3D Printing / Additive Manufacturing
Introduction to 3D printing
3D printing, also called additive manufacturing (AM), has been used since the early 1980s. It was initially only used for rough rapid prototyping, but technological and material advancements in the past two decades have enabled 3D printing of end-use-ready parts using engineering-grade materials. 3D printing relies on data from digital 3D models or computer-aided design (CAD) files to create physical objects. 3D printers use various methods to deposit a wide range of materials onto a build platform, constructing the part shape and geometry layer by layer.
Common 3D Printing Technologies
There are dozens of open and proprietary 3D printing technologies available. Each supports a different material range and as such is suitable for different end-use cases.
Fused Filament Fabrication (FFF)
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Fused filament fabrication (FFF), also known by the proprietary name fused deposition modelling (FDM), extrude thermoplastic filaments — such as PLA, ABS, or Nylon — through a heated nozzle. The nozzle melts the plastic and extrudes it in layers onto the build platform. Due to an extremely wide range of available filaments, Fused Filament Fabrication (FFF) is a versatile and affordable AM technology. Thanks to materials like carbon fibre-reinforced filaments, it can produce both fast prototypes and end-use-ready parts with high tensile strength and abrasion resistance. Fused Filament Fabrication (FFF) printing often results in rough surfaces that require sanding or smoothing and can’t produce accurate detail. It requires support structures, which will have to be removed in post-processing.
Ideal applications:
- Rapid prototyping
- End-use part production
- Large-scale modelling
Stereolithography (SLA)
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Stereolithography (SLA) is one of the oldest 3D printing technologies. These printers use liquid thermoplastic resins that they cure into solid shapes with a powerful laser beam. SLA 3D printing can produce extremely fine and accurate details comparable to injection moulding. Engineering-grade resins allow for the production of flexible, strong, and elastic parts and prototypes. Additionally, medical and dental resins make SLA suitable for healthcare applications. SLA-printed parts require extensive post-processing. After support removal, they must be washed with isopropanol to remove excess resin and they may require additional curing.
Ideal applications:
- Rapid prototyping
- Healthcare
Digital Light Processing (DLP)
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Digital light processing (DLP) resembles SLA in that they both use UV-curable resins that the 3D printers solidify with light. But while an SLA 3D printer uses a single-point laser, DLP 3D printer projects a cross-section of each individual layer to cure all of the resin at once. DLP printers work faster than comparable SLA printers as they cure the entire layer at one time.
Although they can produce good surface detail, their detail quality is compromised by the number of
pixels on the projection screen.
Ideal applications:
- Rapid prototyping
- Healthcare
Selective Laser Sintering (SLS)
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Selective laser sintering (SLS) 3D printers use a very fine laser to melt, fuse, and solidify thermoplastic powder particles. The printer spreads a fine layer of material onto the print bed and traces the object geometry onto the powder. The print bed then lowers by the height of one layer and the process repeats until the part is complete. SLA 3D printing can produce extremely fine and accurate details comparable to injection moulding. Engineering-grade resins allow for the production of flexible, strong, and elastic parts and prototypes. Additionally, medical and dental resins make SLA suitable for healthcare applications. SLA-printed parts require extensive post-processing. After support removal, they must be washed with isopropanol to remove excess resin and they may require additional curing.
Ideal applications:
- Rapid prototyping
- Healthcare
Material Jetting 3D printing
Material jetting is an umbrella term covering a variety of often proprietary 3D printing methods, like Multi Jet Printing (MJP). Material jetting resembles 2D printing in that the printer deposits droplets of UV-curable ink through an inkjet head. A UV light solidifies the ink, forming the part structure. Material jetting is highly accurate and enables printing with multiple materials and even colours at once.
Using water-soluble ink for support structures simplifies post-processing. However, due to the
proprietary nature of the technology, the machines and materials can be very costly.
Ideal applications:
- Rapid prototyping
- End-use parts production
- Repair and Restoration
Metal 3D Printing
Metal 3D printing is its own set of technologies, developed alongside plastics since the late ‘80s. Some AM methods, such as metal FDM and SLS can print metals, but there are also other technologies aligned with metal printing, like powder bed fusion. Metal 3D printing can create more complex geometries than casting, forging, or most other
conventional manufacturing methods. It also enables optimising part structures for improved
functionality, lighter weight, and reduced assembly requirements.
3D printing with metals is still a developing field and the economies of scale are not yet ready for mass
adoption. However, the technology is advancing fast and is well-positioned for use in industries such as
aerospace. In addition to prototypes, 3D-printed metal parts can be machined for better surface quality
and tighter tolerances necessary for end-use parts.
Ideal applications:
- Rapid prototyping
- End-use parts
- Repair and restoration
Large-Scale 3D Printing
Any 3D printer with a sufficiently sized build volume can count as large-scale 3D printing. Generally, build chamber dimensions upward of 500 x 500 x 500mm can be considered large-scale. However, there are manufacturers who specialize in large-scale 3D printers. Large 3D printers generally use FFF technology due to its ability to produce sufficiently durable parts at
an efficient cost. However, specific machines using other technologies are also available. Large-scale 3D
printing is often used to create display pieces for marketing or entertainment, but some manufacturers
also use it to produce end-use parts for demanding applications in energy production and other
industries.
Ideal applications:
- Rapid prototyping
- End-use parts production
- Large-scale modelling
Applications of 3D Printing
3D printing and AM are versatile solutions due to the breadth of technologies and material options.
They’re increasingly common in nearly all fields of manufacturing. The most common end-use cases for
3D printing include:
1. Rapid prototyping
2. End-use parts production
3. Large-scale modelling
4. Healthcare
5. Repair and restoration
Rapid Prototyping
3D printing was originally known simply as “rapid prototyping,” which showcases the technology’s ability to shorten product development cycles. Prototyping is the most common application for 3D printers. 3D printers can create functional, detailed prototypes in a matter of hours. They are popular for creating demonstration models and design iterations in all industries, from consumer goods to automotive and aerospace manufacturing.
End-Use Parts Production
Some 3D printing technologies, like SLA and SLS, are capable of using industrial or engineering-grade materials to produce functional end-use components. 3D printed parts are in use across industries, from consumer goods and packaging to fashion, automotive, aerospace, and energy. Additionally, printing a near-net shape in metal and machining it to final tolerances is an emerging application in demanding industries. 3D printers also enable bridge production, defined as manufacturing end-use components through AM until a conventional injection moulding product line can be set up.
Large-Scale Modelling
Large-scale 3D printing is a common prototyping tool in automotive and aerospace production. It’s also used in architecture and arts to manufacture scale models, film props, sculptures, and more. Large-scale 3D printing has also emerged as a marketing tool. It’s well-positioned to produce displays and props for marketing stands rapidly and cost-effectively.
Healthcare
Bio-compatible materials have made 3D printers an increasingly popular tool in dentistry and other medical applications. 3D printers can produce parts fast and they enable doctors and medical professionals to easily customise parts to ensure patient comfort and quality care. It’s possible to 3D print dental appliances such as straighteners, in addition to surgical guides and implants, for example. AM is also ideal for producing prosthetics due to its ability to print durable, cheap, and customisable parts.
Repair and Restoration
3D printers enable the production of spare components for obsolete or out-of-production machinery. 3D scanning existing parts into CAD files makes it possible to reverse engineer components and improve their performance characteristics by modifying and optimising their structures. Some metal 3D printing technologies can repair broken or damaged components by depositing new metal material at the point of breakage. All these options can help manufacturers extend the lifespan of their machinery and reduce lead times and costs when acquiring spare parts.