"rangerssuck" wrote in message
...
On Sunday, October 23, 2016 at 9:27:13 PM UTC-4, Martin Eastburn
wrote:
How big a board are you talking about ?
Will a cnc machine do the job - there are companies that make
enclosed
lasers.
Martin

No particular size, though my work usually fits in 8" x 10" or so.
This was more of an exploration into the practicality of producing
quick protos in my shop rather than sending them out and paying big
bucks or waiting a long time for them to come back.

when you say "cnc" I assume you mean milling machine. That would work
for some boards, but I don't know what kind of resolution you can get
that way, I find it hard to imagine 6 mil traces and 6 mil spaces from
a milling machine, though I haven't looked in that direction recently.

Another possibility is using a laser to remove a resist layer applied
to the board. People are getting promising results that way, but it's
not easy to control a chemical etching process with such small
features. It would seem (to my uneducated mind) that it would be
easier and more repeatable to dial in the parameters for a laser etch
than for chemicals.

The machine I saw a price for was from LPKF. I did not find an online
price, but I did find a public record contract from a college in the
Pacific Northwest to purchase one. Delivered and installed, with a day
or two of training, the prices was around $250K. A bit out of my price
range.

I do have access to a 40W laser cutter at the local makerspace, and I
may take a whack at the etching of a chemical resist (most likely
black Krylon) when I get some free time.
=========================================

I used these with generally acceptable results:
http://www.t-techtools.com/store/

At the time, the 1990's, 6 mils was difficult but possible for them,
IIRC 10 mils was easy. The Z height adjustment of the tapered
engraving cutter relative to an adjacent foot that pressed the board
against the platen set the space width. It was capable of milling a
GPS receiver. I used Mentor's PADS for PCB design .

--jsw