Wendy and CNC Builders... Question on PCBs

[Perik]

Hi Les.

What version(eg lite,standard Free) are you using?
Thanks for replying with great detail, very much appreciated.
Les

The version I'm running is:
DipTrace Non-Profit, 1000 pins, 4 signal layers, non-profit use only Cost: €95

I believe this is a better offer than Eagle at least looking at pricing here in Norway.
Nice thing with Diptrace is - no size limit which is usually the case for Eagle (160x100)
Diptrace have a quite steep learning curve though when you've passed those first basic tutorials,
the sky starts to lightning up a bit...

[iwik]

Hi Per-Erik
Thanks for the reply, i agree, Eagles board size limitation is a killer. Will go for the same as you when ive become more familiar with the package. Steep learning curves seem to be norm today with anything that has some sophistication to it.
By the way you did a great service to us all for the rewrite of the Master card Schematic, the original was terrible to read.

Regards
Les

[Perik]

Hi Les,

The diagram didn't become too much better than the original.

As you may have observed, I’ve done a few changes which suites me well.
I’ve reduced the size of External Bus connector – from 40 to 16 pin and removed one of the 259 IC's.
So if you are not going to use some of those old boards, this should be safe.
I believe the only board in general use today utilizing this connecter is the
Display-II board and then only thirteen pins.
BTW, I’ve done the same change on my own Display-II board.
I’ve also replaced the DB-9 with a 10-pin IDC connector.
The connector symbols used can be confusing – it’s more to get the
drawing easier to make/read.

Just tell when you’re ready.
I have a couple of libraries which you could take advantage of.
Adapted those few components I’m using to CNC – mainly increased
the size of pads in component pattern.
You can also have the Diptrace files (Schematics & Layout)
for misc. board if you like and do your own customizing very quickly.
It's this possibility which is charming. Make simple changes without breaking the
protocol.

[riche543]

Hey Perik Ive been trying to workout the cnc cutting of the pcb,s. Im trying to figure out what is really happening in the cutting process. Now when etching/cutting the pcbs are you cutting away what is not needed of the copper, or am i missing something else. sorry if this is a dumb question im very thick sometimes when i look at the videos of the pcb,s being cut it looks like the tracks are being cut but im then thinking if your removing the copper from the tracks then theres nothing for current to pass??
Cheers
Rich..

[Perik]

Hello Rich

It’s nothing like a dumb question in this “game”.

What we are doing is called “isolation routing”. Search for this topic at
Google and you’ll find a huge amount of information.
When you bring your PCB layout (in my case in DXF format) into your
CAM package all the traces will be shown as they are in the layout program and
with correct width. The traces are continuous curves / line segments – including pads.
I then run “outside contour” tool-path with a 60 degrees V-cutter.
V-cutter for pcb-milling is a science in itself and is available in many shapes and a wide price-range.
Those I’m using are low-cost engraving V-cutters from:
http://www.cnc-plus.de/Fraeser---Boh...uter-Bits.html , but any V-shape can be used.
I know somebody using this type as well:
http://www.cnc-plus.de/Fraeser---Boh...Bits-1007.html with 0,1mm tip-diameter.

The depth is another issue which you need to have control over and that’s all the
way from the CAM software. The path distance from the trace edge is calculated
in the CAM package based on the specification of the V-cutter (angle/tip) and the depth set.
The cobber layer usually have a thickness in the range 30-40um.
I mill at approximate 0,1mm depth but I always starting “high” and goes slowly
down step by step (0,05mm) until the isolation is OK. Use a Ohm-meter to verify.
In the end the depth is not critical – just get properly through the cobber and still have some traces left
This is something you will master within a very short time.

Happy milling

[iwik]

Hi Per-Erik,
All understood, realised you had done a few changes. Would much appreciate Libraries , misc and yes it would make for easier changes without having to start
from scratch. Im not quite ready yet but like to collect this imfo when i can.
Thanks
Les

[riche543]

Thanks Per-Erik for that. Im understanding that much better now. not 100% but my brain seems to take a long time understanding things . Thanks Again...

[Rob65]

Wow,

thanks to Per-Erik for your nice words.
I realize that my website is out of date with my current activities - I should really update and show some of my later work.

I recently started to do some PCB work using a very old version of Protel (9 that had a great user interface in the old days ... Need to update to something like Eagle - which a lot of people are using nowadays. A good thing on Eagle is that there is a freeware version for non-commercial use keeping it all legal

Coppercam is IMHO the tool to convert PCB layouts into milling data. You can change track width, size of the isles, size of drilling holes and one of the best features is that you can isolate regions of a PCB which is a must for small pitched connectors.

Rob