PCBs are an integral part of all electronic appliances. The choice of material of the PCB, however, depends on a number of factors including the environment in which the PCB has to function. Of the many materials used to make custom printed circuit boards, FR4 has emerged as a popular material. Not without reason. Here are the many reasons and aspects about FR4 that you need to know to be able to make the right choice:
What really is FR4 Material?
FR4 is a fiberglass reinforced epoxy laminated sheet, with the FR in FR4 standing for flame retardant. On account of the fiberglass, the material is known for its structural stability. The fiberglass, in turn, is covered with the flame resistant epoxy resin. FR4 is known for its strong mechanical properties as well as durability that explain its widespread use.
Examples of FR4 include:
Standard FR4: It is known for its heat resistance of the order of 140°C to 150°C.
High TG FR4: It has a higher glass transition (TG) of around 180°C.
High CTI FR4: Its Comparative Tracking Index is higher than 600 Volts.
FR4 with no laminated copper: It is ideal for insulation plates and board supports.
Properties of FR4 Material
Let us look at some of the other properties of FR4 material that result in its widespread popularity:
- It has high dielectric strength and hence high electrical insulation properties.
- It is known for its lightweight and thus finds extensive use in today’s environment where miniaturization is key.
- It is moisture resistant and finds use in a wide variety of applications where moisture in the environment is a given.
- It is known for its cost efficiency. Other laminate material like ceramic or Arlon comes at a higher price and can impact your overall project.
FR4 Printed Circuit Boards Types Based on Classification
FR4 printed circuit boards are classified based on several attributes. Some of these include:
Size or Thickness
While the standard FR4 thickness is 0.78 mm, it is available in a wide variety of thickness. Copper clad FR4 boards are available in 18µm to 140µm
Source of FR4 Material
FR4 Printed Circuit Boards are available in types such as Rogers FR4 PCB, FR4 Isola PCB and more basis the manufacturing companies.
Thermal Properties of FR4 Printed Circuit Boards
Glass Transition Temperature
The standard FR4 material has a glass transition temperature of 130 to 140 centigrade. However, factors such as coefficient of expansion, dielectric value, and others determine its standard nature.
The glass transition temperature value of an RF4 material determines the kind of application in which it can be used. An FR4 that has high glass transitional temperature can withstand far higher frequencies. Such material can also withstand high operating temperatures.
It is the temperature at which the FR4 PCB sheet is permanently decomposed. The FR4 Printed Circuit Board decomposition temperature comes at the highest TG value of 180 degrees centigrade. Beyond this point, the FR4 changes its chemical properties permanently.
How to select the right FR4 material for your printed circuit boards?
Here’s how to make the choice of FR4 material for your PCB:
- Thin FR4 material comes in handy where you have a space constraint. Not only can the thin material support delicate components, it also works well for space saving designs.
- Once again thin FR4 material works for applications that demand flexibility. It is therefore widely used for automotive and medical PCBs.
- On the other hand, for designs that have grooves, thin material needs to be avoided on account of the high risk of damage.
- Needless to mention that the thickness of the material impacts the weight of the PCB. Where miniaturization and lightweight of the electronic appliance are a requirement, thin FR4 boards need to be chosen.
To Sum Up
With a wide variety of FR4 material available in the market with diverse capabilities, it is easy to choose the right PCB material that suits your bespoke needs. The boards created using FR4 material are strong, durable and water-resistant besides offering insulation, reducing interference and backing excellent signal integrity. Your PCB Contract manufacturer will be in the best position to guide you through your choices.
Our experienced PCB material management team and advanced material management system can efficiently manage your projects and requirements. We have the resources available to locate parts and materials you need to eliminate the delay and reach quickly to the result.
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