Library

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    Semi-Solid Extrusion of Complex-Shaped Steel Rods Using Ceramic Dies (2008)
    s.l. ; Stafa-Zurich, Switzerland
    Solid state phenomena Vol. 141-143 (July 2008), p. 243-248 
    Details
    ISSN: 1662-9779
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Physics
    Notes: Isothermal semi-solid extrusion experiments using steel grade X210CrW12 as work materialwere performed on an industrial forging machine. An improved and up-scaled tool design wasapplied, based on the concept of self-heating ceramic dies tested in previous laboratory-scale studiesand allowing for die preheating temperatures of up to 1400°C.Steel rods of complex cross sectional geometry were formed at low extrusion forces. Shape accuracyof as-formed rods is accurate and metallurgical examination yields no evidence of liquid phaseseparation. With a view on the intended industrial implementation construction of ceramic tools hasto be improved in order to avoid rupture of ceramic parts due to thermo-mechanically induced stressesand to benefit from the advantages inherent to ceramics in metal forming
    Type of Medium: Electronic Resource
    URL: http://www.tib-hannover.de/fulltexts/2011/0528/02/24/transtech_doi~10.4028%252Fwww.scientific.net%252FSSP.141-143.243.pdf
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Process Window Determination for Thixoextrusion ProcessesUsing a Steel Alloy (2008)
    s.l. ; Stafa-Zurich, Switzerland
    Solid state phenomena Vol. 141-143 (July 2008), p. 61-66 
    Details
    ISSN: 1662-9779
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Physics
    Notes: A direct semi-solid bar extrusion process is characterised by inserting a feed stock in acontainer and extruding through a forming die with a punch. Compared to conventional barextrusion the use of semi-solid material complicates the process due to the requirement ofsolidification of the material. To achieve the solidification of the semi-solid bar, different basic toolconcepts are presented. With a combination of these concepts experiments were carried out usingthe steel alloy X210CrW12 to detect the influence of the most influencing parameters pressvelocity, extrusion channel diameter, length and geometry. Numerical simulations enable a betterunderstanding of the process mechanics like temperature development in the billet and forming dieas well as the material flow in the deformation zone
    Type of Medium: Electronic Resource
    URL: http://www.tib-hannover.de/fulltexts/2011/0528/02/24/transtech_doi~10.4028%252Fwww.scientific.net%252FSSP.141-143.61.pdf
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Investigations on Thermal Influencesfor Thixoforging and Thixojoining of Steel Components (2008)
    s.l. ; Stafa-Zurich, Switzerland
    Solid state phenomena Vol. 141-143 (July 2008), p. 37-42 
    Details
    ISSN: 1662-9779
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Physics
    Notes: At the Institute of Metal Forming (IBF) current investigations within the framework ofthe Collaborative Research Centre 289 are mainly concentrated on forming of semi-solid precursormaterial of the steel grades X210CrW12 and 100Cr6. One important task is the precise temperaturefor the composition of solid and liquid phase fraction in the preheated billet. Experimentalmeasurements and numerical simulations show significant heat losses during transport of the billetand after its insertion into the die. These developing temperature gradients influence strongly theresulting temperature field in the formed component. In case of the forming tools the criticalincrease of the temperature depending on the tool material is shown. As fundamental research in thefield of thixojoining the temperature development of the inserts is analysed and demonstrates thefeasibility of joining higher and lower melting materials into the semi-solid matrix
    Type of Medium: Electronic Resource
    URL: http://www.tib-hannover.de/fulltexts/2011/0528/02/24/transtech_doi~10.4028%252Fwww.scientific.net%252FSSP.141-143.37.pdf
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    A New Incremental Sheet Forming Process Based on a Flexible Supporting Die System (2007)
    s.l. ; Stafa-Zurich, Switzerland
    Key engineering materials Vol. 344 (July 2007), p. 607-614 
    Details
    ISSN: 1013-9826
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Nowadays many industrial sectors use forming processes in order to produce sheet metalcomponents. The most widely used processes are stamping and deep drawing, which are based onbig, costly dies and presses. These processes require large initial investment and specific dies foreach part, which makes them inflexible and only profitable for large batches. A possible approachto small series production is based on the incremental sheet forming technique (ISF), which consistsof a gradual plastic deformation of flat sheet metal by the action of a CNC controlled tool.Equipment such as a 3-axis milling machine can be used for ISF, such that the initial investmentcosts in ISF are around 5-10% of those required to set up a production line for conventionalstamping. In its current stage of development, dedicated dies are often used as support tools in ISF.However, due to the fact that the forming