3D printing with a flexible material like TPU can get challenging at times since it’s generally regarded as a difficult material to print with. Making high-quality models with TPU, therefore, definitely takes some knowledge, which is why I’ve put together this article to show you how to get amazing TPU parts.
To 3D print TPU, you should use a printing temperature between 225-245°C and a bed temperature between 20-60°C for the best results. Cooling fans are not required with TPU, and a print speed of 15-30mm/s is recommended. Also, TPU easily absorbs moisture so it’s best to keep it dry in a dry box or an airtight container with a desiccant.
This article is a simple yet in-depth guide on how to 3D print TPU filament just like the pros do, so stick around to see how it’s done and get your questions answered.
What is TPU Filament?
TPU or Thermoplastic Polyurethane is an extremely flexible 3D printer filament that’s as popular as ABS and PLA. It is a mixture of rubber and hard plastic that makes this material highly durable with enhanced physical properties such as impact and abrasion resistance. TPU is an ideal choice for parts that require flexibility, strength, and durability.
All flexible 3D printer filaments are derived from Thermoplastic Elastomers (TPEs). TPU is simply one of the many types of TPE that is best suited to FDM 3D printing because of its highly desirable properties.
Looking at TPU’s chemical composition, there are soft and hard segments present that lend this filament the adaptability it has. Variations in TPU involve changes in stiffness, softness, and flexibility.
Filaments like ABS, PLA, or Nylon cannot fulfill the role that TPU plays in the 3D printing industry. It’s actively used for making footwear, automotive parts, medical tools, sports equipment like bands, and much more.
What Temperature Does TPU Print At? Printing & Bed Temperature
The best printing temperature that you should use for TPU is lies between 225-245°C. Increasing or decreasing the temperature beyond those values can lead to certain print imperfections such as warping, stringing, and blobs. You should always use the temperature value provided by your filament manufacturer.
The bed temperature for TPU is somewhere between 45-60°C. You can experiment with different values in this range to find out what works best for your 3D printer setup.
One user of NinjaTek NinjaFlex TPU filament says that a bed temperature of 230°C has worked out great for him along with using a 40°C bed temperature.
For reference, let’s take a look at the printing temperatures of some top-rated TPU filaments on Amazon.
Nozzle Temperature: 210-230°C
Bed Temperature: 25-60°C
NinjaTek NinjaFlex TPU
Nozzle Temperature: 225-235°C
Bed Temperature: 30-40°C
Nozzle Temperature: 190-210°C
Bed Temperature: 30-40°C
Nozzle Temperature: 205-230°C
Bed Temperature: 50-65°C
Nozzle Temperature: 195-230°C
Bed Temperature: 40-60°C
What Print Speed Should You Use for TPU Filament?
For TPU filament, the recommended printing speed falls somewhere between 15-30mm/s to make high-quality parts. This is a flexible filament that’s best printed at slower speeds as compared to ABS or PLA. However, if you use a Direct Drive extrusion system, the printing speed can be increased to 40mm/s.
Since TPU is an elastic material, it can get difficult to print it at higher speeds, especially when there are sudden changes in movement.
Evaluating the best print speed for your 3D printer and TPU filament can take some trial and error. People usually start with a speed of 20mm/s to print TPU and experiment from there on out to find the optimal speed.
Does TPU Need Cooling to Print? Fan Speed
TPU does not need a cooling fan if you’re printing at normal speed and temperature. It makes no significant difference having the cooling fans on when printing TPU, but when you’re printing at a higher temperature (250°C) and speed, a 40% fan setting works well. Fans are also recommended when you’re printing bridges with TPU.
Cooling fans usually help solidify the layer of extruded filament so the layer coming next has a foundation to lie on. If you increase the print speed, the filament has less time to cool down, so this is where fan settings can come in helpful.
With that said, if you print TPU with a low speed, which is mostly preferred, and have a decent nozzle temperature, there’s essentially no need to use cooling fans. If you do use them, you’ll find that there’s a negligible difference.
In addition, people have reported that air pressure generated from the cooling fans instead causes warping of the TPU layers. At higher speeds, the fans even make the part brittle.
