What is TPU?

Welcome to our comprehensive guide on Thermoplastic Polyurethane (TPU), a flexible, strong, and highly versatile 3D-printing material. In this blog, we will delve into the fascinating world of TPU, exploring its makeup, advantages, manufacturing process, and its myriad of industrial and everyday applications. You'll discover why this materials exceptional flexibility, symbolized by its 95a Shore Hardness, sets it apart from other printing materials. We'll also equip you with practical advice on how to master 3D-printing with TPU material, covering optimal printing temperatures, bed temperatures, and printing speeds, alongside other essential tips and tricks. So, whether you're a seasoned 3D-printing enthusiast or a curious beginner, this blog has something for you. Get ready to enhance your 3D-printing experience with TPU!

Benefits of TPU

TPU stands for thermoplastic polyurethane. It is a thermoplastic elastomer (TPE) that offers superior flexibility and strength compared to other materials such as ABS and PLA. It's also great for printing 3D objects that need to bend or flex without breaking.

Heat and Solvents Resistance

Resistance is one of the remarkable features of TPU that distinguishes it from other 3D printing materials is its excellent resistance to temperature and solvents. TPU's heat resistance allows it to withstand higher temperatures without degrading or losing its structural integrity, making it an ideal choice for applications requiring exposure to intense heat. Moreover, TPU impressively resists solvents like oil, and even certain acids and alkalis, maintaining its flexibility and strength under challenging conditions. Additionally, TPU exhibits grease resistance, further enhancing its appeal in various application scenarios. TPU is also notably abrasion-resistant, making it an exceptional choice for 3D printing of parts that must endure high-wear environments or frictional forces.

Hydrolysis Resistance

TPU's hydrolysis resistance is another noteworthy characteristic, which essentially refers to its ability to withstand long-term exposure to moisture without breaking down. Traditional materials may deteriorate or lose their structural integrity when subjected to moist conditions over time, but TPU stands out due to its resilience. This resistance to hydrolysis makes TPU an ideal choice for use in aquatic environments or applications that require prolonged contact with water. Its resilience doesn't stop there — TPU is also resistant to fungal growth and bacteria, ensuring durability and longevity in different environments.

How is TPU made?

Thermoplastic Polyurethane (TPU) is a category of plastic that comes into existence when a polyaddition reaction occurs, a process that involves a chemical reaction between diisocyanate and one or more diols. This unique chemical process results in a highly versatile material that combines the best properties of both plastic and rubber, offering superior flexibility and durability. TPU's production process is relatively simple, compared to other materials such as ABS and PLA, making it a cost-effective option for 3D printing enthusiasts.

Creating TPU involves a two step process. First, polyols react with a small excess of diisocyanate to form a prepolymer. Then, the prepolymer reacts with a chain extender. This results in a long chain polymer - TPU, loved by 3D printing enthusiasts for its flexibility, strength, and resilience. The properties of the final product can be adjusted by using different types of diisocyanates and polyols. This controlled and safe process adheres to industry regulations. TPU's manufacturing process makes it an affordable, versatile, and high performance choice for 3D printing applications.

TPU Industrial uses

TPU's remarkable properties make it an ideal material for a variety of industrial applications. It is commonly used in the manufacture of automotive parts such as door seals and engine covers, where its flexibility, heat, and abrasion resistance are key factors in ensuring durability.

MEDICAL Field

In the medical industry, TPU can be found in surgical instruments, catheter tubes, joint implants and more — all thanks to its superior flexibility and biocompatibility. TPU has established itself as a leading material in the production of medical devices. Its resilience, flexibility, and biocompatibility make it ideal for creating respiratory masks, heart valves, IV tubing, and dialysis equipment. TPU's high abrasion resistance is advantageous for reusable medical devices that require regular cleaning and sterilization. With its unique properties, TPU is a top choice in the rapidly evolving medical device industry.

FOOTWEAR & SPORTING GOODS

TPU is also widely used in the footwear industry and sporting goods, thanks to its excellent durability and shock absorption properties. It is often used to make soles for shoes as well as cushioning components in insoles.

TPU EVERYDAY USES

TPU is a popular choice for everyday use because of its many benefits! Thanks to its flexibility and durability, it can be used to manufacture flexible parts like phone cases that offer excellent protection without compromising style or comfort.

TPU is also often used in the manufacture of clothing accessories such as purses, backpacks and wallets — all of which require a material that can stand up to wear and tear while remaining lightweight and stylish.

In addition, TPU can be used to make personal care items such as hair accessories, toothbrushes, and combs. Its superior flexibility makes it an ideal choice for creating these everyday items.

How Flexible is TPU?

