EDM Applied to make PCB's

[D from BC]

Has anyone had a PCB made by an EDM?

I admit, it's perhaps a weirdass method of making a circuit
board but does it work? Is it slow? Anybody have a homemade one?

Background Info

EDM (Electric discharge machine)...There are commercial units
available on the net for metal machining.
An EDM creates an arc that vapourizes the unwanted metal.. I
believe this can be done in pure water. No oxygen..no smoke.

This is like direct printing so no etch chemicals and no etch
resist required.

You know if I find out this works I might convert my ink jet
printer into a CNC and make an EDM for small boards..

As a rough experiment, I used a microwave oven transformer and
zapped a PCB in a tray of water... Cool seeing 2kV arcing in
water. Surprised to see only a few tiny bubbles for such high
energy ....I successfully made a tiny hole in the copper only.
Industrial EDM's I think use much lower voltages.
(Please do not copy my experiment unless you are familiar with
high power& high voltage.)

 

[Eeyore]

Has anyone had a PCB made by an EDM?

I admit, it's perhaps a weirdass method of making a circuit
board

Yes.

Why would anyone bother ?

Graham

 

[Homer J Simpson]

As a rough experiment, I used a microwave oven transformer and
zapped a PCB in a tray of water.

I believe kerosene is a more commonly used fluid.

 

[Luhan]

I believe kerosene is a more commonly used fluid.

Hmmm, 2 kv sparks plus kerosene ???

[Luhan looks for rock to hide under...]

 

[[email protected]]

Has anyone had a PCB made by an EDM?

I had a PCB made with money. Money is a widely used substance that
allows one to transfer onerous tasks over to someone specialized in
said task. Money has no particular storage requirements. I mean, I like
steak, but it wouldn't occur to me to get my own cow.

 

[DJ Delorie]

I mean, I like steak, but it wouldn't occur to me to get my own cow.

Some friends of mine have their own cows. And pigs, and other
animals. They haven't had to pay store prices for meat in years.
They're called "farmers". Without them, you wouldn't be able to get
meat either.

It takes all types. Some of us are DIY, some of us are $$$, some of
us are both. Can't you just accept that different people like doing
different things?

 

[D from BC]

I believe kerosene is a more commonly used fluid.

Hmmm, 2 kv sparks plus kerosene ???

[Luhan looks for rock to hide under...]

Yes I know...1kW energy + fuel=more danger....Isn't kerosene
similiar to jet fuel.. This could spark some ridicule...how
about zapping in liquid propane.
I do recall there are other liquids used for EDM.

 

[[email protected]]

Has anyone had a PCB made by an EDM?

I admit, it's perhaps a weirdass method of making a circuit
board but does it work? Is it slow? Anybody have a homemade one?

I don't think it's a very good fit.

EDM tends to come in two varieties. One is very localized, either
point-type, or a wire "saw" which cuts all the way through something.
Covering a whole pcb with a point type operation would seem rather
slow, but I suppose might be an option for designs where you can leave
most of the copper and simply use thin outlines of removal to isolate
pads.

The other is a larger area operation, but requires a shaped electrode -
essentially, making a die. Usually this is a quite messing operation
of machining a block of graphite.

When photoresist is not used, the preferred choices in practice seem to
be either a specialized milling cutter, or a laser system. My employer
uses both to make small geomotery-critical microwave boards, generally
on teflon substrate.

 

[[email protected]]

Some friends of mine have their own cows. And pigs, and other
animals. They haven't had to pay store prices for meat in years.

Good for them. Ask them how much effort and machinery is required if
all you want is *one* filet mignon. I mean I like wearing T-shirts, it
would never occur to me to open my own sweatshop.
Also ask them if they sell the rest of their meat? Wouldn't your
comparison imply that if you make your own PCBs you should sell some if
it's comparable to the farmer's case? The farmer is just *gasp* like a
PCB shop.

They're called "farmers". Without them, you wouldn't be able to get
meat either.

Exactly, they're called farmers, and god bless them for we are all
parasites on them in the end...

