Milling PCBs

[Joe Lavery]

Hi all,

I'm trying to mill some PCB's using my Zenbot CNC machine with drawings created in AutoCAD. These are then imported into Vcarve but Vcarve doesn't recognise the line width from an imported DXF. Can someone tell me how they mill PCB's or offer a solution to the problem.

Thanks in advance

Joe.

[RomanLini]

Hi Joe, I'm not familar with Vcarve, but for PCBs most people generate a DXF that is a simple 2D tool path, using a fixed line width, then cut it as a 2D cut using the depth of the tool into the PCB to set the line width of the cut lines.

[Joe Lavery]

Hi RomanLini,

Thanks for you info, I understand what you suggest but my problem is relating to the line width. I use Mach3 to control the CNC and Vcarve to generate the G-Code.
It's the track width that's the problem, if I simply import the dxf as a toolpath, the cutter will follow the line but I need it to cut say 1 mm each side of that line not on it. Does that make sense?
I suppose I could reverse the situation and create a toolpath that cuts around the tracks; but thats going to be very complicated when trying to work out pads and intersections...

Cheers
Joe.

[Algirdas]

I could reverse the situation and create a toolpath that cuts around the tracks
there is no other way.
thats going to be very complicated when trying to work out pads and intersections...
its is easy in autocad. Just line shift, for instance.
There are many ways to do that on 'a-cad', not line shift only.
Another solution is 'p-cad' or 'eagle' - the software, designed especially for plane routing. Even some a-cad versions have this feature.
since your dxf is a one line path only, you can use fake tool radius compensation twice to have the path repeated with shift. You need to describe intersections manually if so.

[RomanLini]

If you use Eagle (free version) to design the PCB there is a free plug in (I think it is called "PCBtoGcode"?) that will generate the toolpath for you.

[Joe Lavery]

Thanks for the feedback, as an AutoCAD user I had forgotten the offset command which Vcarve also has, it was a simple process to offset the tracks by 1mm each side to get a 2mm track width. it took a bit of time to reconnect all the tracks to the pads but it worked perfectly. I think sometimes a new thought from someone outside the problem, will suggest a solution I may never have thought of.

Originally Posted by RomanLini If you use Eagle (free version) to design the PCB there is a free plug in (I think it is called "PCBtoGcode"?) that will generate the toolpath for you.

I may have a look at this option also, it may be quicker than the method I'm now using.
Thanks again for you input RomanLini, it's much appreciated.

Kind regards
Joe.

[Bubba]

Joe,
If you decide to go with the PCB-GCode ulp in Eagle, it can be found in the download section of Eagle, on the PCB-GCode Forum site: PCB-GCode Phorum , or in the Ya hoo group pcb-gcode : The pcb-gcode User's Group