Design guidelines for laser additive manufacturing of lightweight structures in TiAl6V4

Abstract

Today, laser additive manufacturing (LAM) is used in more and more industrial applications. Due to a new freedom in design it offers a high potential for weight saving in lightweight applications, e.g., in the aerospace industry. However, most design engineers are used to design parts for conventional manufacturing methods, such as milling and casting, and often only have limited experience in designing products for additive manufacturing. The absence of comprehensive design guidelines is therefore limiting the further usage and distribution of LAM. In this paper, experimental investigations on the influence of part position and orientation on the dimension accuracy and surface quality are presented. Typical basic shapes used in lightweight design have been identified and built in LAM. Thin walls, bars, and bore holes with varying diameters were built in different orientations to determine the process limits. From the results of the experiments, comprehensive design guidelines for lightweight structures were derived in a catalog according to DIN 2222 and are presented in detail. For each structure a favorable and an unfavorable example is shown, the underlying process restrictions are mentioned and further recommendations are given.

An additive manufacturing filter for topology optimization of print-ready designs

“…1. This choice is motivated by the fact that the critical self-supporting overhang angle for the considered processes typically amounts to 45 • (Wang et al 2013;Mertens et al 2014;Kranz et al 2015). In 2D, this results in a region of n S = 3 elements.…”

“…A universal limitation in these processes is that the inclination of downward facing (overhanging) surfaces is limited to a maximum angle with respect to the build direction. This overhang angle limitation has been extensively characterized, and typically the critical angle amounts to 40-50 • (Wang et al 2013;Mertens et al 2014;Kranz et al 2015).…”

Investigation of design for additive manufacturing in professional design practice

“…Adam and Zimmer (2015) conducted a series of experiments in order to optimise the dimensions of geometrical features such as wall thickness, outer and inner edges, slot depth, width and length and overhang length. Similarly, Kranz, Herzog, and Emmelmann (2015) explored detail design guidelines covering a wide range of prismatic features such as cavity, cylinder, wall and bore. Collectively, these feature level rules will indeed help designers ensure 'printability' (successful AM production) of parts, but they will not be helpful in ensuring the part being designed is conceptually optimal compared to alternative designs.…”

“…These rules tend to apply at the detail design stage, to refine or optimise individual geometric features and their dimensions according to the capability of the specific AM process to be used. For example, Adam and Zimmer (2015) and Kranz, Herzog, and Emmelmann (2015) defined a set of detailed rules identifying feature types in relation to their dimensions. Adam and Zimmer (2015) conducted a series of experiments in order to optimise the dimensions of geometrical features such as wall thickness, outer and inner edges, slot depth, width and length and overhang length.…”

Topology Optimization for Additive Manufacturing With Controllable Support Structure Costs

“…An important restriction that applies to popular powder-bed processes such as SLM and EBM, is that the inclination of printable overhanging parts with respect to the build plate is limited. This limitation is associated with a critical overhang angle, that typically amounts to 45 • [5,6].…”