Through the explanation in this article, we have learned about the various raw materials and operating tools required for the production of PCB double-sided boards, as well as the issues that need to be noted in different production processes.

1、Design

PCB engineers should draw circuit diagrams based on the circuit design scheme and use electronic computer-aided design software to automatically generate layouts. Traditional manual drawing means single-sided plate making. Therefore, the double-sided plate drawing must be made using a computer. When designing, attention should be paid to layout and avoid overcrowding to avoid affecting the size of the board's appearance.

2、Plate making

1. Preparation of raw materials

When making PCBs, raw materials such as printed circuit boards, UV photosensitive coatings, UV exposure machines, and etchants are required. Different types of printed circuit boards should be selected according to specific situations, generally including fiberglass boards, PHEN boards, CEM, etc. UV photosensitive coatings are divided into single-sided and double-sided, and double-sided UV photosensitive coatings are selected according to the needs of double-sided boards.

2. Applying UV photosensitive coating

Pour the UV sensitive coating into a container and stir evenly. Then, use a silver scraper to apply approximately 5 millimeters of paint onto the circuit board. If the coating is insufficient, a lighter layer can be applied to make the entire board uniform. When coating, it is necessary to ensure that there is no wind in the environment and leave the board under a UV lamp for a few minutes to let the paint dry.

3. Exposure

Place the printed circuit diagram in the position of the printed board, and place the board with double-sided UV photosensitive coating into the exposure machine. Adjust the parameters of the exposure machine, such as exposure time, UV lamp power, etc. Start the exposure machine and wait for the corresponding time.

4. Development

After exposure, place the board in the developer and add the developer to the developer. Soak the board in the developer solution until the coating is exposed, indicating the outline of the circuit.

5. Etching

After development, excess copper foil needs to be removed, which requires an etching machine. The etching solution is mainly a mixture of sulfuric acid and hydrogen peroxide, and its chemical formula requires very fine precision. When working, place the developed circuit board into the etching solution for 10-15 minutes, then remove the board and clean the surface of the etching solution and residual developing solution with flowing water.

3、Printing

Printing is a crucial step in double-sided PCB production. Common double-sided printing methods include traditional pinhole positioning printing and fine placement positioning printing. The characteristic of printing on double-sided boards is that there is an electrical connection between the two layers.

4、Manufacturing

1. Drilling

Process circular or elongated holes on the board for the installation of plugins. In the process, the material, size, design, smoothness, etc. of the drill bit need to be carefully selected, and the drilling tool project should not be a small trick.

2. Plugins

The idea of inserting the through-hole part into the connector and using brazing or electrical contact points to connect the ink printed part was also explained in detail for the reuse of Type 14 waste at that time.

3. Testing

To ensure stable quality of PCB boards, it is necessary to test each double-sided PCB board. The commonly used testing methods include visual inspection, card insertion, static electrical testing, high voltage testing, heat shock testing, and more.