Dry pressing has established itself as a cost-effective powder technology component forming technique and is one of the standard forming techniques used for many categories of materials, including ceramics, carbides, sintered steel, magnetic materials and materials in the pharmaceutical industry. Increasingly complex component geometries mean that pressing technologies must also meet increasingly high standards – which is why tool design plays a key role. Typical problems are warpage as a result of green density gradients and cracks as a result of expulsions or combustion. The Fraunhofer IWM has developed a method with which to simulate the pressing and sintering of powder-based objects. A combination of the modules we developed for each process and the ABAQUS FE program enables us to quantitatively predict the green density distribution and the resultant deformation after sintering. We are currently developing a model for directly predicting pressing cracks. These simulation tools allow us to optimize tool molds and pressing plans before the tool is built and also to make suggestions on how to improve the finished parts.

Optimization via numerical simulation of a cooling device made using powder technology. (PDF)

Simulation of the burning process during the manufacture of consumer ceramics. (PDF)

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Welding is one of the most common and important joining techniques. The experimental trials needed to determine how to reduce internal stress and the resultant warpage as a result of the thermal effects of welding are often very complex. Numerical welding simulations are an ideal alternative to the experimental approach to minimizing manufacturing costs and shortening development times. These simulations can be used to calculate temperature fields, warpage, internal stress, grain development and hydrogen distribution in relation to the welding parameters. Thermoelement measurements are made on a real component to calibrate the numerical alternative to the heat sources. Thermophysical and thermomechanical material data is determined in the thermophysics lab at the Fraunhofer IWM.

Numerical simulation of welding technology manufacturing stages. (PDF)

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We use modern simulation methods to help our partners design and evaluate their forming processes in the fields of sheet metal and solid metal forming as well as cold and hot forming. As a matter of course, we describe the anisotropy as a result of texture, include thermomechanical coupling phenomena, depict the tribological properties of the bodies in contact with each other and model the damage with the aid of micromechanical based damage models. The most common models often only inadequately describe material properties, in which case, we expand on familiar approaches or develop new models. Current projects involve the development of models with which to describe the material behavior of high strength steels, taking dislocation-based twinning induced plasticity (TWIP effect) and martensitic transformation induced plasticity (TRIP effect) into account.

Spring-back controls edge cracks during sheet metal rolling. (PDF)

Simulation of spring-back during sheet metal forming processes. (PDF)

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