Cutting circles - getting imperfect results

[Explant (Nadeem Sheikh)]

I am having getting true circles; seems I get either a ‘flat’ side on the left side of any circle. I’ve slowed/reduced settings and checked screws/belts etc…no luck. Any advice?

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

Which machine do you have? The SO5 Pro (you posted in the SO5 Pro area) doesn’t have belts.

Post an overall photo of your machine?

Possible causes:

• a mechanical issue with the machine — check the machine per the assembly instructions/checklist
• a wiring issue with the machine — check all connectors and all the wiring
• a lack of lubrication of a linear block/rail

The machine needs to be calibrated (belt-drive machines):

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…

The toolpath — are you trying to cut a slot just as narrow as the tool which is markedly deeper?

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…

The nature of the material can play into this as well — Ii you’re cutting wood a useful test is to rotate the stock 90 degrees and cut the file again.

If your machine is electro-mechanically sound, try cutting a test file such as:

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]

and let us know step-by-step how you secured your stock, set zero relative to it, and managed all tool changes and post photos showing how the stock was mounted and how it cut and how the dimensions turned out.

[Explant (Nadeem Sheikh)]

@WillAdams - apologies for late response, was traveling. I misspoke about belts. I have a ShapeokoPro5

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

If you’ll let us know the specifics of your problem we will do our best to assist.

On an SO5 Pro it is likely loose hardware, (lack of) lubrication, or a toolpath issue.