What Technologies are there in 3D Printing?

24th November 2021

Additive manufacturing is always improving and expanding. New printing technologies are created and new approaches to existing technologies come to light as developers find faster and more secure ways of building.

The various approaches that make up the whole of 3D printing technology sometimes only differ in small ways, but each one comes with its own advantages and strengths. The majority of the technologies deal with plastics, so we’ll focus mostly on them.

FDM/FFF

Fused Deposition Modelling (sometimes called Fused Filament Fabrication) was developed by Stratasys co-founder Scott Crump in 1988. Using spools of filament and heated extruder heads, thermoplastics are melted and deposited, layer by layer, to build three-dimensional parts.

FDM’s main advantage lies in its ability to work with very high-performance materials. Stratasys offers Nylon 12 Carbon Fiber filament, which has already proven itself a gamechanger for manufacturers who need a strong and lightweight alternative to cumbersome metal tooling. 35% carbon fibre content ensures high tensile strength that can meet a wide variety of industry applications.

Other materials useable with FDM printing include food and biocompatibility-certified ULTEM plastics, which possess high heat and chemical resistance, and PEKK-based Antero plastics which hold excellent mechanical properties that make them equally suitable for the factory floor and top-grade aerospace applications.

Whilst not the leading technology for aesthetic jobs that require novel textures and colours – read on for the champion of that particular area – FDM is a reliable printing process that creates tough parts even when handling complex geometries. From prototyping to end-use parts, FDM can handle it all.

Material Jetting

Material Jetting employs a different approach to FDM. It works using liquid photopolymers rather than thermoplastic filament. Additionally, it sprays droplets of the plastics as opposed to heating and extruding them, not dissimilar to an inkjet printer.

As they’re deposited, the droplets are cured using UV light to instantly solidify and harden them. The end results have great surface finish and smoothness. Stratasys’ version of this 3D printing technology, PolyJet, can create simulated textural finishes that look and feel like fabric, wood, and other materials.

Though it can create useable jigs and fixtures, Material Jetting is best when focused on aesthetics. The textures and colours of its photopolymers make it best for fast prototyping with realistic finishes. Material Jetting is the technology of choice for designers and product testers.

SLA and DLP

Differing slightly in their approaches to curing materials, both stereolithography and Digital Light Processing work with resin to create their pieces. The build platform is lowered into a tank of the liquid resin, where it is cured in the shape of each individual layer using either laser or light, respectively. As the layers are cured, the platform lifts up to create the next. In a sense, resin-based printers build upside down compared to other technologies.

SLA was arguably the very first 3D printing technology to be studied and built upon as a method of manufacturing. Using mirrors that direct a laser beam to the correct coordinates, the cured layer of resin is separated from the bottom of the tank and the build platform is raised up to create room for the next.

DLP differs procedurally from SLA by using a digital light projector in place of a laser. The projector flashes an image of the layer onto the resin, curing multiple points at once. Since the layers are projected from a digital screen and composed of pixels, each actual layer is built in voxels, the three-dimensional equivalent of the two-dimensional pixel.

DLP printers like the Stratasys Origin One create parts with a smooth surface finish without the need for post-processing, and though this printer in particular has an optimised build volume, resin-based printers often face a balancing act between build resolution and build volume.

SLS and SAF

Using polymer powders as their build material, Selective Laser Sintering and Selective Absorption Fusion are part of what is called Powder Bed Fusion (PBF) manufacturing.

SLS uses a laser to directly sinter the polymer powder to create a solid part. The powder is heated by the printer until it is just below its melting point, allowing the laser to apply the final points of heat so that it can be fused into a hard material.

The powder is distributed in even layers with a build platform that lowers as each cross section of the part is created. Loose unprocessed powder is left to accumulate and provide support to the part, eliminating the need for separate support material. This allows many nested parts to be arranged within the powder ‘cake’ without concern for overhang or position along the Z axis.

SAF is a Stratasys technology that employs an infrared-sensitive High Absorbing Fluid alongside the powder. This fluid is jetted into specific areas according to the shape of the layer, which is then exposed to infrared energy causing the powder to fuse.

The Takeaway

There are more technologies to 3D printing, and not all of them deal solely with plastics. Ceramic and metal printing technologies have come a long way in recent years, and the results are improving all the time. Additive manufacturing is increasingly being employed across the globe to solve affordable housing problems.

Each 3D printing technology has its strengths and weaknesses, and applications in which it’s better suited than others. Some, like FDM, are adept at handling many areas across low and high-impact uses.

To better understand what one printer can do over another, we always recommend speaking to our dedicated experts at SYS Systems, certified Stratasys Platinum Partner for nine consecutive years.

Get in touch with us here and talk about additive manufacturing today.

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