At present, there are two general FPC welding processes, one is tin press welding, and the other is manual drag welding.
It is generally recommended to use tin press for pressure welding, which has the advantages of flat welding, less false welding, short circuit and other defects. Disadvantages are: high cost, plate design needs to consider component typesetting. Next, we mainly introduce the relevant processes of manual butt welding:
Manual drag welding refers to the manual use of electric soldering iron and tin wire to weld the solder together. For FPC welding, Oki soldering iron and a tin wire are recommended.
The main sequence of FPC welding is: FPC paste alignment - tin delivery and drag welding - visual inspection - electrical testing.
FPC pasting alignment: before pasting alignment, check whether the FPC pad and the corresponding solder surface are flat and oxidized. Note that after pasting, the pad must expose about 1.00mm of wire feet to facilitate tin loading.
Main control time and location
1. Time: before tinning, the soldering iron must be put on the pad for 2-3s to fully heat the FPC and pad, which can effectively prevent false soldering;
2. Position: the inclined direction of soldering iron and golden finger is about 30 degrees.
There are four main control points for tin feeding and dragging welding:
1. Time: generally, the recommended time is 3S / the length of soldering iron head, about 4-10s;
2. Temperature: 290-310 ℃;
3. Tin feeding position: the position of tin should be better if the soldering iron head is inclined to the pad;
4. Strength: when the soldering iron head is in contact with the parts, a little pressure shall be applied, based on the principle of no damage to the golden finger.
Appearance inspection:
1. The tin point forms an inner arc;
2. The tin point shall be complete and smooth without pinholes and rosin stains;
3. Wire feet shall be provided, and the length of the wire feet shall be between 1mm;
4. FPC shape shows that tin has good fluidity;
