TPU is a flexible and elastic material, 3D printing with it can be challenging most of the time. TPU is a difficult material and before producing high quality 3d prints with it, one has to get knowledge. This is the reason why we have put everything about TPU in this article.
In order to 3D print with TPU, the printing/nozzle temperature should be in the range of 230-245 Deg C and the print bed temperature can be between 20-60 DegC. For TPU, cooling fans are not needed and the printing speed should be relatively low as 15-30 mm/s. TPU is sensitive to moisture and can absorb moisture when exposed to free air. It is recommended to keep it in a filament dryer box or airtight container filled with desiccant packs.
If you want to learn how to 3D print with TPU filament like an advanced user, then stick to this guide and get the answers to your questions.
TECBEARS PLA 3D Printer Filament 1.75mm Black, Dimensional Accuracy +/- 0.02 mm, 1 Kg Spool, Pack of 1
What does TPU Filament Mean?
TPU abbreviated as Thermoplastic Polyurethane is a highly flexible and elastic filament similar to PLA and ABS. It is made by mixing rubber and plastic that is hard which turns it to be highly durable. The physical properties of TPU such as impact and abrasion resistance are highly enhanced. TPU finds its applications in the kind of products that demand durability, flexibility and strength.
Most of the flexible 3D printer filaments are by-products of Thermoplastic Elastomers (TPE). Similarly, TPU is one such type of TPE which is highly used in FDM printing because of its useful properties.
The chemical composition of TPU consists of soft and hard segments that grant the adaptability. TPU varies by its softness, flexibility and softness.
TPU is unique and different from that of PLA, ABS and Nylon. In 3D printing, the role of TPU cant be replaced by any other filaments. TPU has special applications such as Medical Parts, Automobile Parts and Footwear.etc.
What Should Be The Printing & Bed Temperature for TPU?
TPU printing temperature varies between 225 to 245 DegC and varies with different brands. Any temperature outside this range can result in problems such as stringing, warping, blobs.etc Refer to the temperature values prescribed by the filament manufacturer and set accordingly.
The print bed temperature for TPU is relatively low as 45 to 60 Deg C as compared to ABS. You can play with different values and see what suits best for your current TPU filament being printed.
One of the TPU users who used NinjaFlex TPU filament said that Nozzle temperature of 230 Deg C and bed temperature of 40 DegC has worked great for him.
Let’s go through the temperatures ranges of some popular TPU filament brands below:
NinjaTek NinjaFlex TPU FILAMENT
Nozzle Temperature: 225-235°C
Bed Temperature: 30-40°C
SainSmart TPU FILAMENT
Nozzle Temperature: 195-230°C
Bed Temperature: 40-60°C
PRILINE TPU FILAMENT
Nozzle Temperature: 190-210°C
Bed Temperature: 30-40°C
TECBEARS TPU FILAMENT
Nozzle Temperature: 205-230°C
Bed Temperature: 50-65°C
OVERTURE TPU FILAMENT
Nozzle Temperature: 210-230°C
Print Bed Temperature: 25-60°C
How Much Print Speed is Good For TPU Filament?
The print speed for TPU filament varies between 15-30 millimeter per second without compromising on quality. This slower speed can produce high quality objects when compared to ABS or PLA. In case of Direct Drive Extruder, 40 mm/s speed can be used.
Printing TPU at higher speeds is difficult due to its elasticity, especially when the extruder moves fast.
Arriving on to the right print speed for TPU needs some trial and error. Many TPU users start from 20 mm/s and increase it step by step to find the right optimal speed.
Is Cooling Needed to Print TPU? Fan Speed Settings
Usually, a cooling fan is not needed for TPU while printing at normal speed and temperature. But when the Nozzle temperature is high (250 DegC) and print speed is 40 mm/s, then a fan could be beneficial. Fans can be used while printing bridges using TPU.
Cooling blower fans cure and solidify the previously extruded layer to lay a foundation for the next layer to settle on. If print speed is increased, then the layer will not get cooled sufficiently, thus fan settings are important.
Thus, it is always better to print TPU at lower printing speeds. Many 3D users prefer low printing speed for TPU with decent Nozzle temperature and this eliminates the need for fans. However, if you use fans, then there will be no difference.
High air pressure coming from cooling fans makes the TPU layers to get warped and they may even make the part brittle.
It is a known fact that the cooling time needed for flexible filament is more to get good adhesion and layer bonding. Thus, in case of TPU, fans will create problem than doing good for TPU parts.
How Does Retraction Settings for TPU Look Like?
The best retraction values for TPU usually ranges as follows:
Retraction Distance: from 0.5mm-2mm
Retraction Speed: 10-20 mm/s
These values are for both Bowden and Direct Drive extruders. For amazing results with TPU it is always preferred to have a low retraction settings with barely noticeable stringing.
