EEVblog Electronics Community Forum

General => General Technical Chat => Topic started by: Simon on March 03, 2010, 12:47:36 pm

Title: hot to solder SMD
Post by: Simon on March 03, 2010, 12:47:36 pm
Well I've never really considered using SMD devices due to the size and lack of "pins". However I suoppose the day will come and many parts are cheaper as SMD. How exactly do you solder SMD devices ? I do have a 1mm soldering iron tip for my antex 12 W iron so maybe I'm already on the right track ?
Title: Re: hot to solder SMD
Post by: Zero999 on March 03, 2010, 01:43:32 pm
I prefer SMT in some case, e.g. when using veroboard it's easy to stick an 805 resistor or capacitor between adjacent tracks.

You really need a temperature controlled iron and a pair of tweezers.

Tin one pad, hold the component in the tweezers, heat the solder on the pad again and solder one pad of the SMT component. If it's a resistor or capacitor, you'll need to ensure it's flat before soldering the other pad. If it's an IC solder the one of the corners first, align the rest of the pads, solder the opposite corner and then the rest. If it's a transistor, solder the middle pin first, solder, align and solder the rest.
Title: Re: hot to solder SMD
Post by: TheDirty on March 03, 2010, 02:49:22 pm
I don't know if it's a matter of cheaper.  Many parts don't come in anything other than SMD anymore.

I think the best advice is just to youtube it.  There's a lot of decent walkthroughs on youtube that show you the procedures that people use.  Then just experiment a bit.  You definitely need a decent temp controlled soldering iron.
Title: Re: hot to solder SMD
Post by: Simon on March 03, 2010, 06:13:21 pm
whjats the difference between SMD and SMT, and yes there are parts that you just can't find in DIP
Title: Re: hot to solder SMD
Post by: armandas on March 03, 2010, 06:35:35 pm
This video got me started: http://www.curiousinventor.com/guides/Surface_Mount_Soldering/101
SMT and SMD both mean the same (well almost): T is for technology, D is for device.
Title: Re: hot to solder SMD
Post by: joelby on March 04, 2010, 01:54:47 pm
You can pick up large packs of 0805 capacitors and resistors from various eBay sellers for next to nothing ($10 for 3600 parts). Vero board actually is pretty good for practicing with SMD passives and building basic circuits with parts up to about four pins.

Title: Re: hot to solder SMD
Post by: migsantiago on March 04, 2010, 03:14:13 pm
You can pick up large packs of 0805 capacitors and resistors from various eBay sellers for next to nothing ($10 for 3600 parts). Vero board actually is pretty good for practicing with SMD passives and building basic circuits with parts up to about four pins.



Hi!

Do you have a link to any of those packs? Maybe 1206 packages, 0805 is a bit uncomfortable to solder for me.
Title: Re: hot to solder SMD
Post by: joelby on March 04, 2010, 03:24:08 pm
Unfortunately I haven't seen any cheap grab bags larger than 0805. There's one here: http://cgi.ebay.com.au/SMD-0805-50-Value-Resistor-32-Value-Capacitor-Kit_W0QQitemZ370344036219QQcmdZViewItemQQptZLH_DefaultDomain_0?hash=item563a39877b

I don't find handling 0805 too hard. Very fine tweezers help, and having a nice PCB with a solder mask helps a lot. A big magnifying glass or stereo microscope may also be worthwhile if your eyes are struggling. I've been dead-bugging RF filters with 0603 parts and it's.. quite frustrating.
Title: Re: hot to solder SMD
Post by: TheDirty on March 04, 2010, 09:07:51 pm
For general pointers and tools for 'on the cheap':

Cheap drugstore reading glasses work well.  You can get the 3X magnification ones.  Sometime these can be too cheap so try looking through them first and make sure they are clear and you can focus on things.  Whatever you do you need lots of light, so a desk lamp.

DealExtreme is a goldmine of high quality tweezers, cheap solder paste, wick, loop lenses, and magnifiers.  Just don't expect it at your door next week.  (two weeks minimum in NA)

I would really suggest 0805 as the maximum size you want to go.  It's really not that hard.

Decent temp controller soldering iron, solder wick, flux...
Title: Re: hot to solder SMD
Post by: migsantiago on March 05, 2010, 12:24:19 am
Ohh thanks for the link.

By the way, what does 0805 stand for? 1206?
Title: Re: hot to solder SMD
Post by: DJPhil on March 05, 2010, 12:38:41 am
By the way, what does 0805 stand for? 1206?

Those are package sizes for SMT components. They usually refer to the width and length of the component in hundredths of an inch, but can also be described by their metric counterparts. For example, 0805 is 2012 in metric. Be careful not to confuse them!

