Take the double-sided circuit board as an example to introduce the PCB production process to readers, as follows:
1. The purpose of cutting: According to the requirements of the engineering data MI, cut into small pieces to produce plates on large sheets that meet the requirements. Small sheets that meet customer requirements.
Process: large sheet → cutting board according to MI requirements → curium board → beer fillet \ edging → plate out.
2. Drilling purpose: according to the engineering data (customer data), drill the required hole diameter in the corresponding position on the sheet material that meets the required size.
Process: stacked board pin → upper board → drilling → lower board → inspection \ repair
3. Purpose of copper sinking: Copper sinking is to deposit a thin layer of copper on the wall of the insulating hole using a chemical method.
Process: rough grinding → hanging board → automatic copper sinking line → lower board → dip 1% dilute H2SO4 → thickened copper
4. The purpose of graphics transfer: graphics transfer is to transfer the images on the production film to the circuit board.
Process: (blue oil process): grinding plate → printing the first side → drying → printing the second side → drying → exploding → shadowing → inspection; (dry film process): hemp board → lamination → standing → right Position→Exposure→Standing→Development→Check
5. The purpose of pattern plating: pattern plating is to electroplate a copper layer with a required thickness and a gold or tin layer with the required thickness on the bare copper skin or hole wall of the circuit pattern.
Process: upper board → degreasing → second washing with water → micro-etching → washing → pickling → copper plating → washing → pickling → tin plating → washing → lower board
6. Purpose of film removal: Use NaOH solution to remove the anti-electroplating coating film so that the non-circuit copper layer is exposed.
Process: water film: insert rack → soak alkali → rinse → scrub → pass machine; dry film: release board → pass machine
7. Etching purpose: Etching is to use a chemical reaction method to corrode the copper layer of non-circuit parts.
8. Green oil purpose: Green oil is to transfer the graphic of the green oil film to the board to protect the circuit and prevent the tin on the circuit when welding parts.
Process: grinding plate→printing photosensitive green oil→curium plate→exposure→exposure; grinding plate→printing the first side→drying plate→printing the second side→drying plate
9. Character purpose: A character is a mark that is easy to identify.
Process: After the green oil finishes → cool and stand → adjust the screen → print characters → rear curium
10. Gold-plated fingers Purpose: to plate a layer of gold on the plug fingers with a required thickness to make it more hard and wear-resistant.
Process: upper plate → degreasing → washing twice → micro-etching → washing twice → pickling → copper plating → washing → plating → washing → gold plating
(A parallel process) tinned circuit board purpose: spray tin is to spray a layer of lead tin on the bare copper surface that is not covered with solder mask to protect the copper surface from corrosion and oxidation to ensure good soldering performance.
Process: micro-erosion → air drying → preheating → rosin coating → solder coating → hot air leveling → air cooling → washing and air drying
11. Forming purpose: The method of forming the shape required by the customer through die stamping or CNC gong machine. Organic gong, beer board, hand gong, hand cutting. Description: The data gong machine board and beer board have higher accuracy, hand gong Secondly, the hand-cutting board can only do some simple shapes
12. Test purpose: Pass the electronic 100% test to detect defects that affect functionality such as open circuits and short circuits that are not easy to find visually.
Process: upper mold → release board → test → pass → FQC visual inspection → unqualified → repair → return test → OK → REJ → scrap
13. Purpose of final inspection: To pass 100% visual inspection of the appearance of the board and repair minor defects to avoid problems and defective boards from flowing out.