What quality problems are most likely to occur in the production process of PCB board?

With the rapid development of science and technology today, various high-tech electronic products emerge in an endless stream, which makes PCB manufacturers more and more stringent on the quality of the board. So, what quality problems are most likely to occur in the production process of PCB board? 1. The difference in the warp and weft directions causes the size of the substrate to change. Solution: Determine the warp and weft direction, and compensate on the negative film according to the shrinkage rate; at the same time, process it according to the fiber direction when cutting, or process it according to the character logo provided by the manufacturer on the substrate. 2. The copper foil on the surface of the substrate is etched away, and the size changes when the stress is relieved. Solution: When designing the circuit, try to make the circuit on the entire board evenly distributed; at least it is necessary to leave a transition section in the space (mainly without affecting the circuit position). 3. Excessive pressure is used when brushing the board, resulting in compressive and tensile stress and deformation of the substrate. Solution: Test brush should be used to make the process parameters in the best state, and then perform rigid board. 4. The resin in the substrate is not completely cured, resulting in dimensional changes. Solution: Take baking method to solve. In particular, bake before drilling, and bake continuously for 4 hours at a temperature of 120°C to ensure that the resin is cured. 5. The storage conditions of the multilayer board before lamination are poor, so that the thin substrate or the prepreg will absorb moisture, resulting in poor dimensional stability. Solution: The inner layer of the substrate is oxidized, baked to remove moisture, and the processed substrate is stored in a vacuum drying box. 6. When the multilayer board is pressed, excessive flow of glue causes deformation of the glass cloth. Solution: need to perform process pressure test, adjust process parameters and then press. At the same time, according to the characteristics of the prepreg, the appropriate amount of glue flow can be selected. The above are the most prone quality problems in the production process of PCB boards. Do you know all of them?