25% less setup and measurement time through optical metrology
Winter sports enthusiasts are certainly already familiar with it. After all, it is hard to imagine any winter sports field without the red PistenBully from Kässbohrer, which ensures that slopes and cross-country ski trails are safe to traverse.
But how are the vehicles constructed, and what systems are used for quality control and the measurement of components? In the PistenBully family, the existing 3D coordinate measurement systems have been supplemented for some time by a portable HandySCAN 3D scanner and the MaxSHOT 3D photogrammetry system from Creaform.
Construction and Quality Control
A PistenBully consists of a large number of parts and complex geometric components. Some are developed in house at Kässbohrer, while others are supplied. For example, semi-finished products, cut-to-order steel sheets and even prefabricated steel constructions are welded together in Kässbohrer Geländefahrzeug AG’s own welding shop. Delivered components are assembled in the pre-assembly and final assembly stages. Like all PistenBully products, these are checked for conformity on a random basis or as required. The various parts and components are dimensionally measured with a 3D scanner. In addition, the entire vehicle undergoes a performance test with subsequent final inspection.
Driver Cab Frame Example
A PistenBully cab frame is mainly made of steel, which comes from various suppliers. The individual components of the frame can have sizes of up to 5 m³ and welding tolerances of up to +/- 2 mm. To ensure that everything has been manufactured in conformity with the dimensions right from the start, the welded construction of the cab frame is precisely measured when a vehicle goes into production, and afterwards only randomly or as required.
Due to the size of the cab frame and the amount of data to be recorded, the measurement is carried out in three stages: the left and right sections and then the middle section of the cab frame. For this purpose, the welded construction is cleaned and assigned targets. For contours that are dimensionally important, i.e. mounting surfaces, interfering contours for other components, sealing surfaces or joining surfaces, the HandySCAN 3D scanner with the VXelements data recording software is used for the measurement. For purposes of “leapfrogging” – i.e. component contours that are not needed, such as straight and flat surfaces, are skipped during scanning – the photogrammetry system MaxSHOT 3D is also used.
After a component has been digitized, a comparison is made in Polyworks with an existing 3D data set (CAD) so that any problem zones can be identified without having to check each individual part. The resulting off-color comparison shows the dimensional accuracy of the framework and thereby also the correct setting of the welding device.
Advantages of Optical Metrology
Armin Zinser from the Quality Center at Kässbohrer Geländefahrzeug AG explains: “We have been using a coordinate measuring machine in quality control for years. However, the portable optical measuring systems from Creaform allow us to measure flexibly and independently. They are easy to handle and can be used anywhere: in the measuring room, during assembly, as well as outdoors, while traditional measuring systems often require a rigid setup and cannot be used in all environments.”
“Our experience with the Creaform systems has been positive all around. They allow us to check mounting surfaces and components which have already been assembled more easily and quickly. Their systems also make it easier and faster for us to perform CAD matching of 3D contours with color comparison. All in all, we save 25% in setup and measuring time, and even more for corresponding components,” explains Mr. Zinser.
About Kässbohrer Geländefahrzeug AG
Kässbohrer Geländefahrzeug AG is the world’s leading supplier of all-terrain vehicles for slope, beach and environmental maintenance. These products stand for reliability and forward-looking technologies. With the SNOWsat brand, digital solutions for slope and fleet management are also part of their portfolio. The PRO ACADEMY guarantees resource-saving slope management. BeachTech beach cleaning equipment ensures clean beaches worldwide. With PowerBully, Kässbohrer is expanding its strong position in the commercial vehicle market even further. K COMPOSITES is a specialist and expert partner for fiber composite technology.