Circuit board production process is what?
The outer line after the completion of the tree layer in overlying insulating ester to avoid oxidation and welding short circuit protection. It is usually necessary to use the method of brush grinding and micro etching to make the copper surface of the circuit board to be cleaned properly. Then screen printing, curtain coating, electrostatic spraying... On the other hand, the liquid light green paint is applied on the surface of the plate, and then the pre baking drying. After cooling into ultraviolet exposure machine exposure, ultraviolet irradiation in green paint film transmission region will produce polymerization reaction (green paint in the region are preserved in the development step in later), using sodium carbonate aqueous solution coating film without developing light removal area. Finally, the high temperature baking to make the green paint in the tree ester completely hardened. The early green paint is the use of screen printing after direct thermal drying (or UV irradiation) so that the production of film hardening. But because of the resulting green paint penetrated into the copper surface contact line terminal on the printing and hardening process usually produce welding parts and problems in use, now in addition to simple straightforward use of printed circuit board, which can be produced by light green paint.
In the production line of the image transfer as inner line, but in the etching is divided into positive and negative two production modes. The negative mode of production as inner line production, after developing direct copper etching, the film is complete. The positive mode of production is in the developer after plating two copper and tin lead (lead tin in the region will later be preserved as a copper etching step etching resist corrosion to copper foil), remove the membrane by alkaline ammonia and copper chloride mixed solution will be exposed, the formation of the line. Then the tin lead stripping liquid tin lead layer stripping (retire after winning merit in the early had retained the tin lead layer, the energy used to coated circuit as a protective layer, are not used).
After the formation of the interlayer conducting hole, the metal copper layer is needed to be arranged on the interlayer to complete the conduction of the interlayer circuit. In severe and high pressure washing brush grinding way to clean dust and lint holes on the then Potassium Permanganate solution for removing rubber residue on the surface of the hole wall copper. Soak up the tin and palladium colloid layer on the clean hole wall, and then restore it to palladium. The circuit board is immersed in a chemical copper solution, and the copper ions in the solution are reduced and deposited on the hole wall by the catalysis of palladium metal to form a through hole circuit. The copper layer in the through hole is thickened to resist the thickness of the subsequent processing and the impact of the environment in the way of the copper plating bath.
The circuit board is used to drill through the through hole of the interlayer circuit of the CNC drilling machine and the fixing hole of the welding part. When drilling through holes previously drilled to the target circuit board is fixed on the drilling machine platform with a pin, and the flat pad (phenolic resin plate or wood pulp board) and the upper cover plate (aluminum) to reduce the occurrence of drilling well.
After the completion of the inner circuit board must be glass fiber resin film and the outer circuit copper foil adhesive. Before pressing, the inner plate needs to be treated by black (oxygen), so as to increase the insulation of the copper surface, and to make the inner surface of the copper wire rough so as to produce good adhesion with the film. The inner superposed circuit board six layer lines, containing more than was paired with rivet riveting machine. And then put it on the plate, and put it in the mirror steel plate, into the vacuum press in the appropriate temperature and pressure to harden the film adhesive. After the pressure circuit board with X light automatic positioning drill drill hole hole as the reference target drone for outer line alignment. And the edge of the plate to do the appropriate cutting, in order to facilitate subsequent processing.
