I will start by explaining the problem to make my question clear.
During the production of diapers , the machine need continuous supplying material. So Butt Splicer is used to attached the end of expended roller with the start of the next roller using double sided tape. So in the production their will be a defected diaper ( a diaper which have a material with double sided tape on it. There is some methods to reject the defected diaper during the process . But to ensure that this diaper is rejected , a Metal Foil Tape is used with the double side tap, and a metal detector used after the packaging to reject the bag with the defected metal.
And here is the question,The client want to find these diaper s with metal while they are in the diaper bag without opening the bags and checking every diaper with the metal detector. A normal metal detector which will generate a magnetic field will detect if the metal is on the bag because of the shape of the magnetic field. So I need a sensing method with linear detection ( to scan diaper by diaper , So the scanning depth most by more that 20cm and the thickness at least 3mm.
The project summery:
A device to identify the position of a defected diaper in the bag.
A motor which is controlled by a microprocessor will hold the sensor (which I am asking about) to scan the diapers bag from the top side
(This picture is only for showing how the plastic poly-bag will be align from the top side) and once a metal is founded, a marker will mark the position of the diaper in the bag , so the operator could find the defected diaper and identify to the technician which material is not rejected in the process.