Sensor to detect plastic film, edge detection

[MyMack]

Hello,  Could someone please recommend a TOF sensor(or other) for reliable plastic sheet detection.

Application: Measure the width of a sheet or film of plastic in production environment.  We would use  two sensors to detect the edges of the film.  We would move the sensors in/out on a carriage mechanism until the edge is detected. Continuous measurement,  plastic film would be passing by the sensor(s).

              Sensors to be mounted between 5 and 20mm from target, plastic film.

               Sensors must be able to detect all types of plastic, from clear or transparent (eg. Cling film) to black (bin liners)  IR light source?

              Sensors must detect presence or absence of plastic film so that edge can be known.  Carriage movement then gives width.

Want to measure width of film with precision of 1mm or better.

I have looked at VL53L4CD for example.  Would this work?  Also looked at the demo video with the 53L0x, but distance range most likely tooo long. Can you recommend a different or better TOF sensor for this application please?

Michael.

[Andrew Neil]

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@MyMack wrote:

it would not be acceptable for the nozzle to touch the plastic.

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isn't the plastic already running over rollers/bars?

[MyMack]

Yes,  the plastic is running over rollers. But there is a difference between that and an air nozzle traversing across the film,  where there might be the possibility of tearing or scratching.   But on second thoughts,  perhaps the nozzle could be built into some form of plate that the plastic could roll across. It is a new concept for me.   I am trying to think what air pressure,  and what pressure sensors could be used.  And what precision (mm) edge detection could be achieved.

[Andrew Neil]

I didn't suggest a nozzle. I said a bar with a hole in it - something like this:

http://www.decodesystems.com/ce-punched-readers.html#:~:text=have%20been%20omitted.-,AIR%20SENSING,-1.%20An

(that shows vacuum; I suggested pressure)

Instead of detecting a  hole in the material, you're looking for the edge of the material

As you can see from the article - it's actually a very old concept!