PCB News - Method of making circuit with rapid corrosion

Using 30% hydrogen peroxide (hydrogen peroxide) and industrial hydrochloric acid to prepare the corrosive solution at a ratio of 1:3 is a good way to make printed circuit boards. However, the precautions and methods in the production have not been specifically explained. The following is a supplementary explanation based on practical experience.

1. Matters needing attention

1. This method releases a small amount of chlorine during the corrosion reaction. The operation should be carried out in a ventilated place, and the operator is best to stand at the windward to avoid chlorine poisoning.

2. This corrosive liquid has a fast reaction rate and should be prepared in strict accordance with the proportions and operating methods. If the proportion is too improper, it will cause boiling and cause liquid water to overflow out of the pan, causing accidents.

3. It is best to use a glass plate to hold the corrosive liquid for corrosion, so as to observe the corrosion status at any time.

Two, the preparation method of etching liquid

The industrial hydrogen peroxide (hydrogen peroxide) with a concentration of 31qo and the industrial hydrochloric acid with a concentration of 37% and water are prepared in a ratio of 1:3:4. During operation, pour four parts of water into the dish, then pour three parts of hydrochloric acid, stir evenly with a glass rod, then slowly add one part of hydrogen peroxide, continue to stir evenly with a glass rod, and the printed copper Put the corrosive solution on the foil and it will be corroded in about five minutes. Take out the corroded copper foil board and immediately put it in clean water to rinse and dry it before use. During the corrosion process, the circuit board can be shaken to accelerate the corrosion rate.

3. Concentration adjustment of hydrogen peroxide and hydrochloric acid

The concentration of the products purchased in the chemical store is mostly higher than the required concentration and is not suitable for direct preparation. So how to dilute? The calculation method of the solution dilution threshold is as follows: divide the difference between the size of the molecule by the small molecule and multiply the amount of the solution, and then the amount of water should be added. For example, if the existing concentration of 85% hydrochloric acid solution is 500ml, how many milliliters of water need to be added to release it to 37%? the way is:

The size difference is 85-37=48; divided by the small molecule is: 48÷37≈1.3; to multiply the solution volume by 1.3*500=650ml, you need to add 650ml of water. After adjusting the required concentration, it can be prepared according to the above ratio.

Compared with using ferric chloride, this method has the advantages of fast corrosion rate, low cost and simple operation. Especially suitable for making large area printed circuit boards. Even people who use this method for the first time can produce exquisite and beautiful circuit boards as long as they follow the operating requirements.

The above is an introduction to the method of making circuits with rapid corrosion. Ipcb is also provided to PCB manufacturers and PCB manufacturing technology