Homebrew PCBs

--- In Homebrew_PCBs@yahoogroups.com, "grantfair2001" 
<grant.fair@s...> wrote:
> Toner transfer is more appropriate for prototypes. Why? There are
> fewer steps with toner transfer - draw PCB art on computer, laser
> print it, iron on to PCB, remove paper, etch PCB. 
> 
> Silk screen is best for mass production. There are more steps: 
obtain
> silk screen and frame, photosensitize the silk with emulsion, draw 
PCB
> art on computer, print to transparency film, use that to expose the
> silkscreen, develop silkscreen, clean, then print PCB with silk 
screen
> ink, dry ink, etch PCB, remove ink from etched PCB. Clean ink from
> silk screen (if you want to use it again!) soon after last print 
made.
> 
> The resolution attainable with silk screen depends on the "mesh" of
> the silk, that is (I think) the number of threads per inch of the
> fabric.  I don't know the limits, but I think pretty good resolution
> is possible. I made some PCBs with silk screen 25 years ago; the
> technology was friendly, that is, with just simple instructions I 
was
> able to make the PCB's without much trouble.
> 
> More equipment is required to do silk screen - silk screen and 
frames,
> work area for printing, some way to get the screens to hinge up, and
> some way to hold the pcb during printing, ink, squeegee, cleaning
> solvents, developer for photosensitive emulsion, the emulsion 
itself,
> chemical to clean screen if you are going to reuse it. All you need
> for toner transfer is an iron and toner transfer paper, which may be
> simple paper of various kinds.
> 
> There is at least one member on the list who used silk screen
> commercially, so if you have questions, he has the answers.
> 
> Grant 

Hi, 

Balan
To make a film for screen printing it must be even better (real 
black) as for pcb's beside that the fabric that is used normaly is a 
stainles steel one with incredible tension normal frame would be 
bending.
so use the film direct on photo imag. pcb then is easyer. 
I do a lot of screen work but only on tshirts and stickers like stuff
To develop a screen you use atleast a 500watt bulp uv at 2 meters 
distand and a special frame with rubber like back to press mesch and 
film together with vacuum pump - why the distands- the sensible 
screen is atleast 0.3mm thick - undercutting is the worst thing u can 
have 

the photo imag. emulsion is mostly a diazo based stuff and got a 
shelf life off 3 months max.
so screen printing is possible but the expensive way to do.

But if you like more info i'm there to help you out !! 

gr. Roel 
 
    
      
> 
> --- In Homebrew_PCBs@yahoogroups.com, Balan <balan3@y...> wrote:
> > Hi
> >  
> > I am just learning the art of PCB making. Can Someone tell me is 
it
> possible to transfer etch resist onto a board using Silk screen and 
if
> possible what is the difference between toner transfer methord and 
the
> silk screen.