What is FR-4 PCB material?
We've all heard the abbreviation FR4 being tossed about at some point when looking for a PCB fab house, however what does it really mean? And what ramifications does it have when selecting a PCB material? This post will help clear the fog and present some popular materials readily available for rigid PCBs.
Probably, 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 option on the PCB order page is the grade classification for the epoxy fiberglass that often forms the PCB core and prepreg layers. It is the residential or commercial properties of this base that offers the PCB the electrical isolation and mechanical strength required to withstand significantly demanding applications.
In a common PCB, the core offers 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, extra layers of FR4 prepreg are sandwiched between the inner core and the outer copper layers. The wanted final thickness of the PCB can be managed by including or getting rid of individual laminates or using laminates of various densities. For example, typically, a 1.6 mm board will have 8 layers of fiberglass sheets, if we wanted a 0.8 mm board we can minimize the variety of sheets to 4.
The name FR4 originates from the NEMU grading system where the 'FR' represents 'fire retardant', compliant with the UL94V-0 standard. You may have observed that on the Speed Fusion order page the FR4 alternative is followed by TG130. The TG refers to the transition glass temperature-- the temperature level at which the glass-reinforced material will begin to soften and deform. For Fusion's standard boards this value is 130 ° C, which is sufficient for the majority of applications. Unique High TG materials can withstand temperatures of 170-- 180 ° C and can be purchased online utilizing the Advanced PCB service.
FR4 laminates owe their flame resistance due to its bromine material, a non-reactive halogen frequently used in industry for its flame retarding residential or commercial properties. This offers FR4 materials apparent advantages as a stock PCB material, especially in prototyping where circuits are still in the initial testing phases and might be pressed to extremes. If your soldering abilities are not up to requirement, it is Additional reading also a little guaranteeing.
Other comparable grades utilized for PCBs consist of FR2, which is a kind of fire retarding 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 actually all however been taken control of by the more secure FR4 standard. Its only use in PCBs now is in designs that prefer this combustible home.
This blog site has actually covered more information on rigid PCB materials than the average hobbyist will ever need, but must you ever discover the usage for High TG or more customized materials, you can examine out Speed Fusion Advanced PCB service for more options including high-frequency boards and rigid-flex PCBs.
The FR4 choice on the PCB order page is the grade designation for the epoxy fiberglass that frequently forms the PCB core and prepreg layers. In a typical PCB, the core offers the rigidity and the foundation 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 between the external copper and the inner core layers. Common thinner densities are utilized in multilayer boards in which the FR4 board is utilized to disperse signals to other boards, in order to not increase the density of the PCB. Greater thicknesses are used when high robustness of the PCB is required because a large PCB is designed.