![]() ![]() These are commonly referred to as copper clad laminates. A thin layer of copper foil is typically laminated to one or both sides of an FR-4 glass epoxy panel. LW Lengthwise CW Crosswise PF Perpendicular to laminate face Applications įR-4 is a common material for printed circuit boards (PCBs). Checking the actual values, for any particular material, from the manufacturer's datasheet, can be very important, for example in high frequency applications.ģ.9 – 4.7, 4.4 1 GHz (Supplier Isola) Ĭoefficient of thermal expansion – x-axisĬoefficient of thermal expansion – y-axisĬoefficient of thermal expansion – z-axis Another manufacturer's material will usually have slightly different values. The values shown below are an example of a certain manufacturer's material. In terms of Cartesian coordinates, lengthwise is along the x-axis, crosswise is along the y-axis, and the z-axis is referred to as the through-plane direction. The abbreviations LW (lengthwise, warp yarn direction) and CW (crosswise, fill yarn direction) refer to the conventional perpendicular fiber orientations in the XY plane of the board (in-plane). Typical physical and electrical properties of FR-4 are as follows. Which materials fall into the "FR-4" category is defined in the NEMA LI 1-1998 standard. Some applications where thermal destruction of the material is a desirable trait will still use G-10 non flame resistant. Hence, FR-4 has since replaced G-10 in most applications.įR-4 epoxy resin systems typically employ bromine, a halogen, to facilitate flame-resistant properties in FR-4 glass epoxy laminates. G-10, the predecessor to FR-4, lacks FR-4's self-extinguishing flammability characteristics. ![]() Of these, FR-4 is the grade most widely in use today. Grade designations for glass epoxy laminates are: G-10, G-11, FR-4, FR-5 and FR-6. These attributes, along with good fabrication characteristics, lend utility to this grade for a wide variety of electrical and mechanical applications. The material is known to retain its high mechanical values and electrical insulating qualities in both dry and humid conditions. With near zero water absorption, FR-4 is most commonly used as an electrical insulator possessing considerable mechanical strength. The designation FR-4 was created by NEMA in 1968.įR-4 glass epoxy is a popular and versatile high-pressure thermoset plastic laminate grade with good strength to weight ratios. "FR" stands for "flame retardant", and does not denote that the material complies with the standard UL94V-0 unless testing is performed to UL 94, Vertical Flame testing in Section 8 at a compliant lab. FR-4 is a composite material composed of woven fiberglass cloth with an epoxy resin binder that is flame resistant ( self-extinguishing). JSTOR ( September 2014) ( Learn how and when to remove this template message)įR-4 (or FR4) is a NEMA grade designation for glass-reinforced epoxy laminate material.Unsourced material may be challenged and removed. Please help improve this article by adding citations to reliable sources. This article needs additional citations for verification. ![]()
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