Re: gEDA-user: best ways to do SMT assembly
On Thu, 14 Aug 2008, Robert Butts wrote: I got pcbs back and now want to assemble them. What is the best way, i.e. solder paste to use, heating method, solder bridge removal...? Most of the components are small SMT parts. The through hole parts I'm fine with. It depends what I'm doing. For discrete components (like 0603 sized Rs and Cs), just a fine tip soldering iron and fine solder wire - what I do is melt a small amount of solder on one pad, get the part with the tweezers, re-melt it and stick the end of the part into the molten blob. Then just solder the other end as normal. I can do this quite quickly. Where I have more components, I find it easiest to use solder paste. Small blobs (you need less than you think!) on each pad. For fine pitch SMD chips, I just put a bead of solder paste where the IC's pins are going to land, rather than attempt to put a blob of solder on each one. I then use a hot air gun. I've found that the air stream won't blow away even 0603 parts - the solder paste prior to melting will hold it, and when it melts, the surface tension is sufficient to stop the part from blowing away. Usually, I need to mop up a little excess solder from fine pitch parts - I just use fine desoldering wick to do this. I use Edsyn CR44 solder paste (available from Farnell if you live in Rightpondia). It has a very good shelf life. The drawback of this particular solder paste is it does tend to spread a little when it's heated, but I have found once it finally melts, it's not an issue (due to the soldermask, and surface tension pulling it back together in a better shaped blob). Generally once you've done a few SMD boards, you'll find you can often do it faster than the equivalent through hole - because you're no longer having to cut off excess bits of wire or turn the board over for each component. ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
Re: gEDA-user: best ways to do SMT assembly
On Fri, Aug 15, 2008 at 09:43:33AM +0100, Dylan Smith wrote: On Thu, 14 Aug 2008, Robert Butts wrote: I got pcbs back and now want to assemble them. What is the best way, i.e. solder paste to use, heating method, solder bridge removal...? Most of the components are small SMT parts. The through hole parts I'm fine with. It depends what I'm doing. For discrete components (like 0603 sized Rs and Cs), just a fine tip soldering iron and fine solder wire - what I do is melt a small amount of solder on one pad, get the part with the tweezers, re-melt it and stick the end of the part into the molten blob. Then just solder the other end as normal. I can do this quite quickly. This is similar to the technique I use (although I don't go smaller than 0805). However, rather than use tweezers, I prefer to put the component onto the board, and then push it around using my fingernail on the top of the component, about half-way between the two soldering ends. I find that this gives a lot more control than tweezers. Of course, my version needs a bit more planning, as I need to make sure I've let my fingernails grow longer than normal to stop my fingers getting burned ;-) -- David Smith| Tel: +44 (0)1454 462380Home: +44 (0)1454 616963 STMicroelectronics | Fax: +44 (0)1454 462305 Mobile: +44 (0)7932 642724 1000 Aztec West| TINA: 065 2380 GPG Key: 0xF13192F2 Almondsbury| Work Email: [EMAIL PROTECTED] BRISTOL, BS32 4SQ | Home Email: [EMAIL PROTECTED] ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
Re: gEDA-user: best ways to do SMT assembly
David SMITH wrote: On Fri, Aug 15, 2008 at 09:43:33AM +0100, Dylan Smith wrote: On Thu, 14 Aug 2008, Robert Butts wrote: I got pcbs back and now want to assemble them. What is the best way, i.e. solder paste to use, heating method, solder bridge removal...? Most of the components are small SMT parts. The through hole parts I'm fine with. It depends what I'm doing. For discrete components (like 0603 sized Rs and Cs), just a fine tip soldering iron and fine solder wire - what I do is melt a small amount of solder on one pad, get the part with the tweezers, re-melt it and stick the end of the part into the molten blob. Then just solder the other end as normal. I can do this quite quickly. This is similar to the technique I use (although I don't go smaller than 0805). However, rather than use tweezers, I prefer to put the component onto the board, and then push it around using my fingernail on the top of the component, about half-way between the two soldering ends. I find that this gives a lot more control than tweezers. Of course, my version needs a bit more planning, as I need to make sure I've let my fingernails grow longer than normal to stop my fingers getting burned ;-) Try using Blu-Tak instead of either tweezers or finger nails. It is more compliant than either and doesn't hurt when burnt :D ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
