Selective Laser Melting
Selective Laser Melting (SLM) has been effectively used to manufacture engineering components at a fraction of the product development time compared to conventional techniques. This amazing technology is best suited for the manufacturing of parts for low-volume fabrication, also allowing parts to be individually customised to suit any need.
SLM is the ‘go to’ of metal additive manufacturing technologies due to the huge variety of metal alloy powders available and the quality of the parts that it produces.
The selective laser melting process
Printing starts with the deposition of the first layer of metal powder, at the designated thickness, on to the build platform. This is done by a powder depositor that also levels the powder on each layer deposition. Once the first layer is evenly distributed, a 2D slice of the part geometry is fused by melting the fine metal powder onto the platform. The build platform is attached to a build table which moves in the vertical, Z axis. Once the first layer is finished, the build table is lowered appropriately for the designated layer thickness and the depositor sweeps a new fresh layer. The melting process is then repeated according to the 2D slice of the part geometry and this cycle repeats until the part is fully built.
All of this takes place inside a build chamber containing a controlled atmosphere of inert gas. The selective melting of each layer is achieved using a high power, fibre laser directed in X and Y with two high frequency scanning mirrors.
Selective laser melting production requires support structures, to anchor parts and over-hanging features to the build platform. The supports also enable the heat transfer away from the melting position, reducing thermal stress and warping. Supports are removed after building, as part of the production process.
Best suited for
• Low-volume fabrication
• Complex parts
Benefits of SLM
• Allows for complex geometries (e.g. tool inserts with conformal cooling channels)
• Ideal process for low-volume production
Materials for SLM
• Titanium Ti-6Al-4V
• Tool steel 1.2709
• Stainless Steel 316L
• Inconel 718