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 FAQ's

  . COMPONENTS (8 fragen)
  . HAND SOLDERING AND DE-SOLDERING (3 fragen)
  . INSPECTION (3 fragen)
  . PRINTED BOARD DESIGN (3 fragen)
  . PRINTED CIRCUIT BOARDS (6 fragen)
  . REFLOW SOLDERING (5 fragen)
  . REWORK (1 fragen)
  . SCREEN PRINTING (2 fragen)
  . WAVE SOLDERING (4 fragen)
  . X-RAY INSPECTION (1 fragen)





INSPECTION

1 . Can you show me typical examples of lead-free solder joints?
2 . During inspection we have seen some lifted solder fillets after wave soldering, is this common and is is a reliability concern?
3 . When I first start to receive boards with lead-free solder joints what inspection criteria should I use?

 

Can you show me typical examples of lead-free solder joints?
Yes there is a link to example solder joints on each of the common terminations with different solder alloys which should help. Generally the solder joints will look slightly duller than tin/lead and have a slight orange peel (matt) effect on the surface of the solder.
See Leadfreejoints.pdf.

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During inspection we have seen some lifted solder fillets after wave soldering, is this common and is is a reliability concern?
Depends on who you talk to. I often see what we refer to as fillet lifting on through hole joints after wave soldering. Testing of boards that contained fillet lifting like the example did not show any failures after 2200 cycles of -55/+125oC.
To date it’s an issue that we don’t seem to be able to eliminate totally in production.

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When I first start to receive boards with lead-free solder joints what inspection criteria should I use?
SMART Group, for example, has inspection CD-ROMs and poster sets of all the different joint types that can be used in manufacture.
IPC 610 D is an inspection standard for conventional and surface mount which also covers lead-free terminations and could be considered. One example of a J lead termination is shown soldered with tin/silver/copper alloy.

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