Homebrew PCBs

On Thu, 29 Jul 2004 13:02:48 -0000, mikezcnc <eemikez@...> wrote:

> a bit of a joke on my part, Stefan, no harm intended.
>
> TT is working for me also very well, but I am concerned with what
> what Jeremy said that he measured the heat distortion of a laser
> print out and it is something on level of 0.010 if I rememebr
> correctly. Stefan, do you make SMD boards also?
>
> The fact that Marcus is making 4 layer boards is an incredible news.
>
> Mike
>

I'm also concerned about distortion, but i found something more unsettling
last time making a board. the fuser/laminator to transfer made
the paper shrink about 1mm on 100mm length. (i discovered that when trying
to align a "silkscreen" component legend on the etched copper side).
There is definitely some more measuring needed.
First to determine how much distortion the laser itself has and then how 
much it
is harmed by the laminator. I believe passing the paper through before 
printing
would "pre-shrink" it and lessen the effect.
I'll let you know when i had time to do a few testprints.

As for SMD - i prefer it 'cause i don't like the drilling.
Populating/soldering too is easier and faster.
There are certain parts i use throughole (old stock, salvaged, high power 
parts,
mechanically strained components) but when there is SMD in my storage i'll 
use it
and it is definitely preferred when buying new parts.
I have no trouble with the resolution as 6,66mil is the limit (my printer).
There is a point where you have "ideal" single-layer boards, which in my 
opinion
is throughhole ICs and SMD passive components. this allows for easiest 
routing.
More SMD makes it harder again.
You can see a very simple (1206) SMD board witht the alignment problem at
<http://stud4.tuwien.ac.at/~e0225977/pub/comp_bot.jpg>
sorry, i have no picture of finer art at the moment but it is easily 
possible.

ST