What are printed circuit boards made of?

A printed circuit board (PCB) consists of conductive and non-conductive layers bonded together to make one whole. The materials for a PCB can differ depending on their purpose and client needs. For example, a double sided PCB (also known as a 2-layer board) comprises: A core layer made of glass fibre reinforced epoxy resin; this provides a solid, rigid and non-conductive support layer, generally referred to as FR4 On each side of the PCB is a conductive layer of traces and pads which make up the circuit. The traces provide the tracks through which signals pass and the pads provide the base for where components will be soldered. The conductive material is copper but other conductive materials, such as gold or silver, may be used, on top of the copper for the final surface finish. The most commonly used surface finish is solder, which is Hot Air Level (HASL) Before assembly, additional layers: a solder mask or solder resist is applied to protect the bare PCB’s conductive layer, is made of a thin layer of polymer ink. It is generally screen printed with either uv or photoimaging ink. Most PCBs are supplied green but other colours such as red and blue are also available and white is used for LED display purposes. a silk screen print or overlay is applied on the PCB with specialist inks to show the symbols and component references for component location during assembly. Tin solder is used during the assembly process to attach the various components to either through hole or surface mount pads. ABL Circuits are experienced in designing the PCBs including single side, double sided and multi-layered boards. We either work to client specifications or design and develop PCBs to meet customer specifications and provide advice on the right materials for your project.

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