TPU's flexibility is truly unparalleled when it comes to 3D printing materials. It exhibits an exceptional level of elasticity, allowing it to be stretched or bent significantly without losing its original shape. For instance, a 3D printed TPU phone case can be twisted and contorted without any signs of stress or deformation, snapping back into its original form as soon as the force is released. Similarly, TPU can be used to create flexible parts like hinges or joints in 3D printed parts, which can bend or pivot while maintaining their structural integrity. This remarkable flexibility opens up a world of possibilities for creating intricate, flexible, and durable 3D printed designs.

TPU and 95a Shorness

The 95a Shore Hardness is a measure of the hardness or, inversely, the flexibility of a material. It's named after Albert F. Shore, who developed a device called a durometer in the 1920s to measure material hardness. The scale ranges from 0 to 100, where a higher number denotes a harder material. For TPU, 95a indicates a high degree of flexibility. It means that this material can significantly bend or stretch without deformation, thus making it an excellent choice for 3D printing applications where flexibility and durability are paramount. This hardness rating points to TPU's remarkable ability to withstand stress, return to its original shape after deformation, and maintain its physical properties even under strain.

TPU 3D Printing

TPU PRINT SETTINGS

SIZE AVAILABILITY: 1.75MM

RECOMMENDED EXTRUSION TEMPERATURE: 205°C - 250°C

RECOMMENDED BUILD PLATFORM TEMPERATURE: 20°C - 60°C

RECCOMENDED PRINTING SPEED: 15 - 30 mm/s

While TPU's exceptional flexibility and strength make it an ideal material for 3D printing, these same properties also present unique challenges. The primary issue is that TPU's flexibility can cause it to bend or warp during the printing process, particularly at higher speeds. This may result in prints that lack precision or show signs of distortion. The material's sensitivity to temperature further complicates the process, as improper settings can cause stringing and blobbing. TPU material also tends to adhere to metal, posing a problem for printers utilizing a Bowden extruder. The hygroscopic nature of TPU makes it susceptible to moisture. If not stored correctly, the material can absorb water from the air, leading to poor-quality prints. Despite these challenges, with the right techniques and adjustments, it's entirely possible to achieve successful prints with TPU. In the next section, we'll delve into how to overcome these obstacles and master 3D printing with TPU.

TPU Printing Temperature

The optimal printing temperature for TPU filament largely depends on the specific brand and model of the 3D printer used, but typically ranges between 205°C to 250°C. At the lower end of this spectrum, TPU tends to print more slowly and with greater precision, making this temperature ideal for intricate designs or parts that require a high degree of accuracy. On the other hand, printing TPU filament at higher temperatures speeds up the process, but may result in minor stringing or blobbing. Therefore, a higher temperature setting might be appropriate for larger, less detailed parts. In all cases, it's crucial to ensure that the temperature doesn't exceed
the TPU's heat resistance limit, as this can cause the material to degrade or emit harmful fumes. Remember, TPU's hygroscopic nature means it absorbs moisture from the air, so maintaining a dry, enclosed environment during the printing process is key to achieving successful prints.

TPU Bed Temperature

The bed temperature for TPU printing is another crucial factor for successful prints. It should typically be set between 20°C to 60°C, but again, this can vary depending on the specific TPU brand and the printer model. A cooler bed temperature might be beneficial for smaller, detailed TPU projects to prevent any unintended warping. In contrast, a slightly hotter bed temperature - closer to the 60°C mark - could help for larger prints, ensuring better adhesion to the bed and reducing the risk of warping. However, too high a temperature may lead to the TPU filament sticking too firmly to the bed, making it difficult to remove the print once completed. Experimentation with the specific TPU and printer you have will ultimately lead to the best settings for successful 3D printing outcomes.

TPU Printing Speed

When 3D printing with TPU, adjusting the printing speed is a crucial factor to ensure successful outcomes. Generally, slower speeds with a consistent feed rate are recommended, usually in the range of 15-30mm/s. The unique flexibility of TPU, while offering remarkable durability and elasticity, can cause difficulties at higher printing speeds, leading to misprints or deformation. Hence, a slow and steady print speed allows for greater precision, and helps to avoid any potential warping or distorting of the object being printed. The slower speed also accommodates TPU's sensitivity to temperature, reducing the risk of issues such as stringing or blobbing. Remember that the exact speed might require some trial and error depending on your specific printer and the TPU filament you're using. As always, take into account TPU's hygroscopic nature; keeping the material dry and properly stored will ensure the highest quality prints.

Does TPU require a cooling fan?

While TPU's resilience and flexibility make it an exceptional choice for various 3D printing applications, regulating the temperature during the printing process is crucial. A common question that arises is whether a cooling fan is required to successfully print with TPU. In most situations, TPU does not necessitate a cooling fan as it isn't significantly prone to warping or distortion. However, if you're operating at speeds or temperatures beyond the recommended range, a cooling fan may become necessary. The fan can help to quickly cool the newly extruded filament, helping to maintain the shape and detail of your print. Despite this, it's essential to remember that every 3D printer and TPU brand may behave slightly differently, so some experimentation may be necessary to find the perfect settings for your specific setup.

