As a manufacturing technique, 3D printing has taken engineering by storm.
The ability to create complex components based upon a building-up process is hugely advantageous in the engineering world, and with a growing number of base materials available to the system, more and more components will be made this way.
Essentially, 3D printing is an additive process. Thin layers are built upon each other and are welded together to form a coherent, void-free artefact that is either net-size and shape or as close as possible. The materials laid down are typically robust enough to allow for secondary machining techniques such as drilling, tapping, and turning, and to a high surface finish. Printed components have a number of obvious advantages compared to other manufacturing processes.
A range of processes.
Rather than being one process used to create all products in all available materials, 3D printing is actually a collection of different techniques that suit different materials, manufacturing processes, and levels of detail. The main types are:
- Stereolithography and Digital Light Processing (SLA and DLP). Two allied processes that employ UV light to cure liquid light-sensitive resins layer by layer until a final form is gradually built up. This too is an ideal 3D build solution for polymeric materials which meet the criteria of being liquid and highly susceptible to localised UV light.
- Selective Laser Sintering (SLS). Polymer components can be produced in high detail using precision laser light into a powder matrix.
- Direct Metal Laser Sintering (DMLS). This process uses a fibre laser to apply energy to a small layer of metal powder to gradually build up a metal structure with high accuracy.
- Selective Laser Melting (SLM) and Electron Beam Melting (EBM). Used to create components from metal and ceramic powders, this process is highly selective method can produce highly precise parts that can further be worked.
- Multi-Jet Fusion (MJF). A mix of adherent and detailing agents are applied to nylon powder to fuse thin layers together, building up successively to create detailed products.
- Material Jetting. Similar in operation to an inkjet printer, successive layers of material are distributed from a printer head at the temperature to create a highly precise component.
- Fused Deposition Modelling (FDM). This process uses a constant string of materials from a ‘printer’ head which is used to build up a model while in a semi-molten state. Typically used to create quick, low-cost space models from polymeric materials.
There are a number of distinct advantages that make 3D printing of components a primary production process, including:
Speed. Generally, a very fast method, 3D printing can create a completed component which requires very little – if any – post processing and further working. That means that like injection moulding services, it produces a net-size and shape more rapidly than any other machining process. This means that from the CAD design, the component only needs printing. Other methods of manufacture could have several steps which might require transport between them, resulting in a much-extended production route.
Cost. Because 3D printing is an additive process it uses only the material that it needs rather than other machining methods which selectively remove material – which then effectively becomes scrap – until the right size and shape are achieved. With printing feedstock becoming ever cheaper, and the industrial-grade equipment required to use it being increasingly accessible, this is a process that is becoming highly competitive among other manufacturing processes.
Design freedom. With 3D printing techniques, if you can design it using CAD, then you can probably print it using one of the techniques discussed earlier. With a huge range of different methods available, there is always at least one method – and potentially many more – that can be used to create your design. Additionally, 3D printing takes full advantage of CAD/CAM, and usually allows your designs to be sent straight to the printer at the touch of a button.
Customisation. Because it has such strong CAD/CAM ties, it becomes very easy to update a design almost at any point, including during the production process, provided that the section has not yet been printed. This huge flexibility allows for parts to be customised too, so standard parts can be modified in line with customers’ requirements.
Sustainable materials. While 3D printing started by using waxy materials, further development has meant that a range of materials are now available in different forms, including powdered woods and recyclable polymers. This means that old and discarded parts – including unwanted components can be recycled with ease, leading to a much-reduced carbon footprint.
The 3D printing process is continually gaining new methods and materials and is likely to become the primary means of manufacture of many components within the near future.
