FR4 is the industry-standard material for printed circuit boards (PCBs) and a wide range of electrical insulation components. A composite material made from woven fiberglass cloth and an epoxy resin binder, FR4 is renowned for its excellent electrical insulation properties, high mechanical strength, and impressive durability. While it is commonly associated with PCB fabrication, its utility extends far beyond. Precision CNC machining unlocks the full potential of FR4, allowing for the creation of complex, high-tolerance parts that are essential in demanding electrical and mechanical applications. From custom insulating spacers to prototype circuit boards, CNC machining ensures dimensional accuracy and flawless performance.
KEY BENEFITS
CNC machining is the ideal manufacturing process for producing critical parts from FR4. It combines the material’s inherent advantages with the precision of computer-controlled cutting.
| Benefit | Description |
|---|---|
| Excellent Electrical Insulation | Provides high dielectric strength, making it perfect for applications where electrical isolation is critical to prevent short circuits and ensure safety. |
| High Mechanical Strength & Rigidity | The fiberglass reinforcement gives FR4 exceptional strength-to-weight ratio and dimensional stability, resisting bending, warping, and creep under load. |
| Superior Precision & Repeatability | CNC machining produces parts with extremely tight tolerances, perfect for intricate features, slots, holes, and complex geometries that are impossible with standard shearing. |
| Thermal & Chemical Resistance | Performs reliably in elevated temperature environments and offers good resistance to solvents, acids, and moisture, ensuring long-term performance. |
| Cost-Effectiveness | FR4 is a readily available and economical material. CNC machining minimizes material waste and reduces the need for expensive tooling, ideal for prototypes and low-to-medium volume production. |
APPLICATIONS
The versatility of machined FR4 makes it a go-to material across numerous high-tech industries. Its unique combination of properties solves complex design challenges.
| Part Type | Industry Application | Why FR4 is Used |
|---|---|---|
| PCB Insulation Mounts & Spacers | Electronics, Aerospace, Automotive | Electrically isolates PCBs from metal chassis, preventing shorts and withstanding vibration. |
| Custom Busbars & Insulating Layers | Power Distribution, Renewable Energy | Provides structural support and high-voltage insulation between conductive layers. |
| Test & Burn-in Sockets | Semiconductor, R&D Labs | Offers dimensional stability and excellent insulation for reliable testing of ICs and components. |
| Transformer & Motor Insulation | Industrial Machinery, Power Generation | Used as slot liners and phase barriers to insulate windings, capable of handling high temperatures. |
| Jigs, Fixtures & Guides | Manufacturing, Automation | Creates non-conductive, wear-resistant tooling for assembly lines and sensitive electronic components. |
| RF Circuit Substrates & Antenna Plates | Telecommunications, Defense | Provides a stable, low-loss substrate for high-frequency circuits and microwave applications. |
TECHNICAL SPECIFICATIONS
This table summarizes the key technical properties of FR4, providing essential data for engineers and designers.
| Property | Value / Description | Test Standard |
|---|---|---|
| Base Material | Woven Fiberglass & Epoxy Resin | – |
| Flame Retardancy | UL94-V0 | UL 94 |
| Dielectric Strength | > 20 kV/mm | IPC-4101 |
| Dielectric Constant (ɛr) | 4.2 – 4.8 @ 1 MHz | IPC-4101 |
| Dissipation Factor (tan δ) | 0.016 – 0.022 @ 1 MHz | IPC-4101 |
| Volume Resistivity | 10^7 – 10^9 MΩ·cm | IPC-4101 |
| Flexural Strength | 415 MPa (60,000 psi) | ASTM D790 |
| Tensile Strength | 310 MPa (45,000 psi) | ASTM D638 |
| Glass Transition Temp (Tg) | 130°C – 180°C (Standard to High-Tg) | IPC-TM-650 |
| Continuous Service Temp | ~130°C | – |
| Density | 1.85 g/cm³ | – |
| Machinability | Good (Abrasive on tooling; requires carbide tools) | – |