next topic »

[on:]

I was wondering if anyone knows what tip would be optimal for a Weller WES50 (or WES51) to use on a .5mm pitch Schmartboard.  I am going to try to mate a ATMega2560 to a 100 lead Schmartboard.  Wish me luck, but better yet, tell me the best tip to use.  Thank you.

[Reply #1 on:]

How wide are the pins?  That comes into play more than the pitch of the pins.

[Reply #2 on:]

How wide are the pins?  That comes into play more than the pitch of the pins.

It's more the width of the tracks on the Schmartboard that are the dominant factor IMHO, you basically take the soldering tip up the track to push solder up onto the pin.  This is the product:

http://www.schmartboard.com/schmartboard_pd_202-0011-02_dim.pdf
http://www.schmartboard.com/schmartboard_pd_202-0011-01_l.jpg

Demo:



I think I have the right tip, I bought this a while ago and in testing it, it seems to follow the track correctly, and rather like in the video.  Wish me well...

http://www.amazon.com/Long-Conical-Tip-1-64/dp/B000ILEUCK/

[Reply #3 on:]

I would solder this with a 2mm tip. Why would anyone want to solder this pin by pin? Apply flux, put enough solder on the tip and solder the whole side of the chip at once. This takes less practice than you might expect.

[Reply #4 on:]

Yes flood all the pins with solder and remove the surplus with braid.

[Reply #5 on:]

Like in this tutorial: http://skywired.net/blog/tutorials/how-to-solder-qfp-tssop-soic-surface-mount/. Or this video: http://arduino.cc/forum/index.php/topic,112531.0.html. The method proposed in the schmartboard promo video is clearly inferior.

[Reply #6 on:]

Like in this tutorial: http://skywired.net/blog/tutorials/how-to-solder-qfp-tssop-soic-surface-mount/. Or this video: http://arduino.cc/forum/index.php/topic,112531.0.html. The method proposed in the schmartboard promo video is clearly inferior.

They sell a lot of these things and I bought one at Frys.  I will look at these other methods maybe for the next time.  Solder paste is not something that I am familiar with, but I can always make myself familiar with.    Thanks for the info.

Now, if you are going to use this solder paste method, there is no reason to use a Schmartboard at all because they are rather expensive and the point is to use their method anyway.  What's a good less expensive breakout to use with the solder paste method?  Something like the 100 pin TQFP adapter here?

http://www.futurlec.com/SMD_Adapters.shtml

[Reply #7 on:]

I did not write "solder paste". I wrote "flux". The solder paste method is more efficient as well but a completely different story. I have no clue how expensive the schmart board is and I do not use break out boards. Usually I design my circuits in Eagle and etch the whole stuff or let it manufacture. So I have no clue about prices for break out boards.

[Reply #8 on:]

I did not write "solder paste". I wrote "flux". The solder paste method is more efficient as well but a completely different story. I have no clue how expensive the schmart board is and I do not use break out boards.

Thanks.  I checked this message right when I got up and before I went to work (just checked again now that I got a cup of coffee).  I misread that completely.  I must have not been fully awake.   I have not watched the videos yet so I will probably understand better after I get home.  Thank you again.

Usually I design my circuits in Eagle and etch the whole stuff or let it manufacture. So I have no clue about prices for break out boards.

That is a useful insight for me.  I have seen PCB manufacturers but that process looks expensive and with a decent wait.  I don't know a lot about the do-it-yourself PCB manufacture except that there are home milling machine options that mill away copper from copper clad boards that give you a decent PCB and of course the chemical etch method.  What I don't know is how precise either of these methods are.  It also looks impossible to use these methods to make vias from one side of the board to the other.  Do the home PCB manufacturing methods give you enough precision to lay down tracks for .5mm parts?  Does the lack of vias create significant challanges for using these methods?  As soon as you drop a 100 pin part on a board you have a lot of traces.

Like in this tutorial: http://skywired.net/blog/tutorials/how-to-solder-qfp-tssop-soic-surface-mount/. Or this video: http://arduino.cc/forum/index.php/topic,112531.0.html. The method proposed in the schmartboard promo video is clearly inferior.

Could you link this video again - second link.  I think you copied in the wrong URL.  Thanks again for the information.

[Reply #9 on:]

Sorry, here is the proper link. .

The chemical process is the proper process and it is usually precise enough. Once you have done this once or twice you get

a) either the hang of it
b) or the insight that the manufacturer are not so expensive as they appear

.5mm is considered easy with the chemical process.

[Reply #10 on:]

OK, two last questions, maybe...  How is this method of soldering working?  Is it just causing the solder plating on the pads to melt and bind to the pins?  Do most pads have solder plating on them?  When I look at this product - http://www.futurlec.com/SMD_Adapters.shtml (second to bottom) they don't say that specifically.  Is that something that can be assumed?   It sure looks like there is solder plating on the ones near the top that have better detail on the pads. 

Also, Edsyn FL22 doesn't seem available in the USA - it's available overseas at $25 for 5cc(!) and who knows how much for shipping.  Is there another good option for this that will produce the same results?  Thanks again.

[Reply #11 on:]

I always buy the cheapest flux that say "lead free" and "no clean". And yes, this stuff is always pretty expensive. But it last pretty very long. At least for me.

The approach is to soak everything with flux.

Then put solder on the tip and smear it over the pins. Surface tension will suck the solder in.

In order for this to work the tip must be sufficiently big otherwise it does not carry enough solder and it will cool down to fast.

The only issue is that this approach tends to create solder bridges. Thus as a final step check for solder bridges and if you find any apply braid.

This yields consistently good results and is much simpler than it sounds. After my second SMD chip I got the hang of it and I will not use any other method any more (except for solder paste + oven).

[Reply #12 on:]

I always buy the cheapest flux that say "lead free" and "no clean". And yes, this stuff is always pretty expensive. But it last pretty very long. At least for me.

The approach is to soak everything with flux.

Then put solder on the tip and smear it over the pins. Surface tension will suck the solder in.

In order for this to work the tip must be sufficiently big otherwise it does not carry enough solder and it will cool down to fast.

The only issue is that this approach tends to create solder bridges. Thus as a final step check for solder bridges and if you find any apply braid.

This yields consistently good results and is much simpler than it sounds. After my second SMD chip I got the hang of it and I will not use any other method any more (except for solder paste + oven).

I see what you say about applying flux, then solder, then the braid in the text tutorial you linked.  But, in the video, I don't see the demonstrator applying solder at all.  So how is the guy in the  video getting the pins to stick down?

[Reply #13 on:]

The solder is on the tip already in that video.

[Reply #14 on:]

The solder is on the tip already in that video.

He either reloads it quickly or there isn't the need for much.  Thank you.  I should point out that I watched the vids at work with the sound off so I have no idea what he is saying.  I will watch it again tonight.  Thanks again.