It takes all types. Some of us are DIY, some of us are $$$, some of
us are both. Can't you just accept that different people like doing
different things?

Farmers call themselves farmers, I'd bet. They don't call themselves
"gourmets" and then go around asking on gourmet groups about how to
make your own steak, am I right?

Just like a farmer grows meat, a PCB shop makes PCBs. It's really quite
simple, otherwise they wouldn't call themselves a PCB shop.

My problem is that this is an electronics group, and we have people
wasting time and energy on something that's been done for 50+ years and
is easily accessible with pocket money today, instead of building
phase-locked oscillators or PIC based LED flashers.
Building my own PCBs is a phase I went through in high-school, and then
quickly abandonned as my projects became more than 1 IC with 1
resistor.
No one asks how to make their own resistors out of nichrome wire...

 

[John Popelish]

My problem is that this is an electronics group, and we have people
wasting time and energy on something that's been done for 50+ years and
is easily accessible with pocket money today, instead of building
phase-locked oscillators or PIC based LED flashers.
Building my own PCBs is a phase I went through in high-school, and then
quickly abandonned as my projects became more than 1 IC with 1
resistor.
No one asks how to make their own resistors out of nichrome wire...

The O.P. might take this idea to one of these Yahoo
discussion groups:
http://groups.yahoo.com/group/CNC-PCB_Design/
http://groups.yahoo.com/group/pcb-gcode/
http://tech.groups.yahoo.com/group/Homebrew_PCBs/

I can imagine this technology becoming an environmentally
friendly way to make boards, if sufficiently developed.

 

[John Devereux]

My problem is that this is an electronics group, and we have people
wasting time and energy on something that's been done for 50+ years and
is easily accessible with pocket money today, instead of building
phase-locked oscillators or PIC based LED flashers.
Building my own PCBs is a phase I went through in high-school, and then
quickly abandonned as my projects became more than 1 IC with 1
resistor.
No one asks how to make their own resistors out of nichrome wire...

I made a couple of test boards last weekend - surface mount, single
sided+ground, couple of square inches each. Took about 1/2 hour for
the pair of them. In fact most of that was waiting for things to
happen, so probably 10 minutes actual "labour". It would have taken me
longer than that to prepare the gerbers and go through the order
process. Then I would *still* have to wait 2 weeks and pay >$60.

I would always out-source actual production, and, these days,
prototypes much more complicated than the above. But I find manual
production still has a place.

 

[Barry Lennox]

On 16 Dec 2006 09:04:55 -0800, [email protected] wrote:

snip

No one asks how to make their own resistors out of nichrome wire...

Probably because it's pretty easy to do. I do still make the odd load
resistor from Nichrome wire, Why? because it's incredibly easy, cheap
and fast. I could make another resistor in the time taken to fill out
a web-based order form. It costs me virtually nothing in materials.
Compare that with waiting 1-2-3 days, the cost of the resistor and
"Freight and handling ", that jolly convenient excuse to pad your bill
a little.


But going back to PCBs, there's a time and place for everything, and I
don't really understand why there's a problem with that. Occasionally
I want a new rev of a board this morning, or today at the latest.
What PCB house can do that ? And while they all produce high quality
PCBs, I have become a little cynical about their advertising and
promises about delivery. Things like:

"Aha, day 1 only counts if you have the design here by 0730, 0800 is
far too late"

"Ohh, the UPS man missed us today for some reason, that's not our
fault that it adds one day"

 

[[email protected]]

The O.P. might take this idea to one of these Yahoo
discussion groups:
http://groups.yahoo.com/group/CNC-PCB_Design/
http://groups.yahoo.com/group/pcb-gcode/
http://tech.groups.yahoo.com/group/Homebrew_PCBs/

I can imagine this technology becoming an environmentally
friendly way to make boards, if sufficiently developed.

There's a description of exactly such an effort on the last group
mentioned, with decent results, IIRC. Raster-scan, EDM, zap, zap, zap!

