You are probably familiar with FR4 because it is the most commonly used substrate in PCB manufacturing.
When we talk about FR4 materials, we are typically referring to a commonly used Glass-Reinforced Epoxy Laminate, which is used to manufacture rigid printed circuit boards (PCBs). FR4 is a substrate material known for its excellent insulation properties, high mechanical strength, and heat resistance. The “FR” in its name stands for Flame Retardant, and the number “4” represents the material’s flame retardant rating, typically UL94 V-0.
Did you know that FR4 actually has several classifications? Understanding the classifications of FR4 can help us select a substrate that is better suited for our PCB projects, optimizing both cost and design.
Classification Standards for FR4
FR4 is a common substrate material for circuit boards, available in various types and specifications, typically classified based on several aspects:
| Classification Criteria | Standards |
| Glass Transition Temperature – TG Value | FR4 substrates are classified based on their glass transition temperature (TG value), which indicates the temperature at which the material begins to soften and lose mechanical strength. Common FR4 materials are classified into low TG, mid TG, and high TG grades based on TG values. |
| Dielectric Constant – Dk and Dissipation Factor – Df | FR4 substrates are classified based on their dielectric constant (Dk) and dissipation factor (Df). Dk and Df affect the performance of materials in high-frequency circuits. FR4 materials with low Dk and Df are suitable for high-frequency applications. |
| Flame Retardant Rating | FR4 substrates are classified based on their flame retardant properties. Common flame retardant ratings include UL94 V-0, UL94 V-1, indicating the material’s flame retardancy. |
| Specific Model and Brand | FR4 substrates are also classified based on specific models and brands. Different brands of FR4 materials may have unique characteristics and advantages suitable for various applications and requirements |
Common FR4 Models
Common FR4 models include but are not limited to the following:
- FR4 TG130, FR4 TG150, FR4 TG170: FR4 materials classified based on Glass Transition Temperature (TG).
- Low Dk/Df FR4: FR4 materials with lower dielectric constant and dissipation factor, suitable for high-frequency applications.
- High TG FR4: FR4 materials with higher glass transition temperature, suitable for applications in high-temperature environments.
- Flame Retardant FR4: FR4 materials with excellent flame retardant properties, meeting safety requirements for electronic products.
Here are several common FR4 models and examples of their suitable products or projects:
- FR4 TG130:
- Suitable Projects: General electronic products such as consumer electronics, household appliances, smart devices, etc.
- Example Products: Smartphones, tablets, household appliance control boards, LED light controllers, etc.
- FR4 TG150:
- Suitable Projects: Industrial control equipment, automotive electronics, medical instruments requiring high stability and heat resistance.
- Example Products: Industrial automation controllers, automotive electronic modules, medical diagnostic equipment, industrial instruments, etc.
- FR4 TG170:
- Suitable Projects: High-temperature environment applications, aerospace electronics, military electronic devices, etc.
- Example Products: Aerospace electronic equipment, military communication devices, high-temperature industrial controllers, etc.
- Low Dk/Df FR4:
- Suitable Projects: High-frequency communication equipment, radar systems, microwave devices requiring reduced signal transmission loss.
- Example Products: High-frequency communication base stations, radar modules, microwave antennas, RF amplifiers, etc.
- Flame Retardant FR4:
- Suitable Projects: Electronics products with high safety requirements, environments with high fire risks, industrial equipment controllers, etc.
- Example Products: Security monitoring systems, fire alarms, industrial equipment controllers, medical devices, etc.
- High TG FR4:
- Suitable Projects: Applications requiring stable operation in high-temperature environments, long-term stability, reliability, and performance in special environments.
- Example Products: Industrial control equipment, automotive electronic modules, aerospace electronics, military communication devices, etc.
These are some common FR4 models and their application examples. Choosing the appropriate FR4 substrate model depends on factors such as the project’s operating environment, performance requirements, and safety standards. Different models offer unique characteristics to meet diverse manufacturing needs for electronic products in various application scenarios.
Conclusion
FR4 materials are commonly classified based on several criteria, aiding in the selection of suitable substrate materials for specific application needs. Factors such as operating environment, performance requirements, frequency specifications, and safety standards guide the rational selection and application of FR4 substrates. Each type of FR4 model possesses specific advantages and application ranges, playing a crucial role in the design and manufacturing of electronic products.
If you have any questions or collaboration needs in PCB design and manufacturing or other related fields, we sincerely invite you to contact us anytime at sales@superpcba.com. The SuperPCBA team is dedicated to providing you with professional consulting services and tailoring the best electronic manufacturing solutions for you. Let’s work together to create a future where your electronic products are infused with greater stability and reliability!
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