TPU cannot withstand rapid movements of the extruder because of its soft nature. Thus retraction settings need to be properly configured to avoid under-extrusion and nozzle clogging.
Its better to not configure the retraction settings at all initially, disable them for the time being. Start the TPU printing by calibrating other parameters like speed, flow rate and usue minimal retraction settings to eliminate stringing.
In many situations, stringing can be avoided by increasing the Retraction distance by small increments as 1mm. The below video shows the retraction settings optimization using Cura slicer software.
You can do trial and error of retraction settings by printing a retraction tower and determine the correct retraction speed and distance for the filament and 3d printer.
Which is the Best TPU Filament?
TPU is known for its flexibility and durability. Many functional parts can be produced using it. TPU filaments are available in different brands by many manufacturers and we are listing the best of those below:
Let’s go through some best TPU filaments that are purchase worthy:
NinjaFlex TPU Filament by NinjaTek
NinjaTek is known for making High-Class flexible filaments that are efficient with great customer support.
THe NinjaFlex filament comes with a shore hardness of 85A and is highly flexible. One of the interesting features of this brand is that the objects built with NinjaFlex doesn’t need any special infill patterns, Layer manipulation and density.
It bonds to the print plate with good adhesion without needing any tape or glue. It is also resistant to chemicals such as Freon, Naphtha, Petrol and ASTM.
The problem that many 3D users have seen with NinjaFlex TPU filament is it shipped without an airtight vacuum sealed bag. Because of this, it attracts moisture due to its Hygroscopic Nature.
However, NinjaTek TPU does a great job even when it comes in exposed air. Dryer is better, always prefer to keep it dry for better performance.
Buy NinjaTek NinjaFlex TPU from Amazon now
PRILINE TPU FILAMENT
PRILINE TPU is one of the Top Class flexible filaments that is being loved by many 3D printing users. They have released great products with attractive prices.
For those who think NinjaFlex is expensive, PRILINE TPU is the best alternative at the price of 25$.
This product has overall 1398 ratings on Amazon with 80% of the users leaving 5 start review. The shore hardness of this material is 98A and comes in multiple colors such as Coral, Navy, Cyan and Black.
Many 3D users have loved this product performance and the quality they achieved using this brand. The printed items by 3D users include mobile cases, plugs, gaskets, sheets, rubber seals, key rings, seals, bike parts and.shoes.etc
One user has certified it as “easiest TPU filament” to print with. The reason is that it is slightly more firm and less flexible than NinjaFlex TPU which is ideal to print 3D models.
Order PRILINE TPU filament from Amazon today.
TECBEARS TPU FILAMENT
TECBEARS is known for its low cost while maintaining the high quality standards. It has more than 7610 ratings and has 4.3 out of 5 stars on Amazon.
TPU is priced at 18$ and worth the price because of its quality and vacuum sealed shipping.
TECBEARS TPU is available in 16 different colors including Yellow, Wood, Black, Green, Marble.etc. It is the filament that has a shore hardness of 95A as that of NinjaFlex at a much lower price.
Many people said that this filament can be directly printed out of the box by using the default TPU profile available on Cura. Yet, this can produce great prints and mesmerize the users.
TECBEARS has also shown excellent bed adhesion compared to pricier NinjaFLex TPU. The customer support is also decent and impressive to help users queries.
Get a roll of TECBEARS TPU filament and start TPU printing today.
Is TPU Resistant To Heat?
Yes, TPU is a heat-resistant filament having a glass transition temperature of 60 DegC. The melting temperature of TPU is higher than PLA. If you want more heat resistance, you can buy High-temperature filaments that are available.
TPU is known for its durability, impact and abrasion resistance, wear and tear resistance and also heat resistance. Many manufacturers have their unique TPUs that have extra heat resistance.
Examples of Heat-resistant and High-temperature filaments are given below:
High-temperature withstanding TPUs are difficult to get. They are available more in Canada and are called “Rigid High Temp TPU ” which can withstand temperatures up to 160 DegC.
TPU Printing Speed : How Much It Should Be?
The printing speed for TPU is 40 mm/s maximum, while Polymaker PolyFlex 95-HF can be printed at a higher speed of 100 mm/s without compromising on the print quality. With a Direct Drive Extruder of high quality, you can 3D print TPU faster than expected.
TPU has become popular as a difficult filament due to its high elasticity and flexibility. The low print speed of TPU has always discouraged many 3D users from using it. The nozzles get jammed If you try to print at faster speeds.
To find out the right temperature and retraction settings to print TPU at faster speed, needs trial and error. You can also employ Ender 3 with a Direct Drive Extruder for faster TPU printing.
With Bowden extruders the print speed should be very low. There is a TPU filament by name PolyFlex 95-HF, which allows the print speed of 100 mm/s shockingly.
