The containers with liquids and metal objects can be recorded reliably and quickly in UHF RFID bulk read operations.
The reliable detection of several RFID tags on a pallet is a challenge, particularly when different objects and liquids are involved. At tests on the verification of shipments with conventional RFID-UHF gates showed that not all substances could be read with sufficient speed and reliability.
The UHF RFID experts took up the challenge and were able to demonstrate with their shipment verification station that even ethanol containers and randomly oriented tags could be identified reliably and quickly.
In the logistics area, the answer to this question had for years inevitably been RFID. For larger ranges and the simultaneous recording of multiple tags with so-called bulk reading, only UHF technology can be considered. However, this technology presents a problem for liquids and metals. Both, liquid materials as well as metal containers such as barrels.
The company therefore had to first of all establish a solid basis of data from which it could be decided whether bulk readings with UHF-RFID could be used at all for the verification of the specific goods and primary products.
As part of this study ,they also carried out a proof of concept with regard to the question how well different chemicals and containers can be identified with UHF-RFID technology. In the test setup for this feasibility study, he tested the technology using examples of seven pallets that reflected the variety of containers and substances.
Variety of substances and containers tested
The first three test pallets contained cartons filled with glass bottles. The bottles on the first pallet were filled with ethanol, while those on the other two were filled with other solvents. The fourth pallet held ethanol containers made from plastic and pallet five two 200 liter metal drums. Pallet six carried eight smaller drums made from metal.
The test with this mixed pallet also included the examination of whether the read results are reliable even with the random positioning of the UHF tags due to optimized packaging processes.
The tests with a conventional RFID gate were promising. The detection of the ethanol pallets did however show differences to the detection of pallets with different solvents. Tags fixed to the inside of the ethanol containers in particular could not be reliably detected. The mixed pallet also presented problems for the conventional RFID gate.
We have had good results with our shipment verification station (SVS) in these kinds of applications.The SVS is a metal box on which the three walls and the ceiling are fitted with UHF read/write heads. The pallet with the objects to be identified is inserted through the remaining opening. “In the SVS we make use of the reflection of the waves on the metal walls. The effect is similar to that of a cabinet of mirrors. The electromagnetic waves are repeatedly reflected and thus also detect points on a pallet that cannot be reached by conventional RFID gates.”