Industrial 3D Scanning
The efficient full-field 3D scanning of manufactured parts is more and more required not only in quality inspection but also in design, CAD construction and rapid prototyping. The capturing of digital surface data with high point density of parts, tools and design studies is necessary for digital subsequent processing respetively for the variance comparison to target models (e.g. CAD).
In comparison to dimensional tactile coordinate measuring technology optical 3D sensors can capture the complete surface data in short time. Achieving measuring accuracies up to approx. L / 15.000 and camera resolutions multiple Mio pixels optical 3D sensors can be applied in development as well as in sampling and serial inspection.
White light projection
White light projection bases on the triangulation principle which is similar to the human stero-vision. With help of a projector different black-and-white-striped pictures are projected onto the object which are recorded by two cameras in stereo arrangement. To capture a complex object normally several pictures from different perspectives are necessary. All taken single pictures are transferred fully-automated in one global coordinate system by so called reference targets. Respective reference targets can be generated either by stationary reference cameras or by fixing physical targets on the object, the object plate or the respective object clamping. The final measuring data is available as point cloud (ASCII, PLY, PIF, GPD etc.) or STL polygon data.
3D quality inspection and surface reconstruction
Within the field of quality inspection full-field 3D scanning data is primarily used for variance comparisons to digital design (CAD) models. Beside this coloured deviation analysises it is also possible to determine 2D dimensions on sections, to make GD&T evaluations according to DIN 1101, to check the wall thickness of complete parts or to apply numerous further evaluations. The alignment to the CAD coordinate system can be done by 3-2-1, RPS, feature-based or per bestfit.
Beside inspection tasks it is possible to create digital models from scan data of physical parts (surface reconstruction or reverse engineering). The reverse engineering enables the efficient creation of parametric surface models which consist of square and quasi-rectangular NURBS patches that can be exported to standard IGES or STEP data format. Reconstructed surface models are equivalent to CAD generated 3D objects which can be downstreamed with popular CAD design software packages without problems.
Self-calibration and automatization
Generally structured-light projection sensors can be run as pre- or self-calibrated systems. By self-calibration where applying photogrammetric methods the calibration procedure runs as a sub-process of the overall measuring process. Precise guiding mechanics or physical reference targets are not required. Temperature instabilities do nearly have not affect on the calibration of the measuring machine. Therefore the robust self-calibrating 3D measuring machines are suitable for running in production environment.
Because there are no demands on the accuracy of guiding mechanics a cost-saving automation respectively integration in production process can be realised. An automation can contain the integration of robots, rotating or translating object stages or portal solutions.
Applicationens of 3D measurement can be found in Industries.