When designing a PCB to factory fabrication, how to choose PCB material? PCB material classification: According to different materials (the most commonly used classification method) Paper substrate (FR-1, FR-2, FR-3) Epoxy glass cloth substrate (FR-4, FR-5) Composite Substrates (CEM-1, CEM-3) HDI sheet (RCC) Special substrates (metal substrates, ceramic substrates, thermoplastic substrates, etc.) Divided by resin Phenolphthalein resin board Epoxy board Polyester