Homebrew_PCBs

Hi list,

Has anyone used EDM to cut the traces on a PCB? You would
still have to drill through holes, but with surface mount parts the
number of holes would be limited. Since EDM uses only minimal contact
and no rotating parts the problems with rigidity are reduced and the
problems with quills go away.

CWR

You would -really- have to plan the cut path carefully. As soon as
an area is cut free from wherever your contact point is at, you can
no longer cut that area.

Steve Greenfield

--- curt_rxr <rxr@...> wrote:

> Hi list,
>
> Has anyone used EDM to cut the traces on a PCB? You
> would
> still have to drill through holes, but with surface mount parts
> the
> number of holes would be limited. Since EDM uses only minimal
> contact
> and no rotating parts the problems with rigidity are reduced and
> the
> problems with quills go away.
>
> CWR

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Hi Curt,

Interesting idea, but I'd be concerned about the contamination of the
board with the arc eroding of the isolation cuts.

Alan KM6VV

curt_rxr wrote:

>
> Hi list,
>
> Has anyone used EDM to cut the traces on a PCB? You would
> still have to drill through holes, but with surface mount parts the
> number of holes would be limited. Since EDM uses only minimal contact
> and no rotating parts the problems with rigidity are reduced and the
> problems with quills go away.
>
> CWR

Curt,
Rather than say it won't work. I would suggest a copper
washer foot that rides on the PCB. This is the return contact.
The copper washer would ensure a return path for the EDM.
The EDM electrode works within the hole in the copper washer.
On the down side, you might find thin traces are zapped away
like the element in a fuse!

John

--- In Homebrew_PCBs@y..., "curt_rxr" <rxr@f...> wrote:
> Hi list,
>
> Has anyone used EDM to cut the traces on a PCB? You would
> still have to drill through holes, but with surface mount parts the
> number of holes would be limited. Since EDM uses only minimal
contact
> and no rotating parts the problems with rigidity are reduced and
the
> problems with quills go away.
>
> CWR

--- In Homebrew_PCBs@y..., Alan Marconett KM6VV <KM6VV@a...> wrote:

> Hi Curt,
>
> Interesting idea, but I'd be concerned about the contamination of

the

> board with the arc eroding of the isolation cuts.
>
> Alan KM6VV

Hi Alan,

The effluvium would be colloidal copper in water. It should
clean up when you scrub the board prior to plating ( I think!? )

I was thinking using water pumped through a grounding sleeve,
which would make certain of return path for the spark and also
constantly flush the eroded copper from the board. Since the
electrode would be a mechanical pencil lead, the sleeve would small
and the dielectric flow would be limited.

The software would have to cut the isolated areas first (
i.e. inputs in guard rings and drill center pips in pads ).

CWR

Hi everyone:
Just out of curiosity I was wondering what the most complex board anyone on this group has ever made... Homebrew style and complicated being number of layers, components, nets density, etc. I am interested in hearing your stories!
Thanks!
Randy Knutson



---------------------------------
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Yahoo! - Official partner of 2002 FIFA World Cup

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

Hi Ken,
My hardest board so far has 12 ICs 2 Transistors 32
diodes 15 resistor 1 parallel port connector and 17 caps. All
on a single sided 4" X 6" board. This is a spin off of my
transistor output board. The board has over 30 wire jumpers.
I almost gave up after putting the L298 in backwards. I used
the data sheets. The drawing led me to think pin one was on
the short pin row. The boards are milled at 6" per minute and
they take an hour an a half to mill. This includes the starter
holes in the pads. The board works and the hold up is the
heatsink. L298s get much hotter than I expected. To cut
costs I designed a homemade heatsink.

John

--- In Homebrew_PCBs@y..., Randy Knutson <ken_ryder@y...> wrote:
>
> Hi everyone:
> Just out of curiosity I was wondering what the most complex board
anyone on this group has ever made... Homebrew style and complicated
being number of layers, components, nets density, etc. I am
interested in hearing your stories!
> Thanks!
> Randy Knutson
>
>
>
> ---------------------------------
> Do You Yahoo!?
> Yahoo! - Official partner of 2002 FIFA World Cup
>
> [Non-text portions of this message have been removed]

Randy: I have done up to seven 14 and 16-pin IC's, double-sided, using
eyelets in the few places a PTH hole was absolutely necessary.
Component-leads often will substitute fine for PTH, but not always! An
irritant!

Anything more than that, I have a professional PC house do 'em.

I DO have a home-brew CNC PCB drill that is faster than a drill-press, even
when you include the time to measure and type-in the X and Y coordinates in a
"file"!

I have TRIED to upload the pic, but I can't see it (yet). Maybe I don't know
how!

Jan Rowland

This is just one of many.. This one has 14 Integrated circuits, a mix
of SMD and thru-hole, plus lots of other components.
I made the prototype ( I try to make all my own prototype) and
production version is an exact duplicate (layout) except for solder
mask.

About half way down the page
http://hans-w.com/ursa.htm

hansw

Dear Hans:
I was wondering how you lay out and solder your surface mount components out or are those not on your prototypes?
Thanks!
Randy Knutson



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Yahoo! - Official partner of 2002 FIFA World Cup

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

Compare this old prototype and you will see it is the mother of the
production version, less SMD(one chip)
http://hans-w.com/Old_Ursa_Prototype.jpg

These are almost all SMD
Last three weeks... I'm really busy at the moment...
http://hans-w.com/past_3_weeks.jpg

I am using a minitature Weller soldering iron with a 0.01" tip, and do
all my SMD soldering work under a stereo B&L Microscope

Hans W

Randy Knutson wrote:

>
> Dear Hans:
> I was wondering how you lay out and solder your surface mount
> components out or are those not on your prototypes?
> Thanks!
> Randy Knutson
>
>

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

In a message dated 30-May-02 07:53:48 Central Daylight Time,
hans@... writes:

> Compare this old prototype and you will see it is the mother of the
> production version, less SMD(one chip)
> http://hans-w.com/Old_Ursa_Prototype.jpg
>
>

Very nice work! Jan Rowland


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