Reasons for Copper Rejection in PCB Lamination of Vacuum Laminator
Under normal circumstances, as long as the high temperature section of the laminate is hot pressed for more than 30min, the copper foil and the prepreg will be basically bonded, so the bonding will not affect the bonding force between the copper foil and the substrate in the laminate generally. However, in the process of laminating and stacking, if PP is polluted or the rough surface of the copper foil is damaged, the bonding force between the copper foil and the substrate after laminating will also be insufficient, resulting in positioning (only for large plates) or sporadic copper wire falling off. However, there will be no abnormality in the peeling strength of the copper foil near the measuring line.
Poor adaptability of copper foil and resin: some laminates with special properties, such as HTg sheet, are now used. Due to different resin systems, the curing agent used is generally PN resin. The resin molecular chain structure is simple, and the degree of crosslinking during curing is low. Therefore, copper foil with special peak value must be used to match it. When the copper foil is used in the production of the laminate, it does not match the resin system, resulting in insufficient peeling strength of the metal foil on the sheet, and poor copper wire falling off during the plug-in.
More technical information: http://www.szvstar.cn