48 research outputs found
PCPro a Novel Technology for Rapid Prototyping and Rapid Manufacturing
PCPro stands for Precise Cast Prototyping, which is a combination of casting technologies and
milling. This method was developed at Fraunhofer IWS in Dresden, Germany. It is patented in
Germany [1] and is applied in the USA under US 10/794,936. The main goal for this
development was to shorten the process chain for making plastic prototypes accompanied by
higher quality. The casting technology was integrated in a machining center in order to enable a
high degree of automation and to avoid an external casting system. This means that Rapid
Manufacturing can be easily implemented using such an automated combination of casting and
machining.
This article describes the PCPro method by means of the fabrication of sample parts. The
advantages and the limitations in comparison to common Rapid Prototyping and Rapid
Manufacturing process chains will be discussed. In addition, the manufacturing of a prototype
machine is presented.Mechanical Engineerin
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Sterelithography of Ceramics
For studies of Stereolithography of Ceramics (SOC), a composite has been produced by
mixing ceramic powder with a photosensitive resin. To obtain high load of ceramics a
lamination preprocess was used. Then, the produced ceramic-binder films have been laminated
and selectively cured in a Stereolithography machine. After cleaning, the green bodies were
fired to burn out the binder and afterwards sintered to achieve full strength.Mechanical Engineerin
Possible explanations for different surface quality in laser cutting with 1 micron and 10 microns beams
In laserăcuttingăofăthickăsteelăsheets,ăqualityădifferenceăisăobservedăbetweenăcutăsurfacesăobtainedăwith 1 micron and 10 micron laser beams. This paper investigates physical mechanisms for this interesting and important problem of the wavelength dependence. First, striation generation process is described, based on a 3D structure of melt flow on a kerf front, which was revealed for the first time by our recent experimental observations. Two fundamental processes are suggested to explain the difference in the cut surface quality: destabilization of the melt flow in the central part of the kerf front and downward displacement of discrete melt accumulations along the side parts of the front. Then each of the processes is analyzed using a simplified analytical model. The results show that in both processes, different angular dependence of the absorptivity of the laser beam can result in the quality difference. Finally we propose use of radial polarization to improve the quality with the 1 micron wavelength
Shared Metadata for Data-Centric Materials Science
The expansive production of data in materials science, their widespread sharing and repurposing requires educated support and stewardship. In order to ensure that this need helps rather than hinders scientific work, the implementation of the FAIR-data principles (Findable, Accessible, Interoperable, and Reusable) must not be too narrow. Besides, the wider materials-science community ought to agree on the strategies to tackle the challenges that are specific to its data, both from computations and experiments. In this paper, we present the result of the discussions held at the workshop on "Shared Metadata and Data Formats for Big-Data Driven Materials Science". We start from an operative definition of metadata, and what features a FAIR-compliant metadata schema should have. We will mainly focus on computational materials-science data and propose a constructive approach for the FAIRification of the (meta)data related to ground-state and excited-states calculations, potential-energy sampling, and generalized workflows. Finally, challenges with the FAIRification of experimental (meta)data and materials-science ontologies are presented together with an outlook of how to meet them
Langstroth hive construction with cement-vermiculite
Exfoliated vermiculite is a light-weight and cheap product that, because of its thermal resistance, has become a valuable insulating material. With regard to its use in beekeeping, this research tested whether the box for honey bees constructed with cement-vermiculite mortar (CVM) presents physical characteristics similar to those of wood. The experiment was carried out at Seropédica, RJ, Brazil, for eight months. The cement-vermiculite mortar was compared with a control material (pinewood), in the construction of Langstroth boxes and boards, in a completely randomized design, with respect to thermal control, thermal conductivity and its capacity to absorb and lose water. The production cost for a CVM box was estimated. There were no internal temperature differences between CVM and wooden boxes. Thermal conductivity values for CVM and pinewood were similar. CVM absorbed more water and lost water faster than pinewood. Since CVM boxes can be easily constructed, at a low cost and with similar characteristics as traditional boxes, made of wood, the material can be recommended for use in non-migratory beekeeping
Flexibel bearbeiten mit der Faser
Moderne Faserlaser mit Leistungen im kW-Bereich eignen sich besonders fĂŒr Anwendungen der Materialbearbeitung. Durch die besonders enge FĂŒhrung des Lichts in der Faser erreichen sie eine ĂŒberragende StrahlenqualitĂ€t. Dazu trĂ€gt auch die gleichmĂ€Ăige KĂŒhlung durch die FaserlĂ€nge bei, thermische Effekte werden dabei verhindert. Hohe StrahlenqualitĂ€t bedeutet insbesondere hohe Fokussierbarkeit, die wichtig fĂŒr die prĂ€zise Bearbeitung von WerkstĂŒcken ist. Dies gilt sowohl fĂŒr das Laserschneiden, LaserschweiĂen sowie HĂ€rten. Der Kurzaufsatz beschreibt die IWS- Scanneroptik zum Schneiden und SchweiĂen komplizierter NahtverlĂ€ufe mit dem Faserlaser
Remote-Schneiden mit dem Faserlaser ermöglicht hohe Konturgeschwindigkeiten
Beim Remote-Laserschneiden wird der Licht-Strahl von einem dynamischen Scanner bewegt. In Kombination mit einem Faserlaser, der sich besonders durch seine hohe StrahlqualitĂ€t auszeichnet lassen sich so Konturgeschwindigkeiten von ĂŒber 100 m/min erreichen. Damit ist der Faserlaser beim Schneiden von Metallen eine echte Alternative zum bisher favorisierten CO2-Laser
Verfahren zur formgebenden Bearbeitung von Werkstuecken
DE 102007002437 A1 UPAB: 20080729 NOVELTY - The shaping process for a workpiece (1) involves the use of a laser beam (2) angled to at least one axis in at least five degrees of freedom. The machining may take place on several parts of the workpiece at the same time. The surface topography of the workpiece is set in three dimensions, and the position coordinates are used to control the laser machining. USE - For shaping workpieces. ADVANTAGE - Shaping can be done more rapidly and with greater precision
Recent development in laminated tooling by multiple laser processing
The quick manufacturing of large metal forming tools, e.g. for car body parts, is a novel and promising application of the Metal-LOM technique. The acronym stands for "Metal Laminated Object Manufacturing", i.e. the metal variant of the established prototyping technique, which classically uses paper as build-up material. In the solution presented in horizontal or vertical layers by a specially developed software. Subsequently, steel sheets with a typical thickness of around 1 mm are cut according to these slices, stacked, and joined to a package. The steel slice are manufactured by high-speed laser cutting, and the joining technique can be laser welding, diffusion welding or other, mechnical/thermal combination techniques. In a laser integrated 5-axes CNC milling center, the active tool parts are clad with wear-resistant coatings by laser or plasma transferred arc cladding. Laser assisted plasma spraying is available for the tool's surface treatment as well. Also, smaller parts of the tools of complex shape can be produced by laser build-up welding directly onto the sheet package. In the end, the final contour of the tool is produced by CNC milling. The aims of the running research project are the reduction of tooling time from 16 to one week, tool dimensions in the meter-range and an application adapted tool life