DMLS – How it works
CRDM currently runs three Direct Metal Laser Sintering (DMLS) machines manufactured by EOS GmbH, the EOSINT M 270 x 2 and the EOSINT M 250 Xtended x 1.
The build process is very simple …
re-coat build plate > scan layer > move build & dispenser pistons > re-coat build plate ….
All this happens under an inert nitrogen atmosphere and careful gas flow extraction.
Repeating this cycle in steps/layers of either 20 or 40µm micron thickness the tool or components are built up in the material. Once finished, the build plate is removed with parts attached, the excess powder is removed and recycled. The parts can then be removed by hand or often wire eroded from the plate.
To ensure the process runs smoothly, slightly different (but simpler) design rules are required for the DMLS process.
Since 1999 the experience of the team at CRDM allows us to advise on the optimum part design for the DMLS process. Optimising the part design ensures good build results, best pricing and fastest delivery.
Stainless Steel 316L
Stainless Steel 316L has a natural colour, good corrosion resistance, non hardenable material suitable for manufacturing direct parts.
Maraging Steel (MS1)
Maraging Steel (MS1) is a pre-alloyed ultra high strength steel in fine powder form. Its composition corresponds to US classification 18% Ni Maraging 300, European 1.2709 and German 3NiCoMoTi 18-9-5.
Parts built from Maraging Steel (MS1) are easily machinable after the building process and can be easily post-hardened to more then 50 HRC by age-hardening at 490 °C for 6 hours.
This material is ideal for many tooling applications (DirectTool) such as tools for injection moulding, die casting of light metal alloys, punching, extrusion etc., and also for high performance industrial and engineering parts, such as aerospace and motor racing applications.
Standard processing parameters use full melting of the entire geometry, typically with 40µm layer thickness, but it is also possible to use Skin & Core building style to increase the build speed. Using standard parameters, the mechanical properties are fairly uniform in all directions.
In both as-built and age-hardened states the parts can be machined, spark-eroded, welded, micro shot-peened, polished and coated if required.
Cobalt Chrome MP1
The chemistry of EOS Cobalt Chrome MP1 conforms to the composition UNS R31538 of high carbon CoCrMo alloy. It is nickel-free (< 0.1 % nickel content), sterilisable and suitable for biomedical applications.
The laser-sintered parts are characterized by a fine, uniform crystal grain structure. They fully meet the requirements of ISO 5832-4 and ASTM F75 for cast CoCrMo implant alloys, as well as the requirements of ISO 5832-12 and ASTM F1537 for wrought CoCrMo implants alloys except remaining elongation.
The remaining elongation can be increased to fulfill even this standard by Hot Isostatic Pressing (HIP).
Inconel 718 / 2.4668
Heat and corrosion resistance nickel alloy with good tensile and fatigue properties at temperatures up to 650⁰C. Mechanical properties can be increased with age-hardening (AMS 5662 / 5664). Commonly used for applications in motorsport, aerospace, and Oil and Gas industries.