‘Specialist’ Filaments; Why you’d use them and best printing tips

Bored of regular ol’ PLA and ABS filaments? Between them, these two 3D printing industry staples can produce the majority of trinkets and basic prototyping required. For those of you with more demanding needs (or clients) there is an impressive range of new 3d print materials fast becoming available. We’re going to run through our various material filaments and their key differences here. This is going to open up a whole new world of exciting new opportunities for you.

PLA PLUS 

This is for a lot of people a very exciting material to print with. PLA filament is often underrated as not being a ‘serious’ print material due to it not have quite the same strength as ABS (although our PLA isn’t far off). PLA PLUS is our special blend of enhanced PLA, giving it the strength of ABS, while maintaining all the easy and all-natural ingredients of our regular PLA. Simple as that. With all the positives of PLA, and the strength of ABS, what other filament would you want to print with?

Printing settings are slightly higher for PLA Plus over our regular PLA, with PLUS printing at around 225-245C (245C in an Ultimaker 2) with a heated bed being optional at 65-75C.

Flexible PLA 

As it sounds, it’s a flexible version of our PLA. The gif image below is a belt drive concept printed using our black flexi PLA filament, and it’s very durable. Printed on an Ultimaker 2. Flexible PLA Belt Drive

OK, so it’s not strictly a PLA, it’s a natural Biopolymer

When printed thick or heavy % infill it produces surprisingly stiff prints.But when printed with thinner walls or lower infill, it’s a very flexible filament.

The Shore hardness rating is 55. It’s very well suited to belt drives or tank tracks for a robot vehicle as an example as although it is flexible it doesn’t stretch much. 

We’ve found the best settings to print flexible are 50% speed on fast printers, with 240-250C hot-end and 75C heated bed. Flexible PLA is also very hydroscopic (it absorbs moisture from the air easily), so it’s really important to keep it in the sealed bag when not in use.

PETG 

Our rigid.ink PETG is tough. This is PET (think strong plastic bottles) that’s glycol PETG Printed Quadcopter Bumpermodified for enhanced properties. Think stiff, clear and strong. These properties make it more durable than ABS or PLA. It’s also an excellent alternative to other filaments due to lower shrinkage, a nice smooth finish and odourless printing. It’s prints very nicely, with low warp, like PLA. This is why Otto S. decided to use PETG to print a crash bumper for his micro-quadcopter. The cat’s not been able to destroy it since.

It’s also a clear filament in its natural form, with all the available colours being translucent – although complete clarity is hard to keep after extrusion. You’re best going for thicker layer heights if this is your goal.

To print PETG for best results, think half way between PLA and ABS temperature settings; around 220-235C with a heated bed of 70-85C. If you’ve not printed with PETG filament before, it could easily be your next favourite.

ASA

“The weather resistant, UV-stable version of ABS” We’re really proud of this fast-becoming-popular material. Full name Acrylonitrile Styrene Acrylate. It’s excellent for printing weather resistant prototype parts, with the full strength of ABS. It has excellent strength and rigidity, high chemical resistance and great thermal stability. Available in a few colours, in its natural form it has a beige/cream appearance, but will not yellow over time.

The most important factor to take into consideration when printing ASA is that it doesn’t like draughty environments. That means, keep the fans way down 10-20% (but not completely off) or your print will warp, especially if it’s a larger model. Try keeping the ambient temperature of its surroundings warm too.

Nozzle temperature needs to be around 240-250C, with a heated bed of 90-110C, lowering a few degrees after the first couple of layers.

Polycarbonate (PC)

This is a really strong and impact resistant thermoplastic. It’s used in bulletproof glass and CDs, and can be bent repeatedly without cracking making it extremely durable. Not to be confused with slightly more brittle acrylics (like PMMA). It’s also very optically transparent, although like PETG this is often lost somewhat during the extruding process.

Polycarbonate filament flows really nicely around 300C hot-end temp, depending on print speed. You can get away with around 280C with a slow enough print speed if your extruder won’t reach 300C. Likewise for very fast printers, you’ll want 300C+ extrusion temp. Heated bed anything from 90C upwards and ideally in a warm environment to avoid warping when printing with PC.

A safety note: Polycarbonate can leave very fine particles when printing, so please ensure when printing any filament to use in a well-ventilated environment.

