Your Guide to 3D Printers: 7 Types of Technologies and Which is Best for You

3D Printers 2019

Want to purchase a 3D printer but not sure which one to select? Want to know more about the various 3D printing technologies, and what is the latest innovation in the market?

3D printing, also known as additive manufacturing, is a process whereby three-dimensional solid objects are created from a digital file. Here are seven technologies that you need to know about 3D printing, and what is good and bad about each of them!

1. Material Extrusion

In material extrusion, the first 3D printing technology we are going to introduce, is a process of using continuous thermoplastic, composite material or Metallic Filament, fed through an extruding nozzle, where it’s heated and then deposited onto a build platform layer by layer to construct 3D parts.

Fused Deposition Modelling (FDM)

In FDM 3D printers, a common material extrusion process in many inexpensive, domestic and hobby 3D printers, the material is drawn through a nozzle, heated and deposited layer by layer. You might also hear about FFF – (Fused Filament Fabrication) which is commonly used for producing non-functional prototypes, or cost-effective rapid prototyping for multiple iterations of the same object. Both are actually similar terms, however, the FDM Technology was invented more than 20 years ago and has been patented under a trademark with Stratasys founder Scott Crump, while the FFF was created by the RepRap community so people could discuss the technology without fear of infringing on trademarks when 3D Printing gained popularity with makers.

PROs of Material Extrusion

Very simple-to-use and easily maintained

Supported production-grade thermoplastics are mechanically and environmentally stable

Complex geometries and cavities that would otherwise be problematic become practical with Material Extrusion technology

A wide range of thermoplastic materials is available in filament, suitable for both prototyping and some non-commercial functional applications.

CONS of Material Extrusion

FDM has the lowest dimensional accuracy and resolution compared to other 3D printing technologies, so it is not suitable for parts with intricate details.

FDM parts are likely to have visible layer lines, so post processing is required for a smooth finish.

The layer adhesion mechanism makes FDM parts inherently anisotropic

2. Vat Polymerisation

In vat polymerisation, a photopolymer resin is exposed to the light of a specific wavelength and undergoes a chemical reaction to become solid, together with a number of additive technologies to build up a solid part one layer at a time.

Stereolithography (SLA)

Under SLA 3D printers, it’s UV light source is a laser, precisely controlled by rotating mirrors to draw out each layer being printed.

PROS of SLA

SLA can produce parts with very high dimensional accuracy and with intricate details.

SLA parts have a very smooth surface finish, making them ideal for visual prototypes, such as clear, flexible and castable parts.

Short Lead time.

CONS of SLA

Resins are too photosensitive which will affect parts quality, More brittle compared to FDM & SLS process

The properties and visual appearance of parts are affected by Heat, Moistures & Chemicals.

Material are costly in large resin volume.

Digital Light Processing (DLP)

Instead of lasers, Digital Light Processing (DLP) printers have UV projectors, which work by using micromirrors to control the projected light.

PROS of DLP

Very high dimensional accuracy and with intricate details.

Fast Lead time, almost faster than SLA printing.

Less running costs than SLA as usually uses a shallower vat of resin, reducing waste.

CONS of DLP

Less Accurate compared to SLA But more accurate than FDM or Material Jetting.

The properties and visual appearance of parts are affected by Heat, Moistures & Chemicals.

Material Are costly in general, resins are far more expensive than filaments, and the regular replacements of resin tanks and occasionally print platforms also adds up

3. Powder Bed Fusion (Polymers)

Powder bed fusion (PBF) uses a heat source (eg, laser, thermal print head) to consolidate materials in the form of powder to form 3D objects.

Selective Laser Sintering (SLS)

This is a 3D printing technique that uses laser to sinter powdered material (typically nylon or polyamide), automatically aiming the laser at points in space defined by a 3D model, binding the material together to form a solid.

Multi Jet Fusion (MJF)

IN MJF 3D printers, materials used are thermoplastic polymers (usually Nylon) that come in a granular form. An ink is dispensed on the powder that promotes the absorption of infrared light. An infrared energy source then passes over the building platform and fuses the inked areas.

4. Powder Bed Fusion (Metals)

This is a 3D printing process whereby complex geometries are created by melting layers of powdered metal with a laser or electron beam.

Direct Metal Laser Sintering (DMLS)

A 3D printing technology that uses lasers to fuse powdered metals into functional prototypes and end-use parts.

Electron Beam Melting (EBM)

A fast prototyping or 3D printing technique designed to use a high power-density laser to melt and fuse metallic powders together.

Selective Laser Melting (SLM)

A 3D printing technology that uses fuses metal powder using an electron beam to build parts.

PROS of Powder Bed Fusion

Relatively inexpensive

Suitable for visual models and prototypes

Ability to integrate technology into small scale, office sized machine

Powder acts as an integrated support structure

Large range of material options

CONS of Powder Bed Fusion

Relatively slow speed

Lack of structural properties in materials

Size limitations

High power usage

Finish is dependent on powder grain size

5. Material Jetting

One of the fastest and most accurate 3D printing technologies. It builds parts layer upon layer using liquid photopolymer droplets, which are cured and made solid with UV light.

Drop on Demand (DOD)

3D printing technology that uses a pair of ink jets to deposit the build materials. One deposits the build materials, which is typically a wax-like material. The second is used for dissolvable support material. As with typical types of 3D printing technology, DOD printers follow a predetermined path to jet material in a point-wise deposition, creating the cross-sectional area of an object layer-by-layer.

PROS of Material Jetting

Fast build speed and excellent targeted dimensional accuracy

Ideal for Aesthetics and smooth surface quality-built parts.

Flexibility in production and options for certain customization.

CONS of Material Jetting

Material and Machine are costly in general.

parts are structurally weak, meaning they’re not ideal for components that must handle some kind of load.

Mechanical Strength are relatively weak and parts are brittle compared to other printing technologies.

6. Binder Jetting

In this 3D printing technology, a binder is selectively deposited onto the powder bed, bonding these areas together to form a solid part layer by layer. Commonly used materials are metals, sand, and ceramics in a granular form.

PROS of Binder Jetting

Parts can be made with a range of different colours

Uses a wide range of materials from metal, polymers and ceramics

The process is generally faster

Large number of different binder-powder combinations and various mechanical properties

CONS of Binder Jetting

Not always suitable for structural parts, due to the use of binder material

Extra post-processing lengthens the overall process

7. ARBURG Plastic Freeforming (APF)

With the ARBURG Plastic Freeforming (APF) 3D printing technology, you can tap into a whole new range of options for industrial additive manufacturing. Currently the newest 3D printing technology in the market, ARBURG’s open freeformer system can produce functional parts using qualified standard granulates via a layer-by-layer application of tiny plastic droplets. A key feature of the open freeformer system is that the same qualified standard granulates as used for injection moulding can be used. This means you can efficiently produce individual parts and small batches from original materials, but also individualise mass-produced items.

PROS of APF

Open-source, able to use any plastic or polymer material of your choice

Save cost by using inexpensive materials instead of being restricted to limited and expensive materials

Flexibility in terms of special support materials for unusual or complex 3D geometries

Able to print functional parts from original materials

CONS of APF

Only for small batch production, unable to cater to massive batch production

Only available for plastics and polymers

References: 

Loughborough University. (2019) The 7 Categories of Additive Manufacturing. Retrieved from: https://www.lboro.ac.uk/research/amrg/about/the7categoriesofadditivemanufacturing/

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