etching printed circuit boards

Jamie <[Only registered users see links. ]> writes:


This is really useful information! I was wondering whether one could
do it with an EDM but I have so little knowledge about the devices
that I wasn't sure what one can or can't use it for. Everything I know
about EDM comes from the catalogue for Lindsay Publications, which sells
a book (24 pages, I think) on how to make your own EDM. Jamie, are you
familiar with this book or did you learn some other way of making an EDM?

More questions: What kinds of fumes does it generate? Also, do the electrical
discharges cause any damage to the underlying board itself? Was it your
own idea to use this for making printed circuit boards or did you read
about it somewhere and, in that case, where? If not, would you consider
writing a more detailed article about your experiences making printed
circuit boards this way? I think that that a sufficiently detailed and
protracted explanation could get published by Lindsay Publications, just
as they have published books (e.g. on how to cast your own pulleys) spawned
by the Gingery series on making your own metal shop. It doesn't have to be
500 pages: some of their books are only a couple of dozen pages, e.g. the
EDM book.

I guess this now also raises the following question, more pertinent to
sci.chem: how might one use an EDM in chemical experiments? I'm sure there
are lots of chemicals to try it on under various conditions, but just to
keep the discussion a little more self-contained, what would happen if
you grew a single crystal of spent etchant and applied an EDM to it?
What would be the chemical effects on the crystal and what would be
the products?

Ignorantly,
Allan Adler
[Only registered users see links. ]

************************************************** **************************
* *
* Disclaimer: I am a guest and *not* a member of the MIT Artificial *
* Intelligence Lab. My actions and comments do not reflect *
* in any way on MIT. Moreover, I am nowhere near the Boston *
* metropolitan area. *
* *
************************************************** **************************

well thanks for your interest on the EDM.
no i wasn't aware of any published books on the
idea use of EDM on clad boards., i got the idea back
when i use to service some machine shop equipment. there
they had 2 EDM's, one for rough cut and one for the fine
cuts.
they would make carbit dyes use in various operations like
stamping out revits, nuts etc..
because the material is very hard it makes it difficult to
use common milling processes..
so what they did was make for example Hex brass stock and use that
for the quill (neg side) the stock material was placed in a holder at
the base of the tank and then the tank was filled with insolating oil.
after a short period of the brass probe inserting it self against the
stock material with regulated currents and servo's on the drive you
would have a nice near perfect hex hole of about 1 " in depth.
this unit simply used rectified DC at around 400 volts low current.
the second unit for the final was polishing used 400 cycles of
pulsed Dc on the probe. the unit had 4 banks of Push-Pull 3-400Z tubes
..
the whole theory is simply a plasma burn much like used today in
plasma cutters etc..
using the insolated oils it cuts down alot on the splatter and
carbon effects.
i call it plasma, some simply call it electro discharge burn.
i maybe miss using the terms but i think i get my point accross.

any ways i use 1 stepper motors to drive the X scan in bidirection
scans to speed things up and the Y motor to move down the clad board.
the head is a retractable hard point tip that is pulled in via a
electromagnet to skip over the area's not required to be removed..
i use a current shunt circuit so that i know when the copper is
fully removed. if a short out takes place the tip is retracted and
inserted again..
when the area is complete the X scan moves to the next possition.
this works well because low side of the board is clamped into the table
for the current path.
i need to remove the pin now an then and clean it up for better edges..
../.
my use of the blue dye actually works quite well too.
how ever that means i need to use etching.



Allan Adler wrote: