TPU 95A vs TPU 98A: Understanding Hardness

Detail	TPU 95A	TPU 98A
Nominal Hardness (Shore A)	95A	98A
Delta On Paper	3 Shore A points (small number, noticeable feel)
“Hand Feel” In Similar Wall Thickness	More compliant, softer squeeze	Firmer flex, more support
Bending Resistance (Same Geometry)	Lower	Higher
Edge Definition / Small Details	Can round easier on tiny features	Typically holds crisper edges
Extruder Feed Stability	More prone to buckling in long paths	Usually more stable in the same setup
Best-Feeling “Grip” Surfaces	Soft-touch grips, anti-slip skins	Firm grips, durable bumpers
Common Functional Parts	Gaskets, seals, vibration isolation, flexible hinges	Protective corners, semi-flex brackets, flex couplers, belts
Hardness Test Standard Often Referenced	Durometer “Shore” methods (e.g., ASTM D2240) [d]

TPU hardness numbers look simple, but the real-world feel is shaped by test method, viscoelastic response, and the way a printed part is built layer by layer. Moving from 95A to 98A is only three points, yet it often changes “squish,” spring-back, and how confidently your extruder can push the filament. If you want a clean mental model (and fewer surprises), focus on what Shore A actually measures and where printed geometry quietly multiplies the difference.

How Hardness Works

What 95A And 98A Mean

Real-World Flex

Printing Behavior

Performance Under Load

Where Each Fits Best

Measure It Properly

FAQ

🧪 How Shore A Hardness Works

Shore A is a durometer scale that reports how much an indenter sinks into the surface under a defined force. It’s not “hardness like metal,” it’s indentation resistance of an elastomer surface. That matters because TPU behaves like a time-dependent spring: press it quickly and it can read differently than a slower, held press.

Two practical takeaways keep TPU comparisons honest:

Shore A is an empirical number. It helps compare materials on the same scale, but it is not a direct conversion to tensile strength, modulus, or “how stiff a part will feel.” [a]
Printed parts can “act harder” or “act softer” than the raw polymer number because infill, wall thickness, and layer bonding change the way your fingers load the material (bending vs compression vs shear).
Surface texture changes perception: matte layers can feel grippier; smoother layers can feel firmer, even at the same Shore rating.

Hardness is not the same as stiffness. Shore A is about a small indentation; bending stiffness is dominated by geometry. A tiny hardness change can still be obvious once the part is thin, curved, or under tension.

🔢 What 95A And 98A Mean In Practice

The “A” in 95A and 98A points to the Shore A scale used for elastomer-like materials. Within standardized durometer methods, the A scale is used in the normal elastomer range, while other scales exist for very soft foams or much harder materials. [b]

So what does a three-point jump usually change?

Contact feel: 98A typically feels less “squishy” on a pinch test, especially on thin walls.
Shape retention: 98A often resists small dents and edge rounding a bit more when handled.
Energy return: both can be springy, but 98A commonly reads as “snappier” in short deflections.

Important nuance: the same label (“TPU 95A”) can hide different TPU chemistries and additives. Hardness is one data point; formulations can vary in tackiness, abrasion feel, and temperature response even when the Shore number matches.

🧩 Real-World Flex Depends On Part Geometry

If you print two parts from 95A and 98A with the same settings, the difference is most obvious when the part is thin, long, or designed to bend. That’s because bending stiffness is heavily geometry-driven: thickness dominates, and material changes are amplified by how the part is loaded.

Use this mental map when comparing “feel”:

Compression feel (pressing a pad): hardness shows up quickly. Small Shore changes are noticeable.
Bending feel (flexing a strip): wall thickness and span length can outweigh the Shore difference.
Tension feel (stretching a band): print orientation and layer bonding play a big role in how safe the part feels under pull.
Infill effect: high infill can make both 95A and 98A feel “much harder” because there is less internal collapse.

Design lever that beats hardness: going from 2.0 mm to 2.6 mm wall thickness can change bending feel far more than 95A → 98A, while keeping the same filament and print profile.

🖨️ Printing Behavior Differences

Harder TPU (98A) is often a little easier to feed because it resists buckling in the filament path, but both 95A and 98A still behave like flexible elastomers. The most reliable wins come from controlling extrusion, slowing down, and keeping the filament dry.

