FPC, also known as flexible circuit board, FPC PCBA assembly welding process and hard circuit board assembly is very different, because the FPC board hardness is not enough, relatively soft, if you do not use a special plate, can not complete the fixation and transmission, also can not complete the printing, patch, furnace and other basic SMT process.
FPC board is relatively soft, usually not vacuum packaging when leaving the factory. It is easy to absorb moisture in the air during transportation and storage, so it needs to be pre-baked before SMT casting line to slowly and forcibly expel moisture. Otherwise, under the impact of high temperature of reflow welding, the moisture absorbed by FPC quickly turns into steam to highlight FPC, which is easy to cause FPC layering, foaming and other defects
The pre-baking conditions are generally 4-8 hours at a temperature of 80-100 ° C. Under special cases, the temperature can be raised to above 125 ° C, but the baking time should be shortened accordingly. Before baking, be sure to test the sample first to determine if the FPC can withstand the set baking temperature. Consult the FPC manufacturer for the appropriate baking conditions. When baking, the FPC stacking should not be too much. 10-20PNL is suitable. Some FPC manufacturers will put a piece of paper between each PNL for isolation. It is necessary to confirm whether the paper for isolation can withstand the set baking. Temperature, if it is not necessary to remove the separator, then bake. The FPC after baking should have no obvious discoloration, deformation, lifting and other defects, and it is necessary to pass the IPQC sampling test before the line can be cast.
