Flexible Filaments

TPU filaments are essentially plastics with rubber-like qualities, making them extremely flexible and durable. Flexible filaments are commonly used to produce household appliances, toys, phone cases, wearables like wristbands, automotive parts, and medical supplies. If you want to 3d print something that is supposed to bend, stretch, or compress, this TPU 3D printer filament should be up for the task.

Designers and engineers take advantage of the flexibility of flexible filaments on a daily basis and use them to create elastic shapes and prototyping tools. Printing TPU filaments and other flexible materials can be daunting for a new 3D printer user, as they are not as easy to use as other filaments. With the right instructions, anyone can achieve the desired results, that’s why we have prepared tips on how to print TPU filaments.

What are Flexible Filaments?

Flexible filaments are materials combining the properties of rigid plastic and rubber. The mix is known as a thermoplastic elastomer (TPE). These rubber-like thermoplastic elastomers can be twisted and stretched without breaking to a large extent, similar to how rubber behaves.

Some flexible filaments are more elastic than others, and they are all available in different varieties. The most popular is thermoplastic polyurethane (TPU). TPU filament is slightly more rigid, which is a good feature in the 3D printing industry because it means that is easier to 3D print it. It is also a little more durable and can better retain its elasticity in the cold. The wear resistance of the TPU Filament is 20% better than the ABS Filament and 70% better than the PLA Filament.

Pros and Cons of Flexible Filaments

Pros

• Excellent elasticity- It is ideal for those who need filament that can be bent, stretched, and maneuvered.
• Resistance to impact- Products printed from flexible filaments are usually unaffected by significant impacts.
• Vibrations are reduced- Materials with rubber-like properties dampen vibration, making them useful for industrial or mechanical parts.

Cons

• Its printing is more difficult. It will take some time to get used to the characteristics of TPU filament if you are used to PLA filament. They tend to string, making aesthetic prints more difficult. Overhangs are seemingly difficult to seamlessly integrate.
• Absorbs moisture- the filament is extremely hygroscopic; it is very important to dry it with a filament dryer before every use.
• Post Processing. Prints produced with TPU usually offer fewer options in post-processing.

Common Flexible Filaments Application

TPU materials can be used in many different ways. They include;

• Fit Testing and Functional Prototyping. Parts or Products designed with elastic properties can be tested for real-life flexibility.
• Custom Tools. It is possible to create tools with ductile parts with flexible filaments, such as gripper parts or handles.
• Designed for end-use. Several parts can be used regularly or as spare parts due to their rubbery-like properties. To prevent machinery from damaging goods on production lines, materials such as TPU provide softer contact points.

Tips for Printing with TPU filaments

• Since there are several flexible materials on the market, it’s critical to check the recommended settings given by the manufacturer.
• If you are printing with flexible filaments, a slow feed rate is often best. As the material is elastic, any sudden changes in the speed of the print can cause the piece to become uncontrollable. The filament can become compressed when print speeds increase, resulting in jams. Therefore, 25- 35 mm/s is a good starting point.
• TPU’s flexibility and elasticity make it extremely sensitive to movements like retractions. For this reason, retraction settings for TPU filament must be optimized to limit movements in 3D prints. We suggest you turn off the retraction completely.
• If you don’t have a direct drive extruder, we suggest you use the TPU filament with the hardness 98A.
• Before every use of TPU filaments, dry them first with a filament dryer.

Most common mistakes that happen when 3D printing TPU filaments

• There is not enough adhesion between the first layers of hot filament and the bed of the printer. This can lead to a 3D product with a deformed shape. We suggest you use Dimafix spray or if there is an option for your printer use a PEI plate.
• When the filament cannot be properly extruded from your 3D printer. This can occur If the nozzle completely stops the process, or there are fluctuations in the feed rate. If your printer has a Bowden-type extruder, is better if you use harder TPU filaments (like 98A) and turn off the retraction.
• The filament was not dried before use. Flexible filaments are very sensitive to moisture, so it is very important that we always store them in a place where there is no moisture, preferably in a plastic box or in nylon. Before each use, the TPU filament must also be dried in a filament dryer.

Azurefilms TPU/Flexible Filaments

The Azure Films TPU comes in two types which include; Flexible Filament Hardness 95A Shore and Flexible Filament Hardness 85A Shore. These flexible filaments are manufactured in Slovenia and come in different sizes.

The strong, flexible, and tough properties of Azurefilm filaments make them a great choice for flexible film applications that require more strength. Unlike vinyl, it is free of plasticizers, so it will not become brittle or lose its performance over time.

Azure Film TPUs exhibit superior resistance to oil, grease, lubricants, and fuels, as well as outstanding resistance to hydrolysis.

The flexibility of Azure Filaments sets them apart from other materials. The material’s Shore is a measure of its resistance to being indented and flexibility. Shore A or Shore D are typically used to describe the durometer of flexible materials. Flexible filaments used in 3D printing are measured on the Shore A scale, while harder rubbers are measured on the Shore D scale. Shore A is softer, more flexible, and provides all that is necessary to meet 3d makers’ demands. Shore D is harder and also easier to 3D print. Its degree of hardness mitigates its shortcomings, making it ideal for introducing flexible filament printing. It is very similar to 98A shore.

How Different Extruders Impact Printing TPU

An extruder is an essential component of a 3D printer, which affects the performance of flexible filament printing. You must understand how the extruder performs and how you can optimize it so that the printing process will get the best results possible.

The job of a flexible filament extruder is to push the filament to be extruded and melted at a heated nozzle. An extruder consists of three identical components: driver gear, stepper motor, and idler. Extruders will always have the same components but come in different types: Direct drive and Bowden. It is the path of the filament and the distance the filament before entering a heated nozzle that makes the difference between the two.

Compared to Direct-drive extruders, the filament travels longer to the nozzle with the Bowden system, which increases the speed of 3D printing. The direct-drive extruders are a better choice for printing with flexible filaments because the location of the extruder is in a better position and there is a smaller chance that the print will go bad. If we compare the Bowden system, the filament needs to travel longer to the nozzle, making it more likely that the softer filaments will have trouble keeping the correct form.

So, Bowden extruders work well with rigid materials such as ASA, PLA, ABS, PETG, Nylon, Carbon Fiber, and other filaments.

Direct drive extruders are extremely popular. Utilizing this extruder offers precise retraction control, which is one of the main benefits. The direct drive position is important to ensure we can get smooth and accurate 3D prints since it minimizes the distance to the hotbed.

Direct Drive systems have the drawback of putting more weight on the gantry, which can cause bigger backlash and vibrations at a faster speed. Regardless, a DDE system operating on a 3D printer rubber will often print at lower speeds due to the limitations of the printer’s other hardware features and assemblies.

Conclusion

Flexible filaments have become popular mainly because of their properties and because of their rubbery appearance. When printing TPU 3D filaments, it is important to take the time to allow the 3D printer to print slowly. You may also need additional adhesive tape or Dimafix spray to ensure good adhesion of the filament to the table. A special PEI plate has also recently entered the market, which represents a revolution among plates. The filament adheres perfectly to the PEI plate, but when the product cools down, you can easily remove it without any tools. When you finish