What are the difficulties in the production of soft and hard boards

Rigid-flex board is a circuit board with FPC characteristics and china PCB characteristics formed by combining flexible circuit boards and rigid circuit boards through processes such as pressing and combining them according to relevant process requirements. However, the manufacturing process of the rigid-flex board is more complicated, and some of the key technologies and difficulties are more difficult to control. Due to the different structure and materials of the soft board and the hard board, the difference in size expansion and contraction between the two is obvious. Therefore, the selection of the appropriate soft-hard board material is very important, and the main purpose is to ensure a good alignment. So, what are the manufacturing difficulties of the rigid-flex board?

Soft board part:

1. Rigid PCB production equipment makes flexible PCBs. Due to the soft and thin material of the flexible PCBs, all horizontal lines of the flexible PCBs need to be carried by a traction board to avoid scrapping of the card.

2. The positioning holes are punched by OPE, and the single-chip processing before lamination also has a great influence on the alignment between layers. Since the polyimide material is not resistant to strong alkalis and swells in strong alkali solutions, in the process of black and browning treatments, in the strong alkaline process such as degreasing, blacking, browning, etc., the temperature and Reduce the time.

3. Because the flexible single sheet is easy to deform, the flatness before lamination is poor, and the resin fluidity of the adhesive sheet used is much lower than the prepreg used for rigid board lamination. Therefore, in order to make the adhesive sheet and the single sheet good combination And embedded in the fine line spacing, we choose to use materials with better covering shape as the laminated gasket material, such as polypropylene film, polytetrafluoroethylene (PTFE), silicone rubber sheet, etc., which can improve the layer of the flexible board.Quality.

Hard board part:
1. Regardless of whether it is substrate pressing or pure prepreg pressing, it is important to note that the warp and weft directions of the glass cloth should be consistent, and the thermal stress should be eliminated during the pressing process to reduce warpage.

2. The expansion and contraction control of the soft and hard board. Due to the poor expansion and shrinkage stability of the soft board material, it is necessary to give priority to the production of the soft board and the laminated PI cover film, and the hard board part is made according to its expansion and shrinkage coefficient.
3. For the processing of the flexible window, there are usually milling and milling after the processing, but it needs to be processed flexibly according to the structure and thickness of the rigid-flex board itself. If the flexible PCB window is milled first, it should be processed. To ensure the accuracy of milling, neither the welding nor the deflection should be affected too much.