A Guide To 3D Printing Technologies in 2020

What 3D printing technologies are in the market today?

3D printing, otherwise known as Additive Manufacturing, refers to the building of a three-dimensional object from a computer-aided design (CAD) model. “3D Printing” is an umbrella term. This general term consists of many types of 3D printing technologies including solid, liquid and powder processes. Each of these 3D printing technologies provides a different finishing for your product. Use this handy guide to determine which additive manufacturing process is most suitable for your end product.

1. Fused Deposition Modeling (FDM)

3D Printing Singapore FDM

Let’s start with the most basic and common 3D printing technology – Fused Deposition Modeling (FDM). If you’re a complete newbie to 3D printing, this is the easiest one for you to experiment with. 

FDM involves the depositing of material, layer by layer, onto the printing bed until an object is formed. It works by first loading a spool of filament into the 3D printer. Common filament materials include ABS, PLA, TPU or PETG. The material is then pushed into the nozzle to be melted upon reaching its melting point. Afterwhich, the filament is then extruded to create a 3D object layer by layer along a specifically determined path. 

Many choose to use FDM due to its low cost and fast turnaround time in comparison to other additive manufacturing technologies. The 3D printing process is also clean and simple to use. Therefore, it is highly suitable for home and office use. 

As the technology is widely accessible, it has a large range of thermoplastic filaments and materials available for selection. One of the key benefits of FDM is that its materials are highly durable. Their mechanical properties are also stable over time. Therefore, the production-grade thermoplastic materials used in FDM are suitable for detailed functional prototypes, end-use parts, durable manufacturing tools as well as low volume manufacturing parts.

You can usually spot some fine lines on parts printed with FDM technology.

2. Stereolithography (SLA)

SLA 3D Printing Technology

Stereolithography (SLA) is the world’s first 3D printing technology. It was invented by Chuck Hall in the 1980’s. The 3D printing technology works by making use of light-reactive thermoset materials called “resin.” SLA uses a light source (a laser or projector) to cure and harden liquid resin into the desired 3D shape.

In comparison to FDM technology which prints from bottom to top through material extrusion, SLA forms the object from top to bottom. In SLA, the build platform eventually lifts the solidified model upwards, out of the resin bath. 

Key benefits of SLA include smooth finishing, high precision and accuracy as well as fine detail. It is among the most accurate forms of 3D printing. Therefore, SLA is preferred for producing objects such as prototypes and moulds that can facilitate production of structures of complex geometries, like jewellery.

3. Digital Light Processing (DLP)

DLP

Digital Light Processing (DLP) is a 3D printing technology similar to SLA. However, unlike SLA, the technology uses a safelight (light bulb) in place of a UV laser to cure the photopolymer resin. It makes use of more conventional light sources, controlling the light using micro mirrors to control the light incident on the surface of the object being printed. The liquid crystal display panel works as a photomask. This mechanism allows for a large amount of light to be projected onto the surface to be cured. Therefore, the resin hardens quickly. 

In comparison to SLA, DLP can print at a faster speed. This is because an entire layer is exposed all at once rather than tracing the cross-sectional area with the point of a laser. The technology uses the same photopolymer resins as SLA.

DLP is suitable for objects that require high detail. 

4. Selective Laser Sintering (SLS)

Selective Laser Sintering (SLS) is a powder-based 3D printing technology. The 3D printing technology was first invented in the mid 1980s. SLS makes use of a high powered laser that selectively scans a thin layer of powder and sinters the small powder particles together to form 3D object, layer by layer. 

Unlike most other additive manufacturing technologies, SLS does not require any form of support as the leftover unsintered powder acts as self supporting material. Thus, extremely complex geometries are made possible. 

The 3D printing technology is a great choice when 3D printing functional prototypes as SLS printed parts are robust and will not become brittle over time. In fact, the durability of parts created with SLS technology is on par with those produced through traditional manufacturing methods such as injection moulding. 

In comparison to MJF, SLS also has more material options.

Therefore, SLS is suitable for a variety of applications from rapid prototyping to low volume manufacturing due to low cost per part, high productivity and established materials.  

5. Multi Jet Fusion (MJF)

MJF 3D Printing

Multi Jet Fusion is a relatively new 3D printing technique unveiled by HP in 2016.

Similar to Selective Laser Sintering (SLS) technology, MJF is a powder 3D printing technique. The main difference between the two techniques lies in the heat source, as the latter requires less heat in the process.

During MJF, a fusing agent is applied on a material layer where the powder particles are supposed to fuse together. Simultaneously, a detailing agent that inhibits sintering is printed near the edge of the part. Afterwhich, a high-power IR energy source runs through the build bed. It simultaneously sinters the areas where the fusing agent was dispensed while leaving the rest of the powder untouched. The process repeats until all parts are complete.

MJF can  also create ultra-thin layers of 80 microns, which produces parts with high density and low porosity compared to the same PA 12 parts printed with SLS. In addition, parts printed are stronger and more precise.

6. Selective Laser Melting (SLM)/Direct Metal Laser Sintering (DMLS)

Both Direct Metal Laser Sintering (DMLS) and Selective Laser Melting (SLM) produce objects in a similar manner to SLS. The main difference is that these types of 3D printing technology are applied to the production of metal parts. SLM uses a high power-density laser to melt and fuse metallic powders together. 

SLM manufactures functional components with high structural integrity at a low cost. The technology is compatible with various materials including biocompatible titanium alloys. 

Unlike SLS, the DMLS and SLM processes require structural support. This is to limit the possibility of any distortion that may occur. 

DMLS/SLM parts are at risk of warping due to the residual stresses produced during printing, because of the high temperatures. Parts are also typically heat-treated after printing, while still attached to the build plate, to relieve any stresses in the parts after printing.

7. Electron Beam Melting (EBM)

Electron Beam Melting (EBM) uses a high energy beam, or electrons, to induce fusion between the particles of metal powder. 

The 3D printing technology uses an electron beam to fuse metal particles and create the desired part, layer by layer. An electron beam scans across a thin layer of powder, causing localized melting and solidification over a specific cross-sectional area. These areas are built up to create a solid object.

In comparison to SLM and DMLS types of 3D printing technologies, EBM boasts of a superior build speed due to higher energy density. However, its powder particle size, layer thickness, and surface finish are typically larger.

The technology is usually applied in aeronautics and medical applications. One common application is for turbine blades or engine parts. 

8. Laminated Object Manufacturing (LOM)

Laminated Object Manufacturing (LOM) is a technology for the purpose of rapid prototyping. During LOM, layers of adhesive-coated paper, plastic or metal laminates are glued together and cut to shape with a knife or laser cutter.

An LOM apparatus uses a continuous sheet of material — plastic, paper or (less commonly) metal — which is drawn across a build platform by a system of feed rollers. Plastic and paper build materials are often coated with an adhesive. To form an object, a heated roller passes over the sheet of material on the build platform, melting its adhesive and pressing it onto the platform. A computer-controlled laser or blade then cuts the material into the desired pattern. The laser also slices up any excess material in a crosshatch pattern. This makes the support material easier to remove when the object is fully printed.

After forming one layer of the object, the build platform lowers by about one-sixteenth of an inch, which is the typical thickness of one layer. New material is then pulled across the platform. The heated roller again passes over the material, binding the new layer to the one beneath it. Until the final object is formed, this process repeats itself.