TPU 95A (Thermoplastic Polyurethane, Shore 95A) for FDM

Material Profile: TPU 95A (Thermoplastic Polyurethane, Shore 95A) for FDM

FDM Engineering Material Technical Report Series

Compiled from manufacturer technical datasheets and peer-reviewed literature

Abstract—TPU 95A is a Shore 95A hardness thermoplastic polyurethane — the most popular flexible FDM filament because it sits at the boundary between rubbery and semi-rigid behaviour, making it printable on most direct-drive (and many Bowden) extruders. It combines the rebound and abrasion resistance of rubber with the printability and post-processability of a thermoplastic.

Index Terms—additive manufacturing, FDM, thermoplastic polyurethane, TPU, elastomer, flexible filament.

I.  MATERIAL IDENTIFICATION

This section establishes the canonical names and commercial designations under which the material is supplied.

A.  Designation

Trade name: TPU 95A (generic; Shore 95A is the canonical descriptor). Examples: Polymaker PolyFlex™ TPU95, Bambu Lab TPU 95A, BASF Ultrafuse TPU 95A, NinjaTek Cheetah (95A).

B.  Full Chemical Name

Thermoplastic polyurethane — segmented block copolymer of alternating hard urethane domains (formed from diisocyanate + chain extender) and soft polyol domains (typically polyether or polyester diols).

C.  Aliases and Alternative Designations

II.  COMPOSITION AND MOLECULAR STRUCTURE

A.  Empirical Chemical Formula

Idealised: [-CO-NH-R-NH-CO-O-R'-O-]ₙ where R is a diisocyanate residue (e.g., MDI, TDI) and R' is a polyether (PTMG) or polyester polyol soft segment.

Fig. 1.  Repeating unit / structural schematic of the polymer matrix.

Fig. 2.  Schematic of the single-phase polymer (no reinforcement).

B.  Composition Breakdown

TABLE I
 COMPOSITIONAL BREAKDOWN OF TPU 95A (TYPICAL / PER SUPPLIER DATASHEET)

III.  MECHANICAL PROPERTIES — XZ PRINT DIRECTION

In the XZ orientation the tensile load is applied parallel to the deposited rasters; for fibre-reinforced grades this is the strongest orientation because the fibres align preferentially along the extrusion direction.

TABLE II
 MECHANICAL PROPERTIES — XZ ORIENTATION (TPU 95A)

IV.  MECHANICAL PROPERTIES — ZX PRINT DIRECTION

In the ZX orientation the tensile load is applied perpendicular to the print layers, so failure occurs through inter-layer (Z) bonds. Properties are markedly lower than in XZ — this anisotropy is intrinsic to FDM.

TABLE III
 MECHANICAL PROPERTIES — ZX ORIENTATION (TPU 95A)

Anisotropy in TPU is dominated by inter-layer elongation: XZ elongation may exceed 1000% but ZX elongation is typically 30–60% of XZ because layer-to-layer bonds tear before the bulk polymer fully extends. Hardness and modulus, however, are nearly isotropic.

V.  RECOMMENDED PRINT PARAMETERS

Values summarised below give consensus operating windows from public datasheets. Specific suppliers may differ within ±10 °C; the supplier datasheet always supersedes this table.

TABLE IV
 RECOMMENDED PRINT TEMPERATURE RANGES FOR TPU 95A

VI.  GLASS TRANSITION TEMPERATURE (TG)

Reported / typical Tg: ≈ -30 °C (soft polyether segment); hard segment Tg ≈ 80 – 100 °C.

TPUs have two glass transitions — the soft segment Tg (~ -30 °C) governs low-temperature flexibility, while the hard segment Tg (~ 80–100 °C) governs upper service temperature. Service range is therefore approximately -30 °C to +80 °C continuous, +100 °C short-term.

VII.  HEAT DEFLECTION TEMPERATURE (HDT)

Heat deflection temperature is the temperature at which a standard bar deflects 0.25 mm under a specified flexural load (ASTM D648 / ISO 75).

TABLE V
 HEAT DEFLECTION TEMPERATURE OF TPU 95A UNDER STANDARD TEST LOADS

VIII.  DISTINGUISHING CHARACTERISTICS AND STANDARDS

A.  Most printable flexible material

Shore 95A is the 'sweet spot' for FDM elastomers: hard enough that the filament does not buckle in standard extruders (especially direct-drive), but flexible enough to deliver useful rubber-like behaviour. Significantly easier to print than 85A or softer grades.

B.  Abrasion and tear resistance

TPU is one of the most abrasion-resistant thermoplastics — outperforming most rubbers in Taber abrasion testing. This makes it suited to wear-prone parts (gaskets, wheels, seals).

C.  Chemical resistance

TPU resists oils, greases, fuels, alcohols, and many solvents. Polyester-based TPU has better oil resistance; polyether-based TPU has better hydrolysis resistance and low-temperature flexibility. Attacked by strong acids, ketones, and esters.

D.  Limitations

Highly hygroscopic — must be dried before printing. Limited service temperature (~80 °C). Not flame-retardant in standard grades; FR variants exist but reduce flexibility.

IX.  REPRESENTATIVE APPLICATIONS

TPU 95A is typically deployed in the following applications:

1)  Gaskets, seals, and O-rings: Custom-geometry sealing parts where moulded rubber tooling is not justified.

(Source : Dwartindustries)

2)  Phone cases and consumer wearables: Drop-protection, soft-touch surfaces.

3)  Robotic grippers and end-effector pads: Compliant gripping surfaces for soft-handling robotics.

4)  Vibration damping and isolation mounts: Anti-vibration pads for sensors and electronics.

5)  Sporting goods and protective equipment: Helmet pads, mouth guards, custom-fit insoles.

Photographs of representative parts in these applications are not reproduced here for copyright reasons; the table below provides direct manufacturer / case-study URLs where original imagery and project descriptions can be viewed.

TABLE VI
 SUGGESTED IMAGE / CASE-STUDY SOURCES

X.  REFERENCES

[1]  Polymaker, “PolyFlex™ TPU95 Material Data Sheet,” 2024. Available: https://us.polymaker.com/products/polyflex-tpu95

[2]  Bambu Lab, “TPU 95A Product Datasheet,” 2024. Available: https://us.store.bambulab.com/products/tpu-95a

[3]  BASF, “Ultrafuse TPU 95A Material Data Sheet,” 2024.

[4]  NinjaTek, “Cheetah TPU Datasheet (95A),” 2024.

[5]  ASTM D638-14, “Tensile Properties of Plastics,” ASTM.

[6]  ASTM D2240, “Standard Test Method for Rubber Property — Durometer Hardness,” ASTM.

[7]  ISO 7619-1, “Rubber, vulcanized or thermoplastic — Determination of indentation hardness — Part 1: Durometer method (Shore hardness),” ISO.