A ready-to-install handling gantry from Festo is helping a fully automatic in-line alloy wheel testing system achieve high throughput rates in quality checks.
Alloy wheels should not only look great, but also contribute to a safe and enjoyable driving experience. Even the smallest air bubbles, pinholes or foreign bodies in the aluminium cast can cause the wheels to break, explains Felix Richter, engineer with Bavarian automation specialists Erhardt + Abt, who developed the ‘HeiDetect Wheel’, a fully automatic in-line testing system that offers significant benefits in mass production. At the heart of the system is an X-ray test system with a detector developed by the Fraunhofer Institute for Integrated Circuits (IIS).
The fully automatic testing system X-rays the cast parts for the tiniest of flaws, delivering fast quality checks thanks to a ready-to-install handling gantry.
Festo’s handling gantry is responsible for delivering the high process speed, transporting up to 140 wheels per hour through the system. It was implemented according to the exact specifications of Erhardt + Abt.
According to Richter, the system has an extremely compact design with the distance to the housing at some points being just 2-3mm. Festo delivered the gantry as a ready-to-install unit, requiring Richter’s team to simply connect up the interfaces and base plate of the system and then mount the radiation-safe steel-lead-steel chamber on top.
Before the wheel enters the system, an upstream station reads its technical data, including diameter and height, using a bar code. The gripper unit in the X-ray cabinet gets ready for action in accordance with the registered values and moves into the optimal position. As soon as the partition opens and the alloy wheel enters, the gripper grasps it using its support wheels. A multi-position cylinder ADNM ensures a perfect grip by adapting the movable front pair of rollers precisely to the wheel size. Two servo motors of type EMMS turn the wheel clockwise around the hub during the X-ray process to ensure even the smallest details are recorded.
Including the fixed alloy wheel, the gripper supports up to 168kg. Wolfram Turnaus, sales engineer at Festo was responsible for ensuring that the gantry construction had the necessary rigidity and dynamic response, especially since the operating temperatures could fluctuate between 15°C and 60°C depending on the time of year and throughput.
He also needed to find high performance cushioning for the 90kg partition since it dropped like a trap door in just 0.6 seconds as soon as an alloy wheel entered the X-ray cabin. Turnaus decided to use a cushioning block since it held a certain air volume, enabling the partition to fall into an air cushion.
The entire system including its steel-lead-steel outer shell weighs 6.2 tonnes. To prevent X-rays from escaping when the partition is opened, the system restricts the X-ray voltage, which also significantly increases the service life of the X-ray source and also eliminates the need for an upstream double door system.
Felix Richter is very pleased with the end result as the Festo solution not only gives them the freedom to concentrate on other tasks, but also contributes to the construction of one of the fastest wheel testing systems on the market.