Flexible pcb solder paste printing

Flexible pcb does not have any special requirements on the solder paste composition. The size and metal content of the solder ball are based on whether there is the fine pitch IC on the flexible pcb. However, the flexible pcb has high printing performance requirements for the solder paste, and the solder paste should have excellent properties. Superior thixotropy, solder paste should be able to print off the mold easily and firmly adhere to the surface of the flexible pcb, without the problem of poor mold release, clogging of the stencil, or collapse after printing.

Because the flexible pcb is loaded on the carrier, the flexible pcb has a high temperature resistant tape for positioning, so that the plane is inconsistent, so the printed surface of the flexible pcb cannot be as flat as the PCB and the thickness is the same, so it is not suitable to use a metal scraper, but the hardness should be 80. -90 degree polyurethane type scraper. The solder paste printing machine preferably has an optical positioning system, otherwise it will have a great influence on the printing quality. Although the flexible pcb is fixed on the carrier board, there will always be some slight gap between the flexible pcb and the carrier board, which is biggest difference compared with the rigid PCB. So the setting of the device parameters will have a greater impact on the printing effect.

The printing station is also the key station to prevent the flexible pcb from being dirty. It is necessary to wear finger cots. At the same time, it is necessary to keep the station clean and clean the stencil to prevent the solder paste from contaminating the flexible pcb's gold fingers and gold-plated buttons.