Electronics Forum | Wed Oct 31 21:52:10 EDT 2007 | davef
We wouldn't expect the ceramic of the capacitor to conduct very much heat. [We're surprised how high the thermal conductivity of Al2O3 is: (30W/m-�C).] Can we assume that you're talking about parts that are defective at incoming inspection?
Electronics Forum | Fri Nov 02 10:57:11 EDT 2007 | 85638
7500 mm3 in combination with very small devices like 0402 in the same assembly ?. I am facing profiling problems due to this extreme mix. Thanks in advance for your valuable inputs.
Electronics Forum | Sat Nov 03 09:42:13 EDT 2007 | davef
There is no such standard, nor should there be. BIG boys [and girls] solder products like this. What temperatures are you measuring on the terminations of these components?
Electronics Forum | Fri Nov 02 19:02:28 EDT 2007 | yshiau
Hi experts, 1) Do you think a non-operating temperature cycling would do good for screening some marginal BGA joints? 2) If yes, what the exterm temperatures I should go? 3) Any particular profile that is suitable for my need? Thank you!!
Electronics Forum | Sat Nov 03 09:29:17 EDT 2007 | davef
IPC-9701, SMT Solder Joint Reliability Qualification and Performance Standard is an update of D-279, Design Guidelines For Reliable SMT PCA that includes BGA and PbFree
Electronics Forum | Thu Nov 08 22:27:52 EST 2007 | jkhiew
Did the PTH barrel ends in massive copper clad ? If yes this type of poor thermal layout topside heating is often recommended.
Electronics Forum | Tue Nov 13 22:20:50 EST 2007 | davef
We'd add poor thermal recipe development, focusing on some QPF but not others that may a have a peculiar plating that requires extended time above liquidus.
Electronics Forum | Wed Nov 28 06:52:33 EST 2007 | davef
So, you're curing glue on a thermal recipe intended for reflow even though your supplier recommends that you cure at 150C, because you want to use paste that isn't necessary.
Electronics Forum | Mon Jan 14 08:52:09 EST 2008 | geb
Have you considered metal Clad IMS PCBs rather than ceramic ones? "The circuits can be shaped drilled and formed, an advantage when compared to ceramic based product." Have a look at DK Thermal Solutions website http://www.dkthermal.co.uk
Electronics Forum | Wed Dec 26 19:45:06 EST 2007 | weekong
Delta T is the temparture different between the highest and lowest measured point on a profile. Ramp and cooling rate should not exceed 4deg c/sec to prevent thermal shock to the components and pcbs. This will also minimise delamination.
.gif)