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TPU (Shore 85A)

TPU at Shore 85A is a flexible thermoplastic elastomer combining rubber-like elasticity, about 500% elongation, with excellent abrasion, tear, and oil resistance. It bridges rubber and plastic: soft and stretchy enough to seal and flex, yet melt-processable so it can be molded, extruded, or 3D printed rather than vulcanized.

How TPU (Shore 85A) machines

Rated 2/5, the lowest here, and honestly TPU is poorly suited to machining. Its flexibility makes it deflect, grab, and tear instead of cutting cleanly, so holding tolerances is difficult. Produce TPU parts by molding, extrusion, or 3D printing; reserve machining for rough trimming only.

Manufacturing & processing

Injection molded, extruded, and widely 3D printed for flexible functional parts. As a thermoplastic it remelts and is recyclable, unlike thermoset rubber. Drying before processing is important because it absorbs moisture. The 85A durometer gives a flexible-but-firm feel, softer than rigid plastics yet more robust than soft gels.

Typical applications

Seals, gaskets, bushings, and vibration dampers; caster and roller wheels; protective phone and equipment cases; flexible tubing and hoses; cable strain reliefs; and footwear components. Its abrasion and oil resistance suit dynamic wear parts that rigid plastics cannot flex into.

When to choose it

Choose TPU 85A when a part must flex, stretch, seal, or absorb impact while resisting abrasion and oils, and when melt processing beats vulcanized rubber for tooling speed or recyclability. If you need rigidity or precise machined dimensions, TPU is the wrong tool; pick a rigid engineering plastic instead.

Suitable surface finishes

Common finishes for TPU (Shore 85A): bead blasting, powder coating. Use the finish selector →

FAQ

Can TPU be CNC machined?
Not effectively. Its flexibility makes it deflect and tear rather than cut cleanly, earning a 2/5 machinability, so precise machined features are impractical. TPU parts are made by injection molding, extrusion, or 3D printing. If a design demands machining, it likely needs a rigid plastic, not a flexible elastomer.
What does Shore 85A hardness feel like?
Shore 85A sits at the firm end of the soft-rubber scale, roughly like a skateboard wheel or a rigid shoe sole: clearly flexible and able to bend and compress, but not squishy. Softer grades feel rubbery and stretchy; harder TPUs approach the stiffness of rigid plastics.
How is TPU different from rubber?
TPU is a thermoplastic elastomer: it melts and reflows, so it is injection molded, extruded, or printed and can be recycled, with generally better abrasion and oil resistance than many rubbers. Traditional rubber is thermoset and vulcanized, not remeltable, but can offer better high-temperature and compression-set behavior in some uses.

Property values are typical/nominal for early guidance and vary by temper, grade, supplier and heat treatment. Confirm critical specs against a certified datasheet or with an mfgiq engineer.