Re: gEDA-user: best ways to do SMT assembly
On Fri, Aug 15, 2008 at 07:12:14PM +1000, andrewm wrote: Try using Blu-Tak instead of either tweezers or finger nails. It is more compliant than either and doesn't hurt when burnt :D You mean to stick them to the board? Seems like a lot more hassle to have to stick the parts down first, rather than just push them into place. -- David Smith| Tel: +44 (0)1454 462380Home: +44 (0)1454 616963 STMicroelectronics | Fax: +44 (0)1454 462305 Mobile: +44 (0)7932 642724 1000 Aztec West| TINA: 065 2380 GPG Key: 0xF13192F2 Almondsbury| Work Email: [EMAIL PROTECTED] BRISTOL, BS32 4SQ | Home Email: [EMAIL PROTECTED] ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
Re: gEDA-user: best ways to do SMT assembly
Robert Butts wrote: I'm sorry to start a new thread on this, I can't find saved mail I've seen before. I got pcbs back and now want to assemble them. What is the best way, i.e. solder paste to use, heating method, solder bridge removal...? Most of the components are small SMT parts. The through hole parts I'm fine with. Thanks Lot's of good comments in this thread already. I've done SMT assembly both by hand, and I've experimented with toaster oven reflow. For a single board, especially for first time checkout, hand soldering is just fine, since you can assemble and test a small area at a time more easily than when you reflow the whole board. I find the main challenge with any homebrew SMT soldering is getting a small enough amount of solder laid down. It really only takes a tiny amount. For doing things by hand, get the smallest tip you can round up, or file one down. Equip yourself with a syringe of flux as well as a syringe of solder, and some of the smallest solder braid you can find. If you live in bifocalville like me, a microscope is nice. For two-pad parts, use a toothpick or tweezer to hold it down while heating the first pad, then then solder the second pad without any clamping of the part in order to avoid mechanical stresses. For TQFP's, apply a stripe of solder across all the pads, and tack solder just two pins on opposite corners. After you are happy with the alignment you can solder the rest down. Probably you will have bridges, which is easily handled with flux and solder wick. Hand soldering SMT is tedious, but not difficult. -dave ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
Re: gEDA-user: best ways to do SMT assembly
On Fri, Aug 15, 2008 at 11:20 AM, Dave N6NZ [EMAIL PROTECTED] wrote: [good advice elided] For TQFP's, apply a stripe of solder across all the pads, and tack solder just two pins on opposite corners. After you are happy with the alignment you can solder the rest down. Probably you will have bridges, which is easily handled with flux and solder wick. Here's a video of the process: http://vivara.net/smt1.mov (mirrored from bdmicro.com, their link is broken at the moment.) Regards, Mark [EMAIL PROTECTED] -- Mark Rages, Engineer Midwest Telecine LLC [EMAIL PROTECTED] ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
Re: gEDA-user: best ways to do SMT assembly
David SMITH wrote: On Fri, Aug 15, 2008 at 07:12:14PM +1000, andrewm wrote: Try using Blu-Tak instead of either tweezers or finger nails. It is more compliant than either and doesn't hurt when burnt :D You mean to stick them to the board? Seems like a lot more hassle to have to stick the parts down first, rather than just push them into place. No - you use the blu-tak like the tweezers or your fingernail. Roll a small amount of it to a fine point. Use this point as a poker to move around the component like your fingernail. Push down on top of the component and the tacky properties of the blu-tak will allow it to pick up the component (like tweezers). Once one side of the component is soldered - just pull it off. Huge advantage over tweezers is that it is compliant. So it is easier to get the component to lay flat on the board. ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
