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Forum Index : Microcontroller and PC projects : SOIC Soldering
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| Intellecta Newbie  Joined: 07/05/2016 Location: AustraliaPosts: 22 |
Dear All, Just a quick one re the ease of soldering. All of my past designs have taken into account that parts may be hand soldered and hence the standard footprints are not optimum. For example, if the pins on a TQFP part are slightly longer and there is exposed copper outside the actual pin, it is easy to run the iron over the copper and heat will be transferred to the actual pin. Flux and a reservoir of solder will assist this. We have designed many boards to take this into account. Now, look at the latest 28pinner design on Silicon Chip. It is almost impossible to solder the USB mini connector. The pins are hidden by the body and I cannot see the efficacy of the solder. I had to check the continuity with a meter. Then look at the two smd mosfets. THe pads could be a tad bigger to make it easier to solder. In conclusion, we should take into account the upstream manufacturing skill set in the design. That would remove some of the frustration and errors. Thanks Tony Pugatschew |
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| paceman Guru  Joined: 07/10/2011 Location: AustraliaPosts: 1329 |
Yes with many boards there's lots of scope to make things easier by modifying pads. The 1206/0805 combo is one of my favourites because it's simple to change either pad design to make using the alternate size possible. That way people who need to use the larger size because of their eyes can do so, but it also allows others who have their own 'catalogue' of 0805's to use them without having to double-up with 1206's. There is often also an issue with supply or cost of the different sizes, especially with caps - having the choice would make life easier. Another one is the USB connector - accessing the rear pads is often difficult and the choice between having to use a micro or mini can be a nuisance. Having the choice would be far preferable. Greg |
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| isochronic Guru Joined: 21/01/2012 Location: AustraliaPosts: 689 |
The usual B socket smd connector has a small metal cover plate shielding the pins. I have found that usually the plate can easily be removed by bending it out using a sharp edge to lever it a bit and then it breaks off. Careful not to mangle the pins ...makes it mucho easier. |
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Grogster Admin Group  Joined: 31/12/2012 Location: New ZealandPosts: 9083 |
Mini-USB-B connectors I am OK with, but the micro-USB sockets can be a bit of a pain!  Smoke makes things work. When the smoke gets out, it stops! |
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| Andrew_G Guru Joined: 18/10/2016 Location: AustraliaPosts: 842 |
I finally cleared away some other duties and got to use my new microscope to solder up my recently arrived LCD Backpack Mk2. It has a few SMD devices, including the mini USB referenced above, and some very small capacitors. They were all dead easy with the scope. Most satisfied! and can thoroughly recommend at least a x10 (and x30) one. Some observations: - my ageing hand/eye coordination fairly quickly adapted to the challenge but I did at first have to consciously think 'where are the tips of the tweezers'. Pretty quickly I could get both hands contributing. Practice will make better. - the overhang above the USB connectors didn't help but by angling the whole board up a little I could get a clearer view from the scope (which has only a vertical view). Doing this first helped (the comment about bending the metal plate hadn't yet been made but I wouldn't rush into doing that unless I was having trouble) - it was a bit like a flea circus with tiny black components 'spronging' everywhere - until I got my act together - the Blue Tack helps but you only need a tiny amount and it can leave a gooey mess to clean up (even not getting it hot - it would be impossible if it got hot). I'll keep experimenting and practicing. Cheers, Andrew |
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GoodToGo! Senior Member  Joined: 23/04/2017 Location: AustraliaPosts: 188 |
Some of the SD card sockets aren't much better either......  GTG!  ...... Don't worry mate, it'll be GoodToGo! |
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| Andrew_G Guru Joined: 18/10/2016 Location: AustraliaPosts: 842 |
In my post above they are of course transistors and not capacitors. Andrew (I couldn't see how to edit the above post rather than adding this one??) |
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| Grogster Admin Group Joined: 31/12/2012 Location: New ZealandPosts: 9083 |
Blu-Tack does not like being heated, so I always only use it to hold the chip in the right place, while I solder the OTHER side(s) of the chip, then remove the blu-tack, and solder those sides. If you roll the blue-tack with your finger as if you were rolling dough for making bread, it comes away completely cleanly. If you just try to pull the blu-tack up and away from the board, it does tend to want to stay there. Rolling it away works for me. When I first started using my scope, it was quite un-nerving not being able to see my hand and the iron while looking through the eyepiece, but you DO get used to it - quite quickly, actually, and now I never even think about it. Smoke makes things work. When the smoke gets out, it stops! |
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| paceman Guru Joined: 07/10/2011 Location: AustraliaPosts: 1329 |
That's certainly true but there are a thousand B--Micro cables around (from phones etc.) compared to B--Mini cables; in fact B--Mini are a bit hard to find. The Mini connectors are certainly more robust but I read somewhere that they have been officially 'deprecated' by the official USB body. Maybe we should be thinking about going USB-C Greg |
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| paceman Guru Joined: 07/10/2011 Location: AustraliaPosts: 1329 |
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| Andrew_G Guru Joined: 18/10/2016 Location: AustraliaPosts: 842 |
Thanks Greg. I hadn't appreciated the timeout on the Edit. My other edits have been more timely. Cheers, Andrew |
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| kkoppert Newbie Joined: 12/04/2017 Location: New ZealandPosts: 17 |
OK, unfortunately in New Zealand (maybe even moreso than Oz) we live on the end of a long supply chain and Chinese sellers know how to reduce shipping costs. I can buy Kester 44 solder via DigiKey or Mouser the the cost is horrendous $84 for 250gm. Since this is a hobby I can't afford to spend that sort of money. On ebay I found Kester 44 in 10 foot lengths for $2.63 + $71 shipping. Jaycar sell Duratech solder but only 0.7mm, element 14 sell Multicore for $26. So what I need is info on good quality brand name solder which is available in New Zealand/OZ where the shipping costs don't involve selling my greatgrandchildren into slavery. |
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| Grogster Admin Group Joined: 31/12/2012 Location: New ZealandPosts: 9083 |
You can edit your post as many times as you like, provided your post is the most recent one. As soon as someone else posts to the thread, you cannot edit your post anymore. Administration(Gizmo) has said this is done on purpose, so that once extra posts are added, people can't go back and edit what they said to make it look like other posts are wrong. I personally think this is a fab idea, and should be adopted by more forums, IMHO..... @ kkoppert - If you want some 0.5mm 60/40, as as you are a fellow Kiwi, PM me and I can flick you some. I have plenty. If you want to buy your own rolls, then Element-14 is where I get mine from, as it is free freight on any order NZ$40 or more. I can post a link to the E14 solder if you want to buy your own roll, but you might not want that much. Smoke makes things work. When the smoke gets out, it stops! |
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MicroBlocks Guru Joined: 12/05/2012 Location: ThailandPosts: 2209 |
Some video (just released today) showing how to solder SOIC. https://youtu.be/hoLf8gvvXXU?t=250 Microblocks. Build with logic. |
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| Andrew_G Guru Joined: 18/10/2016 Location: AustraliaPosts: 842 |
Grogster, thanks - that explains it. I can see the logic but it is a shame we can't be trusted (but neither is it a big deal to own up that someone "mis-spoke" (to quote George W)). Andrew |
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