FR-4 (also known as G10 FR-4) is a thermosetting composite material made by bonding woven fiberglass cloth with electrical grade epoxy resin under high temperature and pressure.

As a high-performance insulating material, FR-4 has the following advantages:

Excellent mechanical strength

High electrical insulation performance

Stable dielectric properties

Good dimensional stability

Flame retardant properties (UL94 V-0 rating available)

Due to these properties, FR-4 is widely used in electrical, electronic, industrial, and structural insulation applications.

SJ Tech offers high-quality FR-4 sheets and provides precision CNC machining services for custom insulation components.

What is the difference between FR-4 and G10?

Both G10 and FR-4 are glass fiber reinforced epoxy resin laminates.

The main difference lies in flame retardancy:

G10 – Standard glass epoxy resin laminate, non-flame retardant.

FR-4—the flame-retardant version of G10, is usually brominated and meets flame-retardant safety standards.

In most applications that require G10, FR-4 can serve as an alternative.

However, in applications where flame retardancy is required, FR-4 should be specified.

SJ Tech supplies G10 and FR-4 materials in accordance with international standards.

Standard paper size

Manufacturing and CNC machining capabilities

FR-4 can be machined using both conventional and CNC equipment.

SJ Tech’s areas of expertise include:

Precision CNC milling and turning

High-precision machining

Custom insulation component manufacturing

Prototyping and mass production

We process a variety of engineering insulation materials, including: FR-4/G10, G11/FR-5, SMC composites, phenolic resin (bakelite), and engineering plastics.

Our deep understanding of composite insulation materials enables us to optimize toolpaths, reduce processing steps, and efficiently manufacture complex parts—often in a single setup.

Existing product forms

SJ Tech supplies a variety of FR-4 materials: plates/bars/tubes/precision machined parts/gaskets, spacers, insulation components/fully custom structural parts