The Battle of the Flexibles: TPE vs. TPU

If you are looking to 3D print something that bends, squishes, or stretches, you have likely run into two acronyms: TPE and TPU.

To the average person, they both look like "flexible rubbery plastic." But if you pick the wrong one for your project, you might end up with a part that is too stiff to function—or a print that fails halfway through because the material was too soft to handle.

Here is the simple guide to understanding the differences between these two flexible materials.

The "Square and Rectangle" Rule

First, a quick technical distinction: TPU is actually a type of TPE.

• TPE stands for Thermoplastic Elastomer. This is the broad category for all flexible plastics.

• TPU stands for Thermoplastic Polyurethane. This is a specific sub-category of TPE.

In the 3D printing world, however, we treat them as two different things.

• When people say TPE, they usually mean "Very soft, difficult-to-print rubber."

• When people say TPU, they usually mean "Firmer, durable, easier-to-print flexible."

1. TPE (The "Squishy" One)

Think of it like: A rubber band or a soft eraser.

TPE filament is known for being incredibly soft and elastic. It has a high "elongation at break," meaning you can stretch it pretty far before it snaps.

• The Pro: It feels the most like real rubber. It provides excellent grip and vibration dampening because it is so soft.

• The Con: It is a nightmare to print. Because the filament is floppy (imagine trying to push a cooked noodle through a straw), it often gets jammed in 3D printers. It requires very slow print speeds and specialized extruders.

Best Used For:

• Soft handle grips

• Wearable items (like watch bands)

• Seals and O-rings that need to compress tightly

2. TPU (The "Tough" One)

Think of it like: A car tire or a heavy-duty phone case.

TPU is the industry standard for flexible 3D printing. It is flexible, but it has some rigidity to it. It is incredibly resistant to abrasion (scratching and rubbing), chemicals, and greases.

• The Pro: It is nearly indestructible. You can hit a TPU part with a hammer, run it over with a car, or throw it off a building, and it will likely survive. It is also much easier to print than TPE because it is stiff enough to be fed through the printer gears without jamming.

• The Con: It isn't "squishy." If you need something that feels like a soft gel, TPU will feel too hard.

Best Used For:

• Drone parts (bumpers and mounts)

• Phone cases

• Industrial gaskets and bushings

• Robotics wheels and treads

The Shore Hardness Scale (How we measure squish)

To decide between them, engineers use the Shore Hardness Scale.

• TPE usually sits around 60A to 85A (Softer).

• TPU usually sits around 90A to 95A (Firmer).

For reference: A rubber band is 20A, a pencil eraser is 55A, a car tire is 70A, and a shopping cart wheel is 95A.

Quick Comparison Chart

Which One Should You Choose?

• Choose TPE if: Comfort and softness are the priority (e.g., a handle grip for a tool you hold all day).

• Choose TPU if: Durability and function are the priority (e.g., a bumper for a robot that is going to crash into walls).

Still not sure which flexible is right for your project?

Contact us for a free consultation.