Detail Pass is smaller/scaled down/'squished' from Roughing Pass

Hi all,

I am new here and beyond generic operation, new to the CNC world. I’ll get straight to meat and two veg of it…

3D Model: American Flag STL

  • Prepped in Easel
  • Run by Candle

Bit: 1/8 2-Flute Upcut
Feed Rate: 35 in/min
Plunge Rate: 10 in/min
Stepover: 40%
Depth Per Pass: .10
Result: PERFECT! Measurements are exact!

Bit: 1/8 Ball Nose 2-flute Upcut
Feed Rate: 35 in/min
Plunge Rate: 10 in/min
Stepover: 30%
Depth Per Pass: Does show as an option under Cut Settings in Easel

If anyone can point me in the right direction, I would be exceptionally grateful.

Thank you!

Try not to change the Stepover% from what the Roughing pass had done. At 30% Stepover, your now giving the carve a more detailed look, smoother , and tighter carve lines. The lower the Stepover %, the smoother, and longer the carve will take as well.
What i do to when I use a specific bit, in order to get my Stepover % for i.e… I using a .125" bit, so I’ll take .125 x 30%=.0375/2=.01875. The .01875 will be my Stepover % for that .125" bit. you want a 40% stepover, just use the same Formula but plug in 40% instead of 30% and you will get your stepover % at that %.
This is just how I get a good smooth and accurate carve and I’m able to speed the speed rate up, and the plunge depth a bit more for faster carve times. But not much faster. Again, this is what i do, and i hope that this will help your scaling stay consistent from the roughing pass to the detailed.

was the model size altered between the roughing and finishing?
That’s the only way I could see the scale changing as you’ve explained.

Also I agree with John here with the stepover of the Finshing Bit… keep it at the 8-12% range
Here’s some more data on stepovers of ball bits:

And If you’re interested in speeding up the carve time and expediting the carve, I discuss the steps for altering the cnc’s Plunge Rate MAX setting to achieve a faster carve time for the finishing bit in this video: 4 MUST KNOW tips for 3d carving with Easel - Recorded LIVE - YouTube

Thank you both for the information, I read the articles and watched your tutorial, which was well-done and informative. I employed your suggestions,

It seems I am getting the same result.

The stripes in the wavy flag seem to get smaller and smaller as it goes up.

Any other ideas? I’m at a loss.

Made another attempt, Candle estimated 8 hours for the detail pass. 5 Hours in Candle shows that the carve is starting to carve in the stars. Seen here:

However, this is where it actually was…

It crammed 65% 9" tall flag into a space of 1".

Your cnc is not properly moving the y axis. Possibly an issue with the machine itself.

What model cnc are you using?

Have you been able to run other successful 2.5d carves?

It is the FoxAlien Masuter Pro. It’s 4 months old and has roughly 15-20 hours logged. I have successfully been able to carve and ‘cut out’ several projects.

(Nintendo Buttons)

I have noticed a sort-of stuttering-type sound as of recent when the machine is cutting. When I here it I observe the wheels and the belts, the step motors to see if I can see any variable movement that is in rhythm with this stutter.

Nothing is present that I can clearly see and there doesn’t seem to be a rhyme or reason as where it is coming from and what is causing it. I have tightened all the wheels, checked the belts’ tension, nothing out of the ordinary and everything within normal limits.

Though I think you may be right about the Y-axis not moving correctly, especially as in the first flag photo from today, the stripes get smaller and smaller as the carve goes up the Y-axis.

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So after a bit more experimentation, I noticed that when the spindle makes the sudden y axis movement at the end of the run, the Y2 (Right) Step Motor moves very tight, sudden and accurately no matter which side the spindle is on during the Y Movement.

Meanwhile, the Y1 (Left) Step Motor seems to move exactly the same but ONLY when the spindle is on the right side of the machine during the Y Movement. When the spindle is on the Y1 (Left Side) during the Y Movement, it appears as though the Y1 motor is ‘attempting’ to move, but rebounds back. As if the motor did not lock into the new Y position and returned to the previous.

Does that make sense?

Is it possible that the left stepper is just idle, not running at all. and the gantry is being moved by the right side motor only? you can test this theory by unplugging the Y1 and Y2 and testing them one at a time, plug in only one side and then the other side and verify that either side works independent of each other.

There are 2 drivers, and often times, when the gantry is pushed/pulled by hand this generates voltage which causes the driver to burn up because it cannot dissipate this back-fed voltage.

maybe it’s not the fault, maybe it is, worth a test IMO

Tested, Y1 is functional separate from Y2. I tested Y2 just to be sure I was thorough. Is there any possibility that the Y1 motor could be set at a different torque than Y2?

Y1 moves as it should when the makita is on the Y2 side, its only when the spindle is on the Y1 side. The wheels kind of jerk but never actually rotate.

During operation, I put my index finger on the Y1 Motor Mount, and applied a very very extremely slight for pressure on it during the Y axis movement and it cycled normally, wheels turned perfectly in sync with the Y2 side. It is almost as if the Y1 isn’t able to move the gantry when the makita weight is on the Y1 side.

Oddly during the roughing pass, when the bit is taking on more resistance from cutting through the material, the Y1 and Y2 move perfectly in sync.

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There is only one setting for the current usage of the y1 and y2 circuit, its this posentiometer and is value is used for both y1 and y2 motors so no, it cannot be turned up for one and down for the other…

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