1) What do you mean by SMT?1) I'm pretty sure that parts will not fly away with SMT methods.
2) This study from Vishay Electronics is quite intersting, and MLCC caps are the weakest component of the PCB.
3) About solder paste thickness: if you check recommended soldering specifications you will be surprised on how much thin the solder layer should be.
If you're a hobbiest, then don't even consider using solder paste, unless you have a reflow oven. Just bump the pads with solder, apply paste flux, put the part on top of the bumped pads and then use TWO soldering irons with appropriate tips to reflow the part in place. This technique works quite well and leaves beautiful solder fillets. Then clean the flux residue as required.The problem is that you need to be a machine to lay down an exact amount of solder paste. Even with stencil the process is quite empirical for humans.That's an important drawback in SMT for little hobbyists like me. Sometimes, when you deposit a too thin layer, the solder can contracts and nothing remains under the pins (but you cannot visually check that!) Dangerous.
I use the tips as tweezers and hold the part. Another technique is to apply solder to one pad, then apply paste flux, then holding the part with a pair of tweezers, flow the chip into the solder. Now solder the other side.Good trick. Where you apply the two tips? On the part or on the solder?
Hot air guns have the tendency to blow parts all over the board. They are great at removing large parts like QFPs and BGAs. They are also useful at preheating a board that is being reworked. Heating a board to approx 150°F, especially for lead free boards, will make soldering and desoldering easier. Solder "squeeze away" is not a problem, provided a good flux is used. When you pull the tip away, the solder should still be molten. The surface tension will pull everything into proper alignment.
That is an interesting innovation.
Yesss, the PDF posted by thatoneguy is in my bookmarks since before yesterday.
Just remember to use the correct size pads. Pads that are too large will cause resistors and caps to tombstone on a production board during reflow.I'm designing a new PCB board with pads in place of holes for caps. Then I will make some experiments by using your techniques.
Usually - I tack a couple of pins diagonally opposite so its easy to re-melt the solder and position the chip very accurately and all the pins line up.
Take 10 minutes and learn the new techniques. Other than a second soldering iron, what additional "instruments and stuff" do you need?I always return back on this argument because to solder SMDs I have to learn a technique that is 100% new to me (as well as buy new instruments and stuff). On the other hand I feel my self quite able/smart in PTH soldering.
|Thread starter||Similar threads||Forum||Replies||Date|
|First time using a Voltage Regulator sanity check, plus decoupling capacitors questions||Power Electronics||37|
|B||noob filter/ decoupling/ bypass capacitor question||General Electronics Chat||2|
|Calculate Decoupling/Bypass Capacitor for a Delta sigma modulator||Power Electronics||11|
|capacitor in coupling & decoupling||Analog & Mixed-Signal Design||4|
|A||decoupling capacitor and Bulk capacitor||Power Electronics||2|
by Robert Keim
by Gary Elinoff
by Luke James
by Luke James