CNC isn't a milling machine. LPKF has all sorts. I was certified with
them.

CNC is computer numeral control. e.g. commands sent.

CNC laser driven to expose trace and then in the box or outside develop
and etch.

I used to use Ruby and blue tape for IC's. Then PCB's then CAD came and
early cad used a CNC laser to draw on the wall to make large film
sheets. In those days we were into 18x24 many layer. Later we went
large square and special material with fluid cooling on both sides...

The small LPKF I used was to make protype test boards to spec and one
day after the Cad design was completed.

Martin

On 10/24/2016 1:19 PM, rangerssuck wrote:
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.