What is FR-4 PCB material?
We've all heard the abbreviation FR4 being thrown about eventually when purchasing a PCB fab house, however what does it actually imply? And what ramifications does it have when choosing a PCB material? This post will help clear the fog and present some popular materials available for rigid PCBs.
More than likely, you will have seen FR4 as the standard choice for little batch or prototype PCBs like in Speed Fusion. FR-4 refers to a grade of material instead of a material itself and has many sub gradings and types such as TG130, High TG, FR4-Rogers. The FR4 choice 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 top copper layers whereas, in multilayer PCBs, extra layers of FR4 prepreg are sandwiched in between the outer copper and the inner core layers. The preferred last density of the PCB can be controlled by adding or eliminating specific laminates or using laminates of different thicknesses. Normally, a 1.6 mm board will have 8 layers of fiberglass sheets, if we wanted a 0.8 mm board we can decrease the number of sheets to 4.
The name FR4 comes from the NEMU grading system where the 'FR' means 'fire retardant', certified with the UL94V-0 standard. You may have discovered that on the Speed Fusion order page the FR4 choice is followed by TG130. The TG describes the transition glass temperature-- the temperature at which the glass-reinforced material will begin to soften and warp. For Fusion's standard boards this value is 130 ° C, which is sufficient for a lot 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 stages and might be pushed to extremes. If your soldering abilities are not up to standard, it is likewise a little assuring.
Other comparable grades used for PCBs consist of FR2, which is a type of fire retarding fiberglass resin bonded paper and G10 which is not flame resistant at all. FR2 is cheaper therefore has its uses in mass production of low-end electrical devices. G10, a predecessor to FR4, has all however been taken over by the safer FR4 standard. Its only use in PCBs now is in styles that want this flammable residential or commercial property.
This blog site has actually covered more details on rigid PCB materials than the average enthusiast Browse this site will ever require, however should you ever find the use for High TG or more specialized materials, you can have a look at Speed Fusion Advanced PCB service for more choices consisting of high-frequency boards and rigid-flex PCBs.
The FR4 choice on the PCB order page is the grade designation for the epoxy fiberglass that typically forms the PCB core and prepreg layers. In a normal 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 leading copper layers whereas, in multilayer PCBs, extra layers of FR4 prepreg are sandwiched between the external copper and the inner core layers. Normal thinner thicknesses are used in multilayer boards in which the FR4 board is used to disperse signals to other boards, in order to not increase the density of the PCB. Higher thicknesses are utilized when high toughness of the PCB is required because a big PCB is created.