Stuttgart, Germany


Stuttgart, Germany
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Gao X.S.,Shandong University | Wu C.S.,Shandong University | Goecke S.F.,Technische Hochschule Brandenburg | Kuegler H.,BIAS GmbH
International Journal of Advanced Manufacturing Technology | Year: 2017

The oscillating laser-GMA hybrid welding tests with lap joint configuration were conducted to observe the behaviour of welding arc, metal transfer and weld pool. Temperature distribution in the resultant lap joint was monitored. Based on the observations and the resultant morphology and geometry of weld bead, effects of three important process parameters, i.e. welding speed, laser beam oscillation and lateral distance of hybrid heat source relative to top sheet edge (LDHS), on the weld bead defects were examined. Consequently, occurrence mechanisms of the weld defects were proposed. LDHS influenced the defects such as non-uniform weld bead width, discontinuity and lack of fusion at top sheet, whilst the undercutting defect occurred at the top sheet if welding speed exceeded 6 m min−1. The laser beam oscillation could disperse the high concentrated power density of single-mode laser to avoid deep penetration channel through bottom sheet, but had little effect on the weld geometry. © 2017 Springer-Verlag London Ltd.

Baumeister M.,Nurnberg University of Applied Sciences | Scholz T.,Nurnberg University of Applied Sciences | Dickmann K.,Nurnberg University of Applied Sciences | Vollersten F.,BIAS GmbH
Journal of Laser Applications | Year: 2010

High-speed laser micro-perforation ("on-the-fly" technique) represents a processing technique for the time-efficient and cost-effective production of microsieves. In order to increase the perforation rate this process is researched with use of a brilliant laser source. These laser sources combine ample output power with an excellent beam quality. The high perforation rate [<50 000 drillings/s, laser source: YLR-300SM (IPG)], which can be achieved with this technique makes it an attractive option for the creation of large drilling matrices and drilling widths of less than 15 μm. The described experimental work is carried out to validate a theoretical analysis of the maximum obtainable perforation rate and its main influencing factors. It was found that Mie-scattering represents a crucial factor for the whole process with respect to the application of a brilliant laser source. © 2010 Laser Institute of America.

Kujawinska M.,Warsaw University of Technology | Kozacki T.,Warsaw University of Technology | Falldorf C.,BIAS GmbH | Meeser T.,BIAS GmbH | And 8 more authors.
Optics Express | Year: 2014

This paper presents the full technology chain supporting wide angle digital holographic television from holographic capture of real world objects/scenes to holographic display with an extended viewing angle. The data are captured with multiple CCD cameras located around an object. The display system is based on multiple tilted spatial light modulators (SLMs) arranged in a circular configuration. The capture-display system is linked by a holographic data processing module, which allows for significant decoupling of the capture and display systems. The presented experimental results, based on the reconstruction of real world, variable in time scenes, illustrates imaging dynamics, viewing angle and quality. © 2014 Optical Society of America.

Wang N.,BIAS GmbH | von Kopylow C.,BIAS GmbH | Falldorf C.,BIAS GmbH
Production Engineering | Year: 2012

We present an experimental approach to rapidly measure the 3D shape of a micro deep drawing part, which is based on a digital holographic contouring. Inline quality control in a micro deep drawing process requires a rapid and nondestructive measurement technique, which is the significant advantage of digital holography. The surface structure of the investigated object is dominated by the properties of the drawing process. Therefore, we investigate the statistical properties of the light scattered from the surface and show that digital holography is applicable in this case. Finally, we present experimental results which proof the big potential of digital holography in regards to the inspection of micro parts. It is shown that the field of depth can be considerably enhanced by combining several reconstructions associated with different observation planes from a set of two recorded holograms. © 2011 German Academic Society for Production Engineering (WGP).

Wang N.,BIAS GmbH | Falldorf C.,BIAS GmbH | Von Kopylow C.,BIAS GmbH | Bergmann R.B.,BIAS GmbH
Conference Proceedings of the Society for Experimental Mechanics Series | Year: 2011

Fast and accurate measurement of the 3D-shape of mass fabricated parts is increasingly important for a cost effective production process. For quality control of mm or sub-mm sized parts tactile measurement is unsuitable and optical methods have to be employed. This is especially the case for small parts which are manufactured in a micro deep drawing process. From a number of measurement techniques capable to measure 3D-shapes, we choose Digital Holography and confocal microscopy for further evaluation. Although the latter technique is well established for measuring of micro parts, its application in a production line suffers from insufficient measurement speed due to the necessity to scan through a large number of measurement planes. Digital Holography on the other hand allows for a large depth of focus because one hologram enables the reconstruction of the wave field in different depths. Hence, it is a fast technique and appears superior to standard microscopical methods in terms of application in a production line. In this paper we present results of shape recording of micro parts using Digital Holography and compare them to measurements performed by confocal microscopy. The results prove the suitability of Digital Holography as an inline quality control instrument.

Luepke S.H.,BIAS GmbH | Huke P.,BIAS GmbH | von Kopylow C.,BIAS GmbH | Bergmann R.B.,BIAS GmbH
Journal of the European Optical Society | Year: 2012

We present a method to record the wear on samples of micro deep drawing tools. The method is based on the basic idea of comparative holography and captures three dimensionally the surface of the tool in the initial state and compares it with used state after processing several parts. The comparison reveals scratches and other effects caused by wear. In an industrial environment the comparative method must compensate for linear and rotational displacement of the present tool with respect to the initial state. As a consequence to the single-step-measurement with sufficiently high illumination intensity the developed set-up can be made insusceptible against stray light and the method is capable of inline quality control during a production process in a micro deep drawing machine.

Focke O.,BIAS GmbH | Huke P.,BIAS GmbH | Hildebrandt A.,BIAS GmbH
AIP Conference Proceedings | Year: 2011

Standard ultrasound methods using a phased-array or a single transducer are commonly used for non-destructive evaluation (NDE) during manufacturing of carbon fiber reinforced plastics (CFRP) parts and certificated testing schemes were developed for individual parts and geometries. However, most testing methods need direct contact, matching gels and remain therefore time consuming. Laser-Ultrasonics is advantageous due to the contactless measurement technology and high accessibility even on complex parts. Despite the non-destructive testing with body waves, we show that the NDE can be expanded using two-dimensional surface (Lamb) waves for detection of delaminations close to the surface or small deteriorations caused by e.g. impacts. Lamb waves have been excited with a single transducer and with a short-pulse Laser with additionally producing A0-and S0-Lamb waves. The waves were detected with a shearography setup that allows for measuring two-dimensionally the displacement of a surface. Short integration times of the camera were realized using a pulsed ruby laser for illumination. As a consequence to the anisotropy the propagation in different directions exhibits individual characteristics like amplitude, damping and velocity. This has motivated to build up models for the propagation of Lamb waves and to compare them with experimental results. © 2011 American Institute of Physics.

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