LinkedIn·Thursday, 13 August 2026·13d ago

PCB base materials are currently receiving unusual attention. The AI infrastructure boom is increasing demand for high-performance PCB…

Eurocircuits

8,503 followers

PCB base materials are currently receiving unusual attention. The AI infrastructure boom is increasing demand for high-performance PCB materials, and supply constraints, longer lead times and rising prices are being widely discussed across the electronics industry and on social media. For us, this is a good opportunity to clarify a basic term in PCB manufacturing: What exactly do we mean by base material? A typical PCB base material combines three elements: resin, reinforcement and a conductive layer. For FR-4, by far the most widely used base material for PCBs, these are: • Epoxy resin as the binding material • Woven glass fibre as reinforcement • Copper foil as the conductive layer The abbreviation FR stands for Flame Retardant and refers to the flame-retarding properties of the material. FR-4 is used in PCB manufacturing in two main forms: cores and prepregs. A prepreg – short for pre-impregnated – is made by impregnating woven glass fabric with epoxy resin. The resin is partially cured, so it can flow and bond the layers during the multilayer pressing process. A core is a fully cured laminate. It is produced from layers of prepreg that are pressed and cured, with copper foil applied to one or both sides. To build a multilayer PCB, cores and prepregs are combined and pressed together under heat and pressure. Different glass weaves, prepreg constructions, core thicknesses and copper foils allow manufacturers to create different stack-ups for specific electrical and mechanical requirements. This also explains an important aspect of the current discussion: FR-4 is not one universally interchangeable material. Material grades, constructions and thicknesses differ. For PCB designers, this matters: the more specific the material requirements, the more limited the alternatives can become when availability is tight. #eurocircuits #electronics #PCB #pcbdesign #PCBAssembly #PCBManufacturing