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Reflow Profile Library
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Low-temp bismuth alloys still cold-joint on large ground pours.
Process / Thermal / DocumentationProfiles11 characterised
MethodThermocouple trace
AlloysLeaded, SAC305, Bi
StartedMar 2026
Progress90%
The question
How much does the right reflow profile actually change joint quality, measured rather than assumed?
Where it stands
Nine of eleven profiles are characterised and reliable. The remaining two are both low-temperature bismuth alloys, which cold-joint on boards with heavy copper pours because the pour sinks heat faster than the profile’s soak compensates for.
03Bench log
12 Jul 2026
Thermocouple rig built — four channels, board-mounted.
20 Aug 2026
Nine profiles signed off with cross-section photos.
09 Sep 2026
Bismuth failures isolated to boards with >40% pour coverage.
04Next step
Next
Extend soak time on the bismuth profiles and re-test on a deliberately heavy pour. Publish as a Field Note.