Hans,
I use micrograin carbide Mechanical Etching bits. Drilling is
one thing. Speed can be lower than 16,000 rpms. Dragging the bit
through the epoxy for 800 inches is something else. I contacted the
place you are a consultant for. They were unable to supply a milling
bit at that time for less than Think and Tinkers price. I tried all
kinds of tricks. I think if somebody made a different kind of board.
Something that is good for 50 volts or less. Use plastic instead of
glass epoxy.
John
--- In Homebrew_PCBs@y..., hans@c... wrote:
> John,
> OK ... I used to have the same problem with drills until I started
using
> solid carbide, It seems they never wear out.
> Have you tried a 0.031" ball nosed mill in solid carbide, I feel
sure it
> will last a long long time...
> Price is not that bad...
>
http://www.drilltechnology.com/drill/endmill/Micro_EndMills_2_Flutes_B
all_Nose.html
>
> hansw
>
> crankorgan wrote:
>
> > Hans.
> > When you mill a board, you hit the board material. The copper
> > is soft. The glass epoxy board is like sand paper to the bit. I
> > used to coat the board with motor oil before milling. It only
helped
> > to keep the dust down. Lets face it, there is no easy way to make
> > PCBoards. Every method has its drawback.
> >
> > John
> >
> >
> >
> >
> >
> >
> >
> > --- In Homebrew_PCBs@y..., hans@c... wrote:
> > > Alan,
> > > The Gerber files include "empty" layers. The Modular design is
a two
> >
> > > sided PCB, simply discard the empty layers.
> > > BTW I do not mill boards it's far too mauch work, I use Pre
> > Sensitized
> > > stock and exposure for 120 second using a GE 500W bulb,
> > > then developing in a solution of Red Devil Lye, etch with Ferric
> > > Chloride, the same Ferric Chloride I have been suing for 8
years !,
> > most
> > > people do not understand it, and they throw it away far too
soon.
> > Heck I
> > > even use the same Red Devil Lye mixture until it's so green I
can
> > hardly
> > > see the PCB developing.
> > > .... I can make a two side board (without drilling) in about 45
> > > minutes... 5 mill traces at 8 mill spacing are normal.
> > > BTW mill bits, I wonder why mill bits wear out so quickly,
after all
> >
> > > it's only copper! Could it be because people run the bit dry ?
May
> > be
> > > people are not buying real mill bits...
> > > I have a link at my site for a source of really good quality
mill
> > bits,
> > > size down to 0.002" ( yes! 2 mil ) But 2 mil bits are not that
> > cheap....
> > >
> > > hansw
> > >
> > >
> > > Alan Marconett KM6VV wrote:
> > >
> > > > Hi Hans,
> > > >
> > > > That's quite a nice project! I think I counted 8 layers in
one
> > of the
> > > >
> > > > GBR files! And with over 20 apertures, I'll have to get a
parser
> > for
> > > > the header working! I think I can pick a layer or two with
pads
> > and
> > > > traces, and manually build an aperture table for some simple
tests
> >
> > > > with
> > > > my code. I was able to see a lot of the "foil" layers by
using
> > some
> > > > aperture sizes I had defined previously for another (Eagle)
demo
> > > > board.
> > > >
> > > > Thanks for the URL!
> > > >
> > > > Alan KM6VV
> > > >
> > > >
> > > > hans@c... wrote:
> > > > >
> > > > > crankorgan wrote:
> > > > >
> > > > > > What I find is people are unable to find anything on
> > > > > > the internet. Maybe they use the wrong search engine.
> > > > >
> > > > > I posted a complete design with PCB layout files and
schematics
> > at
> > > > my
> > > > > web site, during
> > > > > the past years I have received 100's or emails from people
that
> > have
> > > >
> > > > > successfully built the
> > > > > Modular Design, with or without the "Smart Current Monitor".
> > > > >
> > > > > The design is Free... I do not charge anything for it..
> > > > >
> > > > > When I get time I'm going to post a new design complete with
> > EAGLE
> > > > > files...
> > > > >
> > > > > Hans W
> > > > > http://hans-w.com
> > > >
> > > >
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