If you have any questions or comments, please feel free to post them here.
Re: Isolation Routing
Posted: Wed Jun 14, 2017 8:06 pm
by baysale976
I'd love to see a greater discussion of cutting tools, including brand and model/type.
I have a CNC PC Board drilling & milling machine I built in the 1990s that I've used for (some) isolation routing, and for that I made a fixture to hold PCB material. Basically it was a piece of MDF with a pocket milled perfectly flat (by the machine), with small clamps in each corner to hold the material down. I haven't used it in years - not many PC Boards these days - but it did its job well in the day. I never did get a great tool though, settling on a 1/32" mill and going quite slowly.
As for double-sided, each 2s board had two Index holes, pre-drilled, so I could expose, etch and drill the board and have both sides register (line up) well. the alignment holes were part of the PC Board pattern of course.
Re: Isolation Routing
Posted: Thu Jun 15, 2017 6:50 pm
by msimpson
Did some testing with the 20 degree V-bit today and have to say it exceeded my expectations. While these are not true CAD generated PCBs, they do show how tight the system is.
The spacing on the tiny little rectangle under the CNC text has a spacing of .02" and still leaves enough isolation and clean traces.
The little machine I am using (Titan) needs some calibration on the X-axis but other than that its much better than some of my earlier boards I did on the KRMx01 back in 2011. Titan has a water cooled 3HP spindle on it and it purrs like a kitten even at 24000 RPMs.
Here I was able to run a trace cleanly between two pads on an DIP.
Way big double thumbs up. I hadn't even considered circuit boards when building my KRMx02, but this is a huge un-expected bonus... electronics are my second favorite hobby...
Re: Isolation Routing
Posted: Sun Jun 18, 2017 10:42 pm
by msimpson
Still working on my single sided workflow page.
Here is a quick vid of a circuit I just made.
Re: Isolation Routing
Posted: Sun Jun 25, 2017 3:37 pm
by baysale976
Very nice Michael.
What software are you using to generate the cutter path?
I see that Eagle free software has a board size limitation. I have Diptrace lite (has good reviews) and have laid out a very simple board with LEDs and resistors. PCB houses want a lot of bucks for the board. I found this free program that will convert Gerber 247 files to copper: https://carbide3d.com/copper/
They make three passes with this bit: https://shop.carbide3d.com/collections/ ... 4153728198
it is .01" Ball tip (.005" radius), 60 Degree tip angle and 0.125" shank.
You selected a V tool and gave a link. What feed rate would you suggest for the KRMx02?
Also, do you have any suggestions on how to tin plate the copper?
Thank you for your help.
Re: Isolation Routing
Posted: Sat Apr 18, 2020 11:38 pm
by msimpson
As far as feed rate, for the small bits I would not be going faster than 15 IPM. Practice on a scrap board. Looking at the video, I would guess about 10IPM.
As far as tinning the board, I never did. There is probably a way to do it, but I always liked the raw copper patina.
The most problematic area is making sure the board is flat. I had success with a vacuum fixture I made out of Corian.
The other problem I had was that the copper boards are not always consistent in thickness. This will mess up the traces. Mach3 has a way to probe the board and store the thickness at various points. It will then use the file it creates to properly machine the board. It works well. The problem is it only works with parallel ports.
I'm not sure about UCCNC software, it may work with some of their motion controllers, but you will have to do the research.
I use it to build out a breadboard representations for IoT projects - and from that you can generate a schematic and a PCB (all parts as PDF)
It has a pretty good parts library for IoT and basic electronics, and can do autoroute
Re: Isolation Routing
Posted: Mon Apr 20, 2020 1:11 pm
by Joey427
Thanks for mentioning - I will look into it.
Re: Isolation Routing
Posted: Wed Jul 01, 2020 3:34 pm
by Joey427
FYI: quotes on a circuit board from a Taiwan vendor were two to three times cheaper than quotes from an American supplier even when shipping is included! The small quantity is what really hurts. Board is on hold at present.
Will use isolation routing in the future, especially for power circuits and/or heavy components.