How to Solder QFN MLF Package by Hand (Using a Hot Air Rework Station) | Digi-Key Electronics
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- เผยแพร่เมื่อ 3 ก.ค. 2024
- Soldering some surface mount components, such as QFN and MLF, can be very difficult by hand. These parts do not have leads that extend beyond the component body, which can be nearly impossible to reach with a soldering iron. In this video, we will demonstrate one way to solder a QFN component by hand using a hot air rework station.
A written guide showing these steps can be found here: www.digikey.com/en/maker/proj...
I recommend using no-clean flux and no-clean flux core solder if you do not have access to cleaning equipment that can get under the component. Pre-tin the pads on the PCB using a soldering iron. Try to get the layer of solder to be as even as possible among all pads.
Liberally apply flux to all of the pads and place the part on the footprint, doing your best to carefully line up the part pads with the footprint pads. You might need a microscope or loupe to visually inspect the alignment. You can tape a thermocouple probe near the part to get an idea of ambient temperature.
I set my hot air station to 300°C and 50-60% air flow. You might need to experiment with these numbers to get a good solder reflow without blowing your part off the board.
Start with your hot air nozzle a few inches above the component and draw circles over the PCB to “soak” the board. You want the PCB to reach a temperature of about 150°C over the course of 1-2 minutes.
Slowly lower the nozzle to about ¼-½ inches above the component, and continue to draw circles so that hot air is equally applied to all pads. The solder should reflow in 15-30 seconds, and you should be able to lightly tap the part using some tweezers. The surface tension of the solder should keep the part in place (for the most part).
Once you are satisfied with the part alignment and believe that all of the pads have made a good solder connection, slowly lift the hot air nozzle away from the part while continuing to draw circles. You want the part to cool to 150°C over 15-30 seconds. From there, you can let the board air cool.
Solder the rest of the components and test your board!
You can find the KiCad PCB design files for my custom QFN board here: github.com/ShawnHymel/ldo-pow...
This is the QFN part I used in the video: www.digikey.com/en/products/d...
Product Links:
Hot‐Air Rework Station 303D - www.digikey.com/en/products/d...
FX-888D Digital Soldering Station - www.digikey.com/en/products/d...
Related Videos:
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Related Project Links:
www.digikey.com/en/maker/proj...
www.digikey.com/en/maker/proj...
www.digikey.com/en/maker/proj...
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I must have watched hundreds of hot air SMT reflows. This is the first one I've ever seen somebody use a Fluke 87V temperature probe to monitor the board temperature. So simple, but genius!! Learn something new everyday. 😁
Not the board temperature, though. Ambient temperature.
I was pinching myself, because my Fluke 179 multimeter already came with a temperature probe. I can try adding this temperature probe method *today*. ＼(＾O＾)／
Thanks! I very seldom find myself really being a fan of a company. But being that my shop is full of your boxes. And you have always been great at shipping, accurate orders, ship small and large orders just the same, low shipping prices, ect. You are a great company.
Thanks! this filled in a number of holes in my spotty knowledge about doing hot air rework. Things that were glossed over by pretty much everything else I'd found in the past.
thx, nice video. going to try my first SMD component changes on my DAC, this is very helpful.
Very helpful, straight forward tips camera angle not to bad. looking forward to next one.
Thanks a lot, this is much appreciated
nice tie buddy !
If your part is not fresh out of packaging and has been sitting around - tin the pads on the part too !!, This will increase the chance that all pads make contact with the board. You can thank me later. If you do this for a living you don't need this or temp probe because you bust the temp to 400C and know that the part will be just fine :-)
Good tip, thank you!
Great tutorial! I've managed to solder qfn for prototypes using a heat gun and a solder paste (the paste appears to have a lower melting point than a regular soldering tin). I've applied the solder paste on pads, placed the ic on top of it, and then heated it from the bottom from about 1-2 inches. The heat gun must be on a decently low power to prevent burning the pcb (literally burning it), and there must be no components on the bottom side because they will be blown away. Of course the pcb will be hot, so it's a good idea to make some simple holder.
This is definitely the better approach, as it not only allows the reflow process to be monitored better, but also means that less high temperatures are required for it.
