K’s Lab | The Complete Guide to the Kexcelled TPU Family: Choosing the Right Hardness from 60A to 77D

What is TPU?

In 3D printing, if PLA and ABS build the solid "skeleton," TPU (Thermoplastic Polyurethane) gives structures their "muscles and skin."

TPU is a thermoplastic elastomer that combines rubber-like elasticity with plastic processability. It undergoes significant deformation under external force and rapidly snaps back once unloaded. Featuring high resilience, wear resistance, tear strength, and weather resistance, TPU is expanding the possibilities of flexible manufacturing—from sneaker soles to automotive dust boots.

What is Shore Hardness? 

Because TPU is an elastomer, conventional hardness tests (such as Rockwell or Brinell) don't apply. Instead, Shore Hardness measures material stiffness:

• Shore A: Measures softer TPUs. Lower values feel like skin or jelly, while higher values feel closer to a car tire.
• Shore D: Used for higher-rigidity materials when hardness reaches or exceeds 95A.

More Comprehensive! Covering up to 10 hardness levels

Through advanced molecular chain engineering, Kexcelled achieves a wide hardness spectrum spanning 60A to 77D.

The Kexcelled flexible ecosystem includes 10 core TPU products engineered for various applications and scenarios:

THE K8™ TPU 60A / 65A / 70A / 75A / 80A / 85A / 90A / 95A / 64D / 77D

To streamline material selection, Kexcelled categorizes these into 3 Hardness Tiers:

• Low Shore (60A–70A) | Ultra-Soft & High Deformation:

Tailored for skin-like touch and precision seals. Elongation at break exceeds 2,000%, handling extreme tensile strain. Rebound resilience reaches 60%–65% with an exceptionally delicate tactile feel.

Typical Applications: Simulated medical blood vessels/catheters, soft robotic grippers (capable of safely picking up raw eggs), high-end waterproof seals.

• Mid Shore (75A–85A) | High Tolerance & All-Rounder:

Balances tear resistance with steady printing. Represents the golden jump in tear strength, soaring from 67–71 N/mm at 75A to 99–103 N/mm at 85A.

Typical Applications: High-durability phone cases, industrial dust covers, small drive belts, ergonomic grips.

• High Shore (90A–77D) | High Mechanical Strength & High-Speed Printing:

Built for engineering load-bearing applications. TPU 77D delivers a flexural modulus of 1,100–1,200 MPa and tear strength of 230–240 N/mm, maintaining high crack resistance under heavy impacts.

Typical Applications: Automotive chassis bushings, heavy-duty industrial gears, skateboard wheels, riot-shield casings.

Print Smarter with AMS Compatibility*

Feeding hassles and frequent nozzle clogs can ruin the 3D printing experience. Moving away from traditional manual external feeding, we enable an automatic feeder (AMS) feeding experience*. Kexcelled's proprietary process lowers filament surface tackiness, ensuring smoother feeding with reduced jam and clog risks.

(*Applicable to select materials)

Every Color You Need, All in One Place!

Outstanding print quality deserves outstanding color. Kexcelled offers a professionally curated color palette with vibrant yet refined finishes, making it easier to find the perfect color for every project.

Engineered for Creative Freedom

Guide: How to Choose Your TPU

Tip:
New to TPU? Start with TPU 64D or 95A for easier printing.

Printing Tips: TPU Troubleshooting Guide

Q1. Why does TPU string, bubble, or make popping sounds during printing?

A: Moisture absorbed by the filament can lead to unstable printing performance.

Solution:

• Dry the filament thoroughly before printing.
• We recommend drying it in a convection oven at 80°C for approximately 6 hours (adjust the drying time according to the filament's condition if needed).

Q2. Why is my TPU print so difficult to remove from the build plate?

A: TPU naturally has strong bed adhesion, especially for models with a large contact area.

Solution:

• Do not force the model off the build plate.
• Gently lift one corner first, then apply a small amount of isopropyl alcohol (IPA) around the edge to help release the print.

Q3. How should I remove stringing after printing?

A: Because TPU is a soft, flexible material, fine strings may appear during printing.

Recommended Method:

• Briefly apply hot air with a heat gun to remove the strings. Avoid prolonged heating, as it may deform the model.
• Open flames are not recommended.

Q4. Why is soft TPU (below 95A) more difficult to feed?

A: Lower-hardness TPU is more flexible, making it more likely to bend or encounter additional resistance during filament feeding.

Solution:

• Use a top-mounted spool holder whenever possible to shorten the filament path.
• Use a shorter PTFE (Teflon) tube to reduce feeding resistance.
• Adjust the filament path according to your printer manufacturer's recommendations to improve feeding reliability.

Recommended Printing Settings

Parameter	65A–70A	75A–85A	90A–95A	64D–77D
Nozzle	240–250℃	230–250℃	240–250℃	210–240℃ (64D: 220–240℃)
Bed temperature	30–55℃	30–50℃	35–55℃	35–55℃
Bed modification	PEI frosted board	PEI frosted board	PEI frosted board	PEI frosted board
Cooling fan	50%–100%	50%–100%	50%–100%	50%–100%

 

Technical Data Sheet (TDS)

For matrix integration and engineering records, below is the summary of K+ Lab measured physical properties:

Property	THE K8™ TPU 65A	THE K8™ TPU 70A	THE K8™ TPU 75A	THE K8™ TPU 80A	THE K8™ TPU 85A	THE K8™ TPU 90A	THE K8™ TPU 95A	THE K8™ TPU 64D	THE K8™ TPU 77D
Measured Hardness (GB/T 531.1)	62A	64A	65A	74A	80A	88A	92A	65D	79D
Tensile Strength (MPa, XY)	> 8	> 11	> 13	> 24	> 24	> 36	> 34	30–35	30–35
Elongation at Break (%, XY)	> 2000	> 2000	> 2000	> 1600	> 1400	> 1400	> 1100	540–550	370–400
Tear Strength (ASTM D624, N/mm)	36–40	40–45	67–71	90–95	99–103	121–125	113–117	150–160	230–240

 

3D printing is no longer limited to rigid lines. With 10 flexible filaments spanning the full hardness spectrum, the Kexcelled TPU family brings soft-touch feel, mechanical protection, and heavy-duty impact resistance to your designs.

Stop letting material limits constrain your creativity—let your application dictate the material.