Cutting PCB’s - recommendations, tools etc

[Fivetide]

Hi guys 0/ some of you may have read a post I made about cheap PCB’s. I have my schematic done and working on a proto board. The question is I need to shape the corners and reduce the length of the PCB’s, it has to fit inside a rizla tin :) what recommendations would you have for doing this on the CNC , tooling etc? I’m going to have 2 holes in the PCB so I can locate it on a jig for accuracy.

This might be better off in general CNC but I thought I would start here.

[HankMcSpank]

to cut FR4/copper clad board on a cnc machine (eg the outline), I use a chip cutter....

10x Carbide PCB Print Circuit Board End Mill Endmill 2.0mm for CNC / PCB Cutting | eBay

(though I use smaller diameters...1.6mm & 1.2mm)

To do the board outline & ensure it aligns with the tracks & mount holes.

1. Create a DXF of the board including mountholes in your favourite CAD app (ie get your rizla tin, measure it up...create your board outline from your measurements with mount hole locations etc)
2. Use an app called DXF to Script converter (google it)...convert your DXF file to an eagle script file.
3. Within eagle 'board view' run the script you just created in step 2 (file ->script browse for the file you created & run it)

Voila....you've now got your exact outline on the Eagle Dimension layer...now you can route your Eagle PCB tracks around knowing with 100% certainty that everything will come out right!

Once you've finished your Eagle PCB layout...

Run an eagle job to save pcb track outlines as a gerber (within board layout, file-> cam processor->file->open->job select gerb274x.cam then process job - this creates a gerber file of your pcb tracks)

Now open up the gerber file in cambam (this is your pcb tracks), convert from imperial to metric (within cambam ctrl A, ctrl e-> select convert from inches to mm) ....it can all be cam'ed up now (along with your earlier DXF file for the outline mount holes)

[Fivetide]

As ever Hank Awesome , thanks :) I have ordered some 2mm ones 10 should last me a while I post results but it will be a while before I actually do some.

[C_Bubba]

I do mine same as Hank up to the point of getting it out of Eagle.
Here, I use the pcb-gcode.ulp to create the gcode files directly. Then I run Daedelus's Autolevel program to take care of variations in height and run these programs directly on my router. First doing the "etching", then drilling, and finally the Milling to remove the board.
You can use your favorite units system directly with no conversions needed.

[HankMcSpank]

I do mine same as Hank up to the point of getting it out of Eagle.
Here, I use the pcb-gcode.ulp to create the gcode files directly. Then I run Daedelus's Autolevel program to take care of variations in height and run these programs directly on my router.

I use CNC-USB (vs Mach3) as it has this Z probling/correction feature built in.

You can use your favorite units system directly with no conversions needed.

Can you add a bit more meat here? (not fully understanding what you're getting at ...do you mean with gerber conversion? I convert gerbers from imperial to metric as I've not found a way of getting Eagle to export gerbers in metric yet! That said it's only a 30 second overhead to do the conversion)

[C_Bubba]

I do NO gerber output. Pcb-gcode directly exports gcode file(s). You can set it up to do files for top and or bottom for drilling, etching, milling etc. It will do it directly in metric if that is the unit system that you have chosen to use.
As your system has "warp", the files will be ready to run. No further cam work will be needed.
I don't think there is a pp for your controller yet, but it should not be to difficult to massage one of the existing ones. I personally use Turbocnc and have mangled the heck out of the stock pp's:})

[booski]

Yeah, pretty much. I just tape a piece of wire to the board with a bit of tape and then a croc clip to my spindle. The software then probes the height of the board.

[Fivetide]

Yeah, pretty much. I just tape a piece of wire to the board with a bit of tape and then a croc clip to my spindle. The software then probes the height of the board.

How does the feedback of the tip and croc clip get back to the computer ?

[booski]

Well, I have a simple parallel port chinese TB6560 controller and I use one of the input pins on the controller setup in LinuxCNC as a probe. There are 5 input pins on my controller and 1 common, so with a lead connected to the common and another connected to the input.

With the probe attached to the tool, the Z axis comes down and when the tool makes contact with the board, it measures the height and adjusts the rest of the g-code to suit the board at that point.

[irving2008]

Well, I have a simple parallel port chinese TB6560 controller and I use one of the input pins on the controller setup in LinuxCNC as a probe. There are 5 input pins on my controller and 1 common, so with a lead connected to the common and another connected to the input.

With the probe attached to the tool, the Z axis comes down and when the tool makes contact with the board, it measures the height and adjusts the rest of the g-code to suit the board at that point.

which is fine until you forget to remove the croc clip before cutting :) . Also a solid tool rather than a sprung 'plunger' means the Z-travel, and therefore the mapping speed, has to be much slower to avoid damaging the copper surface... but it works....