What is FR-4 PCB material?
We've all heard the abbreviation FR4 being thrown about eventually when buying a PCB fab house, but what does it in fact mean? And what implications does it have when picking a PCB material? This post will help clear the fog and introduce some popular materials offered for rigid PCBs.
More than likely, you will have seen FR4 as the basic option for little batch or model PCBs like in Speed Fusion. FR-4 refers to a grade of material rather than a material itself and has numerous sub gradings and types such as TG130, High TG, FR4-Rogers. The FR4 alternative on the PCB order page is the grade designation for the epoxy fiberglass that frequently forms the PCB core and prepreg layers. It is the homes of this base that offers the PCB the electrical isolation and mechanical strength required to sustain increasingly demanding applications.
In a common PCB, the core supplies the rigidness and the foundation on which the PCB traces can be 'printed' onto. In addition, the FR4 core and laminates form the electrical isolation separating copper layers. For double layer boards, an FR4 core separates the bottom and leading copper layers whereas, in multilayer PCBs, additional layers of FR4 prepreg are sandwiched between the external copper and the inner core layers. The desired final thickness of the PCB can be managed by including or removing private laminates or utilizing laminates of various densities. Generally, a 1.6 mm board will have 8 layers of fiberglass sheets, if we desired a 0.8 mm board we can minimize the number of sheets to 4.
The name FR4 originates from the NEMU grading system where the 'FR' stands for 'fire retardant', compliant with the UL94V-0 requirement. read more You might have seen that on the Speed Fusion order page the FR4 option is followed by TG130. The TG refers to the transition glass temperature level-- the temperature level at which the glass-reinforced material will start to deform and soften. For Fusion's basic boards this worth is 130 ° C, which is ample for most applications. Special High TG materials can stand up to temperature levels of 170-- 180 ° C and can be bought online using the Advanced PCB service.
FR4 laminates owe their flame resistance due to its bromine content, a non-reactive halogen typically used in market for its flame slowing down homes. This gives FR4 materials obvious advantages as a stock PCB material, particularly in prototyping where circuits are still in the preliminary screening phases and may be pushed to extremes. If your soldering abilities are not up to standard, it is also a little assuring.
Other similar grades used for PCBs consist of FR2, which is a kind of fire slowing down fiberglass resin bonded paper and G10 which is not flame resistant at all. FR2 is cheaper and so has its uses in mass production of low-end electrical equipment. G10, a predecessor to FR4, has all however been taken control of by the more secure FR4 requirement. Its only usage in PCBs now is in designs that desire this flammable residential or commercial property.
This blog site has actually covered more details on rigid PCB materials than the average hobbyist will ever need, but ought to you ever discover the usage for High TG or more customized materials, you can have a look at Speed Fusion Advanced PCB service for more alternatives including high-frequency boards and rigid-flex PCBs.
The FR4 option on the PCB order page is the grade designation for the epoxy fiberglass that often forms the PCB core and prepreg layers. In a typical PCB, the core provides the rigidity and the structure on which the PCB traces can be 'printed' onto. For double layer boards, an FR4 core separates the bottom and top copper layers whereas, in multilayer PCBs, additional layers of FR4 prepreg are sandwiched in between the external copper and the inner core layers. Common thinner thicknesses are utilized in multilayer boards in which the FR4 board is utilized to distribute signals to other boards, in order to not increase the thickness of the PCB. Greater densities are used when high robustness of the PCB is required due to the fact that a big PCB is designed.