Arcam AB fka AMAVF

[charlie T colton]

Additive manufacturing using selective electron beam melting

At researchgate.net - Additive manufacturing using selective electron beam melting - Article · June 2017

The full PDF file is here: Additive manufacturing using selective electron beam melting - Article in Welding and Cutting · January 2017

The abstract and introduction:

Abstract

Additive manufacturing encompasses all the procedures which build up a component layer by layer on the basis of a three-dimensional computer model. Additive building-up permits complex geometrical shapes which are subject to hardly any restrictions and thus could not be implemented with conventional manufacturing procedures or only at great expense. Similar to selective laser beam melting, selective electron beam melting (SEBM) is a powder-bed-based additive manufacturing process in which the powder particles are locally melted completely and consolidated by the beam. The electron beam permits the processing of high-melting and reactive metals in a vacuum as well as a high construction rate for additive manufacturing processes due to high power densities and quick deflection speeds. This article not only describes the installation setup and the process sequence during SEBM but also introduces the material classes investigated until now, selected applications and the numerical simulation of this procedure.

1 Introduction

For decades, technological progress and high competitive pressure have led to the shortening of the time span from the product idea to the placing of a product on the market. This contrasts with a continuous increase in the complexity and with the current trend towards the individualisation of components and systems. In this field of tension, conventional manufacturing procedures are increasingly reaching their limits while additive manufacturing is opening up new possibilities for process innovations and the implementation of totally new product properties.

Additive manufacturing technologies are suitable for manufacturing technically sophisticated products, above all as single items and in small-scale series. On the basis of three-dimensional virtual models, the manufacturing can be carried out at any time in nearly any location, especially close to the place of use too. Additive buildingup permits complex geometrical shapes which are subject to hardly any restrictions. Due to this property, it is possible to manufacture components and finished parts which could not be implemented with conventional manufacturing technologies or only at great expense. Thus, topologically optimised and functional components may, for example, raise the efficiency and productivity of means of transport and technological installations.

In the case of additive manufacturing, components are manufactured by joining in layers. In particular, powder-bed-based procedures in which individual powder layers are locally melted completely and consolidated by a beam source are suitable for the processing of metals[1]. The most widespread beam source is the laser (selective laser melting, SLM [2]). However, the electron beam (selective electron beam melting, SEBM [3]) which permits quicker process management due to its higher power density stands out for the processing of high-melting and reactive metals [4].

Experts from industry and science from all over the world discussed the great potential of this technology at the “1st International Conference on Electron Beam Additive Manufacturing“ EBAM 2016. The conference subjects range from the preliminary processing of the powder via process management and process observation right up to the post-processing of the components. This article takes up the idea of this conference and links the great potential of selective electron beam melting with research-related applications. The main topics of this article are the description of the SEBM technology including possible materials, applications and numerical simulations.



Fig. 1 @BULLET Process chain of selective electron beam melting: After the preheating of the entire powder layer with a defocused electron beam (1), component regions are completely melted selectively according to the computer model (2). After the consolidation and the solidification, the process platform is lowered by one layer thickness (3) and a new powder layer is applied (4); cf. [5].



Fig. 3 @BULLET Structured reactor made of catalyst-coated TiAl6V4 in order to release hydrogen from a liquid organic hydrogen carrier (LOHC) (left), prototype of a heat exchanger structure made of pure copper (right).



Fig. 4 @BULLET Additively manufactured turbine blade made of a nickel-based alloy with a cooling structure (front and rear sides). The blade root has been post-processed mechanically. The blade shows the as-built condition.