Ensinger TECAFIL PEEK EV CF30 black is a fused filament fabrication feedstock supplied at 1.75 mm diameter and composed of a polyetheretherketone matrix reinforced with 30% carbon fibre by weight. The EV prefix identifies the electrically conductive series; the black colour is derived from the carbon filler rather than an added pigment. Spool configurations include 250 g and 500 g, and the filament is produced to a diameter tolerance of ±0.05 mm. The product is intended for heated-chamber systems and hardened extrusion hardware, not open-frame desktop printers. The main differentiating features are the increase in tensile modulus from approximately 4,100 MPa for unfilled PEEK to 21,000 MPa for the reinforced grade, the reduction in coefficient of linear thermal expansion from approximately 50 ppm/K to 25 ppm/K, and the static-dissipative surface behaviour. These characteristics place the material in semiconductor handling, aerospace tooling, automotive underhood fixtures, and oil and gas wear hardware where dimensional stability, stiffness, and electrical conductivity must coexist.

What Limits Interlayer Fusion in Unheated Build Chambers?

Polyetheretherketone melts at approximately 343 °C and forms semicrystalline structures only when the cooling path permits chain packing. In a build chamber below 100 °C, the extruded bead solidifies rapidly and the layer interface remains below the 143 °C glass transition for insufficient time to allow interdiffusion. The carbon fibre content raises melt thermal conductivity, accelerating heat extraction from the bead compared with neat PEEK. The recommended nozzle temperature is 400–430 °C, with a build chamber at 180 °C or higher and build platform temperature of 160–220 °C. Pre-drying at 150 °C for 3–4 h reduces moisture-related voiding. The processing window is narrow; chamber temperature deviations of more than ±5 °C can shift z-axis strength and first-layer adhesion because PEEK crystallization is highly sensitive to cooling rate. The nozzle must be hardened tool steel or ruby because 30% carbon fibre erodes brass orifices within a single spool. Filament path bends below a 50 mm radius generate buckling in high-modulus 1.75 mm filament and should be avoided.

These parameters are not equivalent to those used for unfilled PEEK. An unfilled PEEK filament can often be processed with a lower chamber setting and has lower nozzle pressure; the carbon-filled grade requires the higher chamber condition because the filler increases rigidity and interlayer stress. Failure to hold the chamber at the higher end of the range produces corner lift, delamination, and anisotropic mechanical properties that cannot be corrected by increasing extrusion flow alone.

Dimensional Stability of the 30% Carbon-Fibre Composite Across a 20–200 °C range

The tensile modulus of 21,000 MPa and flexural modulus of 19,000 MPa are documented under ISO 527-2 and ISO 178 respectively for printed XY-orientation specimens. The material exhibits low elongation at break in the 2–3% range, so stress concentrations at sharp corners must be radiused. The heat deflection temperature under 1.8 MPa is in the 300–315 °C range according to ISO 75-2, but the polymer melting temperature remains approximately 343 °C. The coefficient of linear thermal expansion is near 25 ppm/K under ISO 11359-2. On a 300 mm platen cycled from 20 °C to 200 °C, unfilled PEEK grows by approximately 2.7 mm while the EV CF30 grade grows by approximately 1.5 mm. The differential to 6061-T6 aluminium at 23 ppm/K drops from approximately 1.4 mm to 0.2 mm. This is the reason the material is selected for large flat vacuum fixtures that must hold flatness across a thermal cycle.

The difference between the EV CF30 grade and unfilled PEEK is not purely mechanical. The carbon fibre network lowers surface resistivity to 10⁴–10⁶ Ω/sq, whereas unfilled PEEK is an electrical insulator with volume resistivity above 10¹⁵ Ω·cm. This permits the reinforced grade to be used in static-dissipative nests, trays, end effectors, and vacuum pallets. The electrical path is formed by fibre-to-fibre contact; raster direction, layer bonding, and post-machining can raise or lower measured resistance. Ground paths should not rely on layer-to-layer continuity unless the part is tested after the full print and annealing cycle using ANSI/ESD STM11.11.

