Application of Laser-Based Powder Bed Fusion for Direct Metal Tooling

Nader Asnafi

doi:10.3390/met11030458

Abstract

The journey of production tools in cold working, hot working, and injection molding from rapid tooling to additive manufacturing (AM) by laser-based powder bed fusion (L-PBF) is described. The current machines and their configurations, tool steel powder materials and their properties, and the L-PBF process parameters for these materials are specified. Examples of production tools designed for and made by L-PBF are described. Efficient design, i.e., high tooling efficiency and performance in operation, should be the primary target in tool design. Topology and lattice structure optimization provide additional benefits. Using efficient design, L-PBF exhibits the greatest potential for tooling in hot working and injection molding. L-PBF yields high tooling costs, but competitive total costs in hot working and injection molding. Larger object sizes that can be made by L-PBF, a larger number of powder metals that are designed for different tooling applications, lower feedstock and L-PBF processing costs, further L-PBF productivity improvement, improved surface roughness through L-PBF, and secured quality are some of the targets for the research and development in the future. A system view, e.g., plants with a high degree of automation and eventually with cyber-physically controlled smart L-PBF inclusive manufacturing systems, is also of great significance.

Highlights

To build objects by adding many very thin layers of material, layer on top of layer, has historically attracted some attention
Generative design and topology and lattice structure optimization enable, amplify and are a complement to the design freedom provided by laser-based powder bed fusion (L-PBF)
Using high tooling efficiency and performance as the primary target, L-PBF exhibits the greatest potential for hot working and injection molding tools, dies and molds

Summary

Introduction

To build objects by adding many very thin layers of material, layer on top of layer, has historically attracted some attention. It was held that such a layer-by-layer manufacturing was the common denominator of (a) computer aided design (CAD), i.e., solid modelling, (b) enabling technologies, i.e., laser, ink-jet printers and motion control, and (c) traditional technologies, i.e., powder metallurgy, welding, extrusion, computerized or computer numerically controlled (CNC) machining, and lithography. Rapid prototyping would enable a fast visualization and evaluation of the product design and a rapid tooling would shorten the time-critical toolmaking in the industrialization of new products (and thereby reduce the time to market). Direct rapid tooling, through layer-by-layer toolmaking evolved in the middle of 1990s. Direct rapid tooling was defined as an industrial concept aimed at the realization of production tooling through layered manufacturing directly from CAD data files

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