Inspection, Testing and Partitioning of Flexible Circuit Board
Because the carrier plate absorbs heat in the furnace, especially the aluminium carrier plate, the temperature is higher when the furnace is discharged, so it is better to add forced cooling fan at the outlet of the furnace to help the rapid cooling.
At the same time, the operator should wear heat-insulating gloves to avoid being scalded by high temperature carrier plate. When taking the FPC from the carrier board to complete the welding, the force should be uniform, and brute force should not be used to prevent the FPC from being torn or creased.
The removed FPC is inspected visually under a magnifying glass of more than 5 times, focusing on the surface residual glue, discoloration, tinning of golden fingers, tin beads, IC pin blank welding, continuous welding and other issues.
Because the surface of FPC can not be very flat, which makes the misjudgment rate of AOI very high, FPC is generally not suitable for AOI inspection, but through the use of special testing tools, FPC can complete ICT, FCT testing.
Because FPC is mostly connected boards, it may be necessary to divide boards before testing ICT and FCT. Although using tools such as blades and scissors can also complete dividing boards, the efficiency and quality of operation are low and the scrap rate is high.
If it is the mass production of special-shaped FPC, it is suggested that special FPC stamping parting die should be made for stamping partition, which can greatly improve the efficiency of operation. At the same time, the edge of the blanked FPC is neat and beautiful, and the internal stress produced during stamping and cutting is very low, which can effectively avoid solder joint tin crack.
In the process of assembling and welding PCBA flexible circuit board, the precise positioning and fixing of FPC is the key point, and the key to fixing is to make suitable carrier board. Secondly, the pre-baking, printing, patching and reflow soldering of FPC.
Obviously, the SMT process of FPC is much more difficult than rigid PCB, so it is necessary to set the process parameters accurately. At the same time, strict production process management is equally important. Operators must be ensured to strictly implement every rule of SOP. Follow-up engineers and IPQC should strengthen patrol inspection, find abnormal situation of production line in time, and analyze the original. In order to control the defective rate of FPC SMT production line within dozens of PPMs, necessary measures should be taken.
