I've had no trouble with JLCPCB on boards with all-0402. I wonder if your paste mask needs adjustment? I have had a few soldering issues from JLC, but only on QFNs (and in particular with some very tiny ones - my paste mask was definitely wrong initially, causing the part to 'float' on the centre pad, but still some failures on some batches but not others after I had fixed that). The bottom line is that they are running everything on a standard profile with no scope for adjustments, so you have to make your project fit their process - and accept some variability in it - rather than vice-versa.
My normal preference for anything I intend to hand solder is all-0603 apart from decouplers that I go 0402. That lets me have a big pile of decouplers on the bench and solder them to every 0402 footprint without worrying, while all the resistors have readable values on them at 0603 size and the other-value capacitors stand out from the decouplers. I don't find anything larger than 0603 to be materially more convenient.
I disagree with needing flux for all SMT soldering (if indeed that was the intended meaning of the comment above) - resistors and SOIC I solder pin-by pin with flux-cored solder. However, flux is mandatory for drag-soldering fine-pitch QFPs or TSSOP etc. I like ChipQuick's gel flux, and I also very much like their ultra-low-melting-point solder for desoldering (you flux, apply the special 'solder', then you can get all the pins melted at once and just flip the device off - leaving both device and board undamaged). I use hot air only when nothing else will do; for boards that I know will be hand-soldered, QFNs can be handled with extra-long pads so that you can get heat under there by applying the iron to the bit of pad that sticks out, and the belly pad can be sorted by having a large-ish PTH in the middle of it - large enough to get the tip of an iron in and solder pad to board directly from the bottom side, after doing all the pins round the edge.
Magnification is certainly very useful (especially for those of us with aging eyes), but for my eyes at least adequate light is most important, in extremis using a torch or whatever when forced to do soldering on-site. For workshop use, I like the anglepoise-style bench magnifier with a ring of light around it (mine has a toriodal fluroescent tube, but modern ones have LEDs), and I also have a Mantis microscope which is excellent for most purposes (again having lighting and magnification).
Though I've tended to make much less use of these craft techniques now that JLCPCB will assemble boards for me at a low cost....
Auto-routers: I've yet to find one worth using. For easy boards they work fine, but since it was easy already that's not much saving. For slightly harder boards you've got to sanity-check the output of the auto-router and that takes almost as long as routing it yourself. For difficult boards, the autorouter usually proudly proclaims "98% routed!" but that's completely useless as it has used up all the routing resources and you have no chance of fitting the last 2% in without ripping it all up and starting again. Better tools for manual routing (push and shove etc) have improved my productivity (I use Altium currently, though not sure how long I'm going to continue paying for it).
My normal preference for anything I intend to hand solder is all-0603 apart from decouplers that I go 0402. That lets me have a big pile of decouplers on the bench and solder them to every 0402 footprint without worrying, while all the resistors have readable values on them at 0603 size and the other-value capacitors stand out from the decouplers. I don't find anything larger than 0603 to be materially more convenient.
I disagree with needing flux for all SMT soldering (if indeed that was the intended meaning of the comment above) - resistors and SOIC I solder pin-by pin with flux-cored solder. However, flux is mandatory for drag-soldering fine-pitch QFPs or TSSOP etc. I like ChipQuick's gel flux, and I also very much like their ultra-low-melting-point solder for desoldering (you flux, apply the special 'solder', then you can get all the pins melted at once and just flip the device off - leaving both device and board undamaged). I use hot air only when nothing else will do; for boards that I know will be hand-soldered, QFNs can be handled with extra-long pads so that you can get heat under there by applying the iron to the bit of pad that sticks out, and the belly pad can be sorted by having a large-ish PTH in the middle of it - large enough to get the tip of an iron in and solder pad to board directly from the bottom side, after doing all the pins round the edge.
Magnification is certainly very useful (especially for those of us with aging eyes), but for my eyes at least adequate light is most important, in extremis using a torch or whatever when forced to do soldering on-site. For workshop use, I like the anglepoise-style bench magnifier with a ring of light around it (mine has a toriodal fluroescent tube, but modern ones have LEDs), and I also have a Mantis microscope which is excellent for most purposes (again having lighting and magnification).
Though I've tended to make much less use of these craft techniques now that JLCPCB will assemble boards for me at a low cost....
Auto-routers: I've yet to find one worth using. For easy boards they work fine, but since it was easy already that's not much saving. For slightly harder boards you've got to sanity-check the output of the auto-router and that takes almost as long as routing it yourself. For difficult boards, the autorouter usually proudly proclaims "98% routed!" but that's completely useless as it has used up all the routing resources and you have no chance of fitting the last 2% in without ripping it all up and starting again. Better tools for manual routing (push and shove etc) have improved my productivity (I use Altium currently, though not sure how long I'm going to continue paying for it).
Statistics: Posted by arg — Tue Apr 22, 2025 6:21 pm