The Best Flexible Filaments of 2021 (TPU/TPE/TPC)

 

NinjaTek offers four kinds of TPU filament (NinjaFlex, Cheetah, Armadillo, and Eel) and one TPE, all with varying properties in a wide range of colors.

NinjaFlex has a shore hardness of 85A, making it extremely flexible and squishy. The company says its proprietary technology enables a low-tack, easy-to-feed texture ideal for direct-drive extruders. The material has abrasion and chemical resistance and results in consistent printed parts.

Cheetah TPU is designed to be able to print at higher speeds, hence the name, while the NinjaTek Armadillo is a non-flexible TPU that features the extremely tough and abrasion-resistant qualities of TPU in an extremely strong, rigid material that can be used as an alternative to PLA, ABS, and even nylon filaments. This TPU is meant for printing high-wear parts, such as gears, fasteners, and protective cases.

Lastly, the Chinchilla filament is the softest of the bunch, created through a proprietary blend of TPE resins. With Chinchilla, you can create soft, long-lasting printed parts for fashion, healthcare, and grips. Chinchilla has been tested to be skin-safe using EpiDerm Skin Model.

Available sizes & diameters: 0.5 kg, 1 kg: 1.75 mm, 3 mm
Colors: Midnight, snow, sapphire, fire, almond, and six others

Fillamentum is a well-known, reliable filament manufacturer, and their Flexfill TPU is definitely worth a try. Flexfill TPU has two available shore hardnesses: 92A and 98A. The 92A line is very soft, while the 98A line is a bit stiffer than some of the other TPU filaments on this list, plus it’s easier to print.

The company’s Flexible TPE is safe for food-contact applications and for applications in contact with skin. It’s also available in two different hardnesses 90A & 96A Shore. Filamentum’s new Flexfill PEBA 90A is flexible with unique thermal, mechanical, and chemical behavior from other TPEs. It’s especially retains its flexibility at subzero temperatures.

Available sizes & diameters: 0.5 kg, 0.7 5kg; 1.75 mm, 2.85 mm
Colors: Natural, traffic black, signal red, signal yellow, luminous green, and seven others

Recreus Filaflex

Polymaker

Forward AM / BASF

ColorFabb

MatterHackers Pro Series TPU is definitely on the more flexible side of the spectrum. If you want something even bendier, they also sell a Pro Series Flex TPE that’s similarly impressive.

The Pro Series TPU is a highly malleable elastomer that is used to create prints with high toughness while retaining superb flexibility. It also has a high resistance to abrasion. This TPU will adhere to most bed types without any adhesives and a cooling fan is highly recommended.

• Available sizes & diameters: 1 lb (~450 g); 1.75 mm, 2.85 mm
• Colors: Black, white, red, blue, clear, grey, green

European 3D printer and materials reseller 3D Jake ventured into manufacturing its own branded filament years ago and it has gained a following for quality.

The 3D Jake TPU has a low tendency to warp so it can also be printed without a heated bed, but if you have a heated bed the recommended temperature is 60-90˚C. TPU A95 can be used on all common desktop FDM 3D printers. 3D Jake recommends increasing the flow by about 5-10% for more consistent extrusion.

Available sizes & diameters: 1 kg; 1.75 mm, 2.85 mm
Colors: white, blue, red, orange, clear

Dynamism is another 3D printer and materials supplier that has branded its own TPU filament to sell to customers as the most economical of its TPU offerings. But this is no discount filament. Dynamism TPU HS is a workhorse, general-purpose flexible filament formulated for high flow to allow for printing at higher extrusion speeds. As a sustainability bonus, it comes on recycled cardboard spools and with external cardboard packaging also made from recycled cardboard.

Available sizes & diameters: 1 kg; 1.75 mm, 2.85 mm
Colors: black

Because of the difficulty of printing some flexible filaments and, unfortunately, some of the poor quality filaments on the market, several printer manufacturers, including Ultimaker, Big Rep, BCN3D, and others, have worked with chemical makers to formulate their own flexible filaments tuned to specifically to their printers. These filaments can save a lot of time and fine-tuning, which can easily justify the usually higher price tag.

If your printer brand offers its own flexible filament its likely to come with well-tested print profiles and is probably your best bet, or at least your best first step when it comes to successful printing of flexible parts.

If you need your final parts to have a degree of flexibility – anything from super rubbery to just a touch of give – you’ll want to pay attention to a few key measurements that are detailed in your filaments’ technical datasheet. Some filament called “flexible” may not disclose exactly what it’s made of, so to know how parts made from it will perform, you’ll need to understand the following terms.

Shore Hardness

Shore hardness is a common term you’ll hear when it comes to polymers, but it’s more general than the more technical measurements like Young’s modulus or elongation at break. For example, most flexible filament would be Shore A, and within the A category they would have individual values, such as Shore hardness 95A. You may also see Shore values in the C or D category, which more often denote hard rubbers and semi-rigid plastics. The most common Shore value for flexible filaments is 95A.

Elongation at Break

Elongation at break is how much a part can stretch before breaking. This measurement is shown as a percentage and the higher the number the better the material will resist reforming when stretched. Flexible filaments average around 600% elongation at break. By comparison, regular PLA averages around 8%.

