ASA, ABS, PLA, Nylon, polycarbonate, composed materials
Which materials does a 3d printer use, and which ones should I choose? Approaching this world, this is one of the first questions coming on mind. Different 3d printing materials change with the kind of 3d printing technology. Once again we are focusing on FFF – Fused Filament Fabrication (or FDM – Fused Deposition Modeling), that means printing objects through the melting of 3d printer filament made by polymers, because this is the easiest technique. Filament, usually with a diameter between 3 and 1.75 mm, is heated by a resistance and, passing through a nozzle, it lays down layer after layer taking the shape of the object that we are printing. So let’s go into the substance of the main materials used for this technology, analyzing differences and applications.
ABS and PLA are the most widespread 3d printing materials. They are two thermoplastic polymers: it means that they become flexible and manipulable at high temperatures and go back to solid cooling down (reversible process). The choice between these two materials is an eternal dilemma. There are hundreds of supporters fighting for each cause, but it doesn’t mean that it’s not possible to draw up precise features that distinguish the two polymers. The truth is that for a good choice you should just try both ABS and PLA, using them depending on what you want to do.
ABS filaments (Acrylonitrile, Styrene, Acrylate) can be used to create light and rigid objetcs, like, for example, Lego bricks, parts of car body, hydraulic tubes, musical instruments like flutes or clarinets. ABS derives from petroleum. It is soluble in acetone (so you can sand it with a brush, or weld different pieces with few drops of fluid).
Strengths: lightness, strength, durability, resistance to high temperatures (up to 100 degrees), easy to use and to reuse, good flexibility.
Weaknesses: bad smell and toxic fumes, need a heated plate, easily warping.
Structurally similar to ABS, filament ASA (Acrylonitrile, Styrene, Acrylate) resists to UV rays and water: so, getting old, it doesn’t get that typical yellowish colour (for this reason it is frequently used for outdoor furniture and objetcs).
PLA (polylactic acid) is made by a polymer derived from vegetable products processing, including corn. Naturally transparent, it can be painted, made matte or shiny. For this reason, PLA filaments are suitable for artistic and aesthetic uses, small domestic objetcs or for educational purpose in the schools. Its solvent is caustic soda.
Strenghts: ecological (vegetal origin, compostable in industrial structures), it can be extruded at lower temperatures (doesn’t need heated plate), low warping, transparent look.
Weaknesses: less strong, more rigid, it begins to deteriorate at 60 degrees.
The main benefit of Nylon is its resistance: it is much more stronger than previous polymers. Flexible and durable, it melts at high temperatures, often more than 250 degrees. Part of the synthetic polyamide family, it was originally used in textile production. Its main lack is the tendence to warping, like ABS (also with Nylon you need heated plate). Moreover, you must dry it very well before printing, because it easily absorbs water, even from the air: better dry it in the oven for few hours.
Polycarbonate is very resistent to warmth. It is often used as electrically insulating, in medical application and in some mechanical parts of mobile phones. It easily warps, so you always need a heated plate. It is one of the most tough and resistant material. It melts above 260-270 degrees.
Composed materials for 3d printing are products made by the combination of two or more materials from different origins, of which at least one made by fibre. Assembling different materials allows to improve thermal and mechanical performance and also rigidity. One of the most common composed material is polyamide with glass fibre, that needs, however, 50% of fibre at least. Another composed material, that guarantees high performances with lower percentages, is the one made on carbon fibres.