FLIR thermal imaging cameras are being employed in automotive quality control at the BMW plant in Dingolfing.
Robert Halbritter of FLIR Systems’ sales partner and integrator, TOPA GMbH explains that FLIR has been supplying thermal imaging cameras for thermal inspection to the BMW plant since 1997. Primarily used for thermal electro-thermography of switch cabinets and rooms, BMW is now also using FLIR thermal imaging cameras for quality control.
New vehicles are subjected to a number of individual and automated quality control measures including analysis in one of ten separate roller dynamometers. Basic functions from signal horn to engine-specific performance are thoroughly tested, as is the BMW Night Vision System, based on a FLIR detector. The entire process just takes a few minutes, during which each correct function has to be confirmed either automatically or by an inspector who sits in the vehicle monitoring displayed inspection data.
The tests vary in both type and duration according to the specification of each model and are programmed to be conducted in an automated sequence.
While cost- and time-efficient testing is the common goal, identifying the optimum procedure for each inspection task needs individual consideration. For instance, twin tail pipes are a feature of the high performance BMW vehicles with large 8-cylinder engines. On the BMW M5 model, the requirement is different as the exhaust flap on the second tailpipe is only activated at a specified RPM.
To check the efficiency of this operation, BMW employed thermal imaging cameras of a different brand to FLIR for each dynamometer rig to visualise the thermal profile of the respective tailpipes in the dual pipe exhaust system.
Each system comprised of two thermal imaging cameras, mounted to inspect the left and right tail pipes from above and the side. The solution was not only expensive to buy but costs also increased with time as the cameras required frequent repair. After eight years the viability of a new system was therefore evaluated.
Robert Halbritter of TOPA GmbH offered a very attractive solution that would halve the cost of new camera hardware. He recommended the use of a single, fix-mounted FLIR A310 with a 45° lens for each dynamometer. This was possible as the field of view of the FLIR A310 with 45° wide-angle lens was capable of showing the entire end of the vehicle from a distance of approximately two metres. As a result comprehensive inspection could be conducted with just 10 cameras, one for each dynamometer, instead of the 20 units required by the previous system.
The FLIR A310 generates an analogue thermal imaging video signal with a frame rate of 30Hz. This model is particularly suited to recording exhaust flow as it is simple to integrate and provides easy access to PAL video.
Christoph Hörnlen, who is responsible for fixed thermal imaging cameras for automation applications at FLIR Systems GmbH, explains the FLIR A310 has a digital output for alarms and for controlling external devices. The data can also be transmitted via TCP IP or Ethernet; the FLIR A315 even supports the GigE Vision standard as well as the GeniCam protocol.
The performance of the exhaust system is checked on a monitor in front of the vehicle, which displays a thermal image. From this the inspector can see if the flap is functioning properly from changes in the thermal profile. Even though the FLIR A310 can visualise heat distribution using various colour palettes, the simplest and clearest option of black and white is used in this application.
The reason for this is the irregularity in air flow of the exhaust streams. A relatively high amount of air is displaced and the exhaust stream does not remain constant. The flow rate also has to be taken into consideration. These are all factors that could be visualised using a wider colour spectrum but could serve to confuse the inspector. In the final analysis all that is required of this test is confirmation that the flap is opening and closing correctly.
BMW switched to the FLIR camera solution suggested by TOPA based on the supplier’s good reputation for quality service and post-sales support. BMW was also impressed with the technical implementation of the solution.
The reliability of the FLIR A310 speaks for itself. The first FLIR camera systems were installed in the autumn of 2011 and have been in operation, round the clock since then. Although they are not always needed between 23:00 hrs and 05:00 the next day, they are always on true 24/7 operation. A spare FLIR 310 camera supplied in case an urgent replacement is required has never been used.
FLIR thermal imaging cameras are available in Australia from FLIR Systems Australia .