Optical three-dimensional metrology, an innovative machine vision technology, helps to overcome the recession crisis

IndustrySouth-East European INDUSTRIAL Мarket - issue 6/2008

Dr. Norbert Bauer, Fraunhofer-Allianz Vision
Dr. Dirk Berndt, Fraunhofer IFF

Engineers from the Fraunhofer Institute for Factory Operation and Automation IFF are working together with a lot of European companies on an improvement of the manufacturing processes. To improve the competitiveness of the companies they developed innovative technologies to acquire dimensional features directly inline of the manufacturing line. Their aim is to integrate this technology so that defects can be uncovered during production and can give an input to real time quality loops. "Since a lot of manufacturing steps are ready every some seconds, one of the main tasks when developing this technology was to ensure data was recorded quickly to monitor quality. In such circumstances, optical three-dimensional metrology was the only viable option," explains Dr. Dirk Berndt, head of the business unit of Measuring and Testing Technology of the IFF in Magdeburg. Other requirements meant that the technology had to carry out a full inspection, provide reliable feedback on existing defects, be easy to use and interface with existing process control systems. And all that without adding substantially to the manufacturing cycle.
"Industry is therefore crying out for optical three-dimensional inspection techniques", according to Dr. Dirk Berndt. "The processes are fast, contactless and can often be integrated directly into the production process." The automotive and auto components industry in particular are increasingly using optical inspection techniques, a view borne out by the market study on three-dimensional metrology in the German automotive and auto components industry compiled by the Fraunhofer Network ’Vision’. Two thirds of the companies surveyed are already using 3D measurement equipment. 31% even use nothing but non-contact measurement processes. And the figure is likely to increase.
Some examples of applications show that this technology is not specialized to special branches. The  Engineers realized solutions for the aircraft, the automotive, consumer as well as railway industry.
The interaction between wheel and rail during rail vehicle operation causes enormous stresses to act on the wheels. Wheel geometry, the wheels’ radial runout and axial runout, the distance to the inner wheel face and the surface quality of the running surface are quality parameters crucial for a rail vehicle’s operational reliability and a high quality ride. As vehicle speeds increase, using objective metrological acquisition to assure defined quality parameters is extremely important both when wheelsets are manufactured and when they operate. Wheel and wheelset wear are still being measured using manual inspection, which can neither assure that all quality parameters are reliably and comprehensively measured nor that they are documented.
By contrast, automatedly acquiring all the wheelset’s geometry quality parameters makes it possible to capture objective and comprehensive data and document it in only a few minutes.
Profiled materials, such as U, I, square and round profiles or others are used as base material in a multitude of products. As a rule, such raw materials are manufactured in the extrusion process by drawing or rolling. For different applications, the raw material is not straight enough and mechanical straightening is necessary before further processing. To determine which profiles are to be straightened in what way or which can be further processed without straightening, an inspection of the straightness is needed.