Re: gEDA-user: best ways to do SMT assembly
On Fri, 15 Aug 2008 09:20:23 -0700, Dave N6NZ wrote: For TQFP's, apply a stripe of solder across all the pads, and tack solder just two pins on opposite corners. After you are happy with the alignment you can solder the rest down. Probably you will have bridges, which is easily handled with flux and solder wick. Hand soldering SMT is tedious, but not difficult. There is a demonstration on youtube (make sure to click the hires button): http://www.youtube.com/watch?v=wQXhny3R7lk and for the more advanced: http://www.youtube.com/watch?v=4V7tBPsECjc I can confirm, that this technique works even for lead free solder. The key is the correct tip: It is conical with a flat, side. This flat surface is essential. It will suck the solder not needed for the connection. ---(kaimartin)--- -- Kai-Martin Knaak http://lilalaser.de/blog ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
Re: gEDA-user: best ways to do SMT assembly
http://www.sparkfun.com/commerce/tutorials.php Look under Surface Mount Soldering Tutorials. Some good stuff in there. From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Robert Butts Sent: Thursday, August 14, 2008 18:33 To: gEDA user mailing list Subject: gEDA-user: best ways to do SMT assembly I'm sorry to start a new thread on this, I can't find saved mail I've seen before. I got pcbs back and now want to assemble them. What is the best way, i.e. solder paste to use, heating method, solder bridge removal...? Most of the components are small SMT parts. The through hole parts I'm fine with. Thanks ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
Re: gEDA-user: best ways to do SMT assembly
I have solder paste in a syringe. Dab a bit of paste on every pad, place parts, heat it up on a hotplate. Works like a charm, but you have to manually solder the other side's SMTs. Even then, I dab paste, place part, hold part down with something and touch both ends with the iron to melt the paste. For larger boards, I usually make a stencil for the paste and put it on that way. It's not much more accurate, but it's a lot faster. For bridges, just use a bit of copper braid to remove it. ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
Re: gEDA-user: best ways to do SMT assembly
On Thu, Aug 14, 2008 at 2:32 PM, Robert Butts [EMAIL PROTECTED] wrote: I'm sorry to start a new thread on this, I can't find saved mail I've seen before. I got pcbs back and now want to assemble them. What is the best way, i.e. solder paste to use, heating method, solder bridge removal...? Most of the components are small SMT parts. The through hole parts I'm fine with. Thanks I use an fine-tip on my soldering iron with fine wire solder. A list of my tools and supplies is at *http://tinyurl.com/5foeou (* jcl *) * -- http://www.luciani.org ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
Re: gEDA-user: best ways to do SMT assembly
This my own version of a tool a friend of mine had. It is pretty good at holding down SMD parts while I solder them. I just built mine out of scrap I had. I just uses a pencil iron and small diameter wire solder. http://matthewsager.googlepages.com/smdholder Matthew ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
Re: gEDA-user: best ways to do SMT assembly
Matthew Sager [EMAIL PROTECTED] writes: http://matthewsager.googlepages.com/smdholder Ok, that's a neat idea. ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
Re: gEDA-user: best ways to do SMT assembly
You just have to make sure the holder is to heavy or sharp on the point to damage very small or fragile parts. I am thinking of making mine a little lighter. It does not take much to hold the parts down long enough to tack them with solder. On Thu, Aug 14, 2008 at 8:26 PM, DJ Delorie [EMAIL PROTECTED] wrote: Matthew Sager [EMAIL PROTECTED] writes: http://matthewsager.googlepages.com/smdholder Ok, that's a neat idea. ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
Re: gEDA-user: best ways to do SMT assembly
On Aug 14, 2008, at 8:26 PM, DJ Delorie wrote: http://matthewsager.googlepages.com/smdholder Ok, that's a neat idea. A REALLY neat idea. I think I'll be building one of those. -Dave -- Dave McGuire Port Charlotte, FL ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
