welding process acceptability requirements-j9九游会登录入口

welding
1.the nature of the welding process determines that an acceptable connection will exhibit the same characteristics for all three levels;
2.unacceptable connections are likely to be rejected for all three levels;
3.the type of welding process used has been specified in the appropriate description of the connection requirements;
4.whichever of the following welding methods is used, the connection requirements apply:
▸ soldering iron
▸ impedance welding equipment
▸ wave or wafer welding
▸ reflow soldering
▸ through hole reflow welding
5.exceptionally, there are some special welding surface treatments that require the establishment of different special acceptance conditions, which are not shown in the ipc-a-610f.
▸ immersion tin
▸ palladium
▸ gold
such special conditions should be based on design, process capability and performance requirements;

6.the main difference between the process of using tin-lead alloys and the solder connections produced by using lead-free alloys is:
▸ the appearance of solder joints
▸ this standard provides visual inspection requirements for tin-lead and lead-free connections;
▸ the legend that specifically refers to the lead-free connection will be identified by the symbol in figure 5-3.
7. lead-free alloys are more likely to show:
▸ rough surface (grain or gray)
▸ larger wetting angle
▸ other requirements for solder filling are the same

8. typical tin-lead connections
▸ satin-like moist surface
▸ smooth appearance
▸ present lubrication
▸ concave surface formed between objects to be welded
▸ high-temperature solder, may be dry-like
▸ modify (rework) must be judged to prevent other problems