You Guide to 3D Printers:
7 Types of Technologies and Which One 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, a filament of solid thermoplastic material is pushed through a heated nozzle for melting, then deposited on a build platform along a predetermined path, where it cools and solidifies to form a solid.

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.

PROS of Material Intrusion

Common and low cost process

ABS plastic usable – good structural properties and easily accessible

CONS of Material Intrusion

Final quality is reduced and limited by nozzle radius

Low speed and accuracy due to limited thickness of the material nozzle

Requires constant pressure of material to increase quality of end product

2. Vat Polymerisation

In vat polymerisation, a vat of liquid photopolymer resin is used where the model is built layer by layer and ultraviolet (UV) light is used to cure or harden the resin.

Stereolithography (SLA)

Under SLA 3D printers, polymers are formed by creating models, prototypes, patterns, and production parts in a layer by layer fashion using photochemical processes by which light causes chemical monomers to link together.

Digital Light Processing (DLP)

A 3D printing process that works with photopolymers, using a more conventional light source applied to the entire surface of the vat of photopolymer resin in a single pass, generally making it faster.

PROS of Vat Polymerisation

High level of accuracy and quality finish

Relatively quick process

Typically for large build areas

CONS of Vat Polymerisation

More expensive

Longer post processing time and removal from resin

Limited material usage of photo-resins

Requires support structures and post curing for parts to be substantially strong for structural use

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)

A 3D printing technology that uses a pair of ink jets to deposit the build materials and add the soluble support material. It follows the path in a point-wise deposition, creating the cross-sectional area of an object layer-by-layer.

PROS of Material Jetting

High accuracy of deposition of droplets hence low waste

Multiple material parts and colours under one process

CONS of Material Jetting

Support material is often required

Materials are limited and only polymers and waxes can be used

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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