PMMA 

This is a clear plastic acrylic material that’s often used as a replacement for glass (think shatter-proof windows, rulers, ice-rink barriers, similar to Perspex). It’s full name is Poly(methyl methacrylate), PMMA filament is we think – an underused 3D printing material. We now do this in a selection of translucent colours, similar to PETG. We’re one of the very few manufactures to offer PMMA in reel form as a 3D printing filament.

245-255C is an ideal extruding temperature, with a heated bed of around 100C consistently.

Nylon 12 

Our very high grade of Nylon only recently introduced to the 3D printing world. This has been a very popular material in industry for years, due to its excellent performance and properties. Nylon 12 is a very durable, strong and versatile material to print with. It can be printed thin to be flexible and has excellent layer bonding – making it ideal to print fully usable parts, living hinges and snap fit designs for example.

Not to be confused with a lower grade Nylon 6, Nylon 12 has the lowest moisture absorption of all the Nylons, and is the most durable and stable (thermo and chemically) over a wider range of parameters. It’ll keep its strength over very high and very low temperatures. It has an impressive Shore D hardness of 84. Where the other available materials won’t cut it, and you need the best performance for your prototyping or end-use components, Nylon 12 is the superior material of choice.

Nylon parts typically won’t scratch or break, so parts last much longer than with other materials. Post print finishing and machining, where required is also straightforward. It can easily be drilled, tapped and generally used hard to produce an excellent finished part.

Nylon 12’s low density (1.05g/cc) makes it lightweight compared to many plastics, and it’s low friction coefficient and high melting temp makes it ideal for use with moving components, such as low speed bearings or gears.

Printing Nylon is best done around 255-275C, with a heated bed of around 100-110C or higher. It doesn’t bond direct to glass very well, so blue painters tape creates an excellent surface for those first few layers.

TPU 

Thermal Polyurethane is a soft, rubber-like flexible filament. It’s really flexible, more so than our Flexi PLA. It’s main useful properties include transparency, resistance to grease and oil and abrasion. It’s very elastic and durable.

TPU is us used in many industry applications, such as footwear, inflatables, drive belts and medical tools to name a few. rigid.ink has spent a while formulating our TPU filament to perform consistently, so it’s easier to print with than other flexible materials on the market. The layer bonding is unmatched and produces excellent, strong finished parts.

To print TPU, along with most flexible filaments you’ll want to use a lower speed – around 20 - 40mm/s. Print at 245-255C, with a heated bed of around 90C

Dissolvable support filaments:

Supports are used in printing when you want to create a bridge span or angle flatter than 45 degrees (the maximum overhang for non-supported prints) with a smooth underside. The support filament fills the gap, allowing the main printing material to be sufficiently supported. After printing, these dissolvable supports can then be washed away using the appropriate dissolving agent (water for PVA or Limonen for HIPS) leaving an intricate 3D print with smooth surfaces all-round.

When using support materials, you really need to use a 3D printer with either dual or more extruders so that both materials (primary and support) can be printed alternately as required during the print.

PVA 

The perfect support material. PolyVinyl Alcohol (PVA) is cold water soluble (OK, tepid or warm water works best). PVA filament has great high tensile strength and flexibility. It’s resistant to grease and oil with excellent adhesive properties. PVA is non-toxic, odourless and biodegradable which keeps it safe for humans and the environment.

As you’d expect with dissolving it’s ability to dissolve in just a few hours in water, it’s very hydroscopic, so you must keep it sealed in its bag with desiccant when not in use.

Printing settings are similar to PLA, temperatures of around 190-210C. Because of this, PVA is often used as a support for PLA, whereas HPS (below) is used more often for ABS and other higher temperature materials.

HIPS 

Unlike PLA, ABS and many other filaments, HIPS filament is not hydroscopic and is relatively easy to print with. Due to its good strength and durability it can also be used to print parts with, when no being used as a support material. Its best printed between 230-240C with a heated bed of 90-100C.

To dissolve HIPS filament after use you’ll want to use a Limonen solution. You can dilute this down, but it will take longer to dissolve.

We hope this guide has been useful for you to choose your next filament. Please feel free to get in touch if you have any specific questions on choosing a 3d printer filament, or suggestions for the next article you’d like us to write - our trained support ninjas are here to help! Alternatively just leave a comment below and we’ll respond as soon as we can.

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