(1) Determine the variation pattern of the longitude and latitude direction and compensate it on the negative film according to the shrinkage rate (this work is carried out before photogrammetry). When cutting at the same time, process according to the fiber direction or according to the character markings provided by the manufacturer on the substrate (usually the vertical direction of the characters is the vertical direction of the substrate).

When designing the circuit, it is important to ensure that the entire board surface is evenly distributed as much as possible. If it is not possible, it is necessary to leave a transition section in the space (without affecting the circuit position). This is due to the difference in warp and weft yarn density in the glass fabric structure of the board, resulting in differences in the warp and weft strength of the board.

⑶ Trial brushing should be used to keep the process parameters in a state, and then the rigid plate should be carried out. For thin substrates, chemical cleaning or electrolysis processes should be used for cleaning treatment.

Adopt baking methods to solve the problem. Especially before drilling, baking should be carried out at a temperature of 120 ℃ for 4 hours to ensure resin curing and reduce deformation of the substrate size due to the influence of cold and heat.

The substrate with oxidation treatment on the inner layer must be baked to remove moisture. And store the processed substrate in a vacuum drying box to prevent moisture absorption again.

Process pressure testing is required, and process parameters are adjusted before pressing. At the same time, you can also select the appropriate amount of glue flow according to the characteristics of the prepreg