When the material is completely melted in laser-based 3D printing, i.e. a phase transition from the solid to the liquid aggregate state takes place, we no longer speak of selective laser sintering (SLS), but of selective laser melting (SLM).

The SLM process is used particularly in the processing of metals and thus more or less competes with metal casting in a small segment.

What is Selective Laser Melting (SLM)?

Selective laser melting is one of the laser powder bed fusion technologies. It is a laser-based 3D printing technology in which metallic powder materials are selectively melted layer by layer to produce 3D objects. Since the build space is filled with an inert, i.e. inert, shielding gas such as nitrogen or argon, the metal runs little risk of oxidizing, which would render the printed components unusable.

How does selective laser melting work?

Like any other 3D printing process, SLM metal 3D printing needs a CAD file as a blueprint for the desired part. The data set is cut into a number of layers by a slicer. Each layer forms a cross-section through the component. A layer thickness in SLM usually varies between 20 and 60 micrometers. In the printing process, a squeegee spreads a layer of metal powder onto a lowerable build platform. A laser then scans the cross-section of the part and melts the powder in those areas. Because the powder cannot be compressed as densely as in SLS, the process relies on printed support structures in most cases. They serve to keep the components stable in the build space, to dissipate excess heat and to prevent deformation of the parts.

How did SLM technology come about?

Compared to the SLA, FDM or SLS processes, which were all patented towards the end of the 1980s, SLM emerged somewhat later. The first notable successes were announced in 1995 by the Fraunhofer Institute for Laser Technology in Aachen. In cooperation with the company F & S Stereolithografietechnik GmbH, the SLM process was developed. The company split in the early 2000s into Realizer GmbH, which today belongs to DMG Mori AG, and SLM Solutions AG, which is still one of the leading suppliers for SLM metal 3D printing.

What are the advantages of selective laser melting?

Like the vast majority of 3D printing technologies, selective laser melting also brings with it a great deal of geometric freedom. This means that highly complex geometries and bionic lightweight construction projects can be implemented without tools. Assembly consolidation is another advantage of SLM and also other 3D printing technologies. This involves bringing together individual assemblies and printing them directly in one piece to reduce material and labor and assembly costs. But it’s not just the geometric freedom of the technology that makes exciting components possible. The component properties themselves can also be improved by the SLM process. For example, the components are characterized by a particularly high density and almost pore-free surfaces.

What materials are used in selective laser melting?

Selective laser melting is used to process metals. The development of new materials is a continuously advancing field of research, and new suppliers or established companies are constantly entering the market with a greater variety of materials. The most established materials for SLM 3D printing include aluminum (AlSi10Mg), tool and stainless steel (1.2709 & 1.4404) and titanium (Ti6Al4V).

What can selective laser melting be used for?

Many industries benefit from selective laser melting as an additive manufacturing technology. These include aerospace, automotive engineering, dental and medical technology, and mechanical engineering. The technology is used in particular for rapid prototyping, but small series can now also be economically produced using SLM metal 3D printing.

Contact


Would you like to learn more? Then ask us. We will be pleased to help you.

Contact us

Industrial 3D Printing Systems

Our portfolio of industrial 3D printers ranges from compact systems for research to additive mass production.

Learn More
Scroll up