RFID at ProfTech

ProfTech BV in the Dutch city of Hengelo, a manufacturing company for hydraulic systems, is supplying its products to the automotive industry as part of the convertible roofing system for cars.
This manufacturer needed an automatic identification system for its assembling parts and found out that RFID brings the best solution.

The process involved

ProfTech assembles the hydraulic kits in a specific way, which divers from car type and car brand.
The final assembling of the hydraulic kits is done mechanically where, per brand and type of car, the machine is altered with different forms and tooling.
Visually these forms and tooling are hardly to identify, especially the pistons are look-a-like and the differences are minor. However, before starting the machine a visual time consuming check needs to be done and is not foolproof.

Another approach

Staff at ProfTech asked themselves whether it would be possible to identify the individual forms electronically and preferable in process.
There were however difficulties. Many parts in the machine are moving while the process is ongoing, leaving only little or no space at all for sensors.
The manual process of laying the parts in the machine should not be interrupted or as less as possible.
The machine is build out off stainless steel, aluminium and plastic. So are the different forms and tools. Barcode stickers will wear off and are difficult to read in this environment.
And last but not least, the production environment is very noisy.

Solving the problems

It was Dutch RFID consultant Frits van Calker who was asked to help solve the problems.
Frits says that several field tests have given hem the idea how to use RFID transponders creating an usable solution for electronically identifying of the individual forms and tools.

The RFID solution

All tools and forms are fitted with a dedicated, low frequency 125kHz transponder, holding a pre-programmed number. Per hydraulic kit these numbers make a unique table.
Software in the PLC process controller does check all the needed transponder numbers per production batch and starts scanning for the individual forms by a RFID system in advance of its production run. Only if all the scanned numbers do match the complete table in its memory the machine will be enabled to start its production process.

The operator

The system operator scans the forms manually with a short stick antenna after all the forms are installed in the machine. This manual scanning is the only solution due to the lack of space in the machine.
It also allows modifying the existing machines with this system without major work done on the machine itself.

Little stick antenna

The little stick antenna is showing a LED when recognising a transponder and because of the noisy environment there has been added a vibrator in the grip to feel the transponder recognition too. Just like a mobile phone does vibrate when ringing.
The actual reader is fitted in the cabinet at app. 3 meters distance, and linked with the PLC via RS232 communication. The whole system was supplied to ProfTech BV as a plug and play system.

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