Is there any secret people use to successfully solder the STM32F4? About half of my boards come out with solder bridges. I can cut down the size of the paste stencils, but I’m worried about open disconnects. Do you guys have any soldermask between pins on the package?
Just a cheap Chinese desktop model we got off eBay for a few hundred bones. Are you suggesting there’s a problem with my reflow oven’s settings? I couldn’t imagine what that would have anything to do with.
@ jay - What solder paste are you using? Leaded or lead free, No-Clean or watersoluble. A 5mil thick screen is the right thickness. The openings on the screen, are they 100% to the pads, if so reduce the opening size by 10%.
Leaded solder (I can’t remember specifically what I’m using right now, but I think it’s 63/37). I think it’s no-clean flux in the paste.
The pads have been reduced by 10%.
I’ve never had any problems with soldering, and all the other parts on the board come out beautifully.
I’m using N-sized (nominal) landing pattern (not the high-density one).
I might try shrinking the stencil’s pads for that particular part a bit more.
Any other ideas?
I’m using a pretty hot profile (my stupid reflow oven doesn’t seem to solder all the boards properly if I use a cooler profile for the 63/37 solder), but intuitively, I’d think a hotter oven = better soldering.
You only need an oven if you’re building lots of boards or soldering chips with hidden pads (BGAs, chips with thermal pads, etc). A scope is way more useful.
I’d say get whichever you need more urgently. If your design works and you don’t need to debug anything then a scope isn’t going to give you anything except another toy to play with. If your design works and you need to assemble a bunch then an oven will be more useful. If your design doesn’t work and you need a scope to fix it then an oven is going to be useless…
Haha, well, those two things are also in widely different price brackets. You can get a perfectly functional reflow oven for less than $300, but a decent oscilloscope costs quite a bit more than that.
EDIT: I guess I’m seeing quite a few used (but decent) 100 MHz DSOs on eBay for roughly the same price. Never mind! Get both!
in AU at least, the DS1052E isn’t being sold in numbers - the 100mhz variant DS1102E is only $80 more (that’s the genuine way to get 100mhz). Although my eyes have been more than a little taken by the DS2072 at a bit over double the DS1102 price ($923 vs $439 inc tax)