Starting points that are widely used for TPU (then tuned per brand and machine): [c]

Print speed: 20–30 mm/s is a common stability zone for flexible TPU.
Nozzle temperature: 220–240 °C as a starting window (often adjusted by brand and hardness).
Bed temperature: 40–60 °C to support adhesion without overheating.
Drying: TPU is hygroscopic; drying around 40–50 °C for a few hours can reduce bubbling and inconsistent extrusion.
Extruder choice: direct drive typically handles flexible TPU with fewer feed issues than long Bowden paths.

Retraction is the trade-off zone. Too much retraction can deform TPU in the path; too little can increase strings. Short, gentle retractions tend to behave better than aggressive values, especially for 95A.

🧲 Performance Under Load And Wear

Both 95A and 98A TPU are often chosen because they can flex repeatedly while staying tough. The difference is how each one “spends” that toughness.

Indent dents and scuffs: 98A typically shows fewer visible dents under the same finger pressure, which can help protective edges and bumpers look cleaner over time.
Vibration and impact feel: 95A often feels more forgiving when you want a softer landing or a grippier contact patch.
Dimensional creep: under constant load (like a stretched strap), 98A commonly holds shape a bit better, while 95A can feel more “relaxed” if the geometry is very thin.
Layer stress: for parts under tension, the print orientation and bonding quality can matter more than a 3-point Shore change.

Reality check: “95A vs 98A” doesn’t guarantee tear strength or abrasion life. Those depend heavily on the specific TPU formulation, pigments, and print settings that affect layer fusion.

🧰 Where Each Fits Best

Pick based on the kind of flex you want, not the number alone. Here’s a practical split that stays true across many brands.

TPU 95A Tends To Shine When

You want compliance against the skin, a device, or a mating surface.
Grip is the feature: sleeves, covers, anti-slip pads, soft-touch guards.
Sealing and damping matter more than crisp corners: gaskets, vibration isolators.
Living hinges and flexible tabs need easier bending with less force.

TPU 98A Tends To Shine When

You want supportive flex: parts that bend, but must also hold alignment.
Edge definition is valuable: bumpers, corners, guards with sharper profiles.
Feed stability matters: printers that struggle with softer TPU often behave better as hardness rises.
Semi-flex brackets, clips with cushioning, flex couplers that must stay predictable.

📏 Measure It Properly If You Need Numbers

If you need to validate hardness (for consistency between spools, or matching an existing part), measure like a lab would. Durometer readings are sensitive to sample thickness and where you press. Practical testing guidance commonly requires a specimen thickness of at least 6 mm, plus a minimum contact area so you aren’t reading an edge or a void. [e]

A simple, repeatable approach for printed TPU:

Print a solid test puck (thick enough to avoid backing effects). If you must use infill, use a high infill and thick top/bottom skins so the indenter doesn’t “fall into” the pattern.
Take multiple readings across the surface and average them. Avoid the outer edge where the material can flex sideways.
Compare like-for-like: same print orientation, same infill, same wall count, same conditioning time after printing.
Record your method (tool, dwell time, location on sample). Consistency beats chasing a single perfect number.

❓ FAQ

Is TPU 98A always “better” than 95A?

No. 98A is usually firmer and can feel more supportive, while 95A is often more compliant and grippy. “Better” depends on whether you want softness against a surface or shape-holding flex.

Will 95A and 98A print with the same profile?

Often close, but not guaranteed. 98A may tolerate slightly higher flow consistency in the same filament path, while 95A can benefit from slower speeds and gentler retractions. Always validate with a small functional test print.

Why can two “95A” TPUs feel different?

Hardness is one property. TPU chemistry, additives, pigment, and print conditions can change surface tack, rebound, layer fusion, and perceived stiffness. Geometry and infill can also make the same filament feel very different.

Does higher Shore A mean higher strength?

Not automatically. A higher Shore A often correlates with a firmer feel, but tensile strength, tear resistance, and fatigue life depend on the full formulation and the quality of your printed layer bonding.

How do I make a 95A part feel closer to 98A without changing filament?

Increase wall thickness, increase top/bottom skin thickness, and consider a denser infill. These geometry choices can raise the perceived firmness more than small changes in Shore A, while keeping the same material.

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