abb...3BD96&e=us&c=9CBC5A080E8513EBC1256DE4003C3B99

BK

 

[tygerdawg]

Keyence

http://www.keyence.com

has some clever sensors for this purpose. Their catalog has an applications section with picutres of different methods of measuring web thickness.

TygerDawg

 

[PLCRookie]

Thanks All!!

 

[griffengm]

PLCCOOKIE,
From your description, it sounds as though a simple dancer arm to a limit switch could shut down the machine. Cheap and low tech.


Griffy

 

[fixfinder]

PLCCOOKIE I'd have to agree with Griffy usually the simpler the better. Simple and easily adjustable.... KD

 

[Taggy]

PLCRookie

As everyone has said always try for the easy solution, but also TygerDawg mentioned Keyence sensors i have used there sensors and PLCs alot and they are very good easy to set up etc try something like the VG series that keyence do but if you do go down that road speak to a rep and they will be happy to help.

Taggy

 

[PLCRookie]

Thanks all. I went with the keyence color sensor to make thing easier and more reliable, as the vendor doesn't seem to be able to control his process too well. Other sensor would have done it, but the color sensor worked best for all variations of material and splice colors. It also had 8 setpoint/outputs. I like to overkill when possible!!!!