Almost all the non-trivial SMT parts are on the same side, but not quite. All the BGAs and QFNs are on the same side of the PCBs, except for two 28-pad QFN chips (max8717s). And I have oodles of 0603, 0402 and 0201 bypass capacitors and a few less funky packages on the opposite side too (less funky meaning I can see and touch the leads (like SO8, SOIC, TSSOP).NleahciM:
Please tell me that all leadless ICs (BGAs, LGAs, QFNs, DFNs, etc) are on one side of the PCB. If that is the case, a hot plate should be enough to do your prototypes. Getting the BGA to solder properly will require experimentation. I’d recommend getting some scrap PCBs to practice on. If you have leadless parts on both sides, a hot plate will probably not work, especially considering the large size of one of your PCBs. In that case, a pre-heater and a hot air station will do it, but it will be trickier.The keyword here is practice. You’re gonna have a few dead boards. Maybe many.
All the “heavy” (BGA) parts that might “fall off” if inverted in a reflow oven are on the same side. Actually, I just received the parts, and I am rather amazed at how tiny and lightweight even the biggest, baddest, heaviest component is. Even the 256-ball BGA is a tiny featherweight little thing. Working on the PCB layout at 3200% to 10,000% obviously distorted my impression of how tiny these things are. I can barely even see the 0201 bypass capacitors unless I take my glasses off so I can look closer (5.50 diopters).
Absent some vibration or jarring, I’d bet solder surface tension would keep even those components on the bottom side of the PCB in a reflow oven, if necessary. However, no need for that, except perhaps for those two teenie weenie little 5mm square QFNs, which weight about 1/10 gram, I’d guess.
Do you think the extensive “practice” and “scrap” is mostly due to “placement precision errors”? Or “overheating and thereby destroying components”? Or what? And what is the best way to avoid those problems (besides a $30,000 pick-and-place machine)?