Easel says 4.1mm deep, but WebControl says -4.03Z axis

Troubleshooting
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1

Hi,

I like the ease of Easel, but it seems, somewhere the Z-axis gets screwed. The cut is suppose to be 4.1mm deep, but the Z-axis in WebControl says -4.03

Is this an issue with the export from Easel, a wrong setting in Easel by myself, a display error in WebControl, or a real issue where some tool doesn’t work as expected?

Thanks

marie.o

2

Are you worried about the 0.07 mm or the negative(-)?

3

I am worried about the fact, that one system says one depth, and the other says a different depth. In my little blonde brain both system should have the same number.

4

So this is why I asked:

  • The actual depth and the setpoint depth will be off by some value as the system moves and the encoder feedback pid loops of the Arduino work to keep it at setpoint, so that is the 4.1 vs 4.03. it is close, but not quite and may vary over the cut to some degree (based on my limited observation).

  • The negative is symmantics. By definition, the work surface is zero. A depth of 4mm will show up as -4 in gcode be wise the bit is below the surface when it is plunged.

5

I wouldn’t worry over such a small difference. I’m happy to get +/-1mm accuracy at the edges of my machine, which is typically more important than z depth for the projects I want to do. you are talking about an error that is 10-14x smaller than the best calibrated maslow cnc machines typically do.

6

Shouldn’t the depth which is displayed at the WebControl reflect the setpoint depth? Or does it reflect the actual depth?

7

If Z-depth is not so important, how do you make sure that the cuts do get through? Or are you always manually cutting of the last mm or half to get the cut done?

8

It reflects the actual depth. I always overshoot depth by 2 mm if going all the way through.

9

Thanks for the information

I understand why X-axis and Y-axis aren’t really very accurate. I fail to understand, why the Z-axis isn’t. The way the Z-axis is designed isn’t different from other CNC machines, ie. it just is a screw that is being rotated. Why is the actual depth not changed to reflect the setpoint depth?

10

Every engineered device has tolerances and “slop” in the screw driven mechanisms, gear boxes and belts. Nothing is perfect, everything has tolerances. when you buy some 1/2" plywood it is not 1/2" thick it might be 1/2" +/- 1/32".

0.07mm is around the thickness of one piece of human hair. In other words very accurate. Just because the numbers don’t match doesnt’ mean it’s not accurate.

but to directly answer your question the main source of slop might be the lead screw nut which doesn’t’ have an anti back lash design and the 10rmp gear box which has slop in the gears, magnified 2x by the belt gear ratio. assuming you have m2 kit

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