Simulation of micro powder injection moulding: Powder segregation and yield stress effects during form filling

Greiner, Andreas; Kauzlarić, David; Korvink, Jan G.; Heldele, Richard; Schülz, Michael; Piotter, V.; Hanemann, Thomas; Weber, Oxana; Haußelt, J.

doi:10.1016/j.jeurceramsoc.2011.02.008

Cited by 26 publications

(16 citation statements)

References 32 publications

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“…They have considered shear‐induced segregation and convection of powder concentration in their model. A smoothed particle hydrodynamics (SPH) method was used by Greiner et al 16 . to simulate the injection stage of micro‐PIM and reported shear‐induced phase segregation.…”

Section: Introductionmentioning

confidence: 99%

“…[12][13][14] It is reported that multiphase numerical modeling has an advantage over single-phase modeling to detect phase segregation. 15 Researchers 14,[16][17][18] already have adopted the multiphase simulation approach and they have also reported that high shear strain rate and temperature influence the change in drag force between the phases that leads to powder-binder separation. Dissipative particle dynamics (DPD) based on a multiphase simulation approach can handle the moldfilling process as well as the phase interactions at the mesoscale level.…”

Section: Introductionmentioning

confidence: 99%

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A numerical model to predict the powder–binder separation during micro‐powder injection molding

et al. 2022

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The micro‐powder injection molding (micro‐PIM) process has the potential to bridge the gap between the design and manufacturing of micro‐components that are often used in small and handy devices. Numerical modeling helps to analyze and overcome various difficulties of micro‐PIM. In the present work, a numerical model is developed to predict the powder–binder separation (a common defect in PIM and especially severe in micro‐PIM) during the injection of an alumina feedstock. A powder–binder separation criterion is proposed dealing with applied injection pressure and friction force between the powder and binder. An indirect comparison of feedstock travel time between two locations is used to validate the model. The predicted segregation from the simulated result is supported by a qualitative experimental measurement. The developed model can be used to optimize injection parameters to get a defect‐free product.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

A numerical model to predict the powder–binder separation during micro‐powder injection molding

et al. 2022

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“…Powder injection molding (PIM) technology is a popular batch fabrication process for pure polymers or polymeric feedstocks with ceramic or metal particle load [1]. It enables cost-effective mass production of microstructured and complex-shaped components for high performance applications [2].…”

Section: Introductionmentioning

confidence: 99%

“…Usually high-pressure is applied during PIM processes and the binder system serves a very important role [7]. During the injection procedure, the molding compound undergoes extremely high shear rates of up to 10 6 s −1 which may lead to powder binder segregation or non-homogeneous binder extraction during the debinding step [1]. Hence, a homogeneous distribution of processed particles is crucial in order to avoid anisotropic shrinkage of the ceramic part resulting in cracks, porosity or distortions in the final part [1,8].…”

Section: Introductionmentioning

confidence: 99%

PVB/PEG-Based Feedstocks for Injection Molding of Alumina Microreactor Components

2019

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The ceramic injection molding (CIM) process is a cost-effective powder-based near net shape manufacturing process for large-scale production of complex-shaped ceramic functional components. This paper presents the rheological analysis of environmentally friendly CIM feedstock formulations based on the binder components polyvinyl butyral (PVB) and polyethylene gycol (PEG). The prepared PVB/PEG-based alumina molding compounds were investigated with respect to their PVB:PEG ratios as well as to their powder filling degrees in the range between 50 and 64 vol.%. Corresponding viscosities and shear stresses were determined for increasing shear rates to show the effects of increased PEG content and solid loadings on them. Two single reactor components were injection molded and subsequently joined in their green state for fabrication of an alumina microreactor. The intended purpose of the alumina microreactors is their potential application as wear-resistant and hydrothermal stable multifunctional devices (µ-mixer, µ-reactor, µ-analyzer) for continuous hydrothermal synthesis (CHTS) of metal oxide nanoparticles in supercritical water (sc-H2O) as the reaction medium.

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“…Due to the constraints in physical experiments and the availability of measurements for micro-scale factors, the accurate numerical simulation becomes more and more important in designing and manufacturing [4]. Some studies on 3D simulation of the polymer injection molding can also be retrieved in recent years [5,6].…”

Section: Introductionmentioning

confidence: 99%

Algorithm for Improvement of a Wrongly Adverted Filling Profile in Injection Flow

Shi

Barrière

Cheng

et al. 2016

Metals

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Abstract:As Eulerian description is generally used for the simulation of filling flow problems in the powder injection molding process, and the governing equation of the filling state takes the form of an advection equation, the distortion can be easily produced when dealing with the filling process in complex cavities, such as the similar channels in shapes of K and L, inside which the phenomena of opposite joining and bypass are involved. In order to improve the precision, causes of the unrealistic results were analyzed in the present paper. A notion similar to the upwind method was introduced and a corresponding correction method was proposed to settle this problem. Based on the efficient explicit algorithm for PIM simulation, and by means of systematic operation to modify the fluid velocity field, the untrue impact of air flow, represented by the velocity field in front of the filling fronts, can be weakened. Then, the advection of the filling state can be mainly affected by the flow field behind the filling front. The simulation results show that the correction algorithm can effectively inhibit the distortion. The simulation of the filling processes in the complex cavities, inside which the flow directions will be subject to the sudden changes, can be realized correctly.

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Simulation of micro powder injection moulding: Powder segregation and yield stress effects during form filling

Cited by 26 publications

References 32 publications

A numerical model to predict the powder–binder separation during micro‐powder injection molding

A numerical model to predict the powder–binder separation during micro‐powder injection molding

PVB/PEG-Based Feedstocks for Injection Molding of Alumina Microreactor Components

Algorithm for Improvement of a Wrongly Adverted Filling Profile in Injection Flow

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