Everything You Need to Know About Flexible Filament

In the ever-evolving world of 3D printing, the materials we use are just as important as the printers themselves. Today, we're focusing on a unique and versatile player in the filament family: flexible filament, often known as TPU (Thermoplastic Polyurethane). This remarkable material stretches the boundaries of what can be achieved with 3D printing, quite literally. But when should you opt for TPU, and what makes it the right choice for your project? Let's dive in!

Made from MH Build Series TPU.
Made from MH Build Series TPU.

The Flex Factor: Understanding TPU

TPU combines the elasticity of rubber with the strength of thermoplastics, making it an exceptional choice for items that need to bend, stretch, or take a beating without breaking. Its flexibility is measured on the Shore Hardness scale, with lower numbers indicating a softer, more pliable material.

Made from PRO Series TPU.
Made from PRO Series TPU.

The Right Time for Flexibility

Impact Resistance: If you're creating something that needs to stand up to knocks and bumps, like a phone case or protective gear, TPU is your go-to filament. It absorbs shocks with ease, ensuring durability where it counts.

Wear Resistance: For parts that will rub and roll frequently, TPU's resistance to abrasion makes it a top choice. Think wheels, rollers, or belts that need to last.

Vibration Dampening: Anything that buzzes and hums can benefit from TPU's vibration-absorbing properties. It's perfect for reducing noise or protecting components in machinery.

Comfort and Ergonomics: When you're printing items meant to be worn or held, like wristbands or custom grips, TPU's soft touch enhances user comfort and grip.

Seals and Gaskets: Need a watertight seal? TPU's flexibility allows it to conform to surfaces, creating the perfect seal or gasket for your project.

Made from MH Build Series TPU.
Made from MH Build Series TPU.

Printing with TPU: Tips for Success

TPU's unique properties mean it doesn't handle quite like your standard PLA or ABS. To help you navigate its quirks and get the best possible prints, here's a breakdown of key printing parameters, with a special focus on temperature:

Direct Drive Extruder: A must for flexible filaments. The shorter filament path provides better control and reduces the chances of the filament getting twisted or kinked.

Print Speed: Slow and steady wins the race. We recommend starting with a print speed of 15-30 mm/s. This helps prevent the filament from stretching and ensures better adhesion between layers.

Temperature Settings: Getting the temperature right is crucial for TPU. Here's what you need to know:

Extruder Temperature: TPU melts at higher temperatures than PLA. You'll want to aim for an extruder temperature in the range of 220°C to 250°C. The exact temperature can vary based on the specific TPU brand and your printer's capabilities, so it's a good idea to start in the middle of this range and adjust based on your results.

Bed Temperature: A heated bed can greatly improve first layer adhesion. Set your bed temperature to 40°C to 60°C. If your bed isn't heated, applying a glue stick or using a brim can help the first layer stick.

Retraction Settings: Retraction can be tricky with TPU due to its elasticity. Start with a minimal retraction distance and speed. If you notice stringing, increase retraction distance slowly, but be cautious of jams.

Cooling Fan: TPU likes to be cool. Turn on your cooling fan after the first few layers to solidify the print quickly and prevent stringing. However, too much cooling can lead to poor layer bonding, so find a balance that works for your setup.

Layer Height and Wall Thickness: A thicker layer height can help with the flexibility of the final print. For wall thickness, more walls can increase strength, but too many can reduce flexibility. Adjust according to the desired balance of strength and flexibility in your part.

Remember, these are starting points. TPU can vary from brand to brand, and each printer has its own characteristics. Don't be afraid to experiment to find the perfect settings for your specific situation.

Chart taken from PRO Series TPU.
This star chart is based upon our PRO Series TPU. As you can see, it rates a 5 in Impact Resistance.

Embracing the Possibilities

Whether you're looking to create custom gaskets, wearable tech, or just need a part that can take a hit and bounce back, flexible filament is an incredible tool in your 3D printing arsenal. Remember, it's not just about what you print—it's also about choosing the right material for the job.

Want to learn more about TPU or need help with your next flexible filament project? Our team at MatterHackers is always here to help. Drop us a line, and let's make your ideas flexible realities!

Happy Printing!