This blog will tell you what FR4 is, and in the process of making the FR4 PCB boards, what aspects should be considered when choosing FR4, and why this PCB material is so widely used.
To find out more please see below:
Part 1: What is FR4 PCB?
To put it first, FR4 PCBs are the printed circuit boards using FR4 laminates. Most PCBs are made of FR4 (Flame Retardant level 4).
FR4 is not the certain name of the material. It is rather the grade of the material. It refers to the fourth grade of retardant material. The composition of the material constitutes fibers of glass in the epoxy resin. This material has anti-flame properties. The composition of the material is according to the standard UL94V-0.
This grade of laminate material has high strength and performance. Moreover, it has a good ratio between strength and weight. As this material does not have any capability for absorption of water, it has good electrical insulating properties.
Below is the reason why the FR4 own a great demand in the market:
- Compact and easy to design
- Strongest plastic fastener materials
- Low cost but with multiple functions
- Moisture resistance keeps high mechanical strength
- Good insulating capacity in dry or humid environments
First, we use this material as an insulating material for PCB, then by adding copper in it, we made it to use as a conducting sheet. It has a greater strength for resisting and the ability to absorb the moisture on the PCB sheet. Its maximum ambient temperature is 248°F to 266°F depending on its brand and its filler.
FR4 PCB connections
These things make the FR4 perfect for PCB manufacturing.
These qualities make the PCB a small cost and good quality.
Fr4 PC material is basically the backbone of PCB devices.
During the production process of FR4 PCB, the FR4 boards are laminated with copper layers at a specific temperature.
Depending upon the design of PC boards copper is forms on the circuits on both sides.
Talking about the complexity, the PC boards use more than one layer to make complete circuits.
Now we are going to discuss different types of fR4 PCB.
Part 2: Types of FR4 PCB:
Single side FR4 PCB:
The Fr4 single-side printed circuit boards are made of epoxy resin PCB having copper foil on one side, its components are pasted on one side.
Talking to their size we generally have length 100mm, width 70mm, and height 1.5mm.
With time the development of new technologies which include the hard process of production with new machinery, the product becomes more expensive, but single side PC boards are very advanced and affordable.
Double side FR4 PCB:
The Fr4 single-side printed circuit boards also are made of epoxy resin PCB having copper foil on one side, but its components are pasted on two sides which give the path of traces to cross each other.
These boards contain copper for conduction.
In double side Fr4, PCB components are pasted on both sides of PC boards which give the path of traces to cross each other.
Multiple layers FR4 PCB
The multisided PC board has more than two layers. It contains three layers of material for conduction.
That is pasted in the center of the materials. The core material is laminated together under high pressure and high temperature to produce multilayer PC boards. Components are pasted on both sides of PC boards.
Rigid FR4 PCB
In this type of Fr4 PC board, the core materials used are only Fr, so that is why this is called a rigid fr4 printed circuit board.
There are no other materials or impurity added to it it’s a pure circuit, that is why it is rigid for the whole PC board.
Rigid-flex FR4 PCB
In this type of PC board, the core material is rigid as well as flexible so they are called rigid-flex Fr4 PC boards.
The flex is due to circuit flexibility. We used thin boards because it is more flexible and more vulnerable to heat.
During soldering, it can be bending to make a desirable angle.
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Part 3: Factors to Consider When Choosing FR4 PCB:
1.Thickness of Sheet:
Basically, the thickness depends on your project what do you want to make; thinnest boards are widely used for printed circuit boards designed.
Thin PC boards reduce stress. Ideally, we require Fr4 thickness almost from 1 to 3 inches.
2. Impedance matching
In electrical and electronic equipment, impedance or frequency matching is very important for low-frequency or high-frequency printed circuit boards.
Pay more attention to those points would help the boards to derive and run safely.
It also can tell us about the capacitance in multi-sided boards.
During the designing of Fr4 printed circuit boards, space-saving is a very important factor.
For USB connectors and Bluetooth accessories, spacing is very important.
Mostly we used the thinnest boards for designing.
The thinner board is more flexible than the thicker. Most manufacture used thin boards as compared to thick ones due to their flexibility.
While using Fr4, if the substrate used is very thin and the area or dimensions of Fr4 PCB is more it would be a great risk.
In electrical and electronic devices thin Fr4 PC boards having the ability to reduce stress.
Thin boards are more flexible and more vulnerable to heat.
During soldering, it can be bending to make a desirable angle.
Mostly FR4 PCB thickness decides its weight, for small or lighter products it would be lightweight and vice versa.
6. Thermal conduction:
Thermal conduction is a very important term to know while choosing Fr4 PCB.
What’s more, it depends on the temperature.
For the temperature identification we should have to look at the thermal coefficient of dielectric medium or dielectric constant, Fr4 has excellent heat resistance, which is why it is very popular.
7. Compatibility with the Components:
Fr4 is useful to produce different kinds of printed circuit boards and its thickness and spacing tell us about the devices or components to be used in Fr4 PCB.
Like using THT types devices are different from other devices and thus this device requires a thinner PCB design.
We are going to discuss the properties of fr4 PCB and the material used in it.
Part4: Properties and Materials of FR4:
In the abbreviation of FR4, the FR stands for the "flame retardant", which shows that the material used with the UL94-0 standard on plastic materials inflammability. The code 94-0 would be written on all the fr-4 PCBs, which shows the guarantee to protect the device from fire propagation during the burning of the material.
A good FR4 PCB having multiple layers of FR4 pasted between the two thin layers of the laminate copper plate because bromine used for its manufacturing so it also called a halogen element.
The standard FR4 PC board has heat resistance almost of the order of 248°F to 266°F.
During the production process of Fr4 PCB, the FR4 boards are laminated with copper layers at a specific temperature.
It is ideal for insulation as well as for board supports with no laminated copper, and it has a higher TG of around 180°c.
Here we mentioned some of the properties of FR4 PCB now we are discussing the material used for making FR4 PCB.
- It uses bromine that is why it is also called a halogen chemical element.
- It is a very good fire-resistant
- FR4 has the benefit of a good resistance weight ratio
- It does not absorb moisture or water
- It has high mechanical strength
- It has a good insulating capacity in humid or dry environments
- A good FR4 PCB has multiple layers of fr4 pasted on it
- Its maximum ambient temperature is 248°F to 266°F depending on its brand and its filler.
- The core material used is laminated together to produce layers at high temperature and pressure
In conclusion, after reading all the content above we can have a rough understanding of FR4 PCB material. Are you finding the best and the most suitable PCB supplier for yourself? PCBONLINE will meet your demand. If you still want to save cost? There still is a way to help you! The safest way is to avoid solder masks and silkscreen, so the cost will decrease by 5-10%.
In fact, many customers of PCBONLINE are buying these boards for different specific usage. FR4 is just one of those materials. You also can find more material preferences on our website.