If you want to print parts that can bend, stretch, and flex without breaking, flexible filaments like TPU and TPE are your best options. From phone cases and seals to flexible joints and wearable gadgets, these materials unlock a new dimension of functionality in 3D printing.
But not all flexible filaments are the same. Understanding the difference between TPU (Thermoplastic Polyurethane) and TPE (Thermoplastic Elastomer)—and learning how to print them correctly—is crucial to achieving strong, smooth, and high-quality flexible prints.
This guide provides a detailed TPU vs TPE comparison, top product recommendations, and expert tips for successful flexible filament printing.
Why Choose Flexible Filaments?
Flexible materials allow you to print objects that:
- Resist impacts without cracking
- Return to shape after being stretched or compressed
- Absorb vibrations and shocks
- Conform to ergonomic surfaces or body shapes
Applications include:
- Phone and tablet cases
- Seals and gaskets
- Robot tires and wheels
- Wearables and straps
- Shock-absorbing mounts
TPU vs TPE: Key Differences
| Feature | TPU (Thermoplastic Polyurethane) | TPE (Thermoplastic Elastomer) |
|---|---|---|
| Flexibility | Semi-flexible to very flexible (85A–98A Shore hardness) | Extremely flexible, softer (60A–90A Shore hardness) |
| Strength | High tensile strength and durability | Softer but less durable under stress |
| Printability | Easier to print | More difficult, can jam easily |
| Surface Finish | Smooth, rubber-like | Softer and slightly tacky |
| Abrasion Resistance | Excellent | Moderate |
| Chemical Resistance | High | Varies by brand |
| Typical Uses | Phone cases, flexible joints, tires, mechanical parts | Seals, grips, bands, soft-touch parts |
Summary:
- TPU is stronger, more resilient, and easier for most printers.
- TPE is softer, more flexible, but harder to print consistently.
Top Flexible Filaments to Try in 2025
| Brand | Material | Key Features |
|---|---|---|
| NinjaTek NinjaFlex | TPU (85A) | Ultra-flexible, premium quality |
| Overture TPU | TPU (95A) | Affordable, easy to print |
| Priline TPE | TPE (90A) | Good balance of flexibility and strength |
| MatterHackers PRO Series TPU | TPU (98A) | Semi-flexible, easy on Bowden setups |
| Sainsmart TPU | TPU (95A) | Highly popular, good toughness |
📌 Softer filaments (lower Shore hardness) = more flexible but harder to handle.
Tips for Printing Flexible Filaments Successfully
Printing flexibles requires different handling than rigid materials like PLA or PETG.
1. Direct Drive Extruder is Preferred
- Direct drive setups push filament straight into the hotend, reducing bending or compression.
- Bowden tubes can work but require very slow speeds and tuned retraction.
2. Reduce Print Speed
📌 Recommended speed: 20–35 mm/s
- Slow speeds prevent filament compression inside the extruder.
- Allows for smoother and more consistent extrusion.
3. Optimize Retraction Settings
- Low retraction distance: 0.5–1.0 mm
- Lower retraction speed: 10–20 mm/s
- Or disable retraction entirely for very soft materials
Retraction too high often causes jams or clogs with flexible filaments.
4. Use Correct Nozzle Temperature
| Material | Nozzle Temp | Notes |
|---|---|---|
| TPU | 220–250°C | Depends on brand and color |
| TPE | 230–260°C | Often needs slightly higher temps |
📌 Always refer to the filament manufacturer’s specs.
5. Adjust Build Surface Settings
- Use a PEI sheet, textured bed, or blue painter’s tape.
- Apply a light glue stick layer if sticking too hard.
- Bed temperature: 30–60°C, depending on filament.
Too much adhesion can make removing soft parts difficult.
6. Watch Out for Oozing and Stringing
Flexible filaments tend to ooze more. Minimize by:
- Lowering print temperature slightly
- Shortening travel moves
- Enabling coasting if your slicer supports it
7. Keep the Filament Dry
Flexibles are hygroscopic and absorb moisture fast, leading to:
- Bubbles in extrusion
- Poor surface finish
- Weakened prints
📌 Store in airtight containers with desiccants or dry before printing at 40–50°C for a few hours.
Best Practices for Flexible 3D Prints
| Practice | Benefit |
|---|---|
| Print slow and steady | Consistent extrusion |
| Avoid sharp corners | Flexibles prefer smooth curves |
| Design parts with thick walls | Strengthens flexible prints |
| Use gradual overhangs | Reduces sagging or collapse |
When to Use TPU Over TPE (and Vice Versa)
- Choose TPU if you want a durable, impact-resistant part that’s flexible but still somewhat rigid (e.g., tires, phone cases, mechanical mounts).
- Choose TPE if you need ultra-soft, highly flexible parts that stretch dramatically (e.g., seals, wearable straps, soft grips).
FAQs
Q1: Can I print TPU on a Bowden tube printer?
Yes, but it’s harder. Use slow speeds, low retraction, and preferably stiffer (higher Shore hardness) TPU.
Q2: Is flexible filament waterproof?
The material itself resists water, but printed objects may leak through layer lines unless properly sealed.
Q3: How do I prevent flexible prints from sticking too much to the bed?
Use a light layer of glue stick or lower bed temperature slightly to ease removal.
Q4: Can I paint or dye flexible prints?
Painting is difficult because flexibles stretch. Use flexible dyes or specialized paints designed for soft materials.
Conclusion
Choosing between TPU and TPE depends on your project’s needs. For most users, TPU offers the best combination of durability, flexibility, and ease of printing. TPE offers extreme flexibility but challenges even experienced users.
Mastering flexible filament printing requires adjusting your slicer settings, slowing down, and ensuring proper filament handling. With patience and the right techniques, you’ll be producing strong, flexible, and highly functional prints that open up new creative possibilities.