X-ray tomography of powder injection moulded micro parts using synchrotron radiation

Heldele, Richard; Rath, S.; Merz, L.; Butzbach, R.; Hagelstein, M.; Haußelt, J.

doi:10.1016/j.nimb.2005.12.030

Cited by 28 publications

(16 citation statements)

References 7 publications

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“…This corresponds to a 'mean' viscosity h(f) = 100 Pa s, wheref = 0.625. We have simulated different ratios D c /D h and have found that D c /D h = 0.1 reproduces best our CT measurement for a specially prepared injection-moulded test specimen [7,9]. For this case, figure 3a Figure 3b shows the CT data in two dimensions.…”

Section: Simulation Results and Discussionmentioning

confidence: 58%

Smoothed particle hydrodynamics simulation of shear-induced powder migration in injection moulding

Kauzlarić

Pastewka

Meyer

et al. 2011

Phil. Trans. R. Soc. A.

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We present the application of the smoothed particle hydrodynamics (SPH) discretization scheme to Phillips' model for shear-induced particle migration in concentrated suspensions. This model provides an evolution equation for the scalar mean volume fraction of idealized spherical solid particles of equal diameter which is discretized by the SPH formalism. In order to obtain a discrete evolution equation with exact conservation properties we treat in fact the occupied volume of the solid particles as the degree of freedom for the fluid particles. We present simulation results in two-and three-dimensional channel flow. The two-dimensional results serve as a verification by a comparison to analytic solutions. The three-dimensional results are used for a comparison with experimental measurements obtained from computer tomography of injection moulded ceramic microparts. We observe the best agreement of measurements with snapshots of the transient simulation for a ratio D c /D h = 0.1 of the two model parameters.

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Section: Simulation Results and Discussionmentioning

confidence: 58%

Smoothed particle hydrodynamics simulation of shear-induced powder migration in injection moulding

Kauzlarić

Pastewka

Meyer

et al. 2011

Phil. Trans. R. Soc. A.

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“…During injection moulding of micro parts, large inhomogeneities of the powder distribution are produced by the inhomogeneous flow in small channels (Heldele et al 2006). The most characteristic feature, the low-viscous feedstock, helps improve the homogeneity of the powder distribution, as differences between the flow velocities in the core and at the side of the channel are much smaller.…”

Section: Low-pressure Powder Injection Mouldingmentioning

confidence: 99%

Powder injection moulding of metallic and ceramic micro parts

et al. 2011

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Industrial use of micro components is determined by the availability of efficient manufacturing techniques. While micro injection moulding of plastic is common practice, metal and ceramic powder injection moulding (PIM) still is under development. High-pressure and low-pressure injection moulding methods complement each other ideally, covering the entire spectrum from prototype to large-scale production. With high-pressure PIM, micro gear wheels with diameters \300 lm can be fabricated using LIGA mould inserts. Densities between 97 and 99% of the theoretical values are achieved. Apart from oxide ceramics, metal materials like copper or powder metallurgical steels like 17-4PH or 316L are often applied. Multi-component injection moulding requires less mounting steps and, hence, offers decisive advantages for effective production of interesting material combinations like electrically conductive/insulating or hard/ductile. Studies relating to the fabrication of immobile as well as mobile shaft-wheel components were performed. Other activities focussed on in-mould labelling with foils containing ultrafine particles to improve surface quality and detail accuracy. Low-pressure injection moulding allows for the manufacture of small series within 1-4 weeks at low cost. However, the process has features which are not compatible with high-pressure PIM. Although use of a low-viscous feedstock is associated with various benefits, low-pressure injection moulding has not met with acceptance in micro moulding.

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“…This has been observed for example for circular Couette flow (Abbot et al 1991) or Poiseuille flows (Koh et al 1993). There exist reports of segregation in engineering processes as well, for example for ceramic injection moulding (Heldele et al 2006;Kauzlarić et al 2008).…”

Section: Introductionmentioning

confidence: 99%

A non-local extension of the Phillips model for shear induced particle migration

2011

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We present a simple and natural extension of Phillips' model (Phillips in Phys Fluids A 4(1):30-40, 1992) for shear induced particle migration in concentrated suspensions. It is based on considering an effective deformation rate as it is experienced by a solid particle of finite size. In this way the solid fraction does not converge anymore to the maximum packing in the centre of Poiseuillelike flows where the deformation rate vanishes, and the steady state concentration profile becomes dependent on the particle diameter a. In addition, the migration rate in the extended model scales with a n , where 2 \ n \ 3 in contrast to the strict a 2 -scaling of the original Phillips-model.

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X-ray tomography of powder injection moulded micro parts using synchrotron radiation

Cited by 28 publications

References 7 publications

Smoothed particle hydrodynamics simulation of shear-induced powder migration in injection moulding

Smoothed particle hydrodynamics simulation of shear-induced powder migration in injection moulding

Powder injection moulding of metallic and ceramic micro parts

A non-local extension of the Phillips model for shear induced particle migration

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