High density spends what the mixture technology of installation assembles to increase, drive the innovation of a lot of craft. Tailor-made " dot " or " face " wave crest solders the amount of equipment is increasing. Solder optionally tray (Pallet) now more the wave crest that is used at the tradition widely solders on the machine. There is what had soldered on the underside that these tray are assembling in the light of those, large, temperature is sensitive array of bar of active component, ball (BGA, the via component of Ball Grid Array) and QFP(quad Flat Pack) .
Two kinds of older to be being mixed developmentally PWB are designed, new different solderability protective agent is getting wave crest solders with circumfluence the close 眛 of craft. Traditional sirocco soldering tin all besmears (HASL, craft of Hot Air Solder Leveling) , although can have profit to weldability commonly, but exist with developmental design and craft a problem. In entered PWB, the likelihood is in block solder layer (HASL is being absorbed to aid welding flux hangover to wash craft to avoiding in Solder Resist) have a problem. The requirement is used as a child the air pressure that excessive soldering tin keeps clear of in via, perhaps besmearing two of plating apparently pressure are differred, cause sometimes the ply of HASL coating is different between face and face. This differs to bring about very thin on a few surface features that should solder coating possibly. The likelihood is answered the solderability that causes inadequacy and solder dissatisfactorily expression, should use those who have aggressivity to solder even aid welding flux.
Be in to achieve any solder the small ratio of defects in craft, final coating must offer the appearance of PWB and component terminal abiding solderability. Coating must be endured before soldering store time and environment, and for many times temperature itinerate and do not degrade. Soldering the short frit in craft is wet (Wetting) time asks to use exterior component to injure with a few weld defects. Because PWB is every soldering join to supply exterior in part, it must be shown last and enough solderability feature.
Organic solderability protective agent (OSP, organic Solderability Preservative) mixes all sorts of passing to electroanalysis it is with the metallic coating of employ of dip plating craft in a lot of circumstances the proof is the most satisfactory. The solderability protective agent that any use must be satisfied continuously assemble with solder the demand of craft and ask product reliability.
