Homebrew PCBs

My SMT adventures continue... I am making some promising progress, but I have discovered that the bronze sheets I am using to make stencils are destroying my tools! Cutting out one stencil for a small DCDC converter layout left my almost-new V60 tool unusably dull.

The bronze sheets would be fine, I think, for larger pitch components where you can simply do a through-cut with a small end-mill. But my smallest end-mill is 0.02" and that's too large to stencil the pads for the 0.65mm pitch IC I am using.

Has anyone used an alternative material for machining SMT stencils?

I have made stencils using thin (10 mil) Garolite (FR4) that I get 
from McMaster-Carr.

Mark

At 12:56 PM 7/20/2013, you wrote:

>My SMT adventures continue... I am making some promising progress, 
>but I have discovered that the bronze sheets I am using to make 
>stencils are destroying my tools! Cutting out one stencil for a 
>small DCDC converter layout left my almost-new V60 tool unusably dull.
>
>The bronze sheets would be fine, I think, for larger pitch 
>components where you can simply do a through-cut with a small 
>end-mill. But my smallest end-mill is 0.02" and that's too large to 
>stencil the pads for the 0.65mm pitch IC I am using.
>
>Has anyone used an alternative material for machining SMT stencils?
>
>
>
>------------------------------------
>
>Be sure to visit the group home and check for new Links, Files, and Photos:
>http://groups.yahoo.com/group/Homebrew_PCBsYahoo! Groups Links
>
>
>

How about using thin aluminuim plates for printing machines ? They come 
cheap.

Bonus is that they already come presensitised with photosensitive layer...

I always thought those stencils were etched....seems MUCH easier and
probably more accurate.  Just my 2-cents worth  :D)

Charlie

On Sat, 20 Jul 2013 23:45:49 +0000 brane2 <brankob@...> writes:
  
Dne 20. 07. 2013 21:53, pi�e brane2:
> How about using thin aluminuim plates for printing machines ? They 
> come cheap.
>
> Bonus is that they already come presensitised with photosensitive 
> layer...
>
>

And how about etching them instead of machining BTW ?



[Non-text portions of this message have been removed]

I had seen this a couple years ago and tried it myself and got good results, especially considering how surface tension and solder paste 'pulls' parts into alignment - get some .004 copper 'foil', do a toner transfer on it w/ the gerber of the stencil file and then etch like you would a board.  just takes a bit longer to etch and of course protect the back, but other than that works great.  I have also seen it done w/ Al pop cans.  W/ the pop cans you have to clean the inside as there is some coating, but a regular 'prep' for etching seems to work, nothing too thick.

Bob

--- In Homebrew_PCBs@yahoogroups.com, "ohmware" <kaelin@...> wrote:

>
> My SMT adventures continue... I am making some promising progress, but I have discovered that the bronze sheets I am using to make stencils are destroying my tools! Cutting out one stencil for a small DCDC converter layout left my almost-new V60 tool unusably dull.
> 
> The bronze sheets would be fine, I think, for larger pitch components where you can simply do a through-cut with a small end-mill. But my smallest end-mill is 0.02" and that's too large to stencil the pads for the 0.65mm pitch IC I am using.
> 
> Has anyone used an alternative material for machining SMT stencils?
>

On Sun, Jul 21, 2013 at 8:32 AM, dubob4432 <dubob4432@...> wrote:
> I had seen this a couple years ago and tried it myself and got good results, especially considering how surface tension and solder paste 'pulls' parts into alignment - get some .004 copper 'foil', do a toner transfer on it w/ the gerber of the stencil file and then etch like you would a board.  just takes a bit longer to etch and of course protect the back, but other than that works great.  I have also seen it done w/ Al pop cans.  W/ the pop cans you have to clean the inside as there is some coating, but a regular 'prep' for etching seems to work, nothing too thick.

  http://lowpowerlab.com/blog/2013/02/11/diy-smd-metal-stencils-the-definitive-tutorial/

Mitch.

Dne 20. 07. 2013 21:53, pi\u0161e brane2:
> How about using thin aluminuim plates for printing machines ? They 
> come cheap.
>
> Bonus is that they already come presensitised with photosensitive 
> layer...
>
>

And how about etching them instead of machining BTW ?

Where does one source these, exactly? My quick Google on the topic turned up a lot of interesting links about printing ON aluminum plates, and a pretty interesting bit of kit from Epson for professional printing shops, but no obvious source of supply.

--- In Homebrew_PCBs@yahoogroups.com, brane2 <brankob@...> wrote:

>
> How about using thin aluminuim plates for printing machines ? They come 
> cheap.
> 
> Bonus is that they already come presensitised with photosensitive layer...
>

This sounds promising, thanks!

--- In Homebrew_PCBs@yahoogroups.com, Mark Lerman <mlerman@...> wrote:

>
> 
> I have made stencils using thin (10 mil) Garolite (FR4) that I get 
> from McMaster-Carr.
> 
> Mark
> 
> At 12:56 PM 7/20/2013, you wrote:
> >My SMT adventures continue... I am making some promising progress, 
> >but I have discovered that the bronze sheets I am using to make 
> >stencils are destroying my tools! Cutting out one stencil for a 
> >small DCDC converter layout left my almost-new V60 tool unusably dull.
> >
> >The bronze sheets would be fine, I think, for larger pitch 
> >components where you can simply do a through-cut with a small 
> >end-mill. But my smallest end-mill is 0.02" and that's too large to 
> >stencil the pads for the 0.65mm pitch IC I am using.
> >
> >Has anyone used an alternative material for machining SMT stencils?
> >
> >
> >
> >------------------------------------
> >
> >Be sure to visit the group home and check for new Links, Files, and Photos:
> >http://groups.yahoo.com/group/Homebrew_PCBsYahoo! Groups Links
> >
> >
> >
>

Wouldn't know about globally renowned manufacturer, but our local - 
Slovenian manufacturer is here:

http://www.cinkarna.si/en/products/graphic-materials/printing-plates


[Non-text portions of this message have been removed]

--- In Homebrew_PCBs@yahoogroups.com, brane2 <brankob@...> wrote:
>
> Dne 20. 07. 2013 21:53, piše brane2:
> > How about using thin aluminuim plates for printing machines ? They 
> > come cheap.
> >
> > Bonus is that they already come presensitised with photosensitive 
> > layer...
> >
> >
> 
> And how about etching them instead of machining BTW ?
>
I've been using .003" brass shim stock for several years to make
paste stencils.  I already had a laser photoplotter I built for
making master artwork for PCBs, and a dry film laminator.  So,
I make two mirror-image artwork films with black for the pads,
and glue them together in alignment on a light table.  I put
a scrap of film between them as a spacer to equal the shim.
First, I wet-sand both sides of the shim stock to remove
what seems to be some kind of anti-corrosion film they apply
to it.  I use 400 grit sandpaper.  I laminate the dry film resist onto both sides of the shim stock with the heated-roll laminator.
I have to put a paper shim on the other side of the brass shim
as the machine is calibrated for proper pressure on a .062" thick PCB.
I expose to UV, develop the dry film resist and then etch, just like a PCB, in Ferric Chloride.  It takes no more than 2 minutes to etch through from both sides in a heated spray etcher.

This works great, and I routinely do boards with 0.65mm lead pitch,
and have done them down to 0.4mm pitch.  I do reduce the aperture
size to less than the actual pad size on the board.

Jon