Here's a decent list from wikipedia (http://en.wikipedia.org/wiki/Surface-mount_technology#Package_sizes) of the more common package sizes.
Title: Re: hot to solder SMD
Post by: EEVblog on March 05, 2010, 01:05:32 am
SMD soldering is trivially easy. Just get a decent small chisel tip, not those silly conical round tips.

1206 - Stevie Wonder could solder these, they are huge.
0805 - is decent size to solder and inspect by hand and by eye, recommended for most projects unless you have to go smaller for some reason.
0603 - saves space and still solderable by hand and inspection by eye, but requires good eyesight.
0404 - A real pain in the arse by hand. Many others claim to be able to do them by eye (I can), but really you are kidding yourself, you should do it under a microscope to get consistent quality.

SO IC packages (1.27mm) are almost trivially easy to solder. Avoid 0.5mm pitch IC packages unless you have no choice, they get real tricky real fast and are a pain the butt.

As others have said, plenty of online tutorials, and Silicon Chip did an article or two the other year.

Dave.
Title: Re: hot to solder SMD
Post by: TheDirty on March 05, 2010, 01:42:52 am
Oddly I bought a bunch of different soldering tips to try and ended up going back to the small conical tip that came with my soldering iron and it stays there.  I'm pretty much in the minority with this, but it works the best for me.

I have no problem with 0.5mm chips and I don't think it's that hard, but I use the solder wick method that the guy in the above linked video doesn't like.  It's the method SparkFun promotes.

Like this:
https://www.youtube.com/watch?v=auI0tnYzcBc
...though those look like 0.65mm leads it's the same thing.  Tack down two points, solder, then wick.  If you are good at it you can do it fast and leave just enough solder down.  It's helpful to have a fairly high wattage iron.  I've done 0.4mm leads with this without any issue.
Title: Re: hot to solder SMD
Post by: Zero999 on March 05, 2010, 09:36:29 am
I think the best thing about SMT is not having to drill lots of holes.

Almost any ordinary component can be surface mounted if you like: DILS can have the pins flattened out, TO-92s can be layed flat side down with the legs splayed out and resistors and diodes can have their leads formed so they lay flat on the board. I've seen non-SMT devices surfaced mounted in some commercial products before, I remember seeing a piezo buzzer with its driver oscillator build in this manner.

I find 0805 components easy to solder, 0603 gets a bit tricky, 0402 is doable and I haven't tried anything smaller. This was working on a professionally made PCB with a magnifier and all the proper tools, I don't think I could do 0402 on a home made board without solder resist and the huge magnifier I had access to at work.
Title: Re: hot to solder SMD
Post by: joelby on March 05, 2010, 09:47:10 am
I agree about the holes! I have a drill press and PCB bits but have not used them for ages.

Today I gave up on dead-bugging my filter and designed a board in Eagle and had Press 'n Peeled, etched, silver plated, soldered it together, and tested it all within about an hour and a half. Now that I've tried them on a PCB and not just up in the air, I don't actually find 0603 to be much harder than 0805 parts to solder by hand and naked eye. I might get some 0402 next time for fun! :)

My other favourite thing about SMT is that parts come neatly organised on (hopefully labelled) tapes, so for those of us without nice storage solutions, there's no need to hunt through big bags of resistors and capacitors, examining each one. I've even got some parts in a handy ring binder with values in ascending order.
Title: Re: hot to solder SMD
Post by: migsantiago on March 06, 2010, 01:47:46 am
Those are package sizes for SMT components. They usually refer to the width and length of the component in hundredths of an inch, but can also be described by their metric counterparts. For example, 0805 is 2012 in metric. Be careful not to confuse them!

Here's a decent list from wikipedia (http://en.wikipedia.org/wiki/Surface-mount_technology#Package_sizes) of the more common package sizes.

Thanks for the link.

What kind of "tweezers" do you use to hold the tiny resistors and capacitors? The last time I used a screw driver tip but... it didn't work that well  :'(
Title: Re: hot to solder SMD
Post by: joelby on March 06, 2010, 02:01:28 am
I got my tweezers from a company in Sydney: http://www.ultrakeet.com.au/index.php?id=1&cID=5807&bollocks=none . They have plenty of  other interesting bits and pieces too.
Title: Re: hot to solder SMD
Post by: migsantiago on March 06, 2010, 02:11:02 am
Good! I'll try to get one of those.  ;D
Title: Re: hot to solder SMD
Post by: TheDirty on March 06, 2010, 03:45:24 am
These ones:
http://www.dealextreme.com/details.dx/sku.19866

and these ones:
http://www.dealextreme.com/details.dx/sku.19872

...are my favorites.

