BASF 3D Ultrafuse TPC 45D Fused Filament is a thermoplastic copolyester elastomer (TPC) supplied as a fused filament fabrication feedstock in nominal 1.75 mm and 2.85 mm diameters. The grade designation refers to a Shore D 45 durometer value obtained under ISO 7619-1; this places the material above soft polyether TPU in flexural modulus and below semi-rigid copolyesters. The product is intended for direct-drive and Bowden extruders in open or enclosed additive manufacturing systems. Its mechanical profile is generated under ISO 527-2, ISO 178, and ISO 4649-A protocols, and supplier literature reports a ductile failure mode with high elongation before break. The material is commonly used when a printed component must withstand cyclic flexing, impact, abrasion, or contact with aliphatic hydrocarbon fluids without the high moisture uptake of nylon or the low thermal stability of standard TPU.

What Distinguishes a Shore D 45 Thermoplastic Copolyester from TPU and TPE Feedstocks?

Thermoplastic copolyester elastomers obtain recoverable elasticity from phase separation between crystallizable hard polyester segments and amorphous soft polyether or polyester segments. In TPC 45D, the D 45 Shore hardness is achieved by controlling the hard-segment fraction; this produces a melt that solidifies quickly and a solid-state structure that resists oil swelling and retains a higher modulus at 60°C than a TPU of equivalent room-temperature flexibility. Compared with TPE heterophase systems based on styrenic block copolymers, the copolyester grade shows higher tensile strength and resistance to tear propagation, but it also requires higher processing temperatures and more precise drying. Compared with standard polyether TPU, the TPC exhibits less surface tack, reduced moisture sensitivity, and better creep resistance under static load. These differences make the material suitable for functional prototypes and short-run production parts where a soft-touch surface is required but a limp elastomer is not.

On 0.4 mm hardened steel nozzles, the TPC melt exhibits measurable die swell immediately after the initial prime line. Retraction distances should therefore be reduced by 0.5–1.0 mm relative to PETG or ABS settings to prevent air ingestion at the nozzle tip and internal void formation. A direct-drive extruder with an all-metal heat break and drive-gear force in the 25–30 N range maintains stable feeding at volumetric flow rates up to approximately 10 mm³/s. Bowden configurations typically require retraction distances of 2–4 mm, reduced printing accelerations, and short filament guide paths; excessive tube curvature introduces buckling because the filament’s compressive modulus decreases with temperature. Below 220°C, melt viscosity rises sharply, increasing hot-end pressure and the risk of skipped steps; above 250°C, soft-segment degradation generates acrid pyrolysis products and lowers melt strength.

Filament Geometry, Spool Configuration, and Dimensional Control

Supplier documentation specifies a nominal diameter tolerance of ±0.05 mm for both 1.75 mm and 2.85 mm spools. Ovality is controlled to avoid intermittent grip in the extruder drive gear; this is particularly important for flexible filaments because localized deformation can create high feed resistance and under-extrusion. The product is typically packaged on sealed spools with desiccant, and the spool should be returned to an airtight container when the ambient relative humidity exceeds 60%. A filament runout of 0.02–0.04 mm is considered acceptable for machines using passive volumetric extruders; for instruments with laser filament diameter sensors, the measured diameter can be entered as a compensated value to maintain constant melt flow. Industrial hot-end systems with dual-drive extruders should maintain drive-gear pressure below the level that imprints permanent tooth marks into the filament, because deep notches weaken the strand and can cause buckling at the nozzle entry.

During compounding and filament extrusion, the melt is processed in a co-rotating twin-screw extruder with an L/D ratio of at least 40:1 to disperse the hard-segment domains and stabilize filament diameter. The melt filter pack typically uses screens of 150–250 µm to remove char particles that could block printer nozzles below 0.25 mm. Water-ring pelletizing is not appropriate because residual surface moisture must be removed before final filament extrusion; strand pelletizing followed by forced-air drying is preferred. The final filament is extruded under closed-loop diameter control with laser gauges and wound under constant tension to prevent stretching that would change diameter and Shore hardness.

When Ambient Humidity Drives Pre-Processing Drying Requirements

Although TPC is less hygroscopic than PA6 or PA66, absorbed moisture acts as a plasticizer and can degrade interlayer fusion by nucleating steam bubbles in the melt. The manufacturer recommends pre-drying at 60°C for 4–6 h when the spool has been exposed to ambient relative humidity above 60% for more than 24 h. A forced-air oven is acceptable for short spool conditioning, but a desiccant dryer with a dew point below −30°C is preferred for long production runs because it maintains a lower equilibrium moisture content in the hopper or spool holder. Drying should not exceed the recommended time–temperature envelope because prolonged exposure near the softening point can cause filament-to-filament adhesion on the spool and dimensional distortion. Visual evidence of wet filament includes large ooze during standby, rough first-layer surfaces, and reduced transparency or gloss; these symptoms cannot be fully corrected by retraction changes or bed temperature adjustments.