Does TPU need a Direct Drive?

With TPU 3D printing, a common question is whether a Direct Drive extruder is necessary. While TPU can be printed using both Bowden and Direct Drive extruders, the latter often yields better results due to its shorter distance between the motor and the nozzle. This proximity allows for more control and accuracy in filament feeding, reducing the chances of buckling or jamming - common issues with TPU due to its flexibility. Bowden extruders, on the other hand, may struggle with the flexible nature of TPU, resulting in less precise prints. For high precision TPU 3D printing, investing in a Direct Drive extruder is recommended. However, a Bowden extruder can still be used with TPU by adjusting settings and considering other factors. Experimentation with your specific 3D printer and TPU filament will help you find the perfect combination for successful prints.

TPU Tips and tricks

One key tip for successful TPU printing not yet discussed is ensuring the filament path is constrained. Given TPU's flexible nature, it can sometimes veer off-path, leading to sub-optimal prints or even printer damage. To prevent this, ensure your printer has a fully guided filament path, with no gaps where the TPU can deviate. Additionally, fine-tuning your retraction settings can also improve the print quality. TPU tends to ooze or string more than rigid filaments, and adjusting retraction can help counteract this. Start with a low retraction distance (around 1mm) and increase incrementally if needed. Furthermore, using a lower layer height can increase the accuracy of your TPU prints. As TPU is more prone to errors at higher layer heights, employing a smaller layer height (around 0.1mm) can mitigate this issue and lead to cleaner prints. Remember, experimentation is key in achieving the best results when 3D printing with TPU.

When working with TPU, it is vital to note that this material can stretch under pressure, a feature known as negative tolerance, which can potentially cause fitting issues in printed parts that require strict dimensions. This characteristic of TPU makes it essential to account for in the design process to ensure the final 3D printed object accurately fits its intended purpose. To correct negative tolerance in TPU prints, consider adjusting the scale of your design in the slicing software to account for the expected stretch. Alternatively, you can also make use of compensation factors when designing your model, essentially oversizing the dimensions to counteract the expansion during printing. As always, a degree of experimentation may be necessary to determine the precise adjustments required for your specific TPU filament and printer.

FAQs

While TPU has attractive properties for 3D printing, it's not generally safe for food contact. This is due to the porosity of printed objects, which can harbor bacteria. TPU filaments may also contain additives not approved for food contact. If you need a food-safe material, explore other options specifically marked as such. Remember, safety in food-related applications depends on material, processing, handling, and storage conditions.

When comparing the toxicity of TPU (thermoplastic polyurethane) to other 3D printing materials like ABS (Acrylonitrile Butadiene Styrene) and PLA (Polylactic Acid), it's important to understand their chemical compositions. Unlike ABS, which emits harmful fumes when heated, TPU typically doesn't produce hazardous emissions during printing, making it safer for unventilated spaces. Like PLA, TPU is generally safe to handle and print with, but remember that safety can vary depending on the brand and additives of the filament. Always refer to the manufacturer's safety data sheet and work in a well-ventilated area for the best TPU 3D printing experience.

TPU, or Thermoplastic Polyurethane, is often characterized as a soft engineering plastic, offering a high degree of flexibility and elasticity not commonly found in most 3D printing materials. Its unique structure is composed of soft and hard segments, resulting in a material that seamlessly combines the advantages of rigid plastics and flexible rubbers. The soft segments provide TPU with its signature flexibility, while the hard segments contribute to its durability and resistance. This balanced combination of soft and hard elements gives TPU its ability to retain form under tension yet still revert to its original shape when the tension is released. Thus, TPU can indeed be considered a soft material while simultaneously boasting characteristics typically associated with harder materials.

During 3D printing, TPU filament may occasionally clog the extruder nozzle, resulting in subpar prints. To dissolve the TPU and restore optimal performance, perform a 'cold pull' process. Start by heating the nozzle to the typical TPU printing temperature, around 220-230°C. Once heated, manually push filament through to ensure smooth flow. Then, significantly cool the nozzle to 100-140°C for TPU. Applying gentle upward pressure, swiftly pull the filament out when the target temperature is reached. The aim is for the filament to carry any residue, effectively cleaning the nozzle. Repeat the process until the filament comes out clean.

As a member of the thermoplastic elastomer family, this wonderful material stands out for its environmentally friendly and recyclable nature. This makes it an excellent option for eco-conscious users. All of these benefits make TPU a popular material amongst seasoned printers.

Conclusion

We hope that this comprehensive guide has been helpful in understanding the properties, benefits, and techniques for successful 3D printing with TPU. As always, thank you for being a part of our community and for your ongoing support. We're excited to let you know that HATCHBOX carries high-quality TPU filament, ready for all your 3D printing needs. We're committed to providing you with the best materials to bring your creative projects to life. Happy printing!