Oooo, thanks for the conversion. Being metrically challenged, az a skratchin ma haid thar fer a mite. We do a G-10 160 thou and have similar issues.
Now, we�ve talked about barrel fill [ie, slowing belt speed, increasing pre-heat temps, etc] before. And this aint one-a-doz, because we already tried all that stuff a couple months ago. It�s a: * Bin blanked by the designer. * Exhausting the flux before hitting the wave, which is not a good thing ... pikes, bridges, etc.... * So, how much higher than 500�F [260�C] should I go? * Setting the wave depth so low, I could crack a walnut betwixt my cheeks, while watching the board go deep into the wave. In other words, it's a DEEP mamajama!!! And that�s with stiffeners added.
Then try these tricks ... * Turn on the chip wave. * Try a foam fluxer. * Flux, preheat, then flux, preheat, then wave. * Paint flux on the primary side before loading the machine.
Next, you�ve got to convince yourself that these are not process problems by: * X-raying the connections. * Doing destructive analysis of the solder connections.
When all else fails and we can�t follow IPC 75% hole fill rule, we waive the rule, based on: * Theory #1: If 50% of a 0.060" thick board (0.030") is OK, then a 25% hole fill of a 0.150" thick board (0.0375") would also be OK. * Theory #2: For most applications, the 75% rule is overkill. There are tens of thousands of single-sided PCB [= 0% fill] in under-the-hood automotive applications [the worst loading environment for the most common applications] that, unless there are some other dumb design features, last the life of the car.
Be interesting to see which theory your customer bites on, eh?
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