Soldering SMD - Page 1
Forum section: electronics / beginners

author: banedon
author_rank: Regular Contributor
timestamp: July 02, 2015, 08:20:15 pm
content: Hi guysI'm trying to improve the quality of my soldering and was after some opinions regarding my latest effort. Mostly, I seem to struggle with SMD components as I have very little experience (having soldered only two ICs up until now) and find that things become a little too fiddly.The other issue is that I was wondering what the optimal temperature of the iron should be when directly sodlering IC legs? For the moment I use 340 deg C, try not to leave the tip in contact with an IC leg or pad for more than 2-3 seconds if I can help it. I'm also using 0.5mm 60/40 Rosin core lead-free solder. I'm also using 1.6mm tip and the iron is a Weller 80W temp controlled solder-station.Here's a couple of pictures. Please keep in mind that it's not as tidy as I would like as I fear heating the IC too much: BTW I had to put the metal link in between the IC and the top of the appropriate pin header due to a manufactured induced track break in the PCB.

author: KJDS
author_rank: Super Contributor
timestamp: July 02, 2015, 08:28:39 pm
content: That looks ok, might help if you use a little liquid flux

author: banedon
author_rank: Regular Contributor
timestamp: July 02, 2015, 08:41:40 pm
content: Quote from: KJDS on July 02, 2015, 08:28:39 pmI've got a flux pen which I've been using to coat the pads with.

author: Fat
author_rank: Regular Contributor
timestamp: July 02, 2015, 09:29:32 pm
content: Couple of things 60/40 is not lead free. I consider that to be a good thing. Lead free requires a hotter iron. I leave my station at 340 degrees C most of the time. I really prefer 63/37, but my current supply is all 60/40. I have not had much success with the flux pens and have been using no clean flux in a syringe. To me that's way better than the pens. I do a bit of surface mount work and I use a Hakko 888 iron with a 0.8mm tip. Some people like the bigger tips for SMD, I guess it's all what you learned with. I do use a 1.2 mm for my general soldering. I tried one of the Hakko crab type with the divot in the face. That's the cat's a$$ for SMD work. I think they are the BC or BCM series.Fat

author: xrunner
author_rank: Super Contributor
timestamp: July 02, 2015, 09:37:11 pm
content: Quote from: banedon on July 02, 2015, 08:20:15 pmYou might want to skim this thread and see if there are any hints you can use -https://www.eevblog.com/forum/projects/smd-soldering-practice-boards/

author: LabSpokane
author_rank: Super Contributor
timestamp: July 02, 2015, 09:44:25 pm
content: Try more or a more aggressive flux and bit less solder. Honestly, those joints look pretty decent. Better fluxing will help less solder flow better. For small stuff, usually all the solder I need will wick off my iron - particularly with HASL finished PCBs.

author: VK5RC
author_rank: Unknown
timestamp: July 02, 2015, 11:27:59 pm
content: Those joints look ok (prob better than mine) I occ use a very fine solder wick after to tidy up, then a bit of a clean, ipa on a fine cotton rag, be careful not to lift pins/pads with the solder wick, regards Rob

author: savril
author_rank: Regular Contributor
timestamp: July 03, 2015, 12:38:45 am
content: I wouldn't judge your soldering as I'm a beginner too (but I look OK to me). But why did you make a bridge on the pin connected to the breadboard 13 row ? Did you lift a pin ? (well, it happen).If you want to go farther, I would suggest to try drag soldering (you can find some videos on youtube and I think Dave made some too in his soldering series). I've done it with a special spoon tip designed for that and a chisel tip. It's easy if you're not shy on flux (and if your board has a solder mask like your adaptor board). I found it easier to have a equal amount of solder on all the pins and it is also much much faster (that will make your day). Sometime you'll have solder bridges but it is easy to remove with some flux and a chisel tip pulling the solder to the exterior.Did you used a conical tip or a chisel tip ? If you're using a conical tip I would suggest to switch to a chisel tip and either do it pin by pin or by drag soldering.

author: banedon
author_rank: Regular Contributor
timestamp: July 03, 2015, 07:05:18 am
content: Thanks for replying, guys. I've just purchased a 1.6mm and also a 0.8mm (both spade) tips and am using the 1.6mm for now.The link that you're seeing was needed due to the board itself having a defect (the pad is ok). I thought rather than just throw the board away that I might as well put the link in. Seems to be ok.I'll have a look through that SMD soldering ink (have already watched Dave's videos on soldering).My main concern was that things didn't look super neat and there's a few solder spikes - which leads me on to concern about how long I can heat the IC's pin and the pad.But if the iron temp looks ok and no one can see anything major then I'm happy.Thanks again.