Know Your Flexible Plastic Types

There’s more to flexible filaments than thermoplastic elastomers, but do you really need to know polymer chemistry? Probably not. Yet, here are few notable distinctions between the major flexible polymers that could be useful understand.

TPE (thermoplastic elastomers)

TPEs are a class of materials that are a blend of plastic and rubber. TPU, is in this class along with TPC, but there are others. These plastics are very soft and rubber-like. They are common in injection molding and parts made from them can be bent or stretched without any deformation.

• TPU (thermoplastic polyurethane) is a subset of TPE that have become more popular in 3D printing because their hardness can be highly customized. TPUs can be as soft as rubber or as hard as rigid plastics, which makes for easier extruding. TPUs are also generally more durable and can offer higher resistance to abrasion, oils, chemicals, and high and low temperatures than TPE filament.
• TPC (thermoplastic co-polyester) is another common type of TPE that boasts high-temperature resistance, high strength, and excellent UV resistance. It is especially prized in biomedical applications and for wearable and medical devices. More commonly used in powder bed fusion 3D printing, these polymers have a bending memory and make for very durable yet rubber-like parts.
• TPS (styrene-based thermoplastic elastomer) is characterized by its soft touch. Compared to other flexible materials, it shows better non-slip properties, ideal for grippers. TPSs don’t absorb as much moisture as other TPEs, which enables printing without pre-drying.
• PEBA (polyether block amide) is a TPE that can stay flexible under very cold conditions. It features a very low density, which gives it excellent dampening properties, energy return, and flexibility. It’s used widely in sports equipment and also in for electric components.

3D Printing Filament: A Guide for Professionals

You can throw out everything you’ve heard about printing with flexible filament. Today, there is such a wide range of flexible filament types that it’s almost impossible to give general direction, but there are certainly some important points to keep in mind.

Dry Before You Print

Flexible filament is often, but not always, very hygroscopic, meaning that it sucks up moisture from the air. If you open your sealed filament and expose to air, it will have a negative effect on the printing behavior and, of course, the quality of your final print. Even if you follow the printer settings exactly, you can still end up with failed or suboptimal prints because of moist filament.

If your filament’s been left out, you’ll need to dry it in an oven or a filament dryer. How long and what temperature? Well, that can be the tricky part because there’s often no way to know how much moisture the filament has soaked up. Your drying machine may let you know when the filament is dry, and the filament manufacturer may include drying instructions with the filament (such as dry in an oven at 70 ºC for five hours), but in the end, it’s often trial and error. Just remember: if you see steam rising from your hot end, your filament is wet.

Your best bet is to try to keep your filament sealed and stored properly in the first place (also protected from UV light and heat) and for as long as possible. If this isn’t possible, look for flexible filaments that don’t require any drying, including some made of TPS.

Heat & Prep Your Bed

Many flexible filament manufacturers say their products don’t require a heated bed, but most filaments do perform and adhere better with a bed temp around, 40ºC but usually not more than 60ºC. Your filament will come with recommended bed temperatures. Flexible filaments almost never require a closed chamber, but again, keeping your heat consistent is always a help. Whether or not you need tape, glue, or adhesives on your bed depends on your filament type and brand.

Nozzle Temp

Your filament comes with recommended printing temperatures for a reason. Yes, a hotter nozzle can make for faster printing, but printing temperature can affect the flexibility of your final print. Ideally, your 3D printer will have a print profile for the exact brand of flexible filament you’re using, otherwise, prepare to experiment and achieve the ideal balance between heat and speed.

Be Patient, Go Slow

To get those almost-invisible layer lines and a consistent soft-to-the-touch finish, your flexible filament will need time. Thermoplastic elastomers like to go slow and typically print best at slower speeds and smaller layer heights. Filament makers have made great strides in fast-printing flexible materials with some churning out parts at 100 mm/s, but there’s always some sacrifice of print quality with speed.

If your flexible filament clogs your extruder, high-speed is the likely culprit, although it could also be moisture in your filament.

Extruder & Extruder Settings

Many flexible filaments work fine with Bowden extruders but most will work best with a Direct Drive extruder. The reason is that the distance between the drive gear and the hot end should be as short as possible to efficiently feed the filament into the nozzle without stretching it.

As with any material, follow your print profiles, but if you don’t have any or want to experiment, there are some things to keep in mind when it comes to your extruder retraction rate. You may come across advice that says to disable retractions when printing with flexible filament, but that’s a bit outdated. It may apply if you have an older extruder, but newer extruders and professional FDM printers shouldn’t have any issues with retraction. With retractions off, you’ll see some stringing that can be removed in post-processing.

Even in the best FDM printers, you may still need to experiment with your retraction settings. Keeping them to 2 mm and 20 mm/s is a good place to start. If you notice the filament bunching up in the extruder, keep adjusting your retraction settings until you find the sweet spot.

Additional Tips:

• Avoid using rafts because the base layers have a higher extrusion rate, which could lead to problems.
• Where possible, mount the filament spool above the printer to reduce resistance from the extruder pulling the filament
• Part cooling ran is required

Get Your TPU Parts Printed

If TPU doesn’t sound like a material you’re ready to master, you can leave it to the pros at FacFox 3D printing service.

Source: https://all3dp.com/1/flexible-filament-tpu-tpe-tpc-best-brands/