There are lots of different kinds and since they are pretty cheap you can check out a few.
http://www.dealextreme.com/search.dx/search.tweezers
Title: Re: hot to solder SMD
Post by: migsantiago on March 06, 2010, 09:09:06 pm
Man, there are even some bamboo anti-static tweezers  :o

I'll look for them on Newark since I live in Mexico.

http://mexico.newark.com/jsp/search/browse.jsp?N=500004+1002554&Ntk=gensearch_001&Ntt=tweezers&Ntx=mode+matchallpartial

A whole bunch of options   :-\
Title: Re: hot to solder SMD
Post by: Simon on March 07, 2010, 07:47:29 am
Man, there are even some bamboo anti-static tweezers  :o

I'll look for them on Newark since I live in Mexico.

http://mexico.newark.com/jsp/search/browse.jsp?N=500004+1002554&Ntk=gensearch_001&Ntt=tweezers&Ntx=mode+matchallpartial

A whole bunch of options   :-\

Hey that looks exactly like the Farnell website but green instead of orange
Title: Re: hot to solder SMD
Post by: Zero999 on March 07, 2010, 10:14:48 am
That's because it is Farnell.
http://en.wikipedia.org/wiki/Newark_-_A_Premier_Farnell_Company
Title: Re: hot to solder SMD
Post by: Simon on March 07, 2010, 11:30:17 am
I suspected that be the case, to be honest they have a good selection in the UK but can be pricier than RS and have just introduced a min £ 230 order for non business customers (but have free postage whereas RS charges)
Title: Re: hot to solder SMD
Post by: Zero999 on March 07, 2010, 01:43:17 pm
£230! Are you sure you've not got the decimal point in the wrong place?

£23 sounds more fair. It looks like Farnell of sick of people abusing their free delivery buy making small orders.

I have a business account with RS so I get free delivery.
Title: Re: hot to solder SMD
Post by: Simon on March 07, 2010, 02:04:14 pm
sorry meant £ 20
Title: Re: hot to solder SMD
Post by: Simon on March 07, 2010, 02:18:20 pm
how do you get a business account with RS ? I'll have to look into that
Title: Re: hot to solder SMD
Post by: migsantiago on March 07, 2010, 03:21:16 pm
Yeah, it's Farnell, but it's called Newark here in Mexico.

It's a place qhere I can get smd stuff, there are other online stores but they collect so much in taxes from importing and that stuff. Newark is fair, a bit expensive but fair with the taxes.

There is no shipping price.  ;D
Title: Re: hot to solder SMD
Post by: Simon on March 07, 2010, 03:36:50 pm
I was quite a fan of Farnell for a bit but now I am starting to see quite a price shift compared to RS, if you order a lot of gear then it can well work out cheaper with RS, for example my regular supply of 500 78L05 chips
Title: Re: hot to solder SMD
Post by: Zero999 on March 07, 2010, 03:58:41 pm
Rapid Electronics are definitely the cheapest UK supplier but you need to spend over £35 excluding VAT to get free delivery.

RS Components are based in Corby so if you want it urgently you can drive there and pick it up, but it's more convenient you you than it is for me.
Title: Re: hot to solder SMD
Post by: Simon on March 07, 2010, 04:04:02 pm
Yes I've used rapidonline as well and do occasioanlly when amazingly they have what RS/Farnell does not or can beat their price. Their range is not as good as they cater for the hobbiest but they are certainly handy. I've never actually bothered to collect my stuff from RS as I figured the petrol would cost as much if not a bit more and their deliver next day.

Lots of people go on about Digikey but i have found them to be dearer than both RS and farnell in the UK, maybe chesper in the US
Title: Re: hot to solder SMD
Post by: Zero999 on March 07, 2010, 05:51:23 pm
In my experience Rapid beats RS and Farnell most of the time on price. The trouble is that they don't have such a great range and the free delivery threshold is much higher.

I'd also say, never rule out Maplin, I've found them to be cheaper than RS, Farnell and Rapid on the odd occasion and there's a store in Bedford which is convenient for me.
Title: Re: hot to solder SMD
Post by: Simon on March 07, 2010, 06:03:14 pm
yes rapid do beat others on price but generally I find it a task as it is researching my "shopping list" on both farnell and rs and knowing that rapid does not hold anywhere near as much stuff I generally don't bother. another resourse is ebay.

Maplin I hate, they are ok for raw materials ie parts and chemicals but I will never ever trust them again with anything more, I have been done too many times or found them to be of poor quality AND overpriced, basically going to maplin for me is as big a pot shot as getting it on ebay but on ebay but on ebay I will pay a third of the price. maplin's website is not very good either. sometimes I value my time over the small price difference