PCB Traces are Not Isolating (and other oddities)

I’ve been following the excellent guide here on PCB milling with my XCarve. I was able to get Chilipeppr working and autoleveling correctly after finding the right fork for grbl workspaces. I just used isolation traces rather than trimming all the non copper regions.

Anyway, my first PCB is this one from Sparkfun which I legitimately need for a project. However, the actual traces are off in… weird ways?

Basically I’m not even sure what to Google. Some of the isolation traces are not connected. One of them ran way too long somehow, and in one spot the copper is so thin I’m doubtful it’s going to make for a good connection.

Is there anyone out there that can point me in the right direction?

Is your machine dialed in? It looks like you are losing steps. Have you done gone through the steps to check belts, eccentric nuts and motor power?

Did you let it finish the cut? Your board doesn’t look like the one you linked. Can you provide the generated g-code?

Well when I went through the assembly instructions I did all those things. Do I need to go back over those steps in the assembly guide or is there something else you’re referring to?

That’s what I was referring to…have you had a successful cut of anything yet?

I did let it finish. My GCode is here. What exactly looks different than what I linked?

All the cutting I’ve done so far has been wood. I have successfully cut out letters, a box, and some gears.

So what type and size of bit did you use and what feedrate and depth of cut. What type of spindle? the Dewalt?

I’m using the Dewalt 611 on speed 3.5ish. I’m using the 1/8" precision collet from Precise Bits and these PCB milling bits.

Depth of cut is (I think) set to 0.07mm (assuming you set that in FlatCam?). I’m not honestly sure what feedrate I used in FlatCam-- not sure how to see those settings again but I’m pretty sure I used 200 mm.

I’m curious: what are the visible results of depth of cut or feedrate errors? Is there something in the picture that is leading you to believe it’s those values?

The way things don’t quite line up make me believe you are losing steps. moving too fast with too deep a cut will cause missed steps.

200mm per minute? That is crazy slow…

Interesting. So would you recommend first trying with a slower feedrate or a shallower cut?

Oh really? Hmm, from the tutorial I linked to:

“For a quiet cut spindle, use 70-80mm for Feedrate. For the routers, they go quite a bit faster, so use 150-200mm instead. Feel free to fiddle with these Feedrates to try and get better results.”

0.07mm depth of cut - is 0.0027" very shallow
200mm per minute = 7.87 IPM way too slow for anything I’ve ever cut.

speed 3.5 on the dewalt is probably too fast

Had to do the conversion…sorry

I would try 800mm per minute, Depth is fine with the dewalt on speed 1.

Also make sure the bit is only sticking out a little…for what you are doing you need as little runout as you can get.

Thanks for the settings, I’ll try them as soon as I can. Is this documented somewhere that I’ve missed? I’m finding resources for this sort of thing few and far between.

No documentation…just from experience using my x-carve…sorry.

No problem, just thought I’d ask. Thanks so much!

Let me know how it goes. If you get the same looking cut, check the stepper motor currents again for both the X and Y axis.