Printed circuit boards differ not only in the number of layers and the way the components are fixed into them. Various types of PCB materials can also be used, each better for a certain situation. What are they? How to choose the right one?
In general, there are three types of PCB materials (substrates): FR-4, PTFE, or metals. In this article, we will showcase each of them in more detail and discuss when to use them. We invite you to read on.
The Three Types of PCB Materials
Let’s delve into the world of the materials used most frequently in PCB manufacturing services without any further ado. What are they, and how do they work?
FR-4
FR-4 or fiberglass (Flame Retardant class 4) is the most commonly used PCB substrate. It is composed of a woven fiberglass cloth with an epoxy resin binder that is resistant to fire. Why is it used so frequently?
FR-4 offers a good balance of mechanical strength, electrical insulation, and thermal resistance. Moreover, it is relatively inexpensive compared to its properties. Therefore, it is chosen as the standard PCB material for most consumer electronics, which do not require any additional properties due to their use.
There are quite a few variations of this particular material available on the market. You can get the standard FR-4, but also:
- FR-4 Mid Tg—with a slightly improved Tg parameter.
- FR-4 High Tg—with highly increased thermal resistance, used mostly for multi-layer PCB design.
- FR-4 High CTI—with modified epoxy resins, used for PCBs with high operating voltage and those that need to operate in high humidity conditions.
- FR-4 Halogen Free—a PCB material that does not contain halogen, antimony, phosphorus, and similar compounds.
PTFE
PTFE, or Teflon, has been chosen mostly due to its flexibility and excellence in high-speed applications. What is more, it does not weigh much, making it perfect for weight-restricted applications. At the same time, its flame resistance and physical strength are also good, providing you with flexible (literally and practically) PCBs.
This specific material is mostly used for high-frequency and microwave-range PCBs. Similarly to FR-4, it is possible to distinguish a few types of this specific material, namely:
- PTFE—polytetrafluoroethylene polymer reinforced with glass fiber, the standard option.
- PTFE with ceramic filler—PTFE used with a ceramic filler; it’s among the most widely available materials for high-frequency PCBs.
PTFE provides more reliability than FR-4 or other printed circuit board materials. You will most likely see it used in PCBs for radios, antennas, and devices hosting fast digital applications that need to be accurate.
Metals
You may also find PCBs produced from metals like copper, aluminum, or iron. These are mostly utilized for the sake of surface-mount technology. Additionally, such printed circuit boards usually are more durable and have a longer product life. However, they might be a bit more expensive.
Metals are mainly used to achieve specific goals like:
- exceptional mechanical strength,
- great thermal conductivity with low weight,
- corrosion resistance,
- excellent thermal conductivity with disregard for weight,
- strong support for the mounted components.
Therefore, using metals requires a good knowledge of the PCB design process, as specific metals might be better for certain applications. For instance, aluminum is lightweight and has good thermal conductivity, while steel provides excellent mechanical strength but weighs much more. Moreover, like in the case of previous PCB materials, different types of the same metals are used in the industry, so we recommend consulting an experienced engineer if you’re not an expert yourself.
How to Choose Your PCB Material?
While the above are some of the most commonly used PCB materials, there are many more to choose from. Therefore, you need to think carefully about your decision. How to choose the best PCB material?
#1 Start by determining the type of PCB you are building. A different type of material will be good for a flex, multi-layer PCB than for a rigid single-layer board.
#2 Determine the function and the most important properties of your PCB. To select the best material, you need to know whether you’re looking for mechanical strength, thermal conductivity, or low weight.
#3 Contact your trusted engineers. At Conclusive, we won’t only design and manufacture your PCB but also advise you on the best materials to use in your project. Trust us with your embedded systems.
Conclusions
There are many different types of PCB materials, and the choice between them depends on the specifics of your project. Therefore, it is best to consult an expert when making your choice since, this way, you ensure that the material is tailored to the needs of your future embedded system.
Did you like this article? You may also read: What Are the Advantages of Custom PCB Manufacturing