The video below explains the efficiency of this filament.
TPU 3D Prints Post-Processing: Cleaning, Smoothing and Finishing Of TPU.
Smoothing of TPU prints can be done using a filler primer that can stick well to the object and then use flexible spackling and coat it with a spreader. Once the surface is prepared, smoothen the TPU object using sandpaper. The next final step would be to paint it with acrylic paint.
Many 3D nerds have suggested the usage of Alex Flex as flexible spackling in order to post-process TPU 3D prints. It makes the sanding and painting of the flexible object easier.
DAP INC 18743 Alex Flex Quart Spackling, 32 OZ, White (Tools & Home Improvement)
The video below shows the post processing of TPU 3D prints:
Is TPU Moisture Sensitive? Does It Absorb Moisture?
Yes, TPU is highly sensitive to moisture and hygroscopic in nature. It absorbs the moisture when exposed to free air. In order to avoid moisture absorption, it is suggested to store them in a dry box or airtight container. Faulty TPU prints are inevitable if printed with wet TPU filament.
Is Drying TPU Filament a Necessity?
Yes, TPU filaments need to be dried for the best results because of excess moisture absorption. If not dried, then you may face issues such as inconsistent extrusion and stringing.
You can make your own DIY dryer box at home or use desiccant packs for drying your TPU filament.
Usage of the SUNLU Upgraded Filament Dryer is recommended for a more professional drying and excess moisture removal.
How To Store TPU Filament?
Storage of TPU filament should be done using an airtight container or a sealable vacuum bag with dry boxes, silica gel pearls or storage boxes. There is a separate device called Filament Dryer which can be used to store the filament in dry condition. The speciality of the dryer box is that the printing can be done simultaneously while it is getting dried.
Many 3D users have glorified eSUN 3D Printing Filament Vacuum Storage Kit because of its great usage. It is available on Amazon and you will get the following things with it:
- Vacuum Bags = 10
- Hand Pump = 1
- Sealing Clips = 2
- Desiccant Packs = 2
- Humidity Indicators = 15
- 1 User Manual
These Vacuum bags are user friendly and do not allow any moisture to get inside them. Humidity Sensors that come with this kit show the internal temperature and allow us to optimize it.
The Vacuum Bags are Durable, Recyclable and Food-grade. They are also made environment friendly and BPA free.
Apart from vacuum bags, you can store the filament in plastic containers which have the facility to feed filament to a 3D printer.
The video below shows how to make DIY dryer at home.
Can 3D Printed TPU Objects be Watertight / Waterproof?
The objects printed with TPU are highly resistant to heat and water. Hence, it is used in Footwear and water based sports equipment that can be watertight and waterproof.
The word “Watertight” means TPU printed parts will not allow water inside it while “Waterproof” means water cannot degrade or spoil the TPU part. Before printing as a filament, TPU is hygroscopic and absorbs moisture but after printing it gets waterproof and watertight because of the tight bonds that form during the printing process.
Will TPU 3D Printing Produce Smell? Is it Toxic? Safety Tips
As reported by many 3D users, TPU is not toxic and doesn’t smell too. Printing with TPU is considered safe and no health concerns are reported for the users printing TPU for years. However, printing in a well ventilated room is essential and used printer enclosure if possible.
TPU 3D printing won’t even produce fumes as said by many users.
Do You Need 3D Printer Enclosure While Printing TPU?
Printer Enclosure is not recommended while 3D printing TPU. However, usage of it can improve the quality and overall strength. As long as the printing bed ensures good adhesion and bonding with the object, enclosure is not needed. Flexibility, the property of TPU, prevents warping problems while printing.
All in all, usage of enclosure can still benefit by avoiding any emissions and boost the model strength. Usage of enclosure can also maintain consistent temperature.
Is it Possible To 3D Print TPU Using Bowden Extruder ? Not Direct Drive Extruder
3D Printing of TPU filament without Direct Drive extruder is absolutely possible. By keeping the low printing speed and less travel distance, flexible filaments can be printed on Bowden Extruders. It’s recommended to choose rigid TPU with Shore Hardness of 95A while printing using Bowden extruders.
Bowden extruders are criticized for not being compatible to print flexible filaments, but this is not true.
Make use of Capricorn PTFE tube while printing flexible filaments on Bowden extruder. This creates a tighter pathway for the filament for more precise movement.
Sovol Capricorn Bowden PTFE Tubing 1 Meter Tube Cutter XS Series 1.75MM Filament for Creality Ender 3 Ender 3 Pro, Ender 5, CR-10,CR-10S 3D Printer
The video below shows how to print flexible TPU filaments on Prusa i3 with a stock bowden extruder.
How to Stop Stringing in TPU?
