PEI (Ultem) for Drone ESC and Flight Controller Mounts
A polyetherimide (PEI, Ultem 1010) compound for injection-molded or machined electronic speed controller (ESC) mounting plates, flight controller (FC) stack frames, battery management system (BMS) housings, and power distribution board (PDB) carriers in high-performance multi-rotor and fixed-wing UAVs.
Key Features
- ✓UL 94 V-0 at 0.8 mm without halogen additives — self-extinguishing in the event of ESC overload or short circuit
- ✓CTI 175V — prevents creepage paths under high-current switching transients from ESC and motor drivers
- ✓Tg 217°C / continuous use 170°C — stable under 60–120A ESC thermal load in full-throttle operation
- ✓Volume resistivity >10¹⁷ Ω·cm and dielectric strength 28–30 kV/mm — complete electrical isolation of FC stack
- ✓Machineable to ±0.05 mm for precision FC stack alignment and vibration isolation standoff geometry
- ✓Low outgassing in vacuum suitable for high-altitude drone operations above 4,000m MSL
Specifications
| Parameter | Value |
|---|---|
| Density | 1.27 g/cm³ |
| Resin type | Polyetherimide (PEI), Ultem 1010 equivalent |
| Flame rating | UL 94 V-0 at 0.8 mm (no FR additives) |
| Flexural modulus | 3,800 MPa (ISO 178) |
| Tensile strength | 105 MPa (ISO 527) |
| Volume resistivity | >10¹⁷ Ω·cm |
| Dielectric strength | 28–30 kV/mm |
| Continuous service temperature | 170°C |
| Comparative tracking index (CTI) | 175 V (IEC 60112) |
| Glass transition temperature (Tg) | 217°C (ASTM E1640) |
FAQ
FR-ABS (V-0 grade) has a continuous service temperature of only 90–100°C and will creep under sustained thermal load from a 60A ESC running at 70–80°C in an enclosed drone body. FR-PC performs better (Tuse ~120°C) but its CTI of 125V may be marginal for 6S (25.2V) drone systems with high switching transients. PEI's combination of Tuse 170°C and CTI 175V provides genuine safety margin for industrial and racing drone high-power electronics, and its inherent V-0 rating (without halogen additives) avoids the toxic combustion products of halogenated FR-ABS in the event of a thermal runaway incident.