Z cut depth issue

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chomdh
Posts: 179
Joined: Sun Jan 19, 2014 3:43 pm
Location: Bettendorf, IA

Z cut depth issue

Post by chomdh » Fri Dec 26, 2014 7:42 pm

I could use some help troubleshooting a problem I've been having with z axis cut depth. I'm using makerCAM to cut a 2" diameter circle in 0.75" thick pine 1x4. That's the plan for this test anyway.
I enter 0.75 total depth with 0.075 depth of cut. I'm also adding tabs.
When I run the program using UGS latest version I'm only cutting about 0.6-0.64 inches.
When I test z movements using machine control in UGS and measuring with digi calipers, everything seems ok (1" jog measures darn close to 1" on my calipers).
I recently started using tabs and wonder if these are the problem. I haven't had any issues with z cut depth before recently. Though I haven't tried to cut 0.75" thick material before yesterday either.
Any help is appreciated. I'll have more time to troubleshoot later today.
Shapeoko2 #3702:
DW611, arduino uno, gshield v5, NEMA23's on X & dual Y, NEMA17 on Z with ACME rod, 9mm belts, Mean Well NES-350-24V power supply, re-inforced gantry rails.
Soon to have inventables spindle mount and 1M X axis.

tjshape
Posts: 155
Joined: Wed Oct 01, 2014 1:59 am
Location: Madison, WI

Re: Z cut depth issue

Post by tjshape » Fri Dec 26, 2014 9:11 pm

Check to see if the flexible coupler between your z axis motor and screw is tight. I had a very similar issue to yours where I finally noticed the coupler spinning a very slight amount on the screw when plunging into a denser material and therefore not going down as deep as it should have. Tightening up that coupler was the resolution for me. I've since switched to an acme screw and the belt drive upgrades and have been very happy with that setup.
Shapeoko 2, ACME upgrade, Belt Drive Z-Axis upgrade, Dewalt DW660

chomdh
Posts: 179
Joined: Sun Jan 19, 2014 3:43 pm
Location: Bettendorf, IA

Re: Z cut depth issue

Post by chomdh » Sat Dec 27, 2014 1:14 am

Thanks TJ. I cranked down the coupling screws. Couldn't hurt but I don't think it was my main issue in this case.
I'm going to chalk this one up to needing to fine-tune my pulse/step entry after changing to the ACME screw. It was off by 6% or so.
Shapeoko2 #3702:
DW611, arduino uno, gshield v5, NEMA23's on X & dual Y, NEMA17 on Z with ACME rod, 9mm belts, Mean Well NES-350-24V power supply, re-inforced gantry rails.
Soon to have inventables spindle mount and 1M X axis.

Sweetts
Posts: 19
Joined: Sat Nov 29, 2014 12:16 am

Re: Z cut depth issue

Post by Sweetts » Sun Dec 28, 2014 4:28 am

-.75 or .75

chomdh
Posts: 179
Joined: Sun Jan 19, 2014 3:43 pm
Location: Bettendorf, IA

Re: Z cut depth issue

Post by chomdh » Sun Dec 28, 2014 1:54 pm

-0.75 total depth.

Another contributor to my depth issues was that my UHMW dw660 mounts were not doing a very good job of holding my spindle ~perfectly vertical. Especially with the 0.75" thick parts, the deeper I plunged the worse the cut quality was and the more "fuzzys" were created. This issue wasnt as apparent on thinner parts and engravings.

I swapped back