Stainless Steel 316L is a corrosion resistant iron based alloy which has been optimized for processing on DMLS systems. Stainless Steel 316L have chemical composition corresponding to ASTM F138 “Standard Specification for Wrought 18Cr-14Ni-2.5Mo Stainless Steel Bar and Wire for Surgical Implants (UNS S31673)”. This kind of stainless steel is characterized having a good corrosion resistance and evidence that there are no leachable substances in cytotoxic concentrations. Parts built from Stainless Steel 316L can be machined, shot-peened and polished in as-built or stress relieved (AMS2759) states if required. Solution annealing is not necessary because the mechanical properties of as-built state are showing desired values (ASTM A403). Parts are not ideal in temperature range 427°C – 816°C where precipitation of chromium carbides occurs. Due to layer-wise building method, the parts have a certain anisotropy which could be seen from mechanical properties.
Parts built with Maraging Steel are characterized by having very good mechanical properties and being easily heat-treatable using a simple thermal age-hardening process to obtain excellent hardness and strength. The parts can be easily hardened to more than 50 HRC. The parts can be machined, spark-eroded, welded, micro shot-peened, polished and coated. This is typically used for Injection Molding inserts and tooling and mechanical components.
This material is ideal for many high temperature applications such as gas turbine parts, instrumentation parts, power and process industry parts. Material also possesses excellent cryogenic properties and potential for cryogenic applications. Using this material allows to produce parts quickly, while still being affordable. Standard processing parameters use full melting of the entire geometry, typically with 20 µm layer thickness. Parts built from Nickel Alloy IN718 can be easily post-hardened to 40-47 HRC (370-450HB) by precipitation-hardening heat treatments. In both as-built and age hardened states the parts can be machined, spark-eroded, welded, micro shot-peened, polished and coated, if required. Unexposed powder can be reused.
Aluminum AlSi10Mg is a master alloy aluminum powder. AlSi10Mg is a typical casting alloy with good casting properties especially for parts with thin walls and complex geometries. The alloy combination silicon/magnesium results in a significant increase in strength and hardness. It also features good dynamic properties and is therefore used for parts subject to high loads. Parts made of Aluminum AlSi10Mg can be machined, wire-eroded and electrical discharge machined, welded, micro-blasted, polished and coated. Standard building parameters completely melt the powder in the entire partwhile unexposed powder can be reused.
Some of the characteristics that make titanium ideal for aerospace applications also make it difficult to machine. Its hardness and low heat conductivity reduce tool speeds and life and require a great deal of liquid cooling during machining. This can limit the productivity of certain shapes that use thin walls. Laser-sintered titanium retains the beneficial properties of the metal and involves no tool-wear or coolant costs. Nearly any geometry, including thin walls, can be created with laser-sintering. Since DMLS
is an additive technology, it drastically reduces material waste in comparison with traditional processes. Investment casting of titanium is difficult and often has a high scrap rate. The aerospace industry relies on titanium due to its strength, low-weight and high mechanical properties. Many titanium aerospace components are machined from solid stock, often cutting away 90% or more of the original material. This becomes a time consuming, costly operation that can be completely eliminated by using titanium DMLS.