When printing with TPU, keep in mind that this flexible filament requires more time for good layer adhesion and bonding. Therefore, fans can sometimes do more harm than good, aren’t important for TPU parts.
What Retraction Settings Should You Use for TPU?
The best TPU retraction settings for 3D printing usually fall between a Retraction Distance of 0.5-2mm and a Retraction Speed of 10-20mm/s depending on whether you have a Bowden or a Direct Drive extrusion system. TPU is a soft and flexible filament, so I highly recommend using low retraction settings for successful prints with minimal stringing.
TPU is sensitive when it comes to rapid, sudden movements, which is what retraction is all about. Since it is exceedingly soft, you can easily get your nozzle clogged or experience under-extrusion if your retractions settings aren’t dialed in.
I recommend that you start off printing TPU with the retraction setting completely disabled. Once you’ve got the hang of other important parameters such as speed and flow rate, you can use small retraction values to eliminate stringing from your parts.
In most cases, oozing or stringing can be taken care of by slightly increasing the Retraction Distance, say with increments of 1mm. The following video shows you how to optimize retraction settings using the Cura slicer.
You basically print a Retraction Tower with different retraction settings and check how the results differ. In this way, you can find out the perfect Retraction Distance and Speed setting for your filament and printer setup.
What is the Best TPU Filament?
TPU is widely regarded for its flexibility and the role it plays in making top-quality functional parts. It is available in an extensive variety from different manufacturers, but not all of them are purchase-worthy.
Let us now look into some of the best TPU filaments that you can buy today.
NinjaTek is a highly reputable 3D printer filament manufacturer that enjoys the talent of making first-rate flexible filaments with amazing customer service support.
The NinjaFlex TPU filament is exceptionally flexible and has a shore hardness of 85A. This key feature means that the material does not require any special infill patterns, densities, or layer manipulation to perform optimally.
It adheres to the built platform without having to use glue or tape, making usability much more convenient for you. It’s also resistant to a wide array of chemicals, such as Naphtha, ASTM, Petroleum, and Freon.
There is one thing about the NinjaFlex TPU filament that has bothered many customers though. It ships without a vacuum-sealed bag, which is something that even cheaply made filaments are shipped with due to the general hygroscopic nature of these materials.
Even without a vacuum-sealed container, the NinjaFlex TPU works wonders, but it’s a good idea to store it somewhere dry to keep it performing at its best.
You can buy the NinjaTek NinjaFlex TPU filament directly from Amazon today.
PRILINE TPU is another high-ranking flexible filament that many number of people have tried and loved. This trustworthy manufacturer is well-respected in the 3D printing community for great products at good prices.
Their TPU filament is no different than what people usually expect from PRILINE. It costs somewhere around $25 and is a great choice if you’re not looking to buy the more expensive NinjaFlex TPU.
At the time of writing, this product has a 4.5/5.0 overall rating on Amazon with 71% of the customers leaving a 5-star review. It has a shore hardness of 98A and can be purchased in multiple colors, such as Black, Coral, Cyan, and Navy.
Customers truly love how strong and durable this filament has turned out to be for them. Some common items that people have printed with this filament include seals, plugs, gaskets, sheets, shoes, key rings, mobile cases, bike parts, and rubber seals.
One user has called this filament the “easiest TPU to work with.” The fact that it’s less flexible than NinjaFlex TPU and a bit more firm makes the PRILINE TPU a breeze to make 3D printed models with.
You can find some PRILINE TPU filament directly from Amazon today.
TECBEARS TPU is an incredibly cost-effective filament with an overwhelming majority of positive reviews on Amazon. At the time of writing, it sports a 4.4/5.0 overall rating with more than 6,000 global ratings.
TECBEARS TPU comes for somewhere around $16 and provides a lot more value than what it’s worth. Customers have reviewed the filament to come packaged in excellent condition with vacuum sealing and put in a similar performance.
Green, Yellow, Pink, Rainbow, Black, Transparent, Gold, and Copper are some of the few colors available in this filament. Unlike NinjaFlex TPU, you’re getting a shore hardness of 95A with the TECBEARS TPU.
