Covestro Addigy FPU 89A 000000 AF is a thermoplastic polyurethane elastomer supplied as fused filament fabrication feedstock. The grade code FPU 89A identifies the flexible polyurethane product family and nominal Shore hardness of 89 A when measured according to ISO 868. The trailing 000000 AF is the manufacturer’s order code for a specific color or additive package; published technical datasheets do not always decode the AF suffix, and the material safety datasheet remains the controlling reference where regulated end-use contact or chemical compatibility is evaluated. The filament is supplied in 1.75 mm and 2.85 mm diameters, with a dimensional tolerance commonly listed as ±0.05 mm, and the nominal density is 1.22 g/cm³ by ISO 1183-1.

The material is intended for direct-drive extrusion systems and for constrained filament paths in which unsupported elastomer buckling is minimized. In the melt, the polymer exhibits shear-thinning behavior typical of thermoplastic polyurethane elastomers, meaning the processing window is narrower than that of rigid amorphous feedstocks. Moisture, residence time, and nozzle temperature interact because absorbed water can release volatile steam at the melt zone, generating porosity and reducing interlayer fusion. The grade is therefore handled as a hygroscopic elastic feedstock rather than a low-moisture rigid polyolefin or styrenic filament.

How do tensile, tear, and abrasion data define the 89A urethane service envelope?

The nominal datasheet properties of the FPU 89A 000000 AF grade place it within the mid-flexible polyurethane range. The following values are representative ranges from the manufacturer’s published property envelope and should be verified against the lot-specific certificate of analysis for production release.

The tensile data indicate that the material dissipates energy through large deformation rather than through rigid load transfer. The elastic modulus of the printed polyurethane is normally below 40 MPa at 23 °C, which is more than two orders of magnitude lower than filled or unfilled rigid PLA feedstocks. At 500 mm/min crosshead speed, the elongation at break above 500 % allows the material to survive repeated bending and impact without the brittle crack propagation observed in amorphous rigid FFF polymers. The tear strength of 85–100 kN/m by ISO 34-1 B/b is relevant to notched or punctured parts, while the abrasion loss below 50 mm³ by ISO 4649-A supports use in sliding wear applications such as low-pressure pneumatic seals, dust boots, and protective end caps.

Moisture control is the first processing boundary for this polyurethane filament. Before extrusion, the feedstock should be dried to below 0.02 wt% moisture. A desiccant dryer with an air dew point below -30 °C is preferred over a forced-air oven because moisture regain at ambient relative humidity above 60 % can be rapid. The manufacturer’s nominal drying profile is 80 °C for 4 h, though thick spools or long storage at uncontrolled humidity may require 6 h or more. Printing immediately after drying, or feeding from a sealed dry box, prevents steam porosity and loss of layer adhesion. In direct-drive installations equipped with a 0.4 mm hardened steel nozzle, the recommended melt temperature is 230–250 °C, with a heated bed at 40–60 °C. Print speed is normally restricted to 20–40 mm/s because the flexible feedstock can buckle in unsupported Bowden paths. Retraction distance should be minimized to 1–2 mm and retraction speed kept below 30 mm/s to avoid nozzle clogging and filament grinding. Part-cooling fans, when used, are typically limited to 0–30 % airflow because excessive cooling suppresses interlayer diffusion and reduces z-axis tensile strength.

Layer height is constrained by both the elastic nature of the filament and the requirement for dense sealing surfaces. For wear parts and gaskets, a layer height of 0.1–0.2 mm with at least 3–4 perimeters is standard. Full solid infill is used where gas or fluid tightness is required, although printed elastomeric parts should not be assumed pressure-tight without post-printing coating or melt treatment. Extrusion multiplier is typically set between 1.0 and 1.05 on calibrated direct-drive extruders to produce continuous bead stacking without excessive nozzle pressure.

Comparative performance against PLA, ABS, and TPU 95A feedstock classes

The difference between Addigy FPU 89A 000000 AF and common fused filament fabrication materials is defined primarily by modulus, elongation at break, and service temperature. The table below places the product in relation to generic rigid PLA, generic ABS, and a higher-hardness TPU 95A. Values are representative commercial datasheet ranges, not a substitute for grade-specific certification.

Against PLA, the polyurethane offers a completely different mechanical response. PLA fails in a brittle manner under tensile stress, while the 89A urethane deforms elastically and eventually strain-hardens before fracture. That makes the FPU grade unsuitable for stiff brackets, structural frames, or dimensionally stable guides, but suitable for parts that require recoverable compliance. Against ABS, the polyurethane has much lower stiffness and lower thermal resistance, but it does not share the styrene monomer handling concerns and can tolerate large cyclic deformations that would craze or crack ABS. Against TPU 95A, the 89A grade is softer and exhibits a lower modulus, giving improved drape and conformance on uneven sealing surfaces. The trade-off is increased viscous loss under sustained load and a lower upper-use temperature, so mineral oil and hydraulic sealing applications should be qualified according to ISO 1817 and compression stress relaxation procedures.

For functional seals, gaskets, and low-pressure pneumatic tubing, the material is processed with solid infill and the mechanical property envelope provides tear propagation resistance relevant to clamped or bolted joints. In gasket service, compression set behavior is a critical boundary. The published room-temperature compression set of 25–35 % after 72 h is adequate for many static sealing duties, but recovery decreases with rising temperature. At continuous service temperatures above 70 °C, the part should be qualified for compression set under the actual fluid and clamp load rather than relying on room-temperature data. The polyurethane rejects pressure loading and creep only within the defined hardness and modulus range; it is not a replacement for fKM, NBR, or silicone in high-temperature or aggressive sealing systems.

Fluid exposure must be evaluated with ISO 1817 immersion testing before production use. Ketones, esters, chlorinated solvents, and aromatic hydrocarbons can swell or degrade the polyurethane matrix. Dilute acids and many aliphatic oils are less aggressive, but the specific additive package of the 000000 AF order code may influence extraction, odor, or color stability. For outdoor service, ultraviolet exposure can cause surface yellowing and microcracking unless the selected grade is specifically stabilized. Published data for long-term hydrolytic aging of this specific 000000 AF color/additive package is limited; qualification before use in wet, load-bearing, or pressure-retaining service is therefore mandatory.