Problem getting proper depth carved

I am about ready to give up on ever getting my XC to carve the depth I need. I am trying to carve on HDPE and setting the depth to 0.1mm. Every time I try to carve it goes much too deep. I set the last test to 0.1mm and then before carving, after using the probe to set the depth, I raised the bit 1.0mm to see just how much the bit was above the surface. Even after doing that it carved deeper than I want. I am using the cnc4newbie Z-slider. I have used machine setup to confirm the thickness of the probe disc (14.99mm). Everything else is working beautifully. I have surfaced the wasteboard to make sure it is perfectly flat. I am using a 60degree v-bit. I’m not sure what other information to provide. I used a dial indicator to check the accuracy of the Z and it is sometimes out by .01mm and have changed the $102 to get as close as I possibly can. $102=50.35. The XC has been working beautifully but this is the first time I have done a carve where the depth is critical. I am using Easel Pro but don’t use it often so I am using the free days when available. Any thoughts on what else I should try would be appreciated.
Thank you,

When you test for your $102, what distance are you jogging?
You might want to set that value based on some precision measurement on the scale you want to carve.

The dial indicator I am using has a maximum of 14mm. I have tested everything from 1.0mm to 14.0mm. I’m sorry, I don’t understand your second sentence. Thank you for the reply.

Your $102 might be right on for that larger distance, but these machines have their limits. Basically, dial it in for a 0.5mm movement or even a 0.1mm movement to set your $102. And maybe set your zero with a piece of foil as the probe. Or even by eye.

Can you give details of what the resulting depth is? Is is consistently off by the same amount?If so you could design based on those results.
You are on the edge of advertised accuracy with 0.1mm request.

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Advertised accuracy with stock setup. He’s got an aftermarket Z which should get that level of accuracy.

Check in Easel to make sure your 0.1mm isn’t being auto changed to inches or something crazy like that. Easel has a tendency to do stupid things like that.

How does a non Vbit work? Can it do that depth?

I have managed to get it to carve the exact depth I want by using the manual setting. Trying to get it working with the probe has been totally frustrating. I may come back to it at some point but I just spent 4 days tightening and recalibrating everything and I need to break. I must say that the XC has never run as well as it does now! My only concern is the probe. I may have to contact customer service. Thank you to everyone for the suggestions!

Did you measure the probe and enter that exact measurement into the machine?

Is the probe completely flat?

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Yes, I have checked that. Thanks for the reply, Phillip.

Glad seeing zero without the probe worked.
I’m not sure how Easel runs the probe routine, but it may be running too fast.
Does it probe twice before setting zero?
If not, you could send probe commands to do that. Probe at a reasonable speed, retract a couple mm, probe VERY slowly, then set zero. You’ll get a more precise zero.

No, it does not probe twice. Sorry to keep asking dumb questions but: Probe commands?? Is there a place to find out what the different commands are? There must be a chart or list somewhere that I haven’t found.
Thanks again for the help, Neil.

G38.2 is the most common probe command.
The series of commands below will do what I’d recommend (a double-tap probe)

G21 ;make sure we’re in mm
G91 ;Incremental mode
G38.2 Z-25 F75 ;Probe Z (down 25mm, feedrate of 75mm/min)
G0 Z2 ;lift 2mm
G38.2 Z-5 F45 ;Probe Z (slow probe)
G10 L20 P1 Z14.99 ;Set Current Z as plate thickness (14.99mm)
G0 Z3 ;lift Z 3mm
G90 ;absolute mode

As a reference…Grbl closely follows this:


Thank you again, Neil. I have another project that I have to get to so the XC is hanging from the ceiling in my shop again and I probably won’t take it down for quite awhile. Oh, it’s on a torsion table, not just hanging there by itself!! :rofl::joy:
I really appreciate the help, Neil.
Take care,

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