Rigid Double-sided FR4 PCB Prototype
Two common method for PCB circuit etching
Etching refers to putting copper clad laminate depicted circuit into the etching solution to corrode the excess copper foil parts and eventually form a circuit board.The common two methods of PCB circuit etching are as follows.
1.Etching by iron trichloride solution
(1) take a corrosion-resistant container that can hold the circuit board, such as a small plastic basin, put proper amount of ferric chloride (generally solid), and add 2 to 3 times of water, which can submerge the copper-clad laminate that needs to be etched completely.The proportion of ferric trichloride with water is not strictly required. If the concentration is higher, the etching speed is faster.
(2) put the copper clad plate depicted circuits into ferric chloride solution, and the uncovered copper foil part on the copper plate will be gradually corroded away.To speed up the corrosion, the container can be shaken so that the ferric chloride solution flows.
(3) pay attention to the etching process. As long as the bare copper foil has been corroded clean, take out the copper-clad laminate in time and rinse it with clean water to prevent excessive corrosion.
2.Electrolytic salt water etching
(1) take a container of corrosion resistance with proper capacity, add 1 tablespoon of salt and appropriate amount of water to cover the copper-clad laminate that need to be corroded completely.
(2) at any point of the copper foil exposed on the copper-clad laminate, a 20cm or so of solder wire is welded as the electrolytic positive electrode lead (because copper wire as the electrode lead will be corroded off).If the copper foil exposed on the copper plate is divided into several parts by circuits, a solder wire shall be welded from each part of the copper foil, and these solder wires shall be connected together as the positive electrode lead.
(3) take a copper sheet about 2cm*3cm as the electrolytic negative plate, and weld a piece of wire as the negative electrode lead.
(4) put the copper plate and negative plate into the salt water, and note that the copper-clad laminate and negative plate cannot touch each other.The positive and negative electrode leads are connected to the adjustable DC power supply. Gradually adjust the power supply voltage from low to high. When there are blisters on the negative plate and yellow-green flocculation (copper oxide) is produced in the copper foil part of the copper plate, it indicates that the electrolytic etching has started.
(5) after the electrolytic etching is completed, take out the copper-clad laminate in time and rinse it.