PEI GF30 Rod

PEI GF30 is the most heavily reinforced grade in the polyetherimide (PEI) family, incorporating 30% glass fiber by weight to deliver maximum stiffness, high mechanical strength, and exceptional dimensional stability under sustained mechanical and thermal load. This grade is selected when structural integrity and minimal deflection must be maintained at the upper limit of the polyetherimide service range — where lower-filled grades or unfilled PEI cannot provide the required rigidity, dimensional control, or resistance to creep. It is a common choice for aerospace structural brackets, semiconductor equipment frames, and high-voltage electrical housings where both mechanical and thermal demands are highest.

PEI GF30 achieves 19,500 psi tensile strength, 28,000 psi flexural strength, and a flexural modulus of 797,000 psi — a significant step above the 493,000 psi modulus of unfilled PEI. Short-term service temperature reaches 390°F (200°C), backed by a glass transition temperature of 415°F (213°C) and a long-term service temperature of 335°F (170°C). Water absorption at 24 hours immersion is extremely low at 0.04%, supporting precise and stable components in humid environments. The material carries inherent UL 94 V-0 flame resistance, with surface and volume resistivity both at 10¹⁴ Ω, providing reliable electrical insulation in structural electronics housings. Density is 1.51 g/cm³ (0.054 lb/in³), moderate for a heavily reinforced structural grade.

Machining considerations. The 30% glass content makes PEI GF30 the most abrasive grade in the polyetherimide family. Carbide or ceramic tooling is required; tool life is reduced and rigid fixturing is essential for maintaining tight tolerances across a production run. Despite these demands, PEI GF30 is regularly machined into complex structural components for aerospace, semiconductor, and defense electronics. Controlled cutting speeds, sharp tool edges, and positive-rake geometries help manage surface quality and dimensional accuracy. Coolant use and frequent tool inspection are recommended for sustained production-volume machining operations.

Grade selection within the PEI family. PEI GF30 is the right choice when maximum stiffness and dimensional stability are the primary design drivers and the machining process can accommodate a heavily reinforced abrasive material. When intermediate reinforcement is sufficient, PEI GF10 or PEI GF20 offer easier machining and better impact toughness. For cleanroom-grade requirements in unfilled form, see PEI CRS.