Killer PCBs

Step 12 Reflow

Pretty simple stuff here: Heat until solder paste melts, then cool. Be sure to use a fairly stout copper or aluminum plate to evenly spread the heat across the board. Once all the solder melts take the metal plate off the hotplate, and place it on a heat sink to bring the temp back down quickly--cement garage floors work great--just make sure you use oven mits (but don't bake cookies with them afterwards...). You may need to clean up some bridged connections after reflowing. For this, just use solder wick and lots of flux (I like Orange Crush). Apply power and fire it up! BTW, I accidentally ran the temp up too high on the first board and got the cool gradient color effect on the solder mask as a result (see the intro pic). I think the components were still in spec, but I didn't have a good heat spreader under it at the time, so I can't be sure the probe was reading the same temp the board was seeing. The board seems OK so far though...

Well that's it--easy eh? Be sure to watch for my upcoming web site IncoherentLabs.com. Now have fun and go save the world!

Comments

[dynaco]

thats perfect. But why you dont explain the drilling process?

[incoherent]

Wow, I totally spaced that!! Yeah, there are lots of holes required for vias and a few through-hole components. I'll have to add a page on drilling. Thanks for the reminder! --incoherent

[ReCreate]

Wow,where is your avatar?

[ReCreate]

Like this

[dynaco]

if you use some kind of chemical via metalisation - please explain it too.
And of course the minimum diameter of holes =)

[incoherent]

I've attempted electroless tin plating using Philmore/Datak Tinnit with results almost as disastrous as with their spray-on resist. I saw a Howto site that used MG's electroless tin plating, but I haven't tried it yet (and I can't find the site at the moment). This site is worth looking at in the mean time.

[incoherent]

Here's the instructable that uses MG's electroless tin plating solution.

[alex-sharetskiy]

it isn't needed, everything is surface mount

[SuperFungus]

I think he was refering to vias which are commonly used even on surface mount boards.  These are holes which go between layers of a pcb to carry signals from one layer to another.  In a normal pcb process these are plated, it seems with the process described here you'd need to manually solder in conductors to make the vias work.