EEVblog Electronics Community Forum
Electronics => Manufacturing & Assembly => Topic started by: PerranOak on September 26, 2021, 01:23:01 pm
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I am increasingly using SMD parts but find desoldering them is a mega pain.
I’m guessing that the best way to do it is with a heat gun?
Any advice/recommendations gratefully received.
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This was just recently discussed.
https://www.eevblog.com/forum/beginners/desoldering-smd-braid-or-hot-air-station/ (https://www.eevblog.com/forum/beginners/desoldering-smd-braid-or-hot-air-station/)
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So long as the SMD parts are typical passives (0805 resistor or what have you) or chips with outward pointing leads (SOT-23, TSSOP, QFP...), soldering braid can work pretty well with just a normal iron. This becoems impossible though when you've got packages with connectors actually on the underside (BGA, QFN...), even on the underside right at the edge.
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They're all 1206 - I'm crap at soldering anything smaller - no QFN, etc.
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They're all 1206 - I'm crap at soldering anything smaller - no QFN, etc.
for two pin parts, get two soldering irons ...
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Unsoldering is actually a bit easier with smaller ones (0603 or 0805) than with 1206 or larger. Just heat both side and take off with stainless tweezers. With a suitable large tip one can heat both sides togehter an the part may stick to the iron instead of the board, when carefully pushing it sideways. So just pick from the iron.
No braid needed, more like additional solder.
2 soldering irons are an option if many parts are to be removed.
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For resistors, capacitors, etc. parts, I use the Hakko T18-K Knife tip
along the side of the component and sweep them off.
(https://res.cloudinary.com/iwh/image/upload/q_auto,g_center/w_auto,e_trim,c_fill,g_auto/assets/1/26/HakkoT18-K.jpg)
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For small components, this works quite well (unless it's like mine, I've found that in the scrap box with worn out tips and broken cord - cord fixed, new tips considered too expensive)
(https://www.eevblog.com/forum/manufacture/heat-gun-to-desolder-smd/?action=dlattach;attach=1284439;image)
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Great ideas, thanks all.
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A bit late to the party here (as usual), but I use a Weller 6966c heat gun with a 6958 baffle. I've always had great results.
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It depends on how many you have to do.
For rapid work, with minimal collateral damage, the twin soldering iron posted above by capt bullshot works superbly.
Hot air works fine for removing chips but frankly I would not use the removed chip afterwards since it probably got well overheated. If I had to remove SO or QFP chips and re-use them (I have such a job coming up actually, a few hundreds H8/332 processors which got soldered without the OTP EPROM having been programmed, years ago) I would get the proper size tool. Then the chip can be cleaned up and re-attached.