When you're building your own embedded electronics, it is pretty much inevitable that eventually you are going to solder something in backwards/upside-down/in the wrong place. It's going to happen. If it's never happened to you, color me impressed. But for those of us mere mortals, there are times when a bit of rework is necessary. That's where we often turn to our trusty hot-air rework stations.
So today we wanted to share the above video (and this tutorial) to help you learn how to use hot-air to rework with the best of them. We've found that using hot-air is one of the fastest, least destructive ways to do rework. We hope you find the video useful! What tricks do you use to do rework? Let us know in the comments!
David you do a fantastic job on your videos! One small suggestion is slow down a bit. You sound like you are needing to use the restroom in a hurry which tends to happen to people on video for some reason. But keep the fantastic videos coming please!
Thanks for the kind words! I do tend to talk pretty fast, especially after a few cups of coffee :) I've been working on slowing it down, and I think the next few videos will be a marked improvement. Cheers!
Although I have a hot air re-work station, I usally use chip-quick more than the station. I feel it puts less thermal stress on the IC.
I prefer chip-quick as well. I do sometimes have to combine it with the hot air station for larger packages, 144 pin QFN or large power supply chips, but for most chips the heat from the iron keeps it wet long enough to remove the chip. Also a big plus the lower temperature used keeps you from damaging the PCB or the components around what your reworking. I've had nearby electrolytic capacitors pop when just using a rework station.
Link to chip-quick: https://www.sparkfun.com/products/10925
Thanksn a lot for the tuto !! Would appreciate having a vimeo version of the video. Youtube is very slow for me. Thanks again.
Two questions:
Can I use hot air to rework PTH components?
Can I use the hot air gun to set my heat shrink tubing? :)
1.) Yes, you can use the hot air to rework PTH components. I personally use the tapping method for PTH rework before heating the board with hot air. You first cut the excess pins on the legs of the component. Then place the board on a third hand parallel to a table. Heat up the solder and pad with your iron with one hand. Then holding the third hand with the other, you tap the third hand against the table. The excess solder should come out through the via's hole from the sudden stop. Once you are done tapping the excess solder out, it should be easier to pull the component out by touching your iron at each via. If you have multiple legs, you could use the hot air gun to heat the area and lift the component off.
One thing to note is that your pads become fragile as you heat the pads. You need to make sure that the solder on the legs have melted before pulling, otherwise you run the risk of pulling a pad.
2.) Yes, you can use it to heat shrink the tubing.
Hope this helps! ^_^
A good production tip is to hold the end of a solder line at the end of the nozzle when waiting for the machine to heat up. When it starts melting, you know it's hot enough.
All this talk of rework is just a bunch of hot air.
Will the hakko hot air nozzles fit on this?
Just looking at the datasheet on the soldering temperature / duration is not enough for high reliability applications as this assumes that the parts were new and were not exposed to high humidity conditions. If the components were exposed to high humidity conditions for long time periods, it is possible to permanently damage them by rapidly heating them above 100 degrees C. The moisture in the plastic package turns to steam and can cause damage to the die bonds among other things. Some manufacturers have recommended practices for using hot air reflow to solder the parts once the components have been exposed to humidity. Using chip-quick when this will work instead of heating the entire IC may offer less chance for board damage as well as damage to the internals of the IC. However, chip-quick won't work on BGA packages or other packages where the solder points for the IC are hidden under the IC itself.
Excellent point! All components have an MSL (Moisture Sensitivity Level) which defines the baking requirements prior to subjecting the part's body to reflow temperatures if it has been exposed to ambient room environments, not just high humidity environments. New, unused parts with MSL ratings above 2 are always sealed in moisture barrier bags with dessicant and a humidity indicator card. Once placed, the MSL level is no longer a concern unless the part will be subjected to the reflow temperatures, for example, rework. Datasheets for parts will typically denote the MSL level for the part which also denotes the baking time/temps required prior to rework.
Its kinda funny I own a IR Rework station with heat plate and find myself using the hot air rework station the most, even jobs were the IR station would benefit. I just feel I have more control over the area being heated so i won't damage anything and i can use it while under the microscope. Sparkfun should offer more nozzles (unless I haven't found them)
In unrelated news, I'm wondering if you guys had anything to do with this: http://news.yahoo.com/blogs/sideshow/ufos-over-denver-maybe-175541305.html
If we did, no one knows (or is admitting to know) about it currently. It would be cool to find out what was used for it though.
For multi-pin IC, hot air rework is the way to go. But for discrete surface mount parts (caps, inductors, resistors), etc. you can use a solder iron to remove it. Add a lot of solder on both pads, and quickly move your iron from one pad to the other, gently pushing your iron in towards the part when you are on each pad. It only takes about 3-4 seconds of going back and forth for your iron to push the part out.
I typically use this technique when I'm building up boards since I don't have the hot air rework station turned on and ready to go.
Silicone, not silicon...
Silicone, silicon.... It all sounds pretty 'Silly' to me!
I would guess that turning the temp down for cooldown wouldn't actually be necessary once the power switch is turned off - the heater should be completely disabled anyway. Turning the fan up is a good idea.
You are correct. It's just easier to turn it off. The air automatically turns up a little to discharge the hot air, quicker. No need to turn down the heat.
I need those tweezers. Long and slim, keep my hands out of the way.
Im still rocking the Solder pump and Wick. Maybe i should change... Rework Looks fast and quite easy. Thanks!
Both techniques have their place, and pump and wick is necessary for cleaning out the holes after you remove the part with hot air.
Still, a good hot air rework is worth its weight in...something more valuable than dirt, but way less valuable than gold. Candy bars?