Process stability and component design in the binder jetting process

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Contact

Simone  Herzog © Copyright: IWM

Name

Simone Herzog

Group Manager Process Technology

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+49 241 80 96514

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Motivation

Binder jetting (BJT) is an additive manufacturing technology in which binder is introduced locally into layered metal powder. The generated green parts are subsequently debindered and sintered. In contrast to beam-based additive processes, hard materials can also be processed and, in principle, higher volumes or large, complex components can be produced economically.

The process chain in BJT is similar to that of metal injection molding (MIM), an established series production process in industry for complex components. However, MIM is uneconomical for small batches due to high tooling costs. In the finished project "3DP for MIM" (funding no. 19733 N), the research institutes IWM and IFAM Bremen showed that with optimized MBJ parameters and heat treatment of the steel X5CrNiCuNb17-4, the MIM standard values for hardness, tensile strength and yield strength are achieved. However, a challenge for the industrial application of the BJT process is the scattering of characteristic properties depending on the build direction, position, powder condition and different MBJ equipment.

Objectives

  • To perform a sensitivity analysis on the influence of powder and process parameters on position-dependent sinter density and to specify a maximum scatter.
  • Determination of strength data for the constructive design of mechanically loaded components under consideration of anisotropy
  • Elaboration of feasible target values for quality assurance for:
    • Form and position tolerances
    • Roundness of diameters
    • Surface quality
  • Increase of the prediction accuracy of the sintering simulation or specification of an expected prediction accuracy

Contents

  • Specimen fabrication along the process chain (BJT, curing, debinding, sintering, (opt. HIP), heat treatment
    • 17-4 PH (1.4548, X5CrNiCuNb17-4-4)
    • Ferro-titanite Nikro 128 (≈ 30 wt% TiC in Fe matrix).
  • Post-treatment of the functional surfaces
  • Metallographic analyses (porosity, pore bands, green density, surface roughness)
  • Mechanical analyses (green strength, hardness, tensile tests, impact bending tests, vibration tests, bending tests)
  • Sinter simulation taking into account friction and gravity and validation by means of GOM measurements

Partner

  • Fraunhofer IFAM Bremen
  • Fachverband Pulvermetallurgie

Project Monitoring Committee

Arburg, Assonic, Bleistahl, PVA TePla, ExOne, headmade materials, Krämer Engineering, Deutsche Edelstahlwerke, Miba, MIMPlus, OTEC, Carbolite Gero, tricumed, PHA Werkstofftechnik, Zimmer Group

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Grant Number: 21421