The sensor detects packaged products on a conveyor and instructs the control system that a product is present and, given the standard speed of the conveying line, the control system can predict where the product is and tell a machine or robot to act on it e.g. pick it up, put it in tray; or place a label on it.
Reflective packaging
The company claims clear packaging and films are dream materials for food manufacturers, but ever-more transparent and reflective packaging can pose nightmares for production engineers tasked with detecting them accurately and reliably with optical sensors.
Phil Dyas, industrial sensor specialist, Sick UK, told FoodProductionDaily, if every product is not reliably detected on a conveyor, it could be mislabelled or sent to reject which can potentially cause excess wastage, or stop the production line.
“Optical sensors send a light beam light which is reflected back to the sensor, either from a reflector on the opposite side of the conveyor or directly from the object being detected,” he said.
“This works well if a product and packaging would have an opaque surface. However, if the packaging material is transparent or semi-transparent the light from a standard optical sensor may not bounce back reliably; it could be reflected away from the sensor or could travel through the transparent material.
“A standard optical sensor therefore may not reliably detect that every product on the line is present or establish its exact position on the line. If it can’t reliably detect an object on the production line it cannot communicate the object’s presence or position to the control system. If this is the case, then errors in the production process can be caused.”
Pick, place, & labelling
Dyas added the TranspaTect allows for quick and easy commissioning for food and beverage processes such as picking, placing, labelling and printing.
“Instead of a reflector, the metallic surface of a convenient machine component is used a reference surface. This innovation also opens up extra design freedom for packaging machine builders,” he said.
The sensor also comes with an AutoAdapt feature for sudden contamination of the lens by dust or product residue, and then re-establishes the original threshold levels when it is cleaned up.
The detecting range for transparent objects is 0 – 400mm and the background reference range is 150 – 700mm.
“The TranspaTect detects the presence of an object, even where the packaging is transparent or semi-transparent without the need for a special reflector on the opposite side of the line which would add to the expense and require special setting up and alignment,” he added.
IP66/67 rated, TranspaTect has ECOLAB certification of its resistance to aggressive cleaning regimes, disinfectants and chemicals for a long working life.
The rugged die-cast zinc housing (15.6 mm x 48.5 mm x 42 mm) is available with an optional PTFE chemical resistant coating.