Cost-driven build orientation and bin packing of parts in Selective Laser Melting (SLM)

Abstract

Selective Laser Melting (SLM) is an additive manufacturing process capable of producing mixed batches of parts simultaneously within a single build. The build orientation of a part in SLM is a key process parameter, affecting the build cost, time and quality, as well as batch size. Choosing an optimal arrangement of multiple heterogeneous parts inside the SLM machine also presents a challenging irregular bin packing problem. Since the two problems are interdependent, this paper addresses the combined problem of finding an optimal build orientation and two-dimensional irregular bin packing solution of a mixed batch of parts across identical SLM machines. We address this problem specifically in the context of low-volume high-variety (LVHV) production in the aerospace sector, using total build cost as the objective function. To solve this problem, we present an Iterative Tabu Search Procedure (ITSP), which consists of six distinct stages. We test each stage in the ITSP on 27 manually generated instances, based on 68 unique geometries ranging in convexity and size, including six real-life components from the aerospace industry. Two of the six stages, which are driven by support structure volume, returned the highest improvement in cost. Overall, the results showed an average cost improvement of 16.2% over the initial solution. The initial solution of the procedure was benchmarked against a commercial software, showing comparable results.

Automatic determination of part build orientation for laser powder bed fusion

“…Theoretically, a 3D part has an infinite number of possible build orientations. A one-step method generally develops a specialised algorithm (Alexander, Allen, and Dutta 1998;Delfs, Tows, and Schmid 2016;Golmohammadi and Khodaygan 2019;Griffiths et al 2019;Ulu et al 2020;Wang and Qian 2020) or applies an existing optimisation algorithm, such as the genetic algorithm (Hur et al 2001;Masood, Rattanawong, and Iovenitti 2003;Thrimurthulu, Pandey, and Reddy 2004;Ahn, Kim, and Lee 2007;Padhye and Deb 2011;Zhang and Li 2013;Paul and Anand 2015;Brika et al 2017;Chowdhury, Mhapsekar, and Anand 2018), particle swarm algorithm (Padhye and Deb 2011;Cheng and To 2019;Raju et al 2019;Shen et al 2020) or bacterial foraging algorithm (Raju et al 2019), to directly search an orientation enabling one or more part orientation factors to be optimal from infinite possible orientations. In a one-step method, the 3D model of a part is first rotated with a random or fixed angle.…”

“…According to the studies of Edwards and Ramulu (2014), Wauthle et al (2015), Brika et al (2017), Cheng and To (2019) and Griffiths et al (2019), the build orientation factors (i.e. the factors affected by the build orientation) of an LPBF part include support volume, volumetric error, surface roughness, build time, build cost, strength, elongation, hardness, residual stress, fatigue performance, distortion and microstructure.…”

Support optimization in additive manufacturing for geometric and thermo-mechanical constraints

“…The orientation of the part related to various aspects of the AM process was already considered in several works in the literature. Orientation optimization for minimizing the volume and contact area between the shape and supports was considered by [1], [20], [23]. In [15] orientation is optimized for minimizing the stress in vertical supports under overhanging regions.…”

Realization of Rapid Large-Size 3D Printing Based on Full-Color Powder-Based 3DP Technique

“…Three-dimensional (3D) printing is a subversive technology which applies to a variety of materials, such as paper [1,2], powder [3][4][5], and liquid [6]. Based on the principle of additive manufacturing (AM), the technology has the power to greatly reduce the manufacturing time of small-and medium-scale customized products [7], and the majority of 3D printers are equipped with a recycling system to reuse the leftover material in printing process.…”