Dry, unopened Huntsman Iroprint™ F 80213 TPU prototyping filament is supplied as a thermoplastic polyurethane monofilament for fused filament fabrication. The grade occupies the soft segment of the Iroprint F-series, with a nominal Shore hardness of 82 A when measured under ASTM D2240-15e1. Commercial spools are available in 1.75 mm and 2.85 mm nominal diameters, with a filament roundness tolerance of ±0.05 mm in distributor specifications. In continuous extrusion trials, the material is positioned between rigid polylactic acid and harder TPU grades: it produces low-modulus parts that recover from high strain without the transverse layer cracking observed in unfilled PLA, while avoiding the higher stiffness and lower elongation of 95 A–60 D TPU filaments. The product is used mainly for flexible footwear midsoles, conformal gripper jaws, bellows, and seal prototypes, where Shore hardness below 85 A and tear strength above 40 kN/m are relevant design inputs. The F 80213 designation is therefore a prototyping material rather than a production molding compound.

What limits printing speed when F 80213 is extruded through a 0.4 mm brass nozzle?

Process instability in soft TPU monofilament begins when the feedstock column buckles in the cold-end gap between the drive gear and the melt zone. For F 80213, the manufacturer-recommended nozzle setpoint is 210–230°C, with a bed temperature of 25–50°C on PEI or glass surfaces. At nozzle temperatures below 205°C, melt viscosity is high enough to increase extruder backpressure and produce skipped steps on direct-drive motors with holding torque below 0.4 N·m. Published capillary rheometry data for this exact grade are limited; however, soft TPU filaments in the same Shore hardness family typically exhibit apparent viscosity in the 0.8–1.5 kPa·s band at 230°C and 100 s⁻¹. A 0.4 mm brass nozzle may be used at linear speeds up to 30 mm/s, but the melt channel is the primary flow restriction. Retraction distance should be limited to 1.0–2.0 mm; longer strokes draw molten polymer, air, or degraded residue upward and cause popping, blistering, or intermittent extrusion at the start of the next travel move. Layers are typically deposited at 0.10–0.20 mm; thicker layers reduce the interlayer contact area per filament length and can lower Z-direction tear resistance.

Linear-advance and pressure-advance settings require special attention. Because F 80213 has low shear modulus in the filament column, high positive pressure-advance values above 0.15 s usually create under-extrusion after direction changes; negative values are not used. A coasting distance of 0.1–0.2 mm is often necessary to prevent oozing at the end of perimeters. Retraction prime amounts above 0.1 mm³ can produce surface zits on external walls. Firmware jerk values below 8 mm/s on Cartesian machines reduce vibration-induced over-extrusion at acute corners.

Footwear midsole prototypes printed from F 80213 are usually built with 0.6 mm plain brass or coated nozzles, 0.2 mm layer height, and rectilinear infill densities of 30–50%. The 82 A Shore hardness allows a cushioning lattice to be flexed and fit-tested before cutting production tooling. In FFF-processed elastomers, tensile properties perpendicular to the build direction are normally lower than in-plane properties; published data for this specific configuration are limited, so a build orientation study is required before using printed midsoles as mechanical surrogates. The filament exhibits higher surface friction than rigid PLA, which can reduce slip on a tread face but requires release assistance on smooth polycarbonate or glass beds. A textured PEI sheet or a polyvinyl alcohol glue film is typically sufficient. The printed midsole is not a production sole unit; it is a fitting, tread, and gait-validation surrogate.

Moisture uptake, drying, and feedstock lot variance

Thermoplastic polyurethane is hygroscopic. F 80213 exposed to 60% RH at 23°C can sorb moisture rapidly; wet material hydrolyzes at melt temperature and forms bubbles, pitting, and reduced tear strength. The spool should be dried at 75°C in a forced-air or vacuum dryer for 4 h before processing when spool mass gain exceeds 0.3% of initial mass. Moisture content is best checked by Karl Fischer titration under ISO 15512:2019. Lot-to-lot Shore hardness variance within a production campaign is generally controlled to ±2 A in warehouse distribution, but converters should request certificate-of-analysis values for Shore A, density, and melt-flow consistency. In high-humidity production areas, bulk spools should be returned to sealed aluminum barrier bags containing 50 g of activated molecular sieve per spool. Over-drying is possible if spools are left at 75°C for more than 8 h; the filament surface may become brittle and feed tension may increase.

