The open and short circuits of PCB circuit boards are almost daily problems encountered by PCB manufacturers, which have been troubling production and quality management personnel. We have accumulated some experience in improving the open and short circuits of printed circuit boards. We have now written a summary of the discussion on PCB manufacturing. I hope it can serve as a reference for colleagues engaged in production and quality management.

Firstly, we have summarized the main reasons for open circuits in PCB circuit boards as follows:

The reasons and improvement methods for the above phenomenon are as follows:

Exposure substrate:

There are scratches on the copper coated laminated board before storage.

2. The copper-clad board was scratched during the punching process.

During the drilling process, the copper composite plate was scratched by the drill bit.

4. The copper-clad laminate was scratched during transportation.

When copper foil is stacked after sinking, improper operation may cause surface damage.

6. The copper foil on the surface of the production board is scratched when passing through a horizontal machine.

Improvement method for open circuit of PCB circuit board:

IQC must conduct spot checks before entering the warehouse to check for scratches on the surface of the copper-clad board. If so, promptly contact the supplier and handle according to the actual situation.

2. The copper-clad board was scratched during the tapping process. The main reason is that there are hard and sharp objects on the surface of the tapping machine worktable. When struck, the copper-clad board and sharp objects are scratched to form an exposed substrate. Therefore, before tapping, the surface of the workbench must be carefully cleaned to ensure that it is not a hard and sharp object.

During drilling, the copper-clad board was scratched by the drill bit. The main reasons are wear and tear of the spindle clamp, or some impurities in the clamp that are not clean. The PCB sample cannot firmly hold the drill bit, and the drill bit cannot reach the top, which is less than the length of the drill bit group. The height added during the drilling process is not enough. When the machine tool moves, the drill tip wipes the copper foil to form an exposed substrate. Fixtures can be replaced by the number of times they are recorded or the degree of wear of the fixture. Regularly clean the fixtures according to the operating procedures to ensure that there are no impurities in the fixtures.

4. The metal plate was scratched during transportation: When moving, the gearbox lifted too many plates at once, and the weight was too heavy. When moving, the board is not lifted, but dragged along with the trend, causing friction between the corners and the surface of the board, and scratching the surface of the board. When the board is placed down, the surface of the board is scratched due to friction between the boards.

5. Scratches caused by improper placement or stacking of copper plates after electroplating: When the plates are stacked together after placement and electroplating, their weight is not small. When laying the board, the angle of the board is downward, and there is gravitational acceleration, which forms a strong impact force on the surface of the board, causing scratches on the surface of the board and exposing the substrate.

6. When producing soft and hard composite boards using a horizontal machine, they may be scratched. The baffle of the grinder sometimes touches the surface of the baffle. The edges of the baffle are usually uneven, and sharp objects are lifted. The surface of the baffle was scratched when passing through the plate. Stainless steel transmission shaft. Due to damage from sharp objects, scratches and exposure occur on the surface of the copper plate when passing through it.