On Wed, 31 Dec 2003 17:37:42 -0000, mikezcnc <
marabu@...> wrote:
> I am spending lot's of time trying to find the best way of heating and
> pressing.
>
> There appears to be a distinct correlation b/w tempreture and pressure
> (paper being a given for the ezperiment). I won't mention humidity
> either.
You want just enough pressure to make a good bond.
too much and the tracks widen.
I always use highest temp setting so far.
will experiment when i have a other iron (with longer chord and no steam
holes).
I think above a certain temperature it works pretty well.
There must be some upper border but with my iron it seems i don't reach it.
> The other problem I have is that my boards are larger than an iron
> footprint. Iguess if my idea was to make a small board with heavy traces
> it would be trivial. With small board and SMD it would be also relatively
> easy. The problem starts with size. Just yesterday I tried moving from
> one end to the other end of the large board with fine traces and I made
> stops with iron every inch and stayed there for a minute and half, wool
> setting. Some places came up perfect, next to it pads were flattened
> (pressure issue?) and lsewhere I obviously did not laminate long enough.
> The good news is that where the ink stuck it did stuck like enamel. The
> links you are including and are fascinationg how he did it.
>
Which toner do you use and which darkness setting?
For me short ironing works nearly as good as long.
i use very light pressure, perhaps additional 10N to the weight of the iron
itself.
But i mostly make boards smaller then the iron.
First i put it on the whole surface for about 10 seconds.
then i start at one side and go over the board slowly, continuously with
the curved edge.
the hot aluminium leaves on the paper a print through of the underlying
toner areas.
when i can see all areas with the light brown/yellow printthrough i know it
is ok.
if not i go over that place with the curved edge again.
All with very light pressure.
The whole process takes no longer than 30 seconds.
I got better results with lighter pressure.
I assume with that process i coud make larger boards too.
i would first set the iron in the center for 10 seconds, and then the same
offset all around until the whole board has had the 10 second heating.
(I think that gets the pcb up to temp.)
then i would go with the curves edge over it like i do with small boards.
(i tilt the iron very slightly to get the pressure mostly on the edge.)
How do you prepare your boards? (cleaning)
Stefan
> One more thing: lamiantors require 12 to 15 passes... I want a better
> laminator. Just went thru an excercise with the heat press-worse than
> iron. Is there anybody knowledgeable to suggest how to control heat and
> pressure on large size PCBs. Oh, I even had my boards preheated. I use
> dmax pressure but probably not evenly.
>
> Mike
>