Users have reported that you can print this filament right out the box using Cura’s generic TPU profile. Even then, it makes successful prints, showing off how easy it is to handle and work with.
Additionally, this TPU material boasts great bed adhesion, similar to the pricier NinjaFlex TPU. Unlike the latter, it comes at a much affordable price. TECBEARS also has an impressive customer support service that has tended to the issues of customers in due time.
Get yourself a spool of the TECBEARS TPU filament directly from Amazon today.
Is TPU Heat Resistant?
Yes, TPU is fairly heat-resistant with a glass transition temperature of 60°C. It melts at a higher temperature than PLA. There are also specialized high-temp TPU filaments that you can buy for additional resistance to heat and other factors.
TPU is generally highly durable and can withstand impact, abrasion, wear and tear, and heat altogether. However, manufacturers have come up with a unique blend of TPU that lends the filament extra heat resistance.
A quick demonstration of how heat-resistant high-temp filaments are is given in the video below.
High-temp TPU can be a little difficult to locate, but you can get a 0.75kg spool from filaments.ca. They ship locally in Canada as well as internationally, with shipping costs calculated automatically at checkout. It’s technically known as “Rigid High Temperature TPU”, and these modified flexible can withstand temperatures up to 160°C.
How Fast Can You Print TPU?
The recommended print speed for TPU stretches as far as 40mm/s, but the new Polymaker PolyFlex 95-HF can allow speeds up to 100mm/s with consistent extrusion and without sacrificing the print quality. You’ll be able to 3D print TPU faster with a high-quality direct drive extruder and a more rigid TPU.
TPU is generally known as a difficult filament to print with. The print speed has always held it back from fast turnaround times because there’s a good chance you’ll end up with a jammed nozzle at higher than usual speeds for TPU.
It usually takes some trial and error with temperature and retraction settings, along with fine-tuning your printer to get TPU to print at faster speeds. You can get a 3D printer like the Ender 3 to print TPU at fast speeds by installing a good direct drive extruder.
Bowden extruders can still print TPU successfully but at a much lower print speed.
Polymaker is a well-established manufacturer that has recently come out with the PolyFlex 95-HF that makes it possible to print TPU at a shocking 100mm/s.
The following video is a quick explanation of how this filament performs.
How Do You Clean, Smooth & Finish TPU 3D Prints?
To smooth TPU 3D prints, use a filler primer with appropriate bonding to your part, and then use a flexible spackling and apply with a spreader. After preparing the surface, you can use sandpaper to smooth your TPU part. Lastly, you can finish the print by coating it with acrylic paint.
Many experts have advised using Alex Flex as the flexible spackling to use for post-processing TPU 3D prints. It works like a charm, and allows you to sand and paint your flexible object.
The following video briefly explains how you can clean, smooth, and finish TPU 3D prints.
Does TPU Absorb Water/Moisture?
Yes, TPU is a hygroscopic filament that actively absorbs moisture from the air if left exposed. It is highly recommended to store your filament in a dry box or an airtight container after using it to keep it performing at its best. You may notice more imperfections in your 3D prints after moisture has been absorbed.
Most 3D printing filaments out there absorb water so we need to take precautions regardless of what filament we have. PLA, ABS, Nylon, and many other filaments go through the same thing, so we need to make sure to store filament in an airtight container or vacuum-sealed bag.
In the following video, you can see how a dry TPU filament performs in a side-by-side comparison with wet TPU.
Does TPU Filament Need to be Dried?
No, TPU filament does not need to be dried to 3D print successfully. However, it is a hygroscopic filament capable of absorbing excess water from the surrounding environment. If not dried, you may run into issues during printing, such as stringing, and inconsistent extrusions.
There are many options to choose from when looking to dry your filament. You can take any airtight container to keep your filament dry and moisture-free, and can also make your own dry box at home using a desiccant.
If you prefer a more professional approach, you can opt for the SUNLU Upgraded Filament Dryer that’s easy to set up and works efficiently in removing excess water from your filament.
Stefan from CNC Kitchen brilliantly explains the essence of drying your filament in the video below.
