Why Ultem® for standoffs

Ultem® (PEI) is a high performance insulating plastic with a glass transition temperature around 217 °C, so parts retain stiffness and dimensional stability at elevated temperatures found in power electronics, EV peripherals, RF enclosures, and industrial controls. It is inherently flame retardant with UL94 V-0 and 5V listings and offers strong electrical insulation with typical dielectric strength reported around 800+ V per mil in unfilled grades. Its dielectric constant is low and stable versus frequency and temperature, and CTI values commonly fall near 150 to 175 V depending on grade and test method. These attributes make Ultem ideal for stand offs that must maintain clearance and creepage under load and heat.

The product

Electrical Standoffs and Insulators
Geometry: hexagonal, round, and custom standoffs to separate circuit boards, busbars, or chassis panels.
Stockable sizes we support for fast turnaround:

• Threads: 4-40, 6-32, M3, M4
• Typical lengths: 0.25 in, 0.5 in, 1.0 in
  We also machine custom diameters, across flats, shoulder steps, counterbores, and non standard lengths to match your stack up and creepage requirements. Because Enplas machines from our own extruded Ultem stock shapes, you are not constrained by molded catalog sizes, and we can hold tight positional tolerances on thread concentricity and overall length.

Performance advantages in electronics

• Electrical integrity: high dielectric strength and resistivity for reliable isolation between boards and power rails. Dielectric constant and dissipation factor remain relatively stable across frequency bands.
• Thermal resistance: usable in hot compartments where many commodity plastics soften. PEI maintains mechanical properties close to its limits thanks to the 217 °C Tg.
• Flame and safety: inherent flame retardance with UL94 V-0 and available 5V ratings for assemblies that must meet stringent safety standards.
• Creep control: stiffness and low creep help preserve clamp load under continuous service.

How Enplas helps

We combine in house extrusion of Ultem stock with CNC machining to deliver repeatable threads, burr free edges, and clean surface finishes that protect solder masks and conformal coatings. Our team advises on unfilled versus glass reinforced grades when you need extra rigidity, and on thread forms, washer faces, and torque targets to avoid over tightening in plastic. We can mark parts, bag by lot, and provide material traceability per order.

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