O.T My Z Axis dives down into the wood...

[wrench]

I have just finished building my second CNC and have a problem I can't sort out. I have been searching CNCZone and the Mack2/3 Forums for hours now and can't find any help.

I have Mach3 setup and everything connected and working (limit switches,homing etal). When I go to carve either the Roadrunner sample, or any of the test projects I have made from VCarve I get the same result. The bit drives down into the wood.
I zero all axises on the DRO's and click 'Regen Toolpath' before starting to carve. With VCarve project, the bit goes just below the surface then comes up to carving depth and then seems to carve fine. With the Mach3 Roadrunner sample project, the bit goes deep into the wood and then travels for a few inches and then comes to the surface and seems to carve fine (Z0.10 depth) and once it gets to a line with Z0.20 it goes about a half inch deep.
I have tried EVERYTHING I can think of and have just wore myself out.

Wrench

[metalworkz]

Is the toolpath a Vcarving toolpath? If so the depth of the cut is determined by the width of the Vcarved area, unless you use the 'flat bottom' option which will allow you to input the desired flat bottom depth. If the toolpath in question is not a Vcarving style then I am not sure what is the problem. If it is then try adding the 'flat bottom' option and see if that helps.

[CRFultz]

Did you check the actual Z travel with a ruler? If you zero in the air somewhere and then jog exactly one inch, did your axis move exactly one inch?

[dr_when]

Hi Wrench,

As mentioned, make sure your Z is actually traveling the distance you believe it should be.
Then, if you have not done so already, you may want to take a quick look at the Gcode that is being sent to your controller and make sure that Z is not being sent far below the material surface. Also, in "Material Setup" in Vcarve, do you have the Rapid Z value set properly? My guess is that Z is traveling farther than you think. Good luck!

Bob

[wrench]

I set Z on surface and zero on DRO.

One inch on DRO moves Z-axis one inch.

I know it's something simple to figure out, but I can't seem to get it. Will try some new testing and see if I can correct this.

Thanks

Wrench

[James E]

Rapid z set to a minus instead of positive?
Wrong postp?
Inches instead of MM? in Mach3?
good luck

Jim

[coop]

hey wrench,
i had the same intermittent issue, and after ttrouble shooting
everything else..it was a bad gecko drive.
i have had two bad on my machine, one from the start and the other
several months later.
both with the same symptoms !
switch the cables the test the z again see if it works.
good luck !
bo

[wrench]

I'm HAPPY to be Married at this moment!
Wifey comes home and looks in to see how I'm doing. I explain in simple terms of what's wrong, and what's going on as I test yet another piece of foam.
She says it looks wrong!
What looks wrong? I say.
Shouldn't that be going positive if that's moving down?
Uhhhhh?!???
Sure nuff.....I changed my Z Axis Dir LowActive from a check mark to an X, and it WORKS!!!
2 days of this and I decided to listen for once and it works.

Thanks for everyones input here. I rethought every point wondering what was going wrong.
When the bit dove into the foam and dragged a 3 or 4 inch pocket, then rose into the air and carved, I should have seen was happening.
The CNC gcode was working fine....in reverse. Up instead of down. Duh....

Wrench:)

[cabnet636]

i love my wife too!

jim

[Khalid]

i love my wife too!

jim