Designated as Mitsubishi PEI ULTEM™ 1010 3D Printing Filament, the product is an unfilled polyetherimide filament produced from SABIC ULTEM™ 1010 resin. ULTEM™ is a registered trademark of SABIC Global Technologies B.V.; the Mitsubishi designation refers to the filament product, not to an alternative resin synthesis. The material is amorphous and exhibits a glass transition temperature of 217 °C; heat deflection temperature on molded specimens is 216 °C at 1.82 MPa per ASTM D648-18. The resin density is 1.27 g/cm³ per ASTM D792-20, and linear coefficient of thermal expansion below glass transition is approximately 56 × 10^-6 /K per ASTM E831-19. The product is intended for high-temperature fused filament fabrication platforms with all-metal hot ends, actively heated build chambers, and bed temperatures of 160–200 °C. It is supplied in standard 1.75 mm and 2.85 mm filament diameters; diameter tolerance is typically specified at ±0.05 mm. Applications include aircraft interior brackets, semiconductor test sockets, electronic enclosure hardware, and low-outgassing vacuum chamber components.

What Distinguishes Unfilled ULTEM 1010 from PEI-PC Alloy Filaments?

ULTEM 1010 is an unfilled polyetherimide, whereas ULTEM 9085 is a PEI-polycarbonate blend. The unfilled grade provides higher heat deflection temperature, approximately 216 °C versus 153 °C at 1.82 MPa under ASTM D648-18, and higher tensile modulus. The blend grade provides higher notched Izod impact resistance and improved ductility in thin-wall snap-fit features; molded ULTEM 9085 typically yields notched Izod impact values of approximately 130–160 J/m versus 40–55 J/m for ULTEM 1010 under ASTM D256-10. ULTEM 1010 is specified when the service temperature exceeds 180 °C, when flame-smoke-toxicity and outgassing limits exclude polycarbonate-containing formulations, or when dimensional stability during high-temperature exposure is the dominant requirement. In printed form, ULTEM 1010 exhibits greater interlayer strength retention at chamber temperatures above 120 °C, but it is more notch-sensitive and less tolerant of sharp internal corners than the 9085 grade.

Pre-drying is mandatory before extrusion. ULTEM 1010 absorbs moisture from ambient air; 24-hour water immersion values per ASTM D570 are approximately 0.25 %, but equilibrium uptake in high-humidity environments can exceed this value. Filament exposed to relative humidity above 60 % for more than 4 h should be dried at 150 °C for 4–6 h in a desiccant dryer with a dew point below -30 °C to achieve moisture content below 0.02 %. Extrusion through a 0.4 mm nozzle is typically performed at 370–390 °C; build platform setpoints of 160–200 °C and chamber setpoints of 120–160 °C are used to lower residual stress and suppress interlayer delamination. Larger nozzles, such as 0.6 mm or 0.8 mm, may require the lower end of the temperature range to avoid overheating because residence time increases with melt volume. Residual moisture above 0.05 % produces steam bubbles at the nozzle, audible filament popping, and interlayer porosity; the same defect signature appears when a partially clogged nozzle raises local melt pressure and shear heating. On production lines with pellet-fed extruders, a 25 mm twin-screw extruder with L/D ≥ 40 and vacuum venting below 50 mbar is used for compounding; published data for Mitsubishi-branded filament on this specific equipment configuration is limited, but resin behavior is dominated by drying history, barrel zone profiling, and melt residence time.

When the Part Requires Flame-Smoke-Toxicity Compliance in Aircraft Interiors

ULTEM 1010 is specified for aircraft interior brackets, ducting, and shrouds because molded resin can meet FAR 25.853 12-second vertical burn and heat release requirements when tested per FAR 25.853(a), ASTM E662, and BSS 7239 toxic gas method. However, printed FFF parts exhibit raster-induced anisotropy, surface porosity, and internal voiding; compliance must be verified on printed plaques at the same layer height, raster angle, build orientation, and chamber conditions as production parts, not assumed from injection-molded data. Outgassing measurements on dried ULTEM 1010 specimens per ASTM E595 are generally below 1.0 % total mass loss and 0.1 % collected volatile condensable materials, but moisture intrusion can elevate these values. Polycarbonate-containing PEI blends such as ULTEM 9085 may not satisfy the most restrictive aerospace outgassing and toxic-gas generation limits; this is a key reason ULTEM 1010 is selected for cabin air-duct components and proximity electronics housings.

