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Zürich, Switzerland

Tancogne-Dejean T.,Massachusetts Institute of Technology | Spierings A.B.,Inspire AG | Mohr D.,ETH Zurich
Acta Materialia | Year: 2016

An octet truss lattice material is designed for energy absorption purposes featuring an exceptionally high specific energy absorption, a constant plateau stress between initial yield and densification, and zero plastic Poisson's ratio. It is demonstrated through detailed finite element simulations that the meso-structural response of metallic lattice materials under compression changes from an unstable twist mode to a stable buckling free mode at a relative density of about 0.3. Furthermore, it is found that the nature of the macroscopic stress-strain curve changes from mildly-oscillating to monotonically-increasing as the meso-structural deformation mode changes, while a stress-plateau is observed at relative densities above 0.3. Since the specific energy absorption is a monotonically increasing function of the relative density, lattice materials of relative densities around 0.3 feature both a plateau stress and a high specific energy absorption capability. Prototype materials are built from stainless steel 316L using Selective Laser Melting. The basic building element of the micro-lattices are 2.2 mm long beams with a 500 μm diameter cross-sections. Detailed micro- and meso-structural analysis including tomography, microscopy and EBSD analysis revealed substantial local material property variations within the lattice structure. Compression experiments are performed under static and dynamic loading conditions confirming the anticipated exceptional energy absorption material characteristics for strain rates of up to 1000/s. © 2016 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Mayr J.,ETH Zurich | Mayr J.,Inspire AG | Muller M.,Reiden Technik AG | Weikert S.,Inspire AG
CIRP Annals - Manufacturing Technology | Year: 2016

The increased demand for complex precise workpieces requires 5-axis machine tools with a high thermal stability. In this paper a recently developed thermal error reduction technique especially designed for 5-axis machine tools is presented. With a touch probe system clamped in the machine tool spindle all relevant thermal position and orientation errors of the machine tool are measured. The ability of the touch probe system on the machine tool is investigated in detail. The evaluated deviations are used to adjust a compensation model used to reduce a selection of relevant thermal position and orientation errors during measurement cycles applied for validation. The model is of linear type and robust against numerical errors. © 2016 CIRP.

Eberle G.,ETH Zurich | Chiron V.,ETH Zurich | Wegener K.,ETH Zurich | Wegener K.,Inspire AG
Physics Procedia | Year: 2013

3D laser microprocessing using current market available technologies reveals itself to be a cost intensive and complex undertaking which is mostly due to the control architecture and use of moving components. Recent market appearance of electronically tunable lenses exhibiting NIR transmission, large aperture, high damage threshold and fast response times are available for laser based applications. Hence, enabling usage in the field of laser microprocessing. This paper thus introduces the functional principle of electrically tunable lenses, setup arrangement for 3D laser microprocessing, computational simulation of system parameters and comparison with experimental results. © 2013 The Authors.

Walter C.,ETH Zurich | Komischke T.,ETH Zurich | Weingartner E.,Inspire AG | Wegener K.,ETH Zurich
Procedia CIRP | Year: 2014

In the present paper, a novel conditioning method for superabrasive grinding wheels based on surface structuring with ultrashort pulsed lasers is investigated. A picosecond laser (pulse duration tp = 10 ps) is utilised to ablate regular micro patterns into the surface of CBN grinding tools, aiming to reduce grinding forces and improve grinding efficiency. The proposed structuring method enables a high degree of control and flexibility regarding pattern geometry and feature size. An analysis of the ablated structures does not reveal any significant thermal deterioration of the abrasive grits resulting from the laser process. Grinding performance and wear behaviour of the structured tools are tested in a face grinding process of hardened steel type 100Cr6 (60HRC). The test results show that the structured tools enable between 25 to 50% lower forces and significantly improve force stability in long-term grinding operation, due to an enhanced self-sharpening effect of the tool. However, the best surface finish is still achieved with the non-structured tools. The experimental results further indicate that the pattern geometry has a much stronger influence on the grinding behaviour than the degree of structuring (meaning the percentage of active wheel surface compared to a non-structured tool). © 2014 Elsevier B.V. © 2014 Published by Elsevier B.V.

Klahn C.,Inspire AG | Leutenecker B.,ETH Zurich | Meboldt M.,ETH Zurich
Procedia CIRP | Year: 2015

Additive manufacturing (AM) is a cyclic manufacturing process to create three-dimensional objects layer-by-layer directly from a 3D CAD model. Today AM processes like SLM and SLS are already suitable for direct part production. The processes have little restrictions regarding the shape of the object. The challenge to a designer is to use the unique characteristics of additive manufacturing in the development process to create an added value for the manufacturer and the user of a product. This paper presents two design strategies to use additive manufacturing's benefits in product development. A manufacturing driven design strategy allows a substitution of manufacturing processes at a later stage of the product life cycle, while a function driven design strategy increases the performance of a product. The choice of strategy has great impact on the development process and the design of components. Two cases are presented to explain and illustrate these design strategies. © 2015 The Authors.

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