Best,
James Arthur

 

[[email protected]]

Has anyone had a PCB made by an EDM?
...(Electric discharge machine)

Most printed wiring boards are made by chemical etching or by ECM
(electro-chemical machining), using an electrolyte that dissolves
the copper. This is relatively fast, and the 'hazardous' material
is only the copper itself (the etchants are much more benign than
the copper is, chemically). Simple etching leaves the copper
dissolved in the solution, ECM can plate the copper out of the
solution (good for recycling).

The etching or ECM works straight from a printed-on resist coating.
EDM won't. You'll have to raster-scan the board to do the work, just
like the
mini-mill machines do. And, we used graphite, copper, or tungsten
electrodes
for EDM (they wear down slowest); so we would predict that copper is
going to be a very slow material to machine with EDM techniques. The
thermal conductivity makes lots of the heat of the spark dissipate
instead
of removing material, and the dissipated heat IN THE WORKPIECE will
be a limit on cutting speed (turn the current up, you burn the board;
turn it
down, you cut real slow).

Some exotic boards are made in porcelain-on-steel, with additive
(electroplated)
copper. You could make a steel/porcelain/steel board that would be
strong,
mechanically stable, and the steel would ECM just fine. Weld on your
components, and there ya go: ROHS compliant lead-free printed circuits.

 

[Luhan]

The O.P. might take this idea to one of these Yahoo
discussion groups:
http://groups.yahoo.com/group/CNC-PCB_Design/
http://groups.yahoo.com/group/pcb-gcode/
http://tech.groups.yahoo.com/group/Homebrew_PCBs/

I can imagine this technology becoming an environmentally
friendly way to make boards, if sufficiently developed.

I get up at 6am with an idea; prototype by 8:30; board layout by 10:00;
working unit before noon; have a nice lunch; wonder if Law and Order
reruns still start at 2pm?

My workload averages about 10 hours/month lately. So I have more 'free
time' than 'free money'.

http://members.cox.net/berniekm/pcb.html

Luhan

 

[Rich Grise, Plainclothes Hippie]

I had a PCB made with money. Money is a widely used substance that
allows one to transfer onerous tasks over to someone specialized in
said task. Money has no particular storage requirements. I mean, I like
steak, but it wouldn't occur to me to get my own cow.

That's easy for the idle rich to say.

We didn't all inherit billion-dollar estates, and some of us don't even
have a sugardaddy! Imagine that, if you can.

Thanks,
Rich

 

[Ban]

My problem is that this is an electronics group, and we have people
wasting time and energy on something that's been done for 50+ years
and is easily accessible with pocket money today, instead of building
phase-locked oscillators or PIC based LED flashers.
Building my own PCBs is a phase I went through in high-school, and
then quickly abandonned as my projects became more than 1 IC with 1
resistor.
No one asks how to make their own resistors out of nichrome wire...

You should understand the hobbyist approach.
Maybe I find an interesting circuit on a website and because I want to use
these free samples I have already one year, decide to make it. It is just a
small circuit, some audio preamp for a small electret mike to measure
frequency response of speakers, a booster for operating white LEDs on a
single cell, a PWM to drive a small motor, whatever.

I then order the parts, of course in through-hole, because I can breadboard
them. Digikey has too high prices and shipping costs. I also have a great
stock of salvaged parts to reuse, so the order is really small and cheap.
I do not really trust those simulators and I also do not know so well how
to operate the prog.
In the meantime I programm the PIC, and after some trouble because the
website listing is for the 16F84, I manage to programm it.
Now all the parts are there and I plug them into the breadboard. The PIC
still has to be reprogrammed, because I inverted the outputs and some minor
glitches, but the rest of the hardware works. I will try to tweak a few
values, seems a bit sensitive to EMC when I move my hand close, but finally
the board can be made.
I just paint it with that etch resistant marker on the cleaned copper. The
etching is done in 15 min. after some setup time of course.
The drilling is a bit messy, broke that expensive tungsten drill, because it
was difficult to center and the stand is giving away. But anyway, now the
soldering iron is already hot. Lets hope that pot has some flexible leads,
the holes are a bit off...
But it is all my own work, well maybe not the schematic, but at least the
board. Have to show it to my GF!