FR4 (Flame Retardant 4) and G10 are glass-epoxy composite laminates widely used in electronics, electrical insulation, and structural applications. CNC machining FR4 requires specialized tooling and process knowledge to handle the abrasive glass fibers while maintaining tight tolerances.
FR4 vs G10 Material Properties
| Property | FR4 | G10 |
|---|---|---|
| Flame Retardant | Yes (UL 94 V-0) | No (UL 94 HB) |
| Max Temperature | 130°C | 140°C |
| Flexural Strength | 415 MPa | 440 MPa |
| Compressive Strength | 415 MPa | 380 MPa |
| Water Absorption | 0.15% | 0.10% |
| Dielectric Strength | 20 kV/mm | 20 kV/mm |
| Color | Yellow-green | Natural (off-white) |
| Cost | $ | $ |
FR4 CNC Machining Challenges & Solutions
- Tool Wear: Glass fibers are highly abrasive. We use diamond-coated carbide tools and optimized feed/speed parameters to maximize tool life.
- Delamination: Layer separation at edges is prevented by using sharp tools, proper feed direction, and backing support plates.
- Dust Control: FR4 machining produces fine glass dust. Our CNC machines use high-efficiency vacuum extraction and coolant mist suppression.
- Edge Quality: For clean edges, we use compression cutters and staged finishing passes.
FR4 & G10 Machining Capabilities
- Tolerances: +/-0.05mm standard; +/-0.02mm on critical features
- Processes: CNC milling, routing, drilling, countersinking, tapping
- Thickness Range: 0.2mm to 50mm available
- Max Part Size: 600 x 400 mm
- Special Processes: Blind and through-hole plating available
FR4 & G10 Industry Applications
- Electronics: PCB fixtures, insulators, terminal boards, switch spacers
- Electrical: Bus bar supports, transformer spacers, arc barriers
- Oil & Gas: Downhole insulators, electrical isolation rings
- Aerospace: Structural spacers, antenna insulators, radome supports
- Industrial: Wear plates, jigs, fixtures, electrical panel components
FR4 vs Engineering Plastics
Compared to PEEK or POM, FR4/G10 offers higher compressive strength, better electrical insulation, and lower cost. Its main limitation is that glass fiber dust requires careful handling, and it cannot match the chemical resistance of fluoropolymers like PTFE or PCTFE.
FR4 Machining FAQ
Is FR4 machining safe?
Yes, with proper dust extraction. Glass fiber dust is an irritant, not toxic. Our CNC machines use HEPA-filtered extraction systems and coolant mist for safe operation. Finished parts are cleaned and free of loose fibers.
What tolerances can you hold on FR4?
+/-0.05mm standard. For tighter tolerances down to +/-0.02mm, we use compression routers and controlled feed rates. Please note that FR4 is anisotropic — tolerances may vary slightly with fiber direction.
Read our FR4 CNC machining blog for detailed tips.
Need FR4 or G10 CNC machined parts? Upload your drawing for a quote. ISO 9001 certified. Specialists in FR4 machining since 2007.