SHapeoko 3 XXL vs Shapeoko 5 Pro accuracy

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

Start with calibration:

Calibrating the machines over long distances

The typical technique for machine calibration: 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: [image] and put in suitable geometry and assig…

and we have an example test file here:

Diamond-Circle-Square Calibration file

The last one I posted: no longer opens properly in current versions of Carbide Create, so here is how to draw up and assign toolpaths to one. Begin by launching Carbide Create, going into Job Setup, and creating a 4" x 4" stock area with the origin set at the center: [image]

The issue with a CNC which doesn’t use closed loop control is lost steps — feeds and speeds have to be managed so as to ensure that each time the controller sends a signal for the machine to move a step, it does so.

My approach for this has always been to avoid slotting and drilling — where possible avoid slotting and add geometry and cut as a pocket

Making vacuum hose adapters

While cutting up vacuum extension wands for this is expedient, it’s a bit problematic given that Shop Vac recently filed for bankruptcy, was bought at the last minute, and production hasn’t caught up. I need a receptacle for the Sweepy 2.0 dust fitting — one option would be to purchase one from Woodcraft, but Carbide 3D sells blocks of HDPE: which looks to be just barely big enough for things to fit. Measuring the hose fitting I get a diameter of ~63.5mm — offsetting that twice we arrive at…

and/or

Adding geometry to cut as a pocket with a finishing pass

One technique which is often suggested to avoid slotting is to add geometry around a part which one wishes to cut out and cut as a pocket down to tab depth — here’s one technique for that. In this case, the project is a bevel gauge which will be cut out of 0.0625" (~1.5mm) thick aluminum: [bevelgauge] Due to the narrowness of the angles, an 0.03125" endmill has to be used, so after importing and scaling the file (we will be cutting out one which is 3") we select the perimeter and offset it tw…

and consider leaving a roughing clearance and taking a finishing pass.

Best Bit for full cut through

One which has a cutting flute length equal to or greater than the thickness of the stock — pretty much any tool should work. Big thing is the toolpaths — if cutting out, rather than just cutting a slot: [image] Offset to the outside by endmill diameter plus 10% or so: [image] [image] [image] Then cut as a pocket: [image] down to tab height or the penultimate pass: [image] then move the contour down to below the pocket and start cutting at the bottom of the pocket: [image] and…

doing thus, I’ve been able to run quite long cuts, and have done projects where I have re-run a toolpath which has lined up just about perfectly with previous work.

If you’re having trouble, upload a .c2d file, photos showing your stock/part clamped in place, and photos showing how the cut turned out and how you are evaluating it. Note that when measuring, you want to use a tool which is markedly more precise/accurate than you are trying to measure.