Metrological solutions for an adapted inspection of parts and tools of a sheet-bulk metal forming process

Abstract

Processes of the new production technology sheet-bulk metal forming allow a fast and efficient nearnet-shape forming of highly complex parts. Thus the need of energy and raw material as well as the production cycle time can be reduced. In order to guarantee these advantages by avoiding scrap and moreover to ensure the parts' geometrical requirements, production-related metrological solutions for an adapted inspection of parts and tools of sheet-bulk forming processes have to be developed. To fulfill the demands of the differing measuring tasks two prototypical measurement solutions are under development: a multi-scale multi-sensor fringe projection system allows for holistic inspections in feature adapted resolutions, whereas a fiberscopic fringe projection system captures the forming tool partly between forming steps. For the purpose of evaluating the metrological solutions' capabilities of capturing the geometry of filigree structures a comparison of both systems is presented in this work. To guarantee realistic results, the performed measuring tasks have to be comparable to the areas of applications both systems were designed for. During the development of the measuring systems the emphasis was put on the inspection of small complex geometries. These are most challenging for fast and reliable optical inspection under productionrelated conditions. By considering measurements of calibrated standards on the one side as well as of measuring tasks resulting out of real sheet-bulk metal forming processes on the other side a realistic comparison is assured. Next to the measuring systems' performances also an approach for combining the measurement data of both metrological solutions is shown. By combining the advantages of both measuring systems, highly detailed information for further interpretations of the forming processes can be provided.

A 3D measuring endoscope for hand-guided operation

“…The measurement results demonstrate the adaptability of the sensor to different measurement tasks. A comparison using an earlier version of the sensor already demonstrated results comparable to non-endoscopic structured light sensors for micro geometries (GFM MicroCad) [36]. The evaluations performed in Section 4.1 using the conventional measuring mode and a sensor head with a working distance of 10 mm demonstrate the capability of the sensor to achieve accurate results at arbitrary positions in the measurement volume.…”

A Raspberry Pi Based Portable Endoscopic 3D Measurement System

“…So that a full measurement with eight images takes several seconds. The fringe projection system from Matthias [5] is faster because it uses an industrial camera, but is limited to a smaller resolution.…”

“…General Electric developed a fringe projection system with a fixed pattern projector and a chip on tip camera on a flexible shaft [4]. A similar measurement system was developed by Matthias [5]. It uses a bundle of 100,000 single fibers for projection and image acquisition and has therefore a more flexible measurement head.…”

Metal Forming Tool Monitoring Based on a 3D Measuring Endoscope Using CAD Assisted Registration

“…This is done by using a small and flexible measuring head. The system is based on the fringe projection approach in order to quantify the condition of sheet-bulk metal forming tools in an industrial environment [7]. An endoscopic sensor is needed to enable measurements while the tool remains inside the forming plant.…”