forces are low in ISF, the dies can be made out of cheapmaterials like resin or wood. Although this is an additional advantage over stamping, the need touse additional tools still reduces the flexibility of the process.The present paper details the concept of a truly “dieless” incremental forming process. In theframework of the SCULPTOR EU project, the authors are working on an innovative concept ofincremental sheet metal forming which is based on the replacement of the commonly used dies by asecond forming tool which moves in a coordinated way with the first forming tool, thus creating aflexible die system, which does not depend on the specific geometry of the part to be formed.The present work summarizes the results obtained up to now in two fields: (i) the developmentof a prototype for the flexible die system to be included both in milling machines or combined withrobots and (ii) process modelling to improve the understanding of the process
    Type of Medium: Electronic Resource
    URL: http://www.tib-hannover.de/fulltexts/2011/0528/01/54/transtech_doi~10.4028%252Fwww.scientific.net%252FKEM.344.607.pdf
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Analysis of Size-Effects in the Miniaturized Deep Drawing Process (2007)
    s.l. ; Stafa-Zurich, Switzerland
    Key engineering materials Vol. 344 (July 2007), p. 791-798 
    Details
    ISSN: 1013-9826
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: With the increasing trend towards miniaturization and the enhanced demand for smallcomponents, reliable processes for mass production are needed. Today the deep drawing process isalready used to produce large numbers of small parts (diameter 〈 1 mm) at low costs per part. But abetter understanding of the process in relation to miniaturization is required to improve processstability, because several aspects of the process change when scaled down. For example, productaccuracy and process parameters can be influenced by changing the ratio of surface to volume or theratio of grain size to foil thickness. For the analysis of these effects experiments with geometricallyscaled deep drawing tool sets from 8 mm to 1 mm punch diameter have been carried out, usingCuZn37 foils in different annealed conditions and a foil thickness ranging from 0.3 mm to 0.04 mm.Additionally, the deep drawing process is simulated via FE-methods to consider influences thatcannot be measured using the available experimental setup, such as temperature conditions resultingfrom the heat generated due to plastic dissipation and friction
    Type of Medium: Electronic Resource
    URL: http://www.tib-hannover.de/fulltexts/2011/0528/01/54/transtech_doi~10.4028%252Fwww.scientific.net%252FKEM.344.791.pdf
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Metal Flow and Die Filling in Coining of Micro Structures with and without Flash (2005)
    s.l. ; Stafa-Zurich, Switzerland
    Advanced materials research Vol. 6-8 (May 2005), p. 631-638 
    Details
    ISSN: 1662-8985
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: The continuing miniaturization of production systems and products poses a challenge for metal forming technologies to produce precise small scale products with microscopic geometric details. Thin metal plates with channel structures are considered to be typical examples for microfluidic applications [1,2]. In this study the coining process of sheet metal to produce channel and rib structures is examined in terms of geometrical die parameters and tool design. For this reason extensive experimental series and numerical simulations have been realized and evaluated
    Type of Medium: Electronic Resource
    URL: http://www.tib-hannover.de/fulltexts/2011/0528/01/41/transtech_doi~10.4028%252Fwww.scientific.net%252FAMR.6-8.631.pdf
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Experimental and Numerical Analysis of Forming Limits in CNC Incremental Sheet Forming (2007)
    s.l. ; Stafa-Zurich, Switzerland
    Key engineering materials Vol. 344 (July 2007), p. 511-518 
    Details
    ISSN: 1013-9826
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Asymmetric incremental sheet forming (AISF) is a relatively new manufacturing processfor the production of low volumes of sheet metal parts. Forming is accomplished by the CNCcontrolled movements of a simple ball-headed tool that follows a 3D trajectory to gradually shapethe sheet metal blank. Due to the local plastic deformation under the tool, there is almost no draw-infrom the flange region to avoid thinning in the forming zone. As a consequence, sheet thinninglimits the amount of bearable deformation, and thus the range of possible applications. Muchattention has been given to the maximum strains that can be attained in AISF. Several authors havefound that the forming limits are considerably higher than those obtained using a Nakazima test andthat the forming limit curve is approximately a straight line (mostly having a slope of -1) in thestretching region of the FLD. Based on these findings they conclude that the “conventional”forming limit curves cannot be used for AISF and propose dedicated tests to record forming limitdiagrams for AISF. Up to now, there is no standardised test and no evaluation procedure for thedetermination of FLCs for AISF. In the present paper, we start with an analysis of the range ofstrain states and strain paths that are covered by the various tests that can be found in the literature.This is accomplished by means of on-line deformation measurements using a stereovision system.From these measurements, necking and fracture limits are derived. It is found that the fracture limitscan be described consistently by a straight line with negative slope. The necking limits seem to behighly dependent on the test shapes and forming parameters. It is concluded that standardisation inboth testing conditions and the evaluation procedures is necessary, and that a forming limit curvedoes not seem to be an appropriate tool to predict the feasibility of a given part design