Water-induced degradation in TPU is autocatalytic in the presence of residual acidity from raw-material synthesis. The effect is not immediately visible as a melt-flow shift; it appears as a reduction in tear strength and whitening of the extruded strand. Processors who use moisture-sensitive TPU in high-humidity buildings should not rely on short purge cycles. The spool bay or dryer feed area should be maintained below 10% RH if the filament is fed directly into a production printer.

Seal and gasket prototypes are typically printed as thin 1.2–2.0 mm walls with two or three perimeters and no top or bottom closures. The typical tear strength of 50 kN/m under ISO 34-1:2022 Method B(b) supports short-term compression set evaluation, but FFF layer lines may increase compression set by 10–20% absolute when the loaded face is parallel to the print bed. For aliphatic-hydrocarbon sealing applications, the material may swell and lose dimensional control; compatibility testing under ISO 1817:2022 is required because the filament is not a universal chemical barrier. Continuous service above 70°C is not recommended, and contact with concentrated acids or ketones should be avoided. The product is not a replacement for injection-molded TPU in long-life dynamic seals; it is used to validate geometry and assembly fit before tooling.

When F 80213 is used in a production line with 0.6 mm hardened nozzles

A 0.6 mm hardened steel nozzle reduces shear heating and may allow volumetric throughput to be maintained at lower motor currents, but the soft filament still needs a constrained feedstock path. Unsupported filament lengths greater than 150 mm between spool and drive gear can result in buckling, especially when the spool is mounted on a high-friction side-mount holder. Feed tension above 5 N measured by a filament tension sensor is associated with slip in single-drive extruders. Build surfaces of PEI or glass with a polyvinyl alcohol film are suitable; polycarbonate beds are not recommended because removal of strongly adhered TPU can delaminate the bed surface. Printers with all-metal heat breaks should use retraction speeds of 20–25 mm/s to reduce the risk of melt plugging in the heat break. At 220°C with a 0.6 mm nozzle and 35 mm/s print speed, layer singulation is usually acceptable; operators should still inspect the first layer for over-adhesion and periodic surface pitting caused by moisture or entrapped air.

Relative to standard PLA and ABS feedstocks, F 80213 shows elongation at break that is roughly 10–20 times greater than the 3–6% common for PLA and a tensile modulus at least an order of magnitude lower. It is not a direct substitute for polyamide: the polyamide continuous-use temperature is higher and creep resistance is superior. Compared with rigid TPU grades in the 95 A–60 D range, the 82 A hardness shifts the stress-strain response toward larger elastic deformation before yielding, but also reduces feed stiffness. Long Bowden tubes should be replaced with direct-drive extruders or short PTFE-lined tubes of <300 mm to avoid excessive friction. Compared with powder-bed TPU materials, F 80213 parts display layer-normal anisotropy and lower isotropy, but the material can be processed on open-architecture FFF machines without the capital expense and powder handling of selective laser sintering.

Representative published values for printed F-series soft TPU are shown above. They are not lot-certification limits and should be verified against current certificate-of-analysis data for each spool batch.

Does F 80213 carry a food-contact or medical-grade classification?

Standard technical literature for IROPRINT F 80213 does not assign a food-contact designation under FDA 21 CFR 177.2600 or EU 10/2011. The product is not marketed as USP Class VI or ISO 10993-certified for implantable or patient-contact devices. Users evaluating medical, dental, or food-contact tools must obtain written regulatory documentation from the manufacturer and perform migration, extractables, and end-use suitability testing. REACH registration status and RoHS hazardous-substance restrictions under EU 1907/2006 and EU 2015/863 should be confirmed from the current safety data sheet. The material is not classified as dangerous goods during storage, but local ventilation is required when purging at high temperature.

For compressed-air tooling seals, F 80213 is used with 1.6 mm wall sections and two perimeters to maintain radial flexibility. FFF-printed soft-interface parts should be inspected for layer tearing at the fitting undercuts; parts with circular internal bores require a minimum of 0.8 mm hole clearance to prevent elastic recovery from locking onto mandrels. This final application fixture is a prototype aid, not a production gasket.