Glass Fiber Epoxy Unclad Laminate Grade FR-4
ACC Insulation is glass fiber epoxy unclad laminate grade FR-4 manufacturers & process in Maharashtra, India. We offer superior insulation, durability, and thermal resistance. Glass Fiber Epoxy Unclad Laminate Grade FR-4 are also known FR-4 laminate or FR-4 sheet. It is a frequently utilized industrial product that is known for its strength, hardness, and electrical insulating capability.
Our glass fiber epoxy unclad laminate grade FR-4 is widely used in high-performance electronic applications due to its flame-retardant properties, while the fiber glass epoxy laminates offer excellent electrical insulation and mechanical strength.
Features
- Good heat resistance
- Flame retardant
- Excellent electrical insulator
- oven fiberglass fabric reinforcement
- Epoxy resin binder
What is FR-4 Glass Fiber Epoxy Unclad Laminate?
FR-4 is a flame-retardant glass reinforced epoxy laminate manufactured using woven fiberglass fabric impregnated with epoxy resin under high pressure and temperature. It offers exceptional dielectric strength, dimensional stability, thermal endurance, and mechanical rigidity, making it ideal for demanding electrical insulation environments.
Technical Properties of FR-4 Sheets
- High dielectric strength
- Low moisture absorption
- Excellent arc resistance
- Superior flexural strength
- High mechanical load-bearing capacity
- Thermal class up to 155°C
- Flame retardant (UL94 V-0 compliant)
Applications of FR-4 Laminate
FR-4 unclad sheets are widely used in:
- Electrical insulation components
- Transformer insulation structures
- Switchgear panels
- Busbar supports
- Terminal boards
- PCB base material (when copper clad)
- Motor slot wedges
- High voltage insulation barriers
Manufacturing Process of FR-4 Glass Epoxy Laminates
FR-4 glass fiber epoxy laminates are manufactured through a controlled process involving multiple stages to ensure consistent electrical and mechanical performance.
- High-quality woven fiberglass fabric is selected as reinforcement
- Epoxy resin system is uniformly impregnated into the fabric
- Prepreg layers are stacked to required thickness
- Hot pressing is carried out under high pressure and temperature
- Post-curing ensures dimensional stability and thermal strength
- Final sheets are precision cut and surface finished
This process ensures uniform dielectric strength, minimal void content, and excellent bonding between resin and reinforcement.
Available Sizes & Customization
We offer FR-4 glass epoxy sheets in a wide range of standard and customized specifications to meet industrial application requirements.
- Thickness Range: 0.2 mm to 100 mm
- Standard Sheet Size: 1220 mm x 2440 mm
- Custom cut-to-size sheets available
- CNC machined components as per drawings
- Surface finish options available
FR-4 vs Other Insulation Materials
Compared to traditional insulation materials, FR-4 offers a superior balance of electrical, thermal, and mechanical properties.
- FR-4 vs G-10: FR-4 is flame retardant, G-10 is not
- FR-4 vs Bakelite: Higher strength and thermal resistance
- FR-4 vs Polyester: Better dimensional stability and dielectric strength
- FR-4 vs Paper Laminates: Superior moisture resistance and lifespan
Industries Using FR-4 Laminates
Our FR-4 glass epoxy laminates are trusted across multiple industrial sectors where electrical insulation reliability is critical.
- Transformer manufacturing industry
- Switchgear and control panel manufacturers
- Electrical equipment OEMs
- Power generation and distribution companies
- Railway electrical systems
- Industrial automation and drives
Why Choose ACC Insulations for FR-4?
- Precision machining capability
- Custom thickness and sheet sizes
- Consistent resin curing process
- Strict quality control testing
- Industrial-grade raw materials
Looking for Bulk FR-4 Sheets or Machined Components?
Share your drawings or technical requirements with our engineering team. We provide precision-machined FR-4 components with consistent quality and fast delivery.
Get Custom QuoteEngineering Tools Suite
Calculate exact dielectric tolerances, thermal endurance limits, and precise thickness requirements for your FR-4 Unclad Laminates using our interactive engineering tools.
Frequently Asked Questions
FR stands for Flame Retardant, and Grade 4 refers to the NEMA classification of glass epoxy laminates. FR-4 materials are typically compliant with UL94 V-0 flame resistance standards and are widely used in electrical and electronic industries.
Both FR-4 and G-10 are glass epoxy laminates. The main difference is that FR-4 contains flame-retardant additives, while G-10 does not. FR-4 is preferred where fire resistance is required in electrical equipment.
FR-4 has low moisture absorption compared to many other insulating materials, which helps maintain electrical insulation performance even in humid environments.
Yes. FR-4 can be precision machined using CNC routing, drilling, milling, and cutting. It maintains dimensional stability and structural integrity during fabrication.