Layer cooling management has a larger effect on mechanical anisotropy than print speed alone. For a 0.2 mm layer height, prints made at 40 mm/s with 30% fan duty show less delamination than those at 80 mm/s with 80% fan duty, because the melt remains above the crystallization onset long enough to weld. The difference is particularly visible in tall thin walls, where the thermal mass of a layer drops below 10 mg and cooling is non-uniform. Closed-loop hot-end temperature control with PID autotuning reduces overshoot above 250°C and helps maintain a constant melt viscosity across the part.

Thermal Processing Window and Extruder Configuration

The recommended nozzle temperature range is 220–250°C; lower values are used for fast, thin-layer prints on high-flow hot ends, while higher values are applied when layer adhesion is critical or when hot-end thermistor offset is suspected. A heated bed set to 40–80°C improves first-layer adhesion on PEI, glass with polyvinyl alcohol-based adhesion layers, and polyimide sheets. The material does not require a closed chamber for small parts, but an enclosure that maintains 30–45°C is beneficial for build dimensions above 300 mm or wall thicknesses above 6 mm, where differential shrinkage produces corner lifting. Part cooling fan duty should be limited to 0–40% for the first 10–15 layers, then can be increased to 50–70% for short layer times. When using nozzles smaller than 0.4 mm, purge 50–100 mm of material after any nozzle change involving polycarbonate, nylon, or filled PLA to avoid melt-flow instability.

How Does Layer Adhesion Respond to Chamber Temperature Below 15°C?

Interlayer weld strength in semicrystalline TPC depends on the time available for soft-segment diffusion across the melt interface before crystallization arrests chain motion. When printing in an ambient chamber below 15°C, the previous layer solidifies before complete diffusion, producing Z-axis weakness. Quantitative loss values are geometry- and machine-dependent; published data for this specific configuration is limited, but Z-axis ultimate tensile stress can fall by more than 20% relative to XY specimens when no enclosure is used. To reduce this effect, operators should increase extrusion temperature by 5–10°C, reduce cooling fan speed, and set a minimum layer time of 8–12 s for layer heights at or below 0.2 mm. Parts printed with sufficient interlayer fusion typically flex without stress whitening; whitening at a bend radius below 5 times the local wall thickness indicates excessive strain and can precede crack initiation.

Chemical Resistance, Abrasion, and Outdoor Weathering Reference Data

The copolyester structure resists mineral oil, aliphatic hydrocarbons, dilute acids, and dilute alkalis, but it should not be immersed in strong oxidizing acids, chlorinated solvents, or boiling water because hydrolysis and chain scission accelerate above 70°C. Abrasion data generated under ISO 4649-A show lower volume loss than many soft TPU grades; however, performance in abrasive slurries or metal-debris environments requires application-specific wear testing. For outdoor service, UV and thermal-oxidative stabilizers can reduce surface crazing; xenon-arc exposure under ISO 4892-3 is used to compare stabilized and unstabilized formulations. Short-term contact testing with hydrocarbon fluids at 23°C typically shows high retention of ductility, but continuous service above 90°C should be validated by ISO 899-2 creep or stress-relaxation studies before implementation.

Pre-drying and storage consistency have a direct effect on batch-to-batch performance. Once printed, parts can be annealed at 80°C for 30 min in a ventilated oven to relieve residual stress and improve dimensional stability in warm service; however, annealing above the heat deflection temperature can release molded-in stresses and distort thin ribs or bosses. The material is less prone to stress relaxation than TPU 95A, but static long-term loads at elevated temperature should be assessed using ISO 899-2 methods. Because the filament contains no intentionally added halogenated flame retardants, standard REACH and RoHS documentation should be requested from the supplier for export conformity.

Replacing TPU 95A in Collision-Sensitive Mounts and Industrial Grippers

TPC 45D can replace TPU 95A in applications requiring a firmer, less tacky surface and better oil resistance. In gripper jaws and collision mounts, wall thicknesses of 2.5–4.0 mm combined with triangular infill of 35–50% produce a useful ratio of compliance to shape recovery; however, the higher compression modulus means seals and gaskets may require thinner walls or lower infill to conform to mating flanges. The Shore D 45 hardness permits snap-fit details that would deform permanently in TPU, but the die-swell behavior of the melt requires wider corner radii and slower cornering speeds in the slicer to prevent excess material build-up. Compared with rigid ABS or PC-ABS, the TPC filament produces parts with lower tensile modulus but significantly higher impact crack resistance in cold environments down to approximately −30°C, provided exposure is limited to non-halogenated fluids. In such substitutions, test geometries should include a standardized notched impact specimen under ISO 180 or a component-level drop test because printed anisotropy can dominate the result.