2 Layer Blank PCB Board Quick Turn PCB
Drilling and surface treatment of the circuit board
After the circuit board is etched, drilling and surface treatment are required.
Drill mounting holes for components with 0.8mm~1mm drill at the circuit board pads, and drill the fixed holes and circuit board mounting holes of large components such as potentiometers, variable capacitors, transformers and so on with appropriate size drill.
For the circuit board made by knife cutting method, if the circuit is simple, the components can be directly welded to the copper foil surface, avoiding the trouble of drilling, making it easier to make.
2.Surface treatment of circuit board
(1) remove the mulch.For paint besmear layer, can remove carefully after boiled water blanching, also can use bamboo wooden chopstick to scrape to go.The marks can be rubbed off with alcohol or banana oil or ground with fine sandpaper.For polyester tape and other mulch, just remove it.
(2) remove the oxide layer of copper foil. After the circuit board is made, the oxide layer of the copper foil should be thoroughly cleared first. Normally, rubber can be used, so that the copper foil will not be damaged easily.
Some printed circuit board, due to be affected with damp or deposit too long, copper foil surface oxidizes seriously, not easy wipe clean with eraser, can polish gently with fine sandpaper first, reoccupy eraser next, till copper foil face is bright and clean like new.
(3) apply the soldering protective layer.It is best to apply a layer of rosin water to the circuit board for soldering protection. Rosin water is prepared by crushing rosin into powder and dissolving into 2-3 times alcohol.Some of the rosin water is thicker and more effective.
Dip a clean brush in rosin water and apply a layer evenly on the circuit board's copper foil, then air dry.The rosin water coating is very volatile and hard, and covering the circuit board is both a protective layer (protecting the copper foil from oxidation) and a good flux.