Reasons and solutions for open circuits on PCB circuit boards
How to improve? Open circuit and short circuit of PCB circuit board are problems encountered by multilayer PCB circuit board manufacturers almost every day, and these problems have always plagued production and quality management personnel. Problems caused by insufficient quantity of goods (such as replenishment, delayed delivery and customer complaints) are relatively difficult to solve. I have more than 10 years of working experience in the circuit board manufacturing industry, mainly engaged in production management, quality management, process management and cost control. We have accumulated some experience in improving open circuits and short circuits on printed circuit boards. We have now written a summary of our discussion on circuit board fabrication. I hope it can be used as a reference for colleagues engaged in production and quality management.
First of all, the main reasons for the open circuit of some PCB circuit boards are summarized as follows:
Cause the reason of above-mentioned phenomenon and improvement method are as follows:
Exposure substrate:
1. There are scratches before the copper clad laminate is stored. 2. The copper clad board is scratched during the blanking process.
3. The copper clad laminate was scratched during transportation.
4. The copper foil on the surface of the circuit board is scratched when it passes through the horizontal machine. 5. During the drilling process, the copper composite board is scratched by the drill bit.
6. When the copper foil is stacked after sinking, the surface is damaged due to improper operation.
Improve methods:
1. lQC must conduct a spot check before entering the warehouse to check whether there are scratches on the surface of the copper clad board. If so, contact the supplier in time and deal with it according to the actual situation.
2 Scratches caused by improper operation of copper plate sinking or stacking plates after electroplating: When the plates are stacked together after sinking and electroplating, the weight is not small. When laying the board, the angle of the board is downward, there is gravity acceleration, a strong impact force is formed on the surface of the board, scratches are produced on the surface of the board, and the substrate is exposed.
3. The metal plate is scratched during transportation: when moving, the transmission lifts too many plates at one time, and the heavy star is too large. When moving, the board is not lifted, but rather dragged with the trend, causing friction between the corners and the board surface, and scraping the board's surface. When the board is put down, the surface of the PCB board is scratched due to the friction between the boards.
4. The copper clad board is scratched during the tapping process. The main reason is that there are hard and sharp objects on the surface of the tapping machine table. When struck, copper-clad panels and sharp objects are scratched to create exposed substrates. Therefore, before tapping, the surface of the workbench must be carefully cleaned to ensure that there are no hard and sharp objects on the surface of the workbench.
5. When drilling, the copper clad board is scratched by the drill bit. The main reason is that the main shaft clip is worn, or some debris in the clip is not clean, the PCB proofing cannot hold the drill firmly, the drill cannot reach the top, is less than the length of the drill group, and the increased height during drilling is not enough, when the machine tool moves At this time, the drill tip wipes the copper foil to form an exposed substrate. Answer: The fixture can be replaced by the number of times recorded by the fixture or the degree of wear of the fixture. Clean the jig regularly according to the operating procedures to ensure that there are no impurities in the jig.
6. The production of FPC soft and hard combination board will be scratched when it passes through the horizontal machine. The baffle of the grinder sometimes hits the surface of the baffle. The edges of the baffle are often uneven and sharp objects are lifted. The surface of the baffle was scratched when passing through the plate. Stainless steel drive shaft. Due to damage from sharp objects, the surface of the copper plate is scratched and exposed as it passes through the plate.