Stringing in TPU can be stopped by ensuring the proper retraction settings. Set the correct retraction values, by trial and error method with small increments. Before setting the retraction, ensure that the TPU is moisture free and dry. Cura software has an option “Coasting” to prevent TPU stringing.
Stringing is a common problem, while dealing with 3D filaments that too flexible TPU filaments. While it is not so difficult to fix too. Just ensure to process the TPU within the temperature ranges and speed as mentioned by the manufacturer. This stops the TPU stringing.
The below video shows tips on how to reduce TPU stringing.
How to Print TPU Filament on Ender 3?
To successfully 3D print TPU on a Creality Ender 3 which has a Bowden Extruder, choose TPU filament which has Shore Hardness of 95A. If TPU is more flexible, then opt for a Direct Drive Extruder on Ender 3 which is available on Amazon. THis actually narrows the filament pathway which eliminates the TPU bending.
There is a video by Maker’s Muse that explains the techniques to print Flexible TPU filaments using stock 3D Printer. It also shows configurations, settings and some sample tests to get quality TPU prints.
There is a Direct Drive Extruder Upgradation Kit by Unitak available on Amazon which can be used for Ender 3/Pro and other printers. This kit contains an aluminum alloy plate that assists greatly in TPU printing.
UniTak3D Ender 3 Direct Drive Upgrade Kit, Aluminum Alloy Conversion Part for Creality Ender 3 Pro Ender 3 CR 10 3D Printer
Installation of this kit is pretty easy if you follow some Youtube videos along with the instruction manual that comes with the package. All you need to do is to replace the existing plate on Ender 3 with a Direct Drive kit.
There is also an EZR extruder from SEEMECNC which can do great for Ender 3/v2/pro for printing flexible filaments.
The below video shows the installation of EZR Struder on Ender 3 easily:
Can a Glass Build Plate Be Used For TPU 3D Printing?
Yes, Glass build plate can absolutely be used to print TPU upon. To boost the adhesion of TPU objects, a Glass build plate (heated) along with PVA glue stick are used. TPU can also be printed on other bed types such as Aluminum, PEI and others.
TPU Vs PLA : Which Filament is Better for 3D Printing?
TPU does better than PLA whenever flexibility is concerned. TPU offers high durability and great impact resistance. PLA is preferred than TPU when ease of printing is a preference, to get objects with strength and better surface quality. TPU can be used in functional parts as an application.
TPU enables us to make mechanical parts that need flexibility, chemical endurance, abrasion and heat resistance.
TPU printing needs care and is not easy. Flexible filaments need many printing parameter configurations to get a quality output.
TPU is hygroscopic, being moisture sensitive, it has to be stored in dry or airtight containers. Whereas PLA is the popularly used 3D filament which is known for its easy printing in multiple projects.
PLA is non-durable and its heat resistance is very low. This makes it melt at a low temperature which is not suitable for mechanical parts.
To conclude, both TPU and PLA have pros as well as cons. You can choose them based on the applications.
For all flexible parts with good strength, TPU can be preferred. Whereas, PLA can be used to print models painlessly with great details.
Can Supports Be Made With TPU? Can TPU Printing Be Made Using Supports?
Yes, support structures can be used while printing with TPU filaments provided support settings has to be made in the slicer. Many 3D users prefer printing support structures with TPU itself instead of other filament. Support structures can be enhanced by adjusting X & Y infill offsets.
In Cura Slicer Software, an option known as “Support Wall Line Count” can be used to strengthen the Support Structures. By default, its value will be 1 and you can increase it so that the number of walls will get more. It uses more material and becomes harder to remove, but makes sensible to use with TPU.
The X/Y and Z distance values of the Support can be optimized in order to hold the TPU object strongly. The Z Distance of the Support is very influential in adhering the model to it.
Lesser these values, stronger it bonds with model, greater these values reduces its adhesion with model and is easy to remove.
For TPU printing, a triangle Support Structure is preferred as it is easy to remove and at the same time sticks firmly to the model.
The video below shows the method to use flexible filaments for Support Structures.
Can TPU Filament Get Bad/Spoiled?
TPU filament can surely get bad when exposed to free moisture air. Because of its hygroscopic nature, it absorbs too much moisture and reduces the print quality significantly. It’s recommended to keep TPU dry using a Filament Dryer or airtight container with desiccant packs.
When TPU is moisturous, it leads to poor bed adhesion, nozzle clogging, popping, bubbling and other extrusion issues.
Experienced Project Engineer with a demonstrated history of working in the field of Product Design & Development industry in Mechanical Engineering. Skilled in 3D Printing and Re engineering Technologies with CATIA V5 , Materials Science, Finite Element Analysis (FEA), Mimics, ANSYS Workbench and Casting Simulation software. Strong engineering professional with a Master’s Degree focused in Industrial Metallurgy from PSG College of Technology, Coimbatore.