What is FR-4 PCB material?
We've all heard the abbreviation FR4 being tossed about at some time when looking for a PCB fab home, but what does it actually suggest? And what ramifications does it have when choosing a PCB material? This post will assist clear the fog and introduce some popular materials available for stiff PCBs.
Probably, you will have seen FR4 as the basic choice for small batch or model PCBs like in Speed Fusion. FR-4 describes a grade of material rather than a material itself and has many 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 often forms the PCB core and prepreg layers. It is the homes of this base that provides the PCB the electrical isolation and mechanical strength needed to withstand increasingly demanding applications.
In a normal PCB, the core offers the rigidity and the structure 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 top and bottom copper layers whereas, in multilayer PCBs, extra layers of FR4 prepreg are sandwiched in between the inner core and the outer copper layers. The preferred final density of the PCB can be controlled by including or eliminating individual laminates or utilizing laminates of various thicknesses. For example, generally, a 1.6 mm board will have 8 layers of fiberglass sheets, if we wanted a 0.8 mm board we can reduce the variety of sheets to 4.
The name FR4 originates from the NEMU grading system where the 'FR' means 'fire retardant', certified with the UL94V-0 standard. You might have observed that on the Speed Fusion order page the FR4 option is followed by TG130. The TG refers to the shift glass temperature level-- the temperature at which the glass-reinforced material will start to deform and soften. For Fusion's standard boards this worth is 130 ° C, which is sufficient for many applications. Special High TG materials can stand up to temperature levels of 170-- 180 ° C and can be purchased online using the Advanced PCB service.
FR4 laminates owe their flame resistance due to its bromine content, a non-reactive halogen commonly utilized in industry for its flame slowing down properties. This offers FR4 materials obvious benefits as a more info stock PCB material, especially in prototyping where circuits are still in the initial screening stages and might be pushed to extremes. It is likewise a little guaranteeing if your soldering abilities are not up to standard.
Other similar grades utilized for PCBs include FR2, which is a type of fire retarding fiberglass resin bonded paper and G10 which is not flame resistant at all. FR2 is more affordable and so has its usages in mass production of low-end electrical devices. G10, a predecessor to FR4, has all however been taken over by the safer FR4 requirement. Its only usage in PCBs now is in styles that prefer this combustible residential or commercial property.
This blog site has covered more details on stiff PCB materials than the average enthusiast will ever require, but must you ever discover the use for High TG or more specific materials, you can check out Speed Fusion Advanced PCB service for more options including high-frequency boards and rigid-flex PCBs.
The FR4 alternative on the PCB order page is the grade classification for the epoxy fiberglass that typically forms the PCB core and prepreg layers. In a common PCB, the core offers the rigidity and the structure on which the PCB traces can be 'printed' onto. For double layer boards, an FR4 core separates the leading and bottom copper layers whereas, in multilayer PCBs, additional layers of FR4 prepreg are sandwiched between the inner core and the external copper layers. Typical 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 thickness of the PCB. Higher densities are utilized when high toughness of the PCB is required because a large PCB is designed.