CEM1/CEM3
CEM-1 is a composite material composed of woven glass fabric and a paper core combined with epoxy resin. With properties of easy punching, excellent electrical properties, and higher flexible strength, the CEM-1 provides excellent mechanical and electrical properties and punches well up to 2.36 mm (0.093″). The CEM-3 is very similar to FR4 but, instead of woven glass fabric, a ‘flies’ type is used. CEM-3 has a milky white colour and is very smooth. It is a complete replacement for FR4 and has a very large market share in Asia. It is a type of flame-retardant epoxy, copper-clad, plate glass material, and is generally used in electronics for double sided-PCB boards