FR4 Material

The FR4 Material is reinforced epoxy laminate and is made from epoxy and a fiberglass cloth that is flame resistance and super strong material.  The fibers will essentially transpose their elements into the new material. And, the melding of the epoxy with the fibers makes for a very strong board.  As you probably know the FR4 material is great for making printed circuit boards (PCB) because of its custom material characteristics.

FR4 Material

FR4 Material

The PCB industry has a unique issue.  The components need to be able to be soldered to something but keep a low coefficient of thermal expansion as possible.  This is due to the materials themselves are changing. And you wouldn’t want the board to expand and contract greatly with the heat.  Otherwise, this will cause more issues on the PCB board. This is why they like the FR4 Material so much, as it has a very low coefficient of thermal expansion.  This means that heat or cold doesn’t cause this material to expand and contract greatly like some materials.

Another reason that the coefficient of thermal expansion is important as we don’t want it to cause stress fractures on the solder after the component is in place.  This is important to deliver the necessary data, power or whatever else that connection is for.

It is also important when making circuit boards that you have an even dielectric constant.  And, not only from one board to board but from sheet to sheet as well as a lot to lot consistency.  It is required that the parts attached to the FR4 Material Sheet. This will allow the sheet to have the same performance over and over again with minimal tuning.  

Properties of FR4 Material

FR4 Material

FR4 Material

The FR4 material offers extremely high mechanical strength at moderate temperatures.  This means that this material is some of the closest we have to the strength of steel, however, with better properties for the application.  This material is some of the most versatile of laminates. It also boasts good electrical loss properties and good electric strength properties.  The water absorption is virtually non-existent so this material is great for marine materials as well. and it acts as a great insulator.

FR4 material is very widely used in many industries and has a yellowish to light green natural coloring to it and often is left that color as acts as just a component that would go inside your computer, phone, radio or boat.  

In conclusion, this is one of the most popular materials used in the circuit board industry today.  It boasts a ton of great properties from the low coefficient of thermal expansion to the great dielectric properties.  It certainly isn’t a question as to why it’s so popular for such an application. However, this material can be machined into many other components as well as inserts for injection molding.  Because this material doesn’t shrink or contract with heat it makes a great insert for many of our thermoplastic injection molded parts as well.

If you are looking for a very strong material that can act as an insulator and have low expansion than FR4 Material is the material for you.