SLM-Topo

SLM-Topo-Wiki

Welcome! This wiki gives an overview of SLM-Topo - the topology optimization method designed for laser based additive manufacturing.

The SLM-Process is an additive manufacturing method for metal components. In the process, powder layers are applied incrementally and melted locally by a laser beam in order to build up a component layer by layer. Often, the contour of the component is melted first (contour scan) and then the inner zone of the volume is melted (hatch scan). This separation ensures that the surface of the component is generated with as few reversal points of the laser as possible, resulting in a comparatively high surface quality. However, this approach also causes buildup errors to be favored in the interface between the two scanning strategies. These buildup errors and the resulting microstructural anisotropy and gradation in the material, influence the component quality. This results in a reduced density, relative to the density of the solid material, as well as in a direction-dependent reduction in strength and stiffness.
SLM-Topo takes all these effects into account and is therefore the ideal support for product developers designing components for additive manufacturing. Additionally to the [Topology optimization] algorithm, SLM-Topo also provides a [Material Database] containing anisotropic and locally inhomogeneous material properties of the lightweight design aluminum alloy AlSi10Mg processed with SLM. Therefore, a reference component containing representative geometric elements is designed, built and characterized with various methods. The characterization results are stored in a MySQL-[Material Database] which is directly connected to the [Topology optimization].
A [Topology optimization] is a finite element (FE)-based method for creating an initial design of a load-optimized component design. Using the design space and the load case of a component as boundary conditions, the method iteratively adapts the shape of the component until a load-compliant topology is established. The topology optimization method in SLM-Topo should make it possible to obtain a component geometry adapted to the SLM-specific material properties. The aim of the optimization is to maximize the stiffness of the component, which allows higher-quality components to be realized.

Three-point-bending-beam optimized with SLM-Topo.

SLM-Topo2

Currently, we are planning on developing SLM-Topo2 by extending our topology optimization. SLM-Topo2 aims to include local strength restrictions into the topology optimization for the synthesis of stiffness-optimized designs. This enables the consideration of the locally varying yield strengths occurring in the SLM-process in combination with the inhomogeneously distributed elastic material parameters from SLM-Topo.
In SLM-Topo2, the focus continues to be on maximizing components stiffness, but now taking local strength restrictions into account. The material used continues to be the cast alloy AlSi10Mg, which is well known from lightweight material design. The existing, stiffness-based topology optimization method SLM-Topo will be extended to include the locally prevailing yield strengths in SLM components, as they result from the SLM process, and finally validated in component tests.

Project Members:

• Jan Holoch (admin)
• Stefan Dietrich (admin)
• Steffen Czink (admin)