Common Types of Halogen-Free Boards in Use
Common Types of Halogen-Free Boards in Use
In the realm of printed circuit board (PCB) manufacturing, halogen-free boards have gained significant popularity due to their environmental friendliness and compliance with industry standards. These boards, devoid of halogen elements such as fluorine, bromine, and iodine, are not only safer to dispose of but also contribute to a greener production process. Here, we delve into the various types of halogen-free boards commonly in use, their characteristics, and their applications.
1. FR-4 Halogen-Free Boards
FR-4, a popular choice for halogen-free boards, is a flame-retardant epoxy glass cloth laminate. It is characterized by its excellent electrical properties, high mechanical strength, and good heat resistance. FR-4 halogen-free boards are widely used in applications requiring high reliability and long-term stability, such as telecommunications, computers, and industrial electronics.
The FR-4 halogen-free boards typically have a UL 94 V-0 flammability rating, indicating their ability to self-extinguish within a specified time after being ignited. Additionally, they possess high glass transition temperatures (Tg), often exceeding 140°C, enabling them to maintain their structural integrity and electrical properties under high-temperature conditions.
2. CEM-3 Halogen-Free Boards
CEM-3, another halogen-free board option, is a composite epoxy material with a paper core sandwiched between two layers of glass fabric. It offers a cost-effective solution for applications where a certain level of electrical and mechanical performance is required, but not as stringent as FR-4. CEM-3 halogen-free boards are commonly used in consumer electronics, power supplies, and low-end industrial applications.
While CEM-3 halogen-free boards may not possess the same thermal and electrical properties as FR-4, they are still capable of meeting the demands of many applications. Their paper core provides good electrical insulation, while the glass fabric layers enhance mechanical strength and stability.
3. High-Performance Halogen-Free Boards
In addition to FR-4 and CEM-3, there are also high-performance halogen-free boards available for specialized applications. These boards, often utilizing advanced materials and manufacturing techniques, offer superior electrical, thermal, and mechanical properties.
For instance, some high-performance halogen-free boards feature Tg values exceeding 200°C, enabling them to operate in extreme temperature environments. Others incorporate special resins and fillers to enhance their chemical resistance, making them suitable for use in harsh chemical environments.
4. Customized Halogen-Free Boards
In many cases, manufacturers may require halogen-free boards with specific characteristics to meet their unique application requirements. Customized halogen-free boards, tailored to meet specific electrical, thermal, and mechanical specifications, are available from various PCB manufacturers.
The customization process typically involves selecting the appropriate base material, resin system, and additives to achieve the desired properties. Manufacturers can also specify the board thickness, copper weight, and other parameters to optimize the board’s performance for their specific application.
Conclusion
In summary, halogen-free boards offer a wide range of options for PCB manufacturers, from cost-effective solutions such as CEM-3 to high-performance materials for specialized applications. With their environmental benefits and compliance with industry standards, halogen-free boards are poised to play an increasingly important role in the PCB industry.