Although ULTEM 1010 is resistant to many aerospace fluids, aromatic hydrocarbons, alcohols, and diluted acids, it is not suitable for prolonged contact with boiling water, steam, strong alkaline solutions, or hot concentrated acids. Stress cracking may occur when the printed part retains high residual stress and is exposed to ketones, chlorinated solvents, or amine-based curing agents. In chemical service, ULTEM 1010 is often selected over lower-temperature amorphous thermoplastics due to its glass transition temperature of 217 °C, but it is inferior to semicrystalline PEEK or PPSU in hot aqueous acid and steam environments. Parts with thick cross-sections should be annealed at 200–210 °C for 2–4 h after printing to reduce residual stress and improve chemical resistance; annealing above 210 °C risks part distortion if the build chamber was not maintained at an equivalent temperature during printing. Dimensional change after annealing is typically below 0.5 % in the Z direction for solid parts printed with 100 % infill, but published data for this specific configuration is limited.

Mechanical Property Benchmarking Against PEEK and PEKK

Selection between ULTEM 1010 and PEEK-class filaments is not reducible to heat deflection temperature comparisons. Unfilled PEEK typically displays heat deflection temperature of 152 °C at 1.82 MPa per ASTM D648-18, lower than ULTEM 1010, but supplier UL 746B relative thermal index listings for unfilled PEEK can exceed 240 °C depending on thickness and end-use category. ULTEM 1010 has an amorphous glass transition at 217 °C; under sustained load above this boundary, modulus declines sharply. PEKK similarly requires hot-end temperatures of 340–400 °C depending on grade and exhibits a semicrystalline morphology; ULTEM 1010 processes at 370–390 °C, allowing existing high-temperature FFF platforms to be used without the 400 °C hot-end capability required by many PEEK systems. The table below summarizes typical injection-molded resin datasheet values; FFF values shift with raster orientation, chamber conditions, and part fill density.

For electrical connectors and semiconductor test sockets, ULTEM 1010 is used because its dielectric performance remains stable at temperatures approaching 200 °C. The resin exhibits volume resistivity on the order of 1 × 10^15 ohm·cm under ASTM D257 and dielectric strength of approximately 17 kV/mm under ASTM D149; these values are obtained on molded specimens and can decrease with printed void content. A printed socket housing produced at 0.2 mm layer height and 370 °C nozzle temperature showed acceptable dimensional stability in a 150 °C burn-in environment, but published data for this specific printed configuration is limited. Users should validate dielectric performance on their exact build parameters. Compared to ceramic-filled engineering resins, unfilled ULTEM 1010 avoids abrasive wear on nozzle and extruder components; compared to lower-temperature polycarbonate, it permits burn-in testing at temperatures above 130 °C without heat deflection failure.

Melt residence time and molecular weight retention in high-temperature extrusion

Because polyetherimide is amorphous and processed near its degradation threshold, melt residence time must be controlled. At nozzle temperatures above 380 °C, prolonged residence produces chain scission and oxidative yellowing; this is observed as a reduction in melt viscosity and a decrease in interlayer adhesion. Production-scale experience on high-temperature FFF systems indicates that holding the melt at 380 °C for periods longer than 20 min can produce visible brown streaks and increased nozzle clogging, though the exact threshold varies with moisture content and antioxidant packaging. Layer time is therefore a process variable: small parts with short layer times and rapid extrusion retain higher molecular weight; large parts with long dwell times may require reduced nozzle setpoints near 370 °C or increased print speed to limit residence time. Injection molding guidance for ULTEM 1010 resin similarly specifies melt temperatures of 370–410 °C and back pressures below 10 MPa to limit shear heating; transfer of this guidance to FFF is not direct because extruder shear history differs.

Storage conditions directly affect filament diameter stability and hydrolysis. Vacuum-sealed packaging with desiccant is recommended; once opened, filament should be stored at relative humidity below 20 % or in a heated dry box at 50–60 °C. Batch-to-batch variation in filament diameter outside the supplier tolerance—commonly ±0.05 mm—can produce extrusion pressure fluctuations and visible banding on part walls. ULTEM 1010 filament should not be combined with amine-based bed adhesives or certain solvent-borne release agents due to stress cracking; polyimide tape or PEI-compatible adhesion layers are used on glass and carbon fiber build plates. If a part is to be solvent-welded or bonded, epoxy and cyanoacrylate systems should be screened for compatibility with residual low-molecular-weight PEI species.