08-27-2006, 05:08 AM
does any one know in it is possible to reflow a pcb cotaining SMD.I saw a artical on Spark Fun in which they reflow a pcb with SMD.Does anyone alsoknow where i can get syringes,applicator tips , and solder paste(kester 256). Also where can i fine the Weller PL series soldering Tips.
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08-27-2006, 05:55 AM
08-27-2006, 06:08 AM
>>does any one know if it is possible to reflow a pcb cotaining SMD.<<
This is the industry standard for soldering surfacemount parts. Soldering SMD can be done by hand, laboriously, if the parts are 0805 or larger (chip parts like resistors, caps, LEDs), or SOIC (ICs with pins on 50 thousandths centers, pin to pin). A fine pair of tweezers, a very small soldering tip, some kind of magnifier, and a steady hand will suffice. Smaller parts get problematic.
For this you'll need very small solder, 0.015" diameter, and LOTS of flux. Flux is the larger half of the secret. I use organic type flux myself (there is a no-clean formula) as it cleans off readilly with warm water. Brush with a fine acid brush to get in under components and displace trapped flux, like ICs. After this warm flush, spray both sides of the board with distilled water. Blow it off with air, or let it air dry for several minutes, then you're good to go.
>>Does anyone also know where i can get syringes,applicator tips , and solder paste(kester 256)<<
Mouser has a small selection of Kester no-clean pastes. I didn't have too much luck with Digikey. Most of this stuff is non-stock, special order.
We used Contact East and others for our early paste and applicator orders. A Google search will probably find others, real quick.
When applying this by hand, you should practice first. You may hate the idea of spewing expensive paste all over a post it for the practice, but this beats the heck out of reworking every part on the board for massive solder shorts and dry pads.
Solder paste is touchy stuff. If it's thoroughly pre-mixed when you get it, and if you use it all immediately, then life is good. But, even with the required refrigeration, the little balls constantly sink in the paste mixture. Even if you religiously keep turning the container over, at some point you're expected to dump the entire contents, mix the *H* out of it, then store it in the new container. Get the smallest amount you can (1 Gram?) and throw it away at the end of the declared end-of-life, usually 3 to 6 months. I haven't had to use this in quite some time, so take this with a grain of salt.
HOWEVER, it IS considered HAZARDOUS to store this stuff with food of any kind, so the kitchen fridge may not be a good place for this.
>>Also where can i find the Weller PL series soldering Tips?<<
A quick search shows nothing at DigiKey, a few hits at Mouser. Check Mouser for your exact part number.
There are several articles on the 'net about doing reflow in frying pans and toaster ovens. The most interesting one I found was last year. In the article the author details the steps you need to do reflow in a toaster oven. He then recommends several toaster oven models. He gets exact about the model because he then provides "profile code" to use with his PIC powered PID controller to drive each oven through the three phases of reflow.
Hope this helped some,
08-27-2006, 07:31 AM
You may also want to look over the following thread:
8 + 8 = 10
09-10-2006, 08:03 AM
Action Electronics in Santa Ana carries syringes, plungers, tips of all sorts.