14 - 3D printing and rapid prototyping

Submitted by ehanuise on Thu, 07/09/2017 - 19:24

3d printing and rapid prototyping

3d printing is increasingly more affordable, and this is a very useful tool for boardgame publishers. Rapid prototyping is a colloquial term that covers many techniques and tools that allow businesses to create working parts quickly and with very low overhead. 3d printing is only one way to do rapid prototyping, and some other techniques are very interesting for boardgames publishers too.

There are commercial 3d printing services such as http://shapeways.com or http://i.materialise.com where you can upload a 3D file and order a 3D print using miscellaneous 3D printing techniques. Some of these 3D printing techniques such as FDM or Stereo-lithography are also now available as desktop 3D printers, with increasingly affordable prices.

Each 3d printing technique has different properties, so it is interesting to understand the basics and be able to pick the right technology for your parts.

Fused deposition modeling (FDM)

This is the most common 3d printing technology for desktop printers. Filament is melted as it is fed through a nozzle. Motors move that nozzle as it builds your model in thin layers of molten plastic. This is very much like a glue pistol driven by a robot. Small FDM printers with a build size of 200x200x200mm can be found under €500 and they can build small parts with a good level of detail. They cannot however render ultra-fine details such as a detailed miniature. This is good to make pawns or parts, but not detailed enough for a small dice with numbers on the sides.

Schematic_representation_of_Fused_Filament_Fabrication_01.png

(image wikipedia)

Stereo-lithography (SLA)

These printers use liquid polymer resin. A laser or screen exposes the resin to energy in the form of light or UV. That energy triggers the polymerisation process and hardens the resin where exposed. The model built in layers, moving the already hardened parts away from the light source one layer at a time. Once the whole model has been built, it is removed from the printer, cleaned up in alcohol to remove any non hardened polymer, and the cured in UV light to make it definitely hard. The models will become brittle and break if exposed too much to sunlight once cured.

The finished models are very highly detailed, and this technique is used to create masters for jewellery moulds, dental prosthetics, and many other parts. This technique allows for models that are actually more detailed than injection moulding. and is often used by manufacturer for 3d printing samples. A desktop SLA printer can be bought for about 2000€ at the time of this writing.

SLA-Formlabs-compressed.gif

(image sculpteo/formlabs)

Laser sintering

These machines are large and expensive, running in the tens of thousand euros. A very fine layer of powdered resin is melted by a laser. Once the laser has finished melting the shape of the object to print another layer of powder is applied and the laser starts on the new layer. At the end of the print, the printer holds a large cube of powder with the printed object inside. A technician then vacuums all the unmelted powder, which will be reused, and extracts the printed object.

This is the most common technique for 3d printing services, and it can be done using a variety of materials, even metals.

The print quality is comparable to FDM, a bit less precise, with a grainy surface finish. This is good to make pawns or parts, but not detailed enough for a small dice with numbers on the sides. They are however quite sturdy, unless printed in a flexible material.

3d printing services charge by the amount of material used for the print, so hollow pieces are much less expensive than full ones.

780px-Selective_laser_melting_system_schematic.jpg

(image wikipedia)

Polyjet

This is a more recent 3d printing method, the machines are still quite expensive but prints are available through 3d printing services. Polyjet machines print in layers as most3d printers. The printing head jets layers of liquid photopolymers to build extremely detailed models. Furthermore some of these printers can mix colour pigments with the polymers and 3d print coloured models.

3d printing is very convenient to get samples of your parts and check everything is as it should before committing to the huge costs of a mould and industrial production. Many errors and issues can be spotted before the production process, and the cost of a few 3d prints at a printing service is negligible in comparison to the cost of industrial production. 3d printing is also very convenient to produce a small batch of review copies to get journalists and bloggers cover your product ahead of manufacturing. It is not suited for printing of large quantities, but can be used for small batches of exclusive add-ons.