author: wasyoungonce
author_rank: Frequent Contributor
timestamp: July 03, 2015, 10:43:36 am
content: Pre-solder the pads, use de-solderwick to ensure not too much is left on the pad but after awhile you know how much to pre-tin pads (use a fine gauge solder) with this step.Place down IC, square it up, hold it down heat with iron tip on top of one end leg and pad till flows. Now do a a diagonal opposite leg. Now do other legs, they all line up! Cheats way but works especially on fine pitch stuff.

author: GreyWoolfe
author_rank: Unknown
timestamp: July 03, 2015, 11:46:42 am
content: Banedon, switch to the .08 mm tip. Your pin by pin soldering will be easier. I also agree with the more aggressive flux. I use MG Chemicals RA liquid flux in a squeeze bottle and a hypodermic needle for when I need better control. I also use .031" 63/37 solder. I believe your temp is fine, that's where my iron is set. Where did you get that board, it looks very interesting.

author: agehall
author_rank: Frequent Contributor
timestamp: July 03, 2015, 02:10:59 pm
content: Quote from: GreyWoolfe on July 03, 2015, 11:46:42 amPretty sure you are off by a factor of 10 there. 0.8mm is tiny, 0.08mm is virtually non-existing..

author: tggzzz
author_rank: Super Contributor
timestamp: July 03, 2015, 02:17:39 pm
content: Personally I use 60:40 solder paste and the skillet method. It has worked well for me.More details, including sundry equipment (e.g. magnifiers) athttps://entertaininghacks.wordpress.com/category/homebrew-pcbs/especially the "assembling" page.

author: Fat
author_rank: Regular Contributor
timestamp: July 03, 2015, 04:24:29 pm
content: Quote from: tggzzz on July 03, 2015, 02:17:39 pmI also like the solder paste for SMD. Built a reflow oven using the RocketScream controller. It works very well and is a fast way to do multiple components, but when I only do one or two SMD components I just use the Hakko 888 with a 0.8 or a crab tip. Easier than going to the fridge to get the paste.

author: tggzzz
author_rank: Super Contributor
timestamp: July 03, 2015, 04:56:04 pm
content: Quote from: Fat on July 03, 2015, 04:24:29 pmFor the odd component or mod requiring more solder, I use paste plus 0.5(?)mm tip on a dirt-cheap temperature controlled soldering iron.

author: GreyWoolfe
author_rank: Unknown
timestamp: July 03, 2015, 05:00:29 pm
content: Quote from: agehall on July 03, 2015, 02:10:59 pmyes, I meant .8 mm

author: banedon
author_rank: Regular Contributor
timestamp: July 03, 2015, 06:07:02 pm
content: Quote from: GreyWoolfe on July 03, 2015, 11:46:42 amIt's a set of adapter boards which I sourced from a China via ebay. They were really cheap. I got the turned pin headers seperately.http://www.ebay.co.uk/itm/271649487453http://www.ebay.co.uk/itm/121463024213I'll also swap to the 0.8mm tip as recommended

author: banedon
author_rank: Regular Contributor
timestamp: July 04, 2015, 03:16:02 pm
content: Are you guys sure about the 0.8mm tip? It's getting close to being conical by the looks of things. Here's the 1.6mm and then 0.8mm side-by-side

author: Fat
author_rank: Regular Contributor
timestamp: July 04, 2015, 03:57:38 pm
content: Yeah, it's almost conical, but it does have the 0.8mm flat chisel. I really like them.

author: nanofrog
author_rank: Super Contributor
timestamp: July 04, 2015, 04:07:42 pm
content: How does the tips you're using compare to the pad size?They should match, not be over or under sized if at all possible. For example, you should keep a 1.2mm, 1.6mm, 2.4mm, and 3.2mm chisels at a minimum for general purpose PTH & SMD work IME (I use a WSP80 iron).Hakko'sRecommendations for Selection of Tip Sizeexplains it rather well IMHO (photos really help).And If you look a little closer near the top of the page, it also has the ability to show you what each tip shape can be used for or show you the appropriate/recommended tip profile by operation.Makes it an excellent resource.

author: Rasz
author_rank: Super Contributor
timestamp: July 04, 2015, 04:15:54 pm
content: Quote from: nanofrog on July 04, 2015, 04:07:42 pmThat might sound nice, but in practice its a lot easier to use bigger tips and drag solderalso for smd I recommend hotair over iron, especially if you are replacing components

author: savril
author_rank: Regular Contributor
timestamp: July 04, 2015, 05:16:36 pm
content: Quote from: Rasz on July 04, 2015, 04:15:54 pm+1 for tip size. If your tip is just the size of the pad, you have to align precisely your iron to the pad. With bigger tip, you have some margin. Also they have a bigger thermal mass and heat up faster the pads than smaller ones. I mostly use a 2.2 mm chisel for SMD.