According to the placement accuracy requirements and the different types and quantities of components, the current program used the following categories: program 1, multi-chip mount: FPC by positioning multi-piece template located in the half on trust, and fixed to the pallet with the whole PCB Assembly
A, component types: the general volume of more than 0603 chip component, the pin spacing is greater than equal to 0.65 of the QFQ and other components can be. PCBA manufacturer
B, the number of components: Each component to the FPC a few dozen components.
C, placement accuracy: precision mounting medium.
D, FPC characteristics: larger size, there is no appropriate regional components, each piece has two FPC on the MARK for the optical positioning markers and two or more positioning holes.
2. FPC fixed:
Metal drain boards according to CAD data, pcb assembly China read within the FPC's location data, to produce high-precision positioning FPC template. The template FPC pins positioned on the diameter and match the hole diameter, and height of 2.5mm or so. FPC and template there are lower sales of two pallets. CAD data according to the same manufacturing batch of pallets. Pallet thickness of about 2mm is better, and the material after repeated thermal shock warpage is smaller, in order to better FR-4 materials and other better quality materials. Prior to the SMT, the first pallet the pallets on the template set pins, so that the pins through the holes on the exposed pallet.
FPC units will be a piece of insurance PCB Assembly reform in the exposed, and with the thin high temperature adhesive tape located in the pallet, let FPC are offset, and then let the pallets with the FPC and template separation, printing and mounting welding, high temperature tape (PA protective film) stick to moderate pressure, high temperature must be easy to strip after impact. And no residue glue on the FPC.
Of particular note is fixed to the pallet FPC welding began to mount between the printing and storage time as short as possible.