Wednesday afternoon, 13 October

Chairmen:
Dr Thomas Hartwig, Fraunhofer Institut – IFAM

Oral

Simulation Tool for Powder Injection Molding and Its Applications
Chung, S-T (CetaTech, Kyongnam, Korea)

We developed the simulation tool for powder injection molding, where the high solids content often makes for significant differences compared with plastics. Several situations demonstrate the problems, such as the wall slip phenomena, powder-binder separation, high inertia effects in the gate, and rapid heat loss. Thus, the simulations to analyze the PIM process builds from the success demonstrated in plastics, but adapts those concepts for PIM in the filling, packing, and cooling stages. Demonstration of usefulness and optimization for molding defects, balanced filling, delivery system, and design of experiments is discussed and illustrated with several components.

Experimental and Numerical Simulation on the Sintering Process of Alumina PIM Products
Barriere, T (ENSMM, Besancon, France)

The densification behaviors and microstructural evolution of alumina powder injection molded components have been investigated. The effects of process parameters of the sintering cycles such as heating rate, sintering temperature and holding time on the final parts are presented in this study. The continuum sintering model is used to predict the shrinkage and distortion of the sintered parts. The involved parameters in the constitutive model can be identified by the dilatometric sintering tests. The finite element simulation has been conducted based on the presented sintering model and determined parameters for hip implant part in a complex geometry. In order to deal with the variational contact conditions during sintering, the explicit algorithm has been used. A comparison between the experimental and numerical results is also presented.

Numerical and Experimental Investigation of Backbone Binder Removal from MIM Copper Compacts
Mohsin, I U (Austrian Institute of Technoloty AIT, Seibersdorf, Austria)

A finite element (FE) model based on kinetic analysis was developed to describe the thermal de-binding process of previously solvent debinded MIM copper compacts. The proposed model is solved numerically to study binder removal and binder distribution during thermal de-binding. The investigations included the analysis of residual (backbone) binder content for cylindrical MIM copper compacts at different temperatures and positions. The FE simulated and thermo gravimetric (TG) experimental results were compared to validate the underlying FE model based on FE temperature field calculations. Satisfactory agreement between simulated and experimental results was achieved at lower temperature but at high temperature, a deviation was found due oxidation during quenching in air. Furthermore, some improvements are needed in temperature field calculation of FE model to obtain more accurate simulated results.

Micro-PIM Process With 316L Stainless Steel Feedstock And Numerical Simulations Of The Sintering Stage
Gelin, J-C (ENSMM, Besancon, France)

Adapted from the technology PIM, micro powder injection molding process continually grows and demonstrates excellent economic prospects due to its competence to meet the increasing interest in smaller parts and miniaturization. Researches in this area have been developed in our lab. Mono-injection and two-material injection experiments with a fine 316L stainless steel powder of 3.4µm (D50) have been realized by using the feedstocks prepared according to an adaptive formulation. The stages of debinding and sintering have been carried out also. Numerical simulation has been involved to study the behavior of sintering stage. Identification of the parameters introduced for the simulation has been done by optimizing the experimental data obtained from a vertical dilatometer. In this paper, the results of the numerical simulations realized with Abaqus© software to predict the shrinkage during and after the sintering stage have been investigated.

Simulation of the interdiffusion at the interface of co-sintered parts
Benedet Dutra, G (Fraunhofer IFAM, Bremen, Germany)

Quality control of the manufacturing processes has been intensively required of the industry, here for Two Components Metal Injection Moulding (2C-MIM). The joining of different materials in the same part has several advantages for the production of functional materials; still, the weld line is a critical point for failures during the co-sintering. To understand and describe the interdiffusion and phase formation at the interface during the co-sintering, the simulation software package Thermo-Calc and DICTRA has been recently investigated for applications in particulate materials. Simulations of the alloying elements interdiffusion of bulk parts were adjusted to extend the application for powder parts. The simulations were compared with the experimental data (EDX/SEM profiles). These results show that Thermo-Calc and DICTRA can be used to predict the interdiffusion of 2C-MIM and probably other PM processes.

Related features for download:

• Application of a simulation tool in powder injection moulding (PIM)
• Simulation-based design for powder injection moulding
• Mixing simulation for powder injection moulding feedstock: Quantification by the mixing entropy