Page 1 of 2

My first tiny PCB with Shapeoko

Posted: Mon Nov 19, 2012 10:08 am
by PsyKo
Hello,

I did a really quick test this weekend with the Shapeoko, on a really tiny PCB, and it worked fine :)
Below is a picture of the result.
I used a pretty worn 30° V shaped end mill. I also used the hobby.dru style in Eagle, which lead in pretty thick paths.
I still have to run the drills and the cutting of the board, but it looks good to me.

I plan to do some improvement, such as using a touch plate for auto Z leveling.

FIY, each square on the paper below the PCB is 5mm wide.
What do you guys think ?

Re: My first tiny PCB with Shapeoko

Posted: Mon Nov 19, 2012 11:32 am
by cvoinescu
That looks very, very good -- except for the parts where the traces aren't completely cut off from the ground plane, but that seems to be a CAD or CAM problem, not an issue with the actual milling (or maybe it was intentional). The quality of the cut is excellent. Can you give us more details about your machine and settings? Any upgrades such as dual-Y? What kind of spindle? What feed rate? How deep did you lower the bit below the surface of the PCB? Was it one pass?

Re: My first tiny PCB with Shapeoko

Posted: Mon Nov 19, 2012 11:56 am
by PsyKo
Hello Catalin,

the pads that are not completely cut off the ground plane is totally intentional. It's actually the GND pin of the parts :)
As for my machine :
- Dual Y drive
- Acme Z Axis upgrade
The rest is default from Inventable kit (spindle).
Settings are default one (except the Z axis step/mm due to Z Axis upgrade)
It was done using 3 or 4 passes, but only to make path largers, not deeper (and probaby because it was the first time I used pcg-gcode for eagle).
I do not remember the feedrate. It was pcb-gcode's default. For depth, I set 1 mm but this might be off because of my innacurate Z zeroing (next upgrade = touch plate).

So nothing very fancy.

Re: My first tiny PCB with Shapeoko

Posted: Mon Nov 19, 2012 2:25 pm
by cvoinescu
Thank you. I'm planning to mill PCBs as soon as I find the time to do it, so any detail from someone who'd already done it helps a lot.

And you're right, that's definitely not 1mm deep. :)

Re: My first tiny PCB with Shapeoko

Posted: Mon Nov 19, 2012 2:54 pm
by PsyKo
As for the feedrate, I'm not quite sur of the depth. I don't have the CAM software under the eye, so I can't check.
But this depth definitely looks good :) even if not done on purpose !

Re: My first tiny PCB with Shapeoko

Posted: Mon Nov 19, 2012 4:01 pm
by edwardrford
This is really great! Thanks for posting.

-Edward

Re: My first tiny PCB with Shapeoko

Posted: Mon Nov 19, 2012 7:18 pm
by fito
Fantastic looking cuts on that copper. Please keep us updated, I am interested in milling pcbs as I have learned that I do not like drilling tiny holes in copper.

Re: My first tiny PCB with Shapeoko

Posted: Tue Nov 20, 2012 3:00 pm
by levlandau2
PsyKo,

Congratulations on the first proof-of-concept of PCB milling. This is great progress. I have been trying to do the same for some time, but have encountered speed bumps due to Eagle and gcode generation from the PCB layout file.

Right now I am trying out the Diptrace path, which can export DXF files. These are read natively by CamBam, so I am hoping this makes it easier.

Questions:

1) What is the ideal depth for milling PCBs? Is more depth always better?
2) Is a V-shaped endmill needed, or can a small regular endmill (center-cut, two-flute) be used? There are some very small diameter (0.2mm) ones which I think would work well...
3) Do you have a smart solution for flipping the PCB and milling the other side? It seems to me that a fixture to hold the PCB down in the same exact place, as well as homing switch upgrade is needed, otherwise this would be challenging....


Anyway, great stuff, keep up the good work.

Re: My first tiny PCB with Shapeoko

Posted: Tue Nov 20, 2012 3:53 pm
by PsyKo
Hello,
levlandau2 wrote:PsyKo,
Questions:

1) What is the ideal depth for milling PCBs? Is more depth always better?
2) Is a V-shaped endmill needed, or can a small regular endmill (center-cut, two-flute) be used? There are some very small diameter (0.2mm) ones which I think would work well...
3) Do you have a smart solution for flipping the PCB and milling the other side? It seems to me that a fixture to hold the PCB down in the same exact place, as well as homing switch upgrade is needed, otherwise this would be challenging....
1. I'm not sure that deeper is better. It has some pros (prevent from not very flat table issues,...). I would recommand deep enough to remove the copper, so not more than 0.5 mm. (or ~1mm top)
2. I'm using V shaped end mill because it's the smallest mill I have. The very small mill could work, but I can't say for sure.
3. One solution would be to have a touche plate to align X, and Y axis with the edge of the pcb, and auto Z zeroing. Otherwise, using a fixture as you is needed. Even without homing sequence. Simply move to 0,0,0 at the end of your first job, flip the PCB, align it with the fixture and run the second job.

Re: My first tiny PCB with Shapeoko

Posted: Wed Nov 21, 2012 4:22 am
by levlandau2
Stupid question....

So when the PCB is flipped, the corresponding CAD have to be flipped as well right? Also what happens to the 0,0 alignment at this point, assuming one did not start at the extreme edge of the PCB??

The exact process for getting this working has been frustrating me for some time, and I have been too chicken to actually try it.