To all of you afraid of SMD/SMT

C

chilloutdocdoc

Full time elf
Joined
Jun 5, 2010
Messages
114
Location
Central Florida
DON'T BE!

But in all seriousness, don't be. I just did my first board last night.

I used an electric griddle and solder paste. I let the board heat up to a "soaking/drying" temperature and then turned the temperature (following a generic profile I found here: http://www.breeeng.com/photos/reflow.jpg). Let me just say that it was EASY as pie. You put a dab of paste on each pad, Stick each component on the pasted board, and put the board on the griddle. That's IT!

Really all you need is: Griddle, Solder Paste, and a pair of tweezers. The tweezers I thought wouldn't be essential. Let me just say it is a PAIN to put tiny components on a packed board without the tweezers (they're cheap too). They ARE essential. Just any cheap pair of SMD tweezers will do. ESD protection a bonus!

Overall it was easy, and you can do multiple boards at once without much more effort.
 
I would agree with you there, I found it to be easier than normal through hole soldering. As long as you ensure you dont have too much paste applied its just a matter of applying the paste then placing the components on the board and then using a hot air gun to melt the paste into solder. Take your time to evenly heat up the board and components and thats it.
I do advise on having a magnifying light of some sort especially for us old fellows who's eyes are not the best.
 
Do you recommend butter or vegetable oil, and when should it be seasoned.

It sounds so easy and with the price of those electric frypans starting in the $40.00 range, it makes economic sense for the next big project. When finished could be re-gifted in time for Christmas. :)

Steve
 
Doc, Eddy or anyone else who has done this method could you post a picture or 2 of the boards with paste applied and after they've been baked. I use paste for some smd but i find that hand soldering with 0.35mm solder, a fine tipped soldering iron and head magnifiers is way faster than using paste on resistors and chips. I use the paste on smd DPAK mosfets as it does a neater job and i hope that it provides better heat transfer to the copper.
 
I used bothe methods while assembling the ACL strobes last season and also, for me, found it just as quick to do via hand method. But, that's just me....
 
I recently did some strobes for supersteve after he had some failed attempts. I was putting together the strobes in a little over 3 minutes each when doing them as a panel of 45. I'd reckon of that time you'd struggle to apply paste neatly and evenly to the 22 smd pads and then hand solder to 3 pads for the transistor. If you were using a paste stencil then I imagine that you could cook them up faster than by hand as it would only be a few seconds to apply all the paste.
I am quite happy to be proven wrong if someone can show me a nice neat reliable method that is faster than hand soldering as I solder a LOT of smd components by hand.
 
I'll try and get those pic's as requested as soon as I get my real tweezers in (hence the recommendation . I prefer the SMT with Paste as I don't have to fiddle with holding the part, solder, and an iron in two hands, i can just place everything and let it bake.


What size tip were you using on the syringe AAH? I honestly just eyeballed it then had to go back and touch one pad I didn't paste enough.
 
The way I hand solder SMD items is pretty simple. I work with the board just sitting on my (anti-static) work mat. This stops it from sliding all over the place.

First, I tin (add solder to) one pad of every component position.

Then, I pick up a component with the tweezers and slide it into position as I heat up the solder I previously put on that pad.

I then take away the iron, let the joint cool for a second then release the tweezers.

Repeat for all the other components, then go back and solder the remaining pad(s) of each component. You may have to add a tiny bit of solder to some of the first ones you did if the joint looks "dry" from being heated a couple of times.

Here's a video clip I just found that shows what I mean.

SMT Hand Soldering - Surface Mount SOIC IC
 
David, another good method, and i used that for the ACL strobes, I found it to be much more difficult honestly, but I guess with practice, it becomes easier (45 ACL strobes wasn't enough).


There are many ways, and I think each will have their own preferred way, but I would definitely encourage trying it out if you can.
 
Time for another cooking lesson.
Just my $20 craft embosser.

About 15minutes to lay down the solder and place the parts.
5 minutes to cook.
10 minutes to clear bridges and continuity check all connections.

a half hour for two boards start to finish.

Jump to 2:20 to see the action
LEDancer solder cooking

Joel
 
That looks good Joel. I do love the way that smd components centre themselves when they're used with paste and heat. With experience and the right tools a competent person should be able to do those boards in about 5 minutes each via hand soldering. It does take a fine soldering tip, preferably fine solder (0.35 to 0.45mm) and if possible head magnifiers or a maggy lamp. Applying flux also reduces the bridging of joints but I seldom use it except on really fine smd chips. I hate it because you pretty much have to clean the pcb after you've soldered using flux.
 
Nice boards joel. Looks like an 8 channel DMX board.. Great minds think alike.


I too have a embossing gun, but I was afraid of blowing away some of the smaller chips so I went with the griddle method. I'm very happy to see that a lot of people here are willing to do SMT soldering without "fear" that it's difficult.


Personally I have more trouble doing them with an iron, but that could be due to a less than fine solder size.


When I have more stuff in, i'll do a video of them cooking on the griddle.
 
ChillOutDocDoc said:
Nice boards joel. Looks like an 8 channel DMX board.. Great minds think alike
Click to expand...

I think those are the LEDancer prototype boards... Just ordered 12 of them in the groupbuy on DIYC :)
 
To :AAH
I am neither good, or competent.
I could maybe get chips soldered without messing them up to badly,
but resistors usually wanted to stick to my iron more than the board.
the solder paste is quite forgiving, even if your hands are not a steady as they once were.

To :ChilloutThat is an LEDancer,
DMX in 56 chiplexed LEDs out.
the paste has a good amount of tack to it.
the embosser is low velocity, unless you get really close, then I blow straight down.

To :Slite
Phil Short actually liked this design better
but the thru hole is still the one that went to the group buy.

Mine are encased in clear heat shrink, so the programming header was not needed or an option.

Joel
 
You must log in or register to reply here.
Back
Top