Polymer Filaments (3D Printers)
the most common consumables used in consumer 3D printers using the FDM (fused deposition modeling) technology. A traditional inkjet printer needs ink cartridges in order to be able to print – the situation is similar for 3D printers, except that 3D desktop-type printers need plastic filament. These consumables are mostly available online in a variety of types of material (ABS, PLA, PVA, etc.), colors, diameters and lengths
ABS (Acrylonitrile Butadiene Styrene)
ABS is used in a very large variety of applications in the industry nowadays. Examples include, among many others, the manufacturing of pipes (like drain, waste or vent pipes), automotive components, electronic assemblies, protective headgear (ABS has good shock absorbing properties), kitchen appliances, music instruments, protective carrying cases and toys, among which the most notable are the famous Lego bricks
ABS is generally very durable and strong, slightly flexible and quite resistant to heat. 3D printers able to process ABS plastics normally operate with a hot end (the heated part melting the plastic, before it’s forced through the print nozzle) at a temperature around 210-250°C. Therefore, a 3D printer able to process ABS is necessarily equipped with a heated printbed, in order to prevent warping or cracking of the printed materials.
When it comes to cost, ABS is the cheapest plastic of the three filament types analysed and until recently was the favourite material of the 3D printing community. The material is suitable for a very large variety of purposes, especially as it can easily be sanded (to smooth the printed objects and remove jagged edges) and painted. Printed or broken parts can simply be glued together with ABS glue and it is easily soluble in acetone (i.e. nail polish remover). ABS is generally available in white, black, red, blue yellow and green colors or transparent and has a matte appearance.
But ABS also has some drawbacks. First of all, it is a petroleum-based non-biodegradable plastic, that can be recycled though. Another problem is that ABS does create (mild) fumes which may irritate more sensitive persons – an installation of the printer in a well ventilated area or even a specific fume hood may be necessary. More recently, 3D printers with integrated HEPA filters have been hitting the market. ABS can also deteriorate by prolonged exposure to sunlight.
If you are not using your ABS spool over a longer time, you should store it properly in an airtight container. ABS does attract moisture from the ambient air, which may affect your prints.
PLA (Polylactic Acid)
PLA is a biodegradable thermoplastic which is derived from renewable resources, such as cornstarch, sugar cane, tapioca roots or even potato starch. This makes of PLA the most environmentally friendly solution in the domain of 3D printing, compared to all the other petrochemical-based plastics like ABS or PVA. PLA is used for example in medical suturing as well as surgical implants, as it possesses the ability to degrade into inoffensive lactic acid in the body. Surgically implanted screws, pins, rods or mesh simply break down in the body within 6 months to 2 years
But, PLA is also used in food packaging, bags, disposable tableware, upholstery, disposable garments, hygiene products and even diapers. PLA is therefore considered as pretty safe. For those wanting to print PLA drinking cups or other recipients destined for food or drink, a word of caution though: do not forget that the coloring pigments in the filament may not be as harmless as the PLA itself. Unfortunately, the notice of use nearly never documents the chemical composition of those pigments in order to inform about their harmlessness or potential toxicity.
PLA is tough, but a little brittle, once it has cooled down. Its temperature threshold is lower than the one of ABS, as PLA is normally extruded around 160°C-220°C. A heated printbed is not mandatory, but it may (at temperatures around 50-60°C) be beneficial to the quality of the printed object. PLA is quite slow to cool – experts recommend sometimes to install a fan pointed at the extruded material in order to speed up the cooling process. Once it is heated, PLA does emit a slight odor, best described as sweet corn, pancakes or maple syrup – but it does not emit fumes like heated ABS. No fume hood will be necessary and you may safely print with PLA in-house.
PLA can be sanded down and may be painted over with acrylic paint, but some people recommend using a primer. Glueing PLA is however not as easy as glueing ABS. Most people seem to get some results with cyanoacrylate (i.e. super glue), but this does have some disadvantages of its own (use of safety glasses and gloves, extreme stickiness to fingers and other body parts, very quick hardening, etc.).
PLA has become a very popular choice in the 3D printing community, considering its low toxicity and its better environmental friendliness, compared to all the petroleum-based plastics. Its main drawbacks are that it cannot stand too much heat, as standard PLA becomes soft around 50°C (i.e. you can re-heat your printed object with a hot air gun, for example). On the other hand, one may consider this an advantage in order to easily repair, bend or weld printed parts.
PVA (Polyvinyl Alcohol)
PVA is a special plastic that is water-soluble. It is most commonly used as paper adhesive, as thickener, as packaging film, in feminine hygiene and adult incontinence products, as mold release agent or in children’s play putty or slime. Another wide use is in freshwater sport fishing, where PVA bags filled with bait are thrown into the water. The bag rapidly dissolves, releasing the bait, in order to attract the fish.
In 3D printing, PVA is sometimes used in printers with dual or multiple-extruders, in order to provide a support structure to an object with overhang issues. Some complex prints involving lots of overhangs (areas where there is no support under the upper layers) can be realized only by printing such a support structure. Otherwise, the printed structure would warp or simply collapse. The finished object can be put into water until the PVA has completely dissolved, freeing the object of the support structure, without the need of any pesky manual post-printing curing.
PVA is normally extruded a temperature of 190°C, but is not very easy to use, as it attracts water so much. Ambient air moisture will deteriorate the filament very quickly. PVA needs to be stored in a sealed box or container together with a desiccant and may need to be dried before use. Another disadvantages of PVA include its high price and quite difficult sourcing.
PVA is normally extruded a temperature of 190°C, but is not very easy to use, as it attracts water so much. Ambient air moisture will deteriorate the filament very quickly. PVA needs to be stored in a sealed box or container together with a desiccant and may need to be dried before use. Another disadvantages of PVA include its high price and quite difficult sourcing
PET
PET (PolyEthylene Terephthalate) has become well known from plastic bottles. In its original state PET filament is a colorless and crystal clear material. But when you heat or cool down the material changes its transparency. The material has more crystalline structure when allowed to cool down slowly after printing. The filament is fairly hard and shockproof, so it makes it ideal for lightweight items.
Generally PET is nice and easy material to print with quite wide temperature range from 160°C to 210°C without any problems. But it needs to be stored in a place where it would not absorb water from air.
PA (Polyamide)
PA is used for producing some of the cheapest 3D printing filaments. PA is less brittle than PLA and ABS, thus much stronger.Additionally, it features self-lubricating properties, ideal for gears printing.
Polypropylene (PP)
PP has a very broad area of application. The combination of good flexibility, good chemical resistance, and food safe characteristics make this material an excellent choice for various containers, packaging, bottle caps and much more.
It has also found its place in the 3D printing industry offering durability and good flexibility at the same time. PP 3D printer filament enables you to print objects and parts for more specific uses. Since many household objects are made of PP plastic, it is possible to recycle old junk and turn it into new PP filament for your 3D printer.
PP 3D Printer Filament Properties:
Primary benefits are flexible, tough, fatigue resistant
Ideal for household items, containers, packaging
Good durability and flexibility
Not soluble
Food safe in pure form: refer to manufacturer for more details
General print temperature is 210 – 230°C
Shrinkage during cooling
Heated bed required
Printing difficulty is high