Finishing cut messes up the job entirely

Hi Guys.
So I’m a very occasional user. I use Easel with my little 3020XL CNC which does a great job cutting flat shapes from Carbon, Brass and Aluminum.
I just cannot fathom a few things though and even though I don’t use it much, I’m not a Mong, I fully understand the process.

Example today; I want to cut a flat plate out with a couple of holes for fasteners to screw through it.

I imported the STL file into Easel which it’s perfectly happy with.

  • Easel wants to make two cuts, roughing and finishing. Not required. I just want one cut job, how do I force it to just make one cut ??

  • Easel says the rough cut will take approx an hour and the finishing 10 minutes. In reality the rough cut buzzes the outer shape of the in 10 minutes and does a great job, then the finishing cut takes over an hour and messes it up.

  • Worse than that, the finishing is not running round the cut shape using a linear path, it’s “plunging, lifting, progressing 1/4” and plunging again" again and again, all round it’s finishing path !

  • By the time the finishing is finished it looks terrible whereas the rough cut was absolutely perfect !

If I could get easel to do the one cut all would be great but it insists on drilling the screw holes and shaving the edges in the second cut, even if I make the bits the same in both.

What the heck am I missing.

Fixed it myself.
When I imported the STL I had to resize it as it came in at quadruple it’s intended size. No biggy but I’m thinking that was an early sign things were not right. Easel automatically selected two cuts.
I started with a fresh project and imported it in SVG and not only was it the correct dimensions but it was only one cut.
I guess the STL import is not working

STL is for 3d projects. What you have described is a simple 2d project so yes it will work much better with a SVG.

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I have a similar issue with my STL file, the finishing cut is severely off of the roughing cut, and it isn’t consistently off, its off in different directions at different points of the piece. It also made an irregular cut during the finishing cut that wasn’t on the tool path. I usually just use DXF files, but this file is 3D so I need to do it in STL. I don’t think it’s a zeroing problem as it was significantly off of the roughing cut path and it had an irregular cut, which leads me to think it’s something to do with the file itself. I exported it from onshape and had to resize it in Easel, but it all generated fine. Do you have any advice for me? Any help would be greatly appreciated.

What model CNC are you using?
If X-Carve have you done this settings change? (See Video)

Have you verified the belts and vwheels are properly tensioned?
(Reference the sections on “Tensioning Belts” and “VWheels” here> X-Carve Instructions: Calibration and Maintenace

Thank you for the help! Unfortunately I am still running into problems. I decided to simplify and run my design as a DXF, as well as checking the tension on the belts and VWheels beforehand. I did not have to change bits so the Motor lock fault doesnt apply for me. (Although I do have a pre November 2021 X-Carve)

When I ran it after checking everything you told me to, it seemed to have some sort of mechanical error where it began to carve a circular hole out, then erratically moved on the x-axis about 1/2 an inch. This not only resulted in the hole being messed up, but the zero moved 1/2 an inch when this happened, messing up the remainder of the cut (I have attached pictures if they help). I now believe it is some sort of mechanical issue as DXF files have worked with this machine in the past, we just haven’t cut anything with it in about a year before this week as we use it for robotics season. Do you think something happened that requires maintenence or fixing? I would love to hear any other advice/insight if you have it. I just can’t see this being anything other than an issue with the machine.

More info:
(Cut using 1/8 inch bit on 0.22 in thick Polycarbonate with 20 in/min feed rate, 10 in/min plunge rate, and a depth per pass of 0.025 in)

(I have a pre November 2021 X-Carve 750mm x 750mm that uses a DeWalt 611, X-Controller, 2gt belts)

What this hole was supposed to look like in Easel:

How it turned out (I stopped the cut after I saw that the zero had been moved):

The toolpath generated by Easel:

If you have any questions about my circumstance, please ask. Thank you in advance for any help you are able to give me!

Well this sounds/looks more like possibly the workpiece lifted (you may want to use double sided tape underneath the workpiece to help prevent/reduce this) when working with larger pieces of flexible material like acrylic.

What type of but was used? It is a best practice to use o-flute (single flute, upcut) bits for acrylic material.

Also, if ANY of the plastic chips make their way into the Vwheels ot Rails, this can cause the wheels to bind which can result in lost steps. So keeping rails/wheels clean is vital since plastic chips are harder and usually thicker than wood chips.

A FAST feedrate, slow spindle RPM and depth per pass as need to accomplish those prior 2 are recommended for plastic cutting. I think your Feed Rate is Extremely too slow, which can cause the acrylic to melt and then harden as it cools onto the bit, which then causes issues with chip clearing throughout the cut… this MIGHT be part of the issue as well.

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