The zero-defect production is the goal of every manufacturer. As a pioneer in production automation, the automotive industry has always been a leading force, when it comes to efficient production process and quality controls. But not everything can be automated one hundred percent — and where manual processes are required, potential sources of error arise. This is also true with the inspection of automobiles for leaks. With the current test methods for leakage tests, some faulty vehicles are still not detected and delivered to the customers. This is no longer the case as Turck offers a solution to ensure that each vehicle is leak proof when it leaves the production hall. Any costly rework is no longer required.
Relative Measuring Detects Humidity
Together with its partners Smartrac and Vilant, the company offers a solution for fully automated leakage testing. The system is based on UHF RFID technology and detects all leakages in car bodies without the need for any manual intervention. For this, the car body is fitted during the production process with self-adhesive tags at relevant points, which react to humidity.
Before the vehicle is driven into the rain spray chamber as part of the final inspection, it first of all goes through an RFID gate which registers all the tags. After the spraying process, the car goes through a second RFID gate at the exit, which in turn reads in all the tag data. If humidity has penetrated at any point, the system detects a discrepancy between both read operations and sends an appropriate fault message to the MES system of the user. Car bodies that are affected can as such be removed directly and reworked.
In close collaboration with an automobile manufacturer, the company has drawn up a requirements profile for the system solution for leakage testing. Once the initial test phase is successfully completed at the user and the feasibility determined in the actual application, it hands over the functional turnkey leakage testing solution.
Project partner Vilant is responsible for the provision of the gates and the integration in the MES system of the user. The Finnish company is a supplier of turnkey RFID information systems for production and logistics applications. The sensor tag for detecting humidity was developed and produced by project partner Smartrac. The Smartrac Technology Group is a developer, manufacturer and supplier of RFID inlays and solutions based on the Internet of things.
The passive UHF-RFID sensor tag can be stuck directly on metal and later also read in positions that are difficult to access in spite of the surrounding structures of the vehicle. Thanks to this capability and its compact format of 21.5 x 73 mm, the self-adhesive sensor tag can be mounted without any problem at many points in the car body. If areas have to be monitored where direct mounting is not possible, tag variants with extension strips are available in different lengths. The water reaches the tag via the extension even from places that are otherwise inaccessible.
If the tag detects humidity, it reacts with a change in impedance, which is registered by the RFID read/write heads in the gates. A powerful evaluation software enables the affected point in the vehicle to be localised precisely by means of the collected data. In Europe the tag works in the 865 to 868 MHz frequency range. Being a passive RFID sensor tag, it does not require a power supply and can remain in the car for its entire lifetime so that it can be read again at any time. The tag draws the required energy from a handheld or the read/write heads of the gates.
The fully automated quality control in the production line reliably excludes user faults resulting from manual operations. Faulty vehicles are immediately detected and removed. All detected data is available directly in the MES and ERP system of the user. As only checked vehicles which have been verified as leak-proof are delivered to the customer, complaints from the customer about leaks are a thing of the past. As such both the customer and the brand can benefit from the increased level of quality.