1. Definition and Characteristics

Glass fiber is a fine filament drawn from an inorganic, non-metallic material. It possesses high strength, heat resistance, and electrical insulation properties. In PCBs, glass fiber is typically combined with epoxy resin in the form of glass fiber cloth (such as 7628 cloth and 2116 cloth) to form a copper-clad laminate, which is currently the most common PCB substrate. Its main characteristics are as follows:

Excellent electrical insulation: Prevents short circuits and leakage.

Thermal stability: Ensures that the PCB does not deform during high-temperature soldering or operation.

Dimensional stability: Low water absorption ensures flatness of the circuit board.

High mechanical strength: Enhances the PCB's impact and bending resistance.

2. Advantages

High reliability: The glass fiber-reinforced substrate ensures long-term stable circuit operation.

Affordable cost: Compared to ceramic substrates, it offers a more cost-effective solution and is suitable for large-scale production.

Strong chemical resistance: Resists common chemical corrosion during soldering and operation.

Proven process: FR-4 material is widely used in PCB manufacturing and has a well-developed supply chain.

3. Application Scenarios

Consumer Electronics: Motherboards for smartphones, laptops, tablets, etc.

Communications Equipment: Routers, switches, 5G base station circuit boards.

Automotive Electronics: In-vehicle control systems, navigation, and sensors.

Industrial Control: Power equipment, sensors, and control systems.

Aerospace and Military: High-frequency and high-speed PCB substrates require higher-quality glass fiber cloth.

4. Selection Guide

Fabric Options: Common options include 7628 fabric, with thicker fabrics suitable for multilayer substrates, and 2116 fabric, with thinner fabrics used for high-density wiring PCBs.

Resin Systems: Formulated with epoxy resins, high-frequency PTFE resins, and other materials to meet diverse signal transmission requirements.

Performance Requirements: Requirements include high-temperature resistance (halogen-free materials), low dielectric constant (high-speed PCBs), and flame retardancy (UL94 V-0).

5. FAQs

Why is glass fiber used in PCBs?

Glass fiber provides mechanical strength, dimensional stability, and excellent insulation properties, making it key to ensuring stable PCB performance.

What's the difference between glass fiber cloth used in high-frequency, high-speed PCBs and conventional PCBs?

High-frequency PCBs require glass fiber cloth with low dielectric loss (such as ultra-thin cloth and plain weave) to minimize signal attenuation.

6. Summary

Glass fiber plays a core role in PCB manufacturing, providing not only structural support and insulation but also ensuring the reliability of circuit boards in high-temperature, high-speed, and complex environments. With the development of 5G, automotive electronics, and high-performance computing, the demand for glass fiber cloth will be even higher. Companies must select the appropriate cloth type and resin system based on application requirements to ensure stable PCB performance. We are a Chinese glass fiber manufacturer. If you are looking for high-quality 7628 cloth for electronic boards, our products are an excellent choice. For more information, please contact us by email at annayu@169chem.net or WhatsApp: +86 18909016373.