Damaged pallets have to be detected before they are sent back out into the world again. Reflex array sensors can detect all kinds of pallets and reduces the investment of sensors in comparison to a small light grid.
Chep distributes, collects, cleans and repairs pallets and containers. Things are extremely busy at Chep´s Belgian site in Bornem. The question is how do they detect damaged pallets?
The handling machine at Chep in Bornem processes 900 pallets an hour, in both the 1200 x 800 mm and the 1200 x 1000 mm versions. Thanks to two detection positions, both dimensions are covered. Chep, refuse to allow damaged pallets back into circulation.
A firstly installed small light grid was too sensitive against dust in the air coming from transporting the pallets. The ambient conditions were underestimated. Therefore the detection of the pallets was not efficient and caused delays in the transport of the pallets sometimes.
The reflex array sensor has a longer scanning range and a continuous adjustment of the switching threshold in comparison to the installed light grid. But the detection height of the WL27-3 reflex array sensor is 50 mm instead of 100 mm of the light grid. Chep´s engineers mount two WL27-3 one on top of the other, so that they always detect a height of 100 mm.
Such a light array can detect a pallet perfectly, even if (for example) one block of the pallet is missing. Due to the continuous automatic adjustment of the switching threshold the sensor still works perfectly after 4 months operations in that harsh, dusty environment.
Thanks to its 50 mm detection height, the new photoelectric sensor from Sick , the WL27-3 reflex array sensor, detects even broken pallets. Thereby it helps Chep to increase the availability of the pallet conveyor and keeps it on that high level.