    Type of Medium: Electronic Resource
    URL: http://www.tib-hannover.de/fulltexts/2011/0528/01/54/transtech_doi~10.4028%252Fwww.scientific.net%252FKEM.344.511.pdf
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    Quantitative Validation of FEM Simulations for Incremental Sheet Forming Using Optical Deformation Measurement (2005)
    s.l. ; Stafa-Zurich, Switzerland
    Advanced materials research Vol. 6-8 (May 2005), p. 509-516 
    Details
    ISSN: 1662-8985
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: The present paper focuses on a new methodology to quantitatively evaluate finite element calculations on incremental sheet forming (ISF). ISF is a new manufacturing process for prototypes and small lot sizes. In ISF, a part is manufactured by the CNC-driven movement of a simple tool, giving rise to very challenging problems concerning the efficient modeling of the alternating contactconditions and the material's response to the cyclic deformation. The quantitative validation of the finite element analysis is achieved by an optical deformation measurement system which has been enhanced by a new calibration procedure, yielding a precisely defined local coordinate system for deformation measurements during forming. In combination with mapping algorithms for large point sets, this allows for a quantitative validation of process simulations and material input data
    Type of Medium: Electronic Resource
    URL: http://www.tib-hannover.de/fulltexts/2011/0528/01/41/transtech_doi~10.4028%252Fwww.scientific.net%252FAMR.6-8.509.pdf
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    Economical and Ecological Benefits of Process-Integrated Surface Structuring (2007)
    s.l. ; Stafa-Zurich, Switzerland
    Key engineering materials Vol. 344 (July 2007), p. 939-946 
    Details
    ISSN: 1013-9826
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Properties and functional behavior of modern products are strongly influenced by theirsurface characteristics - like their appearance and haptics as well as their optical, tribological andfluidic performance [1]. In present production processes these functional features are mostlygenerated by surface treatment processes (e. g. grinding, etching, coating). In contrast to these costintensiveand complex off-line sequences rolling provides an opportunity to apply functionalstructures on sheet metal products using non-pollutive synergy-potentials of the process
    Type of Medium: Electronic Resource
    URL: http://www.tib-hannover.de/fulltexts/2011/0528/01/54/transtech_doi~10.4028%252Fwww.scientific.net%252FKEM.344.939.pdf
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    Thixoforming of Steels - A Status Report (2007)
    s.l. ; Stafa-Zurich, Switzerland
    Materials science forum Vol. 539-543 (Mar. 2007), p. 4297-4302 
    Details
    ISSN: 1662-9752
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: The Thixoforming of metals is a new forming technology, which combines the advantagesof casting and forging. This technology focuses on structural components with complex shapes,which can not be manufactured using conventional processing methods. Different components madeof aluminum and magnesium are already industrially produced. Apart from this, the use of steels inthe Thixoforming processes is still being researched and developed. During the last years it becameobvious that the Thixoforming of steels may not be a complete substitution for highly automateddie-casting or forging processes, but rather a new process route to produce special components withhigh quality and geometrical demands. Special interest lies in the development and production offiligree components, parts with voids or undercuts, integrated elements such as tubes or tube-systemsand joining pieces or products made of different materials. Beside the design of suitable toolmaterials and tool concepts, the development of homogeneous heating strategies and thedevelopment of thixoformable steels is at the center of current research. Therefore, this paper focuseson material requirements which are needed for the Thixoforming of steels and on the production ofcomponents and occurring problems. By use of a failure catalogue for Thixoforming of steels,reasons for characteristic failures and suggestions are given to avoid them, so that the quality ofthixoformed parts can be improved
    Type of Medium: Electronic Resource
    URL: http://www.tib-hannover.de/fulltexts/2011/0528/02/15/transtech_doi~10.4028%252Fwww.scientific.net%252FMSF.539-543.4297.pdf
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...