Wear behaviour in printed TECAFIL PEEK EV CF30 black is anisotropic. A horizontal raster places carbon fibre-rich planes on the sliding surface; a vertical raster exposes layer edges and may produce higher wear against a steel counterface. The carbon fibre increases the wear rate of unhardened mating surfaces, so shafts and rails should be hardened or coated. Dry-running PV limits for printed reinforced PEEK are lower than those for machined compression-moulded PEEK stock because layer boundaries act as preferential wear initiation sites. For continuous sliding service, printed parts should be machined or polished and qualified under ISO 7148 polymer bearing test procedures. Production-scale fused filament cells show that raster angle, chamber temperature, and cooling history affect tribological outcomes as much as the base polymer; batch-to-batch consistency therefore requires locking the print file, chamber profile, and post-annealing cycle.

When Continuous Service Exceeds 200 °C, Thermal and Electrical Performance Shift

The short-term heat deflection temperature should not be read as a continuous service limit. PEEK is commonly rated for continuous use at 260 °C, but the reinforced grade’s long-term ceiling depends on oxidative aging, creep, and load direction. For parts operating between 200 °C and 260 °C, the matrix may undergo surface oxidation unless the service environment is inert. The carbon fibre does not prevent oxidation of the PEEK surface; it changes mechanical and electrical behaviour. At temperatures above 200 °C, repeated cycling can generate microcracking at the fibre-matrix interface because the radial thermal expansion of carbon fibre is lower than that of PEEK. For static-dissipative use, surface resistivity is typically in the 10⁴–10⁶ Ω/sq range, but resistance can increase after abrasion, thermal aging, or contaminant deposition. Electrical verification should be performed in the as-printed and post-processed state using ANSI/ESD STM11.11 for surface resistance or ASTM D257 for volume resistivity.

Oxidative aging of PEEK at 250 °C in air can produce a brittle surface layer after extended exposure. Qualification should include tensile testing after 1,000 h at the intended service temperature under ISO 527-2 and comparison with an unaged control specimen. Published data for this specific configuration is limited in high-oxygen environments above 250 °C; users should request thermal aging data from Ensinger rather than extrapolating from unfilled PEEK. Annealing at 200–250 °C for 2–4 h can stabilise crystallinity and reduce first-cycle growth caused by relaxation of amorphous regions. The annealing cycle must be qualified against drawing tolerances because the part can grow or shrink by 0.1–0.3% depending on processing history. This is a process-specific effect, not a material defect.

Operational Boundaries in Abrasive and Chemical Service

The PEEK matrix provides broad chemical resistance to many acids, bases, steam, and hydrocarbons, but concentrated sulfuric acid, concentrated nitric acid, and some halogenated solvents at elevated temperature degrade polyetheretherketone. The carbon fibre phase is not chemically inert in all environments; carbon fibre can oxidise in strong oxidisers or in oxygen at high temperature. The EV CF30 grade should not be specified for continuous immersion in strong oxidising acids without immersion testing at the exact service temperature and concentration. The carbon fibre also makes the part electrically conductive, so insulating standoffs or creepage paths require additional design consideration; the printed material cannot be assumed to act as an electrical insulator unless the surface is coated or the design includes isolation.

Food-contact and medical-device status are not automatically conferred by the base PEEK resin. The specific additive package and carbon fibre feedstock must be covered by grade-specific regulatory documentation. The user should request a full compliance statement from Ensinger based on the intended print process, post-processing, and service conditions. Compared with carbon-filled PEI or polycarbonate, the EV CF30 grade requires a higher chamber temperature and is therefore unsuitable for open-frame machines sold for general-purpose carbon-fibre filament. Compared with unfilled PEEK, the grade offers higher stiffness and lower thermal expansion but lower toughness and higher nozzle wear. The selection decision should be based on measured part performance under the actual load, temperature, and electrical test conditions rather than on the material’s short-term datasheet ranking.