Carbide Create: Custom Toolpath Zero?

[Smorgasbord (Ben)]

I have a Standard Size Shapeoko Pro. Turns out one of the shapes I need to cut out is too big to fit in the “normal” orientation, but if I rotate it 60º clockwise, it’ll fit, like so:

In this setup, the grid is sized about 7-8mm smaller than what my Shapeoko Pro Std can do in terms of bit center movement, so that I can use a ¼" diameter bit to cut things out.

As you can see, the object fits with some room to spare, but now I have a problem in choosing and finding an XY zero. I’ll almost certainly start with stock that’s rectangular, but the lower left corner of that stock isn’t in any of the choices for Toolpath Zero.

What’s the best way around this in Carbide Create? Yeah, I could go to Fusion360, but these are simple cut-outs in 1/4-3/8" stock, so CC is just way easier all around.

The only thing I can think of is:

1. Attach a top horizontal reference board at Y=425mm.
2. Mark that board at X=100mm. This is the top point.
3. Now, ideally I could find the leftmost point of the object, but CC doesn’t tell me that. Here’s the best I can do:
   
   

So, the X-location is slightly over 5.25mm.
Question: Is there come way to get the exact X/Y location of that point?

4. What I’ll do next is mark the top reference board at X=5.26mm. This would be my zero point, and use “Top-Left” in CC. Of course I won’t be able to mark that board to a 0.01mm accuracy.
5. Attach a piece of scrap to the bed such that the leftmost corner of the object (a right angle) will be fully embedded. Run Carbide Motion to cut it out. I don’t care about the whole object - just need to capture where that leftmost corner (which is a right angle) is.
6. Now, mark the bed to capture that leftmost corner.
7. Now I can stick my stock to the bed such that the right angle corner of the stock overlaps that marked corner a bit (since it might not be perfectly square) and cut out my piece. Repeat for multiples.

Anyone got a better process?

PS: I also want to calibrate the cutting dimensions of my Shapeoko. I just got a nice 200mm digital caliper, so my idea is to cut a 200mm block on the Shapeoko, measure it, and then adjust G-code values accordingly. I assume that process is documented somewhere, right? Thanks.

[mhotchin (Michael Hotchin)]

You don’t have to keep the item to be worked on inside the ‘Stock’ that is shown in CC. It won’t preview well, but there is no reason you can’t set things up like this:

[Smorgasbord (Ben)]

OK, that’s pretty tricky.

For this to work, Carbide Motion doesn’t know, or at least doesn’t enforce, the limits of the machine it’s operating on? Since I’m close to capacity, that means locating that zero point pretty accurately on the bed so that none of the XY limits are hit.

I’ll still have to know that stock right angle’s rotation (60º), but that shouldn’t be too difficult to get good enough is the raw stock is big enough.

[WillAdams (William Adams (Carbide 3D))]

Or use Center Left:

[Smorgasbord (Ben)]

OK, that should work.

Now, how do I go about adjust the XY scale? I’m sure there’s a procedure somewhere, but I couldn’t find it, sorry.

[WillAdams (William Adams (Carbide 3D))]

For belt stretch calibration see:

Calibrating the machines over long distances

The typical technique for machine calibration: https://my.carbide3d.com/faq/belt-stretch/ depends on precision measuring tools, and is limited by the reach of the tools in question. EDIT: It also depends on access to the MDI — if using Carbide Motion v6 it will be necessary to enable this in Settings | Options: [image] It should be possible to cut strips from a suitable blank of material, one along each axis — so we set up a square file which matches an available blank of material: [ima…

[Smorgasbord (Ben)]

FWIW, Taylor Toolworks has a 12" digital caliper with 0.0015" accuracy over its length on sale for about $30.