Gideon Levy

RAPID MANUFACTURING AND RAPID TOOLING WITH LAYER MANUFACTURING (LM) TECHNOLOGIES, STATE OF THE ART AND FUTURE PERSPECTIVES

Abstract Additive processes, which generate parts in a layered way, have more than 15 years of history. These processes are not exclusively used for prototyping any longer. New opportunities and applications in appropriate manufacturing tasks open up, even though the economical impact is still modest. This review starts with the definition of Rapid Manufacturing and Rapid Tooling, dealing only with direct fabrication methods of components. A systematic material dependent classification of layer manufacturing and process oriented metal part manufacturing techniques are proposed. The generic and the major specific process characteristics and materials are described, mainly for metallic parts, polymer parts and tooling. Examples and applications are cited. The paper attempts to understand the state of the art and the prospective, to put questions, to understand limits, to show opportunities and to draw conclusions based on the state of the art.

Influence of the particle size distribution on surface quality and mechanical properties in AM steel parts

Purpose – A recent study confirmed that the particle size distribution of a metallic powder material has a major influence on the density of a part produced by selective laser melting (SLM). Although it is possible to get high density values with different powder types, the processing parameters have to be adjusted accordingly, affecting the process productivity. However, the particle size distribution does not only affect the density but also the surface quality and the mechanical properties of the parts. The purpose of this paper is to investigate the effect of three different powder granulations on the resulting part density, surface quality and mechanical properties of the materials produced.Design/methodology/approach – The scan surface quality and mechanical properties of three different particle size distributions and two layer thicknesses of 30 and 45 μm were compared. The scan velocities for the different powder types have been adjusted in order to guarantee a part density≥99.5 per cent.Findings ...

Influence of Nd:YAG Parameters on the Selective Laser Sintering of Metallic Powders

Compared with CW CO2 laser sources, Nd:YAG lasers with Q-switching capability offer a wider parameter range, with improved sintering control, due to the short pulsed energy delivery. In particular, thermal diffusion being strictly limited by the nanosecond interaction between the energy pulse and the powder, higher accuracy can be achieved, while caking can be minimized. By systematically varying average power, scan velocity and repetition rate, process maps are established, for various materials, such as nickel and cobalt alloys, and titanium. Sintering depth and macrostructures are determined for different parameter sets. Basic models and physical explanations are given, for the various phenomena and consolidation processes. This mapping provides a correlation between the process parameters and the structure and properties of the produced parts. Results show that roughness and density are related to the pulsed energy delivery. For example, it is shown that multi-layer Ti samples can be sintered to a density close to 80 %.

On the use of SLS Tools in Sheet Metal Stamping

Abstract A few rapid tooling technologies have been recently proposed and among them Selective Laser Sintering is probably one of the most relevant and promising. In the paper, the authors report some results of a wide experimental research on the application of SLS tools in sheet metal forming. A wear test was earned out to investigate the progressive degradation of laser-sintered materials in comparison with traditional cold-work steels. In particular SLS tools were utilized in a sheet metal stamping process of S-shaped parts: their performances (in terms of tool wear and dimensional quality of the stamped part) were compared with the ones of traditional tools.

Additive manufacturing cost estimation for buy scenarios

Purpose To design for additive manufacturing (AM), the decision to use AM needs to be taken early in the product development process. Therefore, engineers need to be able to estimate AM part cost based on the few parameters available at this point in the process. This paper aims to develop suitable cost estimation models for this purpose, focusing on buy scenarios, as many companies choose to buy parts at service providers. Design/methodology/approach This study applies analogical cost estimation techniques to a data set of price quotations for laser sintering and laser melting parts. Findings The paper proposes easy-to-apply cost estimation models for laser sintering and laser melting for buy scenarios. Further, it generates new insights on the AM service provider market. Research limitations/implications The proposed models are only suitable for buy scenarios and are only a snapshot of cost achievable in 2014. Practical implications The proposed cost estimation models enable engineers to approximate AM part costs early in the product development process and thereby ease the decision to rapid manufacture certain parts. Originality/value This study addresses two gaps in the AM cost literature. It is the first study to take a qualitative approach to AM cost estimation, which is more suitable early in the product development process than the currently available quantitative studies. Further, it develops the first cost estimation for buy scenarios.

Digital Layer Manufacturing Chances and Challenges

The industrial expectation and future of the additive process, also DLM (Digital Layer Manufacturing) called, is the extensive use in Rapid Manufacturing (RM). These manufacturing technologies are at this point in time emerging. The tool-less economical manufacture of short runs plastic components is real life in several branches. These technologies emerge from the Rapid Prototyping and are on the way to Rapid Manufacturing, demonstrating great future chances. At the same time it puts forward several great research and development challenges. The paper, starting with background information, shows trends toward RM. Case studies from own research and experience as well as pioneer projects demonstrating the transition toward RM. The present challenges are discussed and considered alongside the technical and economical perspectives. Chances like “complexity for free”, individualization of design, mass customization and others are demonstrated, some final conclusions are stated.Copyright