On Mon, 21 Mar 2011 18:32 -0400, "Byron Jeff" wrote:

> I'm planning on testing both the Toner Transfer and the Photo resist with
> precoated boards. Both seem to be about the same amount of time in terms
> of
> speed. Overall the TT method seems to be cheaper as precoated boards seem
> to run about 3x the cost. So it seems to me that the real question is
> process repeatability.

Hi Byron,

I've tried using an XY pen plotter directly to PC board and never got
good enough etch resistance. All over the net there are recommendations
for the RED Staedtler Lumocolor pens but even they are not good enough.

I have used spray-on photoresist. It's OK except for the hairs and dust.
In other words, not good for fine pitch because you will have bad spots.

Laser toner transfer is sensitive to your ironing pressure and
temperature. I always print a border around my artwork to act as a
pressure buffer. It seems to even out the pressure near the edges. Fair
to good results if you have finesse. Prepare for lots of do-overs and
some touchup before and after etch.

Presensitized board works really well. No question, this is the way to
go if you want quality. And unlike the other methods it takes very
little talent. Your first board will be good and every one to follow.

I tend to do toner transfer because I am drawn to how immediate it
seems, and the fact that you don't really need any consumables. But then
after I have ironed on and cleaned off the same board three times before
I get a transfer good enough to etch, I rethink my choice of technology,
wishing I'd used presensitized board instead. And it's not like there
are no consumables, I use acetone to clean the board and lacquer thinner
to remove the toner.

Note to self: Since I don't make more than a dozen boards a year I
should always use the presensitized board.

Cheerful regards,

Bob


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