• craigcone

Material Selection Guide

Updated: May 19, 2019

ProtoPrint Materials:



PLA:

PLA (or polylactic acid) is by far the most common material used in FDM 3D printing today. Reasons abound as to why it's so popular, but the main reason is its ease of printability and low cost. One reason it's great for test prints and prototypes is that its biodegradable. PLA is usually derived from plant starches, so when you're making something that you know you may throw away soon after the print is complete it's good to know that it isn't going to just be filling up a landfill somewhere. Because of its low thermal expansion (meaning it doesn't expand or contract much due to temperature changes) it's a great material for printing large objects, and objects that require tight dimensional tolerances. One problem with PLA is that over time - if your model is holding some kind of load (think shelf bracket) - it will begin to sag. It's biodegradability, while great for landfills, is also its downfall for any model that needs to withstand the elements. Bird houses, electronics enclosures, flower pots, anything of this nature will eventually breakdown and start to decompose around whatever it's designed to hold or protect if left out in the elements.


PROs:

Widely available in many colors.

Low cost.

Eco-friendly.

Holds dimensional accuracy in various temperatures.


CONs:

Will warp and sag under load.

Breaks down if not protected.

Relatively brittle.

Low melting temperature.




ABS:

ABS (aka: Acrylonitrile butadiene styrene) is slightly less common in 3D printing than PLA. The biggest reason for that though is simply; it's harder to print. With the right 3D printer and a good understanding of how ABS behaves, ABS can provide great quality models that are stronger and more durable than PLA. It is not biodegradable. It will sit in a landfill (for a very long time) if not recycled. This makes it a great material for both indoor and outdoor use, though. ABS contains wear-resistance synthetic rubber, which makes it very strong and impact resistant​. It also melts at a higher temperature than PLA, and that's perfect for models that will endure higher temperatures (up to around 150 °C or 300 °F). Phone mounts in your car, flower pots or electronics in direct sunlight (electronics don't like direct sunlight, but your enclosure will hold up fine), ABS is a great choice.


PROs:

Widely available in many colors.

Relatively low cost.

Highly durable and impact resistant.

Great strength under load.

Works well outdoors.


CONs:

Not eco-friendly.

Gives off toxic fumes during the printing process.

Slightly lower dimensional accuracy (especially in larger models).

Models can warp during the printing process.




PET/PETG/Polyester:

PETG (aka: Polyethylene terephthalate glycol) is one of the more recent additions to the 3D printing world and is quickly rising in popularity. PET plastic is something you're probably familiar with and don't even know it. Most soda bottles are made from it. The difference between PET and PETG is the "G" or glycol, which was added to PET in order to make it more suitable for FDM 3D printing. You can think of PETG as the best of both wolds from PLA and ABS. It's relatively easy to print, its super hard, durable, and impact resistant, and like ABS has a high melting temperature. This (like ABS) makes it great for situations like in your car or direct sunlight. One added bonus with PETG is its overall wear resistance which edges out ABS in applications like mechanical parts, or enclosures with removable lids (think gears and hinges, or interchangeable phone cases ). Because of its relative newness, it's harder to find PETG in the wide variety of colors you have available in PLA and ABS. As its popularity grows it will undoubtably have a veritable rainbow to choose from as well.


PROs:

Highly durable and impact resistant.

Great strength under load.

Works well outdoors.

High wear resistance.


CONs:

More expensive than some alternatives (for now).

Tends to be a bit finicky for highly detailed prints.

The surface finish of more detailed parts can contain particles (or ooze) from the printing process.

Finishing and post processing can be a bit of a chore due to its wear resistance.


TPU/NinjaFlex

TPU (aka: Thermoplastic polyurethane) is one of the more problematic filaments in 3D printing and noticeably more costly. Therefore it's not widely used. To put the problem in a nutshell 3D printers push plastic through a hot tiny hole, and this plastic is a lot like a wet noodle. It's simply not rigid enough for the mechanical workings in most printers and causes all sorts of problems. It's not all bad though. With the right printer hardware and a lot of patience you can get amazingly high quality models from TPU. The obvious benefit of using such a soft material is you get soft prints. The particular variation of TPU we use here (NinjaFlex) has a final consistency similar to a rubber bouncy ball. This makes it great for things like smart phone bumpers and gaskets. You can get an air tight seal between two parts with a well printed TPU gasket. It's also incredibly durable. This stuff holds its shape no matter what you throw at it (or what you throw it at). This durability makes it exceedingly difficult to sand or finish using standard 3D print cleanup techniques. If you really need a smooth finish on a model printed out of this TPU your best bet is flexible paints or epoxy.


PROs:

Extremely durable and impact resistant.

Works well outdoors.

Very flexible and squishy.

High wear resistance.


CONs:

Over double the cost of the more rigid materials listed above.

Tends to be very finicky for detailed prints.

The surface finish can contain particles (or ooze) from the printing process - which you may never get off.

Finishing and post processing is all but impossible due to its wear resistance.




Polyurethane/NinjaTech - Cheetah™

Polyurethane (aka: ... well just Polyurethane) is another relative newcomer to the FDM world to the delight of hobbyists everywhere. To quote their own website: Cheetah™ "is a filament that is printable across all types of desktop 3D printers at ABS and PLA speeds, many times twice the speed of other flexible materials on the market." Most of the industry considers this material a "semi-flex" filament. You get a durability better than PETG but with the ability bend and get out of the way slightly (think about that black comb grandpa had in his back pocket). This again make it great for smart phone bumpers, but also some mechanical applications where you need a bit of give without sacrificing structure and wear resistance. Post processing and sanding this stuff is very similar to the TPU above. Again your best bet for a super smooth finish will be flexible paints or epoxy.


PROs:

Extremely durable and impact resistant.

Works well outdoors.

Has a bit of give while still retaining shape.

High wear resistance.


CONs:

Over double the cost of the more rigid materials listed above.

Tends to be very finicky for detailed prints.

The surface finish can contain particles (or ooze) from the printing process - which you may never get off.

Finishing and post processing is all but impossible due to its wear resistance.

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