Electronics Forum | Mon Dec 20 21:01:12 EST 2004 | davef
Bare inconel is NOT ment to take solder, because * Nickel develops a tenacious oxide layer that is very difficult to remove since the nature of the oxide is very dense, coherent, etc. * Chromium is difficult to solder. * Iron is difficult to solder.
Electronics Forum | Fri Aug 21 14:29:37 EDT 1998 | Earl Moon
| HASL: (hot air solder leveling) is a process used to cover the Cu. Either Sn/Pb is used or Ni/Au or some other combo. In one case you create a land pad and in the other (with resin)you cover the Cu so that you only have a "trace." Is that correct s
Electronics Forum | Wed Aug 12 12:32:56 EDT 1998 | Rich Croteau
Have an SRT w/preheat, 18 layer board all copper, 456 BGA needs to be removed and replaced. The manufacturer is Chip Express and during reflow it warps up or down. Causing either opens or shorts on the corners. I was using gel flux with multiple p
Electronics Forum | Fri Nov 03 11:30:29 EDT 2017 | davef
regarding dwl comment, "For low volume hand assembly, deionized water or IPA should work fine." Deionized water: Deionized water is corrosive. It needs to be removed. Proof? Drop a copper coin into a covered jar of DI water and watch what happens ov
Electronics Forum | Tue Aug 07 19:32:40 EDT 2007 | davef
Zinc from the brass diffuses into the solder and reacts with tin causing dezincification. Dezincification is a specific type of de-alloying, or selective, leaching corrosion of brass fittings. This type of corrosion selectively removes zinc from th
Electronics Forum | Sat Aug 22 12:18:12 EDT 1998 | Tryin'
| Board shops and us, the user, have a lot on our hands. As far as getting traces - this is done using an etch resist before solder mask and the HASL processes are performed. So when in the process is HASL performed?? | With tin/lead plated boards,
Electronics Forum | Sat Mar 04 03:48:26 EST 2023 | researchmfg
We had sucessful removed the solder mask by laser machine and got good result and quality without damage the copper layer. You may refer to youtube here by https://youtu.be/cQHaE3_fiqw
Electronics Forum | Thu Jan 06 08:03:47 EST 2005 | davef
On solder in vias: It looks like the via are not solder masked well and pick-up solder either: * Solder coating ... OR * During leveling It's possible that the design specifies openings in the solder mask for these via. On solder in the unsupporte
Electronics Forum | Thu Jul 05 21:42:28 EDT 2001 | davef
Most of our boards are fabricated with solder mask over bare copper [SMOBC], but we have couple where the solder isn't removed before masking. And ever so offin they's a liddy bit mo' solder than we'd like, which when reflowed, ends-up connecting so
Electronics Forum | Tue Feb 02 14:42:55 EST 2010 | davef
smt_guy: In removing passivation coats and handling oil, board fabs do light washes with: * Sulfuric acid * Alkaline * Water ... and then blow dry. They do not see "oil" like you seem to be talking about. Their "oil" is the assumption that someone
