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Date: | Fri, 01 Nov 1996 06:54:00 -0500 (EST) |
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Once the wave soldering process is optimized (DoE), then the SPC plan should
monitor the critical parameters. You might try generating control charts for
things like preheat temperatures, conveyer speed, flux density, solder
temperature, etc. The SPC philosophy is that once these critical parameters
are in control, your process is in control.
Monitoring solder defects is a way of determining how well your SPC plan works.
This also will shed some light on what external factors affect (or effect?)
your process like solderability, environmental conditions, etc. What we do is
inspect the first piece of every lot (or run) and plot % defects based on the
number of soldering defect opportunities... usually the number of PTHs.
Hope this helps...
Jim Marsico
(516) 595-5879
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