It will be just fine Jerry.
I've done 0.5mm spacing a number of times.
The trick is to make slightly narrower pads than spaces. Something
like 6.66mil or 8mil works good for me (select a value which the
resolution of your printer can resolve).
You want to make narrower pads than gaps because this way you have
some margin with the toner spreading and stuff, and soldering will
also be easier.
TQFP can be annoying to solder, because it likes to bridge between the
leads. Flux will help and and desolder braid to clear shorts.
QFN seems smaller at first glance, but because of the leadless nature
i find it much easier to solder, there is much less tendency to
bridge.
ST
On Fri, Feb 20, 2009 at 9:27 PM, jerrytr2.com <jerry@...> wrote:
> Hello,
>
> Since encountering this group a month or so ago, I have refined my
> toner transfer process to the point that I am able to reliably do 15-
> mil traces. Maybe smaller. Hope so.
>
> I'm doing a home project and have settled on PIC24F
> microcontrollers. The latest version needs USB, and all the PICs
> that support USB are surface mount. So I have been dragged kicking
> and screaming into the 21st century.
>
> I bought an Aoyue 968 hot-air SMD rework station and some fine
> tweezers and have been having a good time scrounging parts off some
> defunct computer boards - just to get used to the tool. I'm going to
> need a microscope - half of these parts just look like bits of dirt!
>
> One part I scrounged is the same package as the 24FJ256GB106
> processor I'm planning to use - a 64-pin TQFP. Good LORD those pins
> are small. Can Toner Transfer make boards this tight? According to
> the spec sheet, the pin pitch is .5mm, or about 20 thousandths of an
> inch. So the traces need to be 10 thousandths of an inch, and will
> only have 10 thousandths of separation. Ouch.
>
> - Jerry Kaidor
>
>