PCB circuit board，the provider of the electrical connection in the electronic components.The principal advantage of the circuit board is greatly reduce wiring and fitting error, improves the automation level and rate of productive labor.
The composition of the PCB circuit board
1.Circuit line and the Pattern:Circuit line is as the original tool between components.The design will use another big copper surface as the grounding and power supply layer.Circuit line and the pattern is made at the same time.
2.Dielectric layer:It is used to keep the lines and insulation between the layers, known as base material.
3.Solder resistant /Solder Mask:Not all the copper surface solder is on the parts,So solder area will be printed on a layer of insulated copper solder material (usually called epoxy resin).According to the different process, divided into green oil color, red oil color, blue oil color.
4.Through hole / via:Through hole can make two or more layers of conducting lines each other connected.Larger Through hole is used as parts plug-in,With other guide hole (nPTH) is usually used as a surface-mount positioning.It is used to fix screw assembly.
5.Legend /Marking/Silk screen:This is not necessary.The main function is in the circuit board to mark he parts of name, location, box, convenient maintenance and identification after assembly.
6.Surface Finish:Due to the copper surface in the general environment is easy to oxidation and lead to can't tin (poor solder ability）.Thus we make an protection in tin copper surface.The protect way is HASL, ENIG,Immersion Silver ,Immersion Tin and OSP.
Base material is generally based on base board insulation parts.Common raw material is for the electricity board, glass fiber board.And PCB manufacturers will generally with a glass fiber, fabric material, and the insulation resin composition, again with epoxy resin and copper foil compressed into "bonding" (prepreg) is used.
Common base material and ingredient is as follows.