Powder Bed Fusion – Laser Beam (PBF-LB) is an additive manufacturing process that utilises a laser beam to melt and fuse metal powders together to form a part.
PBF-LB begins with the creation of a 3D CAD model, which is numerically sliced into a number of finite layers. For each sliced layer, a laser scan path is calculated which defines both the boundary contour and the fill sequence, known as a scan pattern. Each layer is then sequentially recreated by melting sections of the CAD model on a layer of powder using a laser beam. After each layer is created, the powder is spread uniformly by a wiper and the process is repeated. The melted particles fuse and solidify to eventually form a component, layer by layer.
PBF-LB is also known by other terms and trademarked technologies such as Selective Laser Melting (SLMTM) and Direct Metal Laser Sintering (DMLSTM).
What are the Benefits of Using the PBF-LB Process?
The design freedom afforded by PBF-LB creates opportunities for the design and manufacture of parts with previously impossible or hard to manufacture geometries. Parts with low volumes but high surface areas, such as advanced heat exchangers or heatsinks, or parts with intricate internal channels, such as components with integrated cooling paths, are well suited to the technology. PBF-LB is also ideal for creating highly customised parts. A number of industries are taking advantage of the offered flexibility, for example, the medical industry are using it to create orthopaedic implants tailored to individual patients, therefore reducing rejection rates owing to the recipient’s immune system response.
There are a wide variety of alloys processable by PBF-LB including:
- Steels (316L, 304, 17-4PH, etc.)
- Nickel base alloys (In718, In625, In713C, Nimonic 90, MP35N)
- Cobalt base alloys (F75 Co-Cr)
- Titanium based alloys, such as (CP Ti, Ti-6Al-4V (grades 5 and 23)
- Aluminium base alloys (AlSi10Mg, etc.)
- Precious metal alloys, based on gold, silver and platinum
- Copper base alloys
- Magnesium base alloys
- Refractory metals (Mo alloys, W alloys, WC, and Ta)
- Metal matrix composites (MMCs) and nano-dispersoid reinforced materials
TWI, with its world leading expertise, is working with industry to extend this portfolio and its use in part manufacture by PBF-LB.
Key PBF-LB Advantages:
- Design freedom
- High resolution and geometrical accuracy
- Reduced material wastage and costs (superior buy-to-fly ratio)
- Improved production development cycle
- Capable of producing functionally graded parts
- Allows for fully customised parts to suit individual requirements
- Unused powder can be recycled and reused
- Increased part performance where functional elements can be optimised
- Component integration reducing part assembly and associated costs
- Weight savings through using material only where needed