Thanks for sharing because I had asumed that QFN parts could just not be soldered by hand without expensive equipment.
it's possible to solder by hand except for the pad underneath. if your ic does nod draw a lot power it might be fine to just ignore the pad and it should still work. I soldered for example cp2102 usb uart chips by hand and they worked great.
cool stuff
I replaced my first smd like component yesterday, a bunch of burned out mosfets on the back of a drone flight controller. Was a lot easier than I thought but putting the right amount of solder paste on the board with enough flux to sit the component in the right place was hard, I had a donor board that I was stealing components from and it was a good job I did because I ended up having to redo a couple of mosfets cause they burned themselves out the second power was reapplied. I don't have multimeter probes that are fine enough to test the mosfet pins. So....accidents happened :)
small tip use a hollow point tip for the small pads. Also with the via's take a hig termal iron. And if your lucky the via's and pad should connect with solder
SOMETIMES if you put enough flux on the bottom of the part and the board you could apply solder to the board and it will flow via surface tension under the part and stick to the bottom pads. That's one way to solder QFN parts with a soldering iron. YMMV ALOT with this one!
'Sometimes' is not good enough.
Great Vid, especially the slow temp warming before hitting with enough to melt and make connections .
I about to try a tiny 1285A reg chip which is only a couple of mm's so pretty small. should i use same tech and temps and time? i worry about overheat insides of chip but have a few spare. Never soldered a chip this small but it makes 3.3 and 5v and about 21 pins and central earth so have to dab solder on that too. Should be fun!!
Great tutorial. Why did you use solid solder instead of solder paste? Surely that would be easier to use?
I can do that with a soldering iron. EAsy! Recently i did some much more difficult metal can transistors. Not easy! But pulled it off. Take some solder wick and load it up with some solder or use used wick and add a bit. Add solder balls (by tinning the pads) to the underside but not too big, use flux, add plenty of flux above and beneath the component. Now with the component placed well you can heat the wick with the soldering iron while holding it with tweezers. The tricky part is removing the wick without knocking the component about. Enjoy!
Excellent tutorial. Can't wait to try it myself. Perhaps there is a practice kit I can buy. I bought a budget hot air gun that works well but does not have an air flow adjustment. I am frustrated that I did not know enough to make sure it had this feature.
Thanks! You can use the gerbers from the board I made here (github.com/ShawnHymel/ldo-power-board) or you can buy a practice kit like this one: www.digikey.com/en/products/detail/chip-quik-inc/ST0001/5978217 (it only has 1 QFN part, though)
Holy shit ! Crazy
can you demonstrate QFN-15?
What is the size of the solder wire at 5:18 ? Thanks in advance
it'd be cool to use a thermal camera instead! expensive as hell tho
I think I killed my STM32 with excessive heat tho D: or maybe the pcb has a problem HMM
where can I get QFN-15 stencils ?
I didn't know Clark Kent teaches electronics
why not use solder paste?
Wonder what luis rossman thinks
@@Kevin-mp5of Rude. Might as well not comment at all tbh. Like for real whats your problem?
@@Kevin-mp5of Wow okay....
@@Kevin-mp5of Stop harassing me. I'll do what I want.
Who's Luis Rossman?
I'd rather make a custom reflow station:
th-cam.com/video/39ij7f1OWtc/w-d-xo.html
Love your videos and content. I'm leaving TH-cam due to censorship. Hence, unsubscribed.
Not so impressed with the soldering job on the small parts. Perhaps get a navy vet with 2m quals. Also, while Zephyrtronics system seem expensive, you really should be using this grade of equipment for the pro audience and the bottom feeder for the one off hobbiest. You would also have better results and fewer steps with a good solder paste.
The problem is your hand.
I ordered some components and almost Immediately i needed to add another
component. They said they couldn't do this (shortly after my original
order) and suggested I had to make another order (And pay a huge 26$
shipping fee). Terrible customer service. I suggest you work on this before posting videos!
I've purchased parts for prototype products for years from them. Generally we'd blast an order in before their closing time and expect a.m. delivery. Once the wheels are in motion they are hard to stop. I wouldn't fault customer service for this. A company with a somewhat slower pace may be in a better position to help.
My friend, get rid of that rubbish iron and rubbish hot air. You have a room filled with Keysight and Fluke, you can afford a proper iron and a proper hot air. A Miniware TS80P iron (and a bent round tip for doing this kind of fine works, preferably also a knife tip for general purpose) with a Miniware MHP30 preheater and a Quick 957DW hot air can do wonderful things, even on some rather large boards like computer motherboards, all for less than $400. Also for the sake of love, treat yourself with a pair of Fluke TL910 probes.