Additive Manufacture and Rapid Prototyping

What goes into a 3d FFD (Fused Filament Desposit) Printer?

3D Printing / Rapid Prototyping

3D printing is an additive manufacturing process. The print material is usually forced through a heated nozzle, giving a fine degree of control over what is being printed. Common plastics used include ABS, and PLA.

3D printing enables direct output from 3D CAD (computer aided design) models. This means that we can get exact reproductions of what the original designer intended.

Another method of 3D printing involves using inert powders which have a release agent inside them, preventing the plastic granules from 'sticking' where the designer does not intend for plastic to be (e.g. the hole inside a cup). When the part is removed the powder can then be reused in another 'print'. This is called Selective Laser Sintering (SLS).

3D printing is often mixed up with rapid prototyping. Rapid prototyping often makes use of 3D printers as these can often be placed inside design facilities and enable designers and engineers to quickly make a prototype, visualise it and then make iteractive changes to their design without the need to wait for specialist tooling.

Amazing fact - The International Space Station even has a 3D printer enabling engineers on the ground to create custom tools to solve problems as they are discovered. They can then be sent digitally to space and made on-site saving the need for a 'space truck' to have to be launched on a rocket on a supply mission.

3D printing is a rapidly evolving technology and it is now possible to 3D print in all sorts of materials, e.g. concrete, metal, even food! Watch the video above to see how it is changing the world.

Additive manufacturing is a process where individual layers of material are positioned one at a time with the print head moving upwards allowing the component to be made taller and taller.

Watch how 3D printing concrete is enabling architects design and builders construct innovative buildings around the world!

Disadvantages of 3D printing

Limited range of materials (presently but getting larger all the time).
Build volume (length x width x height) is limited by the machine.
Post processing required with some materials resistant to finishing e.g. sanding or polishing. PLA notably cannot be finished.
Expensive and large volumes do not bring the cost down further.
Some parts need support structures to stop the build from collapsing.
Some printers have low tolerances reducing the build quality (think like picture resolution. The smaller the print head the more accurate the print resolution, the better the finish).
Digital files can be copied and so other peoples work can be copied without permission (copyright theft) leading to counterfeit goods.

What goes into a 3d FFD (Fused Filament Desposit) Printer?

There are hundreds and hundreds of different 3D printers on the market and more are being produced each week as the technology becomes less expensive and more freely available. All of the FFD type printers share the same core technology.

This document explains them main components.

Anatomy of a 3D Printer.pdf

Support Structures

Consider the low-resolution (print accuracy) of the fox. The orange material is underneath the fox and there to help support the weight of the fox so that the material doesn't fall back down to the print bed.

If it wasn't there, the print would not retain its shape and would end up a 'wormy' mess of spaghetti like print filament.

The support structure is often wasted as it is thrown in the bin, however most 3d print materials are actually 100% recyclable so should be properly reprocessed to make new material. Unfortunately not everyone has access to reprocessing facilities so it is not always recycled.

Not all 3D printed parts need support structure, however any parts which have large overhangs will need it and it must be considered during the design of the part.

Careful consideration must also be given to the orientation (which way up) the part goes into the printer as this will affect the strength and the quality of the final print.

Examples of 3d printed parts which require support structures

Post Processing

Many people mistakenly believe that objects which have been 3d printed can 'magically' be put into use straight after manufacture. This is not the case as it is often necessary to remove the imperfections which are caused as a result of the making process. For example: the removal of burrs (sharp edges), structural supports (required to prevent overhangs or protrusions from drooping or sagging due to their weight) or even removing the lines or striations caused by the different layers.

This video helps explain some of the post processing required for 3d prints.