Flexible 3D Prints with TPU: Phone Cases, Gaskets and Squishy Toys

Most people picture 3D prints as hard plastic, but one family of filaments bends, squishes and bounces back. TPU is what makes printed phone cases, watch straps, seals and stress toys possible. This guide covers what TPU actually is, how flexible it can be, what it is good for and what to tell a studio when you order.

What TPU is

TPU stands for thermoplastic polyurethane. It is a rubber-like plastic that can be melted and extruded by an ordinary FDM printer, then returns to a flexible, elastic state as it cools. Think of the material in a soft phone case or the sole of a running shoe: that is the same chemical family.

Compared with PLA or PETG, TPU has three standout properties:

• Elasticity. It stretches and returns to shape instead of cracking.
• Impact absorption. Drops and knocks are cushioned rather than transmitted.
• Grip. The surface is slightly tacky, so it does not slide off tables or out of hands.

It is also resistant to oils, greases and many solvents, and it tolerates cold better than rigid plastics, which makes it popular for outdoor and automotive parts.

How flexible is "flexible"? Shore hardness

TPU is sold in hardness grades measured on the Shore A scale (higher number, harder material). The grade matters more than the brand.

Shore hardness	Feels like	Typical uses
85A	Soft rubber, easily squeezed	Squishy toys, soft grips, seals
95A	Firm rubber, like a car tyre	Phone cases, bumpers, watch straps, gaskets
98A to 64D	Semi-rigid, bends but does not squish	Hinges, protective covers, wheels

95A is the everyday workhorse. It prints reliably, holds detail, and still flexes enough to snap around a phone. Softer 85A is wonderful in the hand but harder to print accurately, so very fine details and thin walls come out slightly rounded. If a part needs to be both rigid and flexible in different places, wall thickness and infill can be tuned so the same material behaves differently across the object.

What people order in TPU

Phone cases and device bumpers. A case printed to your exact phone model, in a colour you cannot buy, with a name, logo or pattern embossed on the back. Ports and buttons are cut out from the model, and the 95A material grips the phone snugly.

Gaskets, seals and feet. Replacement rubber for appliances, aquarium lids, camera housings and furniture. If the original seal is discontinued, a measured copy in TPU often outperforms a generic one. See our post on replacement parts you can print.

Squishy toys and fidgets. Stress balls, flexi-dragons with articulated joints, dice cups, teething-safe shapes for pets (not for infants; see our note on toy safety).

Protective parts. Drone landing gear and bumpers, controller grips, tool handles, cable strain reliefs, laptop corner guards.

Wearables. Watch straps, bracelets, cosplay armour joints that need to bend when you walk.

What TPU is not good at

• Sharp details. The material is soft, so tiny text and crisp edges blur a little. Larger, bolder shapes work best.
• Speed. TPU prints slowly because the filament must be pushed gently. A phone case that would take an hour in PLA can take two to three in TPU.
• Heavy loads at hot temperatures. Above roughly 60 °C it softens further. It is not a gasket for an engine.
• Painting. Paint cracks when the part flexes. Choose the colour of the filament instead; TPU comes in dozens of colours, including translucent.

If your part needs to be rigid, compare the stiff plastics in PLA vs PETG vs ABS instead.

Designing a flexible part

A few rules make a TPU order succeed on the first attempt:

1. Send dimensions. For a phone case or gasket, the exact device model or the measured inside diameter is essential. A 0.5 mm difference changes the fit.
2. Avoid razor-thin walls. Below about 1 mm the part becomes floppy and tears. Around 1.5 to 2 mm gives a firm, protective feel.
3. Think about infill. A low-density gyroid infill makes a part squishier; solid walls make it stiffer. Tell us how the part should feel and we will pick the settings.
4. Keep overhangs modest. Supports are harder to remove from soft material, so shapes that print without scaffolding come out cleaner.

Fantasy Lab 3D prints in TPU alongside PLA, PETG and resin, and can help adapt a rigid model into something flexible or design a gasket from your measurements.

Ready to order?

Have a device that needs a case, an appliance missing a seal or an idea for a squishy toy? Send a photo, measurements or a model file through the contact section, or DM us on Instagram @fantasylab3d.almaty. The price depends on size, hardness grade and quantity, so request a quote and we will get back to you.