How Do You Store TPU Filament?
TPU filament can be stored in any dry airtight container, a sealable vacuum bag with silica gel pearls, dry boxes, and even storage boxes. You can also purchase a specialized filament dryer to store your filament, and print directly from the dry box efficiently for the best results.
A great product that is working well for many users is the eSUN 3D Printing Filament Vacuum Storage Kit w/ Hand Pump from Amazon. You get:
- 10 Vacuum Bags
- 1 Hand Pump
- 2 Sealing Clips
- 15 Desiccant Packs
- 15 Humidity Indicators
- User Manual
These are really easy to use and get the job done well since it doesn’t let moisture get into the storage area. The humidity sensors are a great addition to this kit since they show you whether your storage environment is optimal.
The vacuum bags are BPA-free, meaning they are environmentally friendly. It’s also food-grade, durable, and recyclable.
In the following video, you can see how easy it is to make your own dry box at home. You have some great options when it comes to drying filament.
Is 3D Printed TPU Waterproof/Watertight?
3D printed TPU parts are widely recognized as waterproof and watertight since this filament is used to make water-based sports equipment along with footwear that is resistant to elements like heat and water.
The terms “waterproof” and “watertight” are commonly misunderstood. A watertight object is one that does not let water inside it, nor lets it escape. Being waterproof would mean that water cannot deform or degrade the object.
When it boils down to the filament itself, TPU is not watertight as it is hygroscopic and readily absorbs moisture from the air. TPU printed 3D parts, however, are fairly waterproof and watertight since they are bonded together during the printing process.
There are also methods to make your parts waterproof yourself, which I wrote in my How to Waterproof 3D Prints article, so check that out to find out more.
Is 3D Printing TPU Toxic or Smelly? Safety
3D printing TPU is not known to be toxic nor smelly. It is one of the safer filaments to print with as many people who have been printing with TPU for years report no health or safety concerns. It’s still recommended to 3D print TPU in a well-ventilated room and an enclosed print chamber if possible.
Many people say they don’t smell any fumes when it comes to 3D printing TPU filament with different brands.
Do You Need an Enclosure to 3D Print TPU?
No, you do not need an enclosure to 3D print TPU, though it can be beneficial for overall strength and quality. As long as your heated bed provides good adhesion, your TPU 3D prints should come out successfully without an enclosure. The flexibility of TPU is good at preventing warping further into the print.
I’d still recommend using an enclosure for TPU 3D prints so you can reduce any emissions from the heating of the filament. Some people state that using an enclosure can lead to better strength in models, as well as higher quality due to the more constant temperature.
Can You 3D Print TPU Without a Direct Drive Extruder? – With Bowden
Yes, you can 3D print TPU without a Direct Drive extruder. Bowden extruders can be used for printing flexible filaments by printing slowly and using less travel distance. It’s also recommended to use a bit more rigid type of TPU, preferably of Shore Hardness 95A, to print more successfully with Bowden extruders.
Bowden extruders are infamous for not being able to deal with flexible filaments, but that isn’t true.
Sure, there are some difficulties compared to a Direct Drive extruder, but printing cautiously by using a Capricorn PTFE tube is known to work great for flexible filaments.
They have a tighter filament pathway which allows for a stricter movement for the flexible material.
In the following video, a YouTuber has shared a neat trick to teach fellow users how to print TPU on a Prusa i3 that uses a stock Bowden extruder.
How Do You Stop TPU From Stringing?
To stop TPU from stringing, dial in your retraction settings and increase Retraction Distance using trial and error with small increments. Make sure that your TPU filament is moisture-free and stored somewhere dry. Cura has a special setting called “Coasting” that helps prevent stringing as well.
Stringing is a common issue when printing with a flexible filament like TPU. Fortunately, it’s not something difficult to fix. People recommend that staying within the manufacturer’s recommended range of temperature and speed also helps stop TPU from stringing.
The following is a quality video that shares many useful tips on reducing stringing with TPU.
How Do You Print TPU on an Ender 3?
To 3D print TPU on an Ender 3, you can use the stock Bowden extruder with a rigid TPU like a Shore Hardness of 95A. For a more flexible TPU, you should upgrade your Ender 3 to a Direct Drive setup by using an upgrade kit purchasable from Amazon. It provides a tighter filament pathway so the TPU doesn’t bend.
The video below by Maker’s Muse shows how you can 3D print TPU and flexible filaments on a stock 3D printer. It takes some settings adjustments and tests to get things working well.
I’d recommend getting the UniTak3D Direct Drive Upgrade Kit from Amazon. It is compatible with an Ender 3/Pro, CR-10, and other similar printers. The plate is made from aluminum alloy and does a great job of allowing users to 3D print TPU successfully.
Installation is easy to do as you can follow video tutorials on YouTube or the instructions that the package comes with. You simply have to remove the original plate on your Ender 3, then mount the direct drive kit onto the printer.
You can also purchase the SeeMeCNC EZR Struder from the manufacturer’s official website. It is known to work great for all Ender 3D printers, such as the Ender 3, Ender 3 V2, and the Ender 3 Pro.
In the following video by CHEP, Chuck shows you how to install the EZR Struder on your Ender 3 easily.
Can You 3D Print TPU on Glass?
Yes, you can 3D print TPU on glass. A combination of a heated glass bed with a PVA glue stick applied to it for better adhesion is an ideal choice for printing TPU parts. You can also print TPU on other types of beds, such as PEI, aluminum, and other composite surfaces.
TPU Vs PLA – Which is Better?
PLA is usually better than TPU when it comes to ease of printing, functional objects that require strength, and surface quality. TPU is better than PLA when you need a flexible filament that has great impact resistance and long-term durability. It’s definitely possible to use TPU for functional parts depending on the project.
Using TPU definitely unlocks more possibilities in 3D printing. You get to make mechanical parts of all sorts that require flexibility and endurance to chemicals, abrasion, and heat.
However, printing TPU is no piece of cake, as flexible filaments are generally regarded as hard to print. You need to adjust your settings according to this material or you may run into print failures.
Additionally, TPU is hygroscopic and always needs to be stored in a dry environment. Printing in humid settings can be difficult with this material.
On the other hand, we have PLA – the most popular 3D printer filament that’s known for being easy to print and use in multiple projects.
That said, PLA isn’t extremely durable or tough and melts at a relatively low temperature, which may not make it suitable for mechanical parts.
In conclusion, both filaments have their pros and cons, and it mostly depends on what kind of parts you’re looking to make.
If you want flexible models with good toughness, TPU is a great option. If you’re interested in a material that prints painlessly with great details, PLA is the way to go.
Can You Print & Use Supports With TPU Filament?
Yes, you can print and use supports with TPU filament, but you will need to adjust the support settings in your slicer for good results. People usually recommend printing supports with TPU itself rather than another filament. Adjusting your Infill X & Y Offsets in your slicer can improve supports.
In Cura, there is a setting called “Support Wall Line Count” which defaults at 1. You can increase the number of walls for your supports to improve the likelihood that they topple over. It does use more material and make supports harder to remove, but can be worth it for TPU.
The Support X/Y Distance and Support Z Distance settings can be adjusted to assist in 3D printing TPU supports successfully. The Support Z Distance setting specifically is described as the most influential factor to how well your supports adhere to the model.
Reducing these settings results in supports sticking to the model better, while increasing it makes the supports easier to remove afterward.
It’s also recommended to print using the “Triangles” support structures for easier support removal, which is known to get hard when printing with TPU.
The following video describes how flexible filaments can be used for support structures.
Does TPU Filament Go Bad?
Yes, TPU filament can go bad when it absorbs too much moisture in the environment due to being left out in the open. TPU is a hygroscopic material which means it absorbs moisture, so you should store it somewhere dry when not in use. You can see a significant decrease in quality when printing moist TPU.
Some people have reported that the filament on the spool can start to bond together, leading to parts that don’t look so great.
It’s similar to when Nylon absorbs moisture and starts giving symptoms such as poor bed adhesion, popping and bubbling, clogging up nozzles, and other extrusion problems.