Isolation Routing

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msimpson
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Isolation Routing

Post by msimpson » Wed Jun 14, 2017 10:46 am

I am starting an in-depth web series on isolation routing printed circuit boards.

I will start by creating a fixture that will help create an easy way to mill a board with as little setup as possible.

I will start with some easy tests to make sure your physical setup is sound, then move into single sided board milling.

Finally, I will jump into dual sided milling.

I will cover the software and process needed to create the board drawings.

You can find my initial postings here:
http://www.kronosrobotics.com/isolation ... troduction

If you have any questions or comments, please feel free to post them here.

baysale976
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Re: Isolation Routing

Post by baysale976 » Wed Jun 14, 2017 8:06 pm

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.

msimpson
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Re: Isolation Routing

Post by msimpson » Thu Jun 15, 2017 6:50 pm

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.
_MG_7067.jpg
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.
_MG_7076.jpg
Here is my writeup on the tests:
http://www.kronosrobotics.com/first-tests-1/

munsonryan
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Re: Isolation Routing

Post by munsonryan » Thu Jun 15, 2017 10:39 pm

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...

msimpson
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Re: Isolation Routing

Post by msimpson » Sun Jun 18, 2017 10:42 pm

Still working on my single sided workflow page.
Here is a quick vid of a circuit I just made.

baysale976
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Re: Isolation Routing

Post by baysale976 » Sun Jun 25, 2017 3:37 pm

Very nice Michael.

What software are you using to generate the cutter path?

msimpson
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Re: Isolation Routing

Post by msimpson » Sun Jun 25, 2017 9:41 pm

I'm using Eagle software and the PCB Gcode plugin.
http://www.kronosrobotics.com/setting-up-the-software/

Joey427
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Re: Isolation Routing

Post by Joey427 » Sat Apr 18, 2020 1:06 pm

Michael,

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.

msimpson
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Re: Isolation Routing

Post by msimpson » Sat Apr 18, 2020 11:38 pm

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.

What is the size limitation for free Eagle?

Joey427
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Joined: Sat Apr 18, 2015 5:09 pm

Re: Isolation Routing

Post by Joey427 » Sun Apr 19, 2020 11:53 am

Note: Includes 2 schematic sheets, 2 signal layers, and 80 cm2 board area in demo version.
this is from: https://www.filehorse.com/download-autodesk-eagle/


this place https://www.soselectronic.com/articles/ ... tware-2004 says:
EAGLE Standard includes:
99 schematic sheets
4 signal layers
160 cm2 board area


From the Autodesk website it says: EAGLE is only available with a Fusion 360 subscription. $495 /year


I am making a board that is 5" x 8".

ggibeau
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Location: Rogersville, MO

Re: Isolation Routing

Post by ggibeau » Sun Apr 19, 2020 2:44 pm

Do you think you could use Fritzing (it is like a $9 donation) - https://fritzing.org/home/

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

Joey427
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Re: Isolation Routing

Post by Joey427 » Mon Apr 20, 2020 1:11 pm

Thanks for mentioning - I will look into it.

Joey427
Posts: 70
Joined: Sat Apr 18, 2015 5:09 pm

Re: Isolation Routing

Post by Joey427 » Wed Jul 01, 2020 3:34 pm

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.
:D

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