I. different definitions
1. Solder layer -- solder mask refers tothe part of the printed circuit board to be covered with green oil. In fact,this resistance welding layer USES a negative output, so after the shape of theresistance welding layer is mapped to the board, is not on the green oilresistance welding, but is exposed copper.
2. The welding aid layer is actually steelmesh -- paste mask, which is used for machine mounting. Its main function is tohelp solder paste deposition; The purpose is to transfer the exact amount ofsolder paste to the exact location on the empty PCB
.
2. Different functions
1. The resistance welding layer is to opena window on the whole piece of green oil for resistance welding. The purpose isto allow welding.
2, the welding layer is used to make thesteel mesh for the steel mesh factory, and the steel mesh is on the tin canaccurately put the solder paste on the need to weld the smudge welding pad, isused for smudge packaging;
Three, the process is different
1. The resistance welding process is: theresistance welding material must be used by liquid wet process or dry filmlamination.
Dry film resistance welding materials aresupplied at a thickness of 0.07-0.1mm (0.03-0.04 ") and are suitable forsome surface mount products, but are not recommended for close spacingapplications. In general, the resistance weld opening should be 0.15mm (0.006") larger than the disc. This permits clearance of 0.07mm (0.003 ")on all sides of the pad.
Low profile liquid photosensitive bondingmaterials are economical and are commonly specified for surface mountapplications, providing accurate feature sizes and gaps.
2. The welding layer (steel mesh) is madeby chemical etch, laser cutting and electroform.
Chemical etch -- data file PCB→ film production → exposure → development → etching → steel sheet cleaning → net;
Laser cutting -- film production PCB→ coordinate → data file → data processing → laser cutting → polishing → net;