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G10 / FR4 (Glass-Epoxy)

G10/FR4 is a woven glass-fabric epoxy laminate, not a moldable thermoplastic — a composite combining excellent electrical insulation with high strength (280 MPa) and rigidity. Rated to 140C with full chemical resistance, FR4 is the flame-retardant variant. It is the go-to for electrical insulators, standoffs, and structural plates needing dielectric strength.

How G10 / FR4 (Glass-Epoxy) machines

Rated 2.5/5 — the glass fabric is abrasive and demands sharp carbide tooling, while the laminate can chip or delaminate at edges if feeds are wrong. Critically, machining dust is a skin and respiratory hazard: always use dust extraction or wet cutting, masks, and skin protection. This is a safety requirement, not a preference.

Manufacturing & processing

Supplied as cured sheet, rod, and tube and processed only by machining — CNC milling, drilling, and routing — since it is a thermoset that cannot be remelted or molded. Stock comes in standard thicknesses; design around available sheet sizes and plan edge support to prevent delamination on thin features.

Typical applications

Best for electrical insulators, terminal boards, standoffs, and structural spacers in electronics and electrical equipment. Its dielectric strength plus mechanical rigidity make it ideal where a part must both insulate and carry load — busbar supports, switchgear components, and printed-circuit substrate (FR4) base material.

When to choose it

Choose G10/FR4 when you need combined electrical insulation and structural strength in a rigid, machinable composite, especially flat plates and standoffs. Choose a thermoplastic when you need molding, complex 3D shapes, or no dust hazard. Avoid it above 140C or where machining-dust controls cannot be enforced.

Suitable surface finishes

Common finishes for G10 / FR4 (Glass-Epoxy): bead blasting, powder coating. Use the finish selector →

FAQ

Is G10/FR4 machining dust hazardous?
Yes — cutting glass-epoxy releases fine glass and epoxy dust that irritates skin and is a respiratory hazard. Use dust extraction or wet machining, wear a proper mask and skin protection, and clean up thoroughly. Treat dust control as mandatory, not optional, when working this composite.
What is the difference between G10 and FR4?
Both are glass-fabric epoxy laminates with nearly identical mechanical and electrical properties. FR4 adds a flame-retardant formulation, meeting UL94 V-0 flammability requirements, which is why it is the standard for printed-circuit boards. G10 is the non-flame-retardant base grade, otherwise interchangeable for structural and insulating use.
Can G10/FR4 be injection molded?
No — it is a cured thermoset composite, not a thermoplastic, so it cannot be remelted, molded, or extruded. Parts are machined from pre-cured sheet, rod, or tube only. If you need molded complex shapes, choose a filled engineering thermoplastic instead of glass-epoxy laminate.

Property values are typical/nominal for early guidance and vary by temper, grade, supplier and heat treatment. Confirm critical specs against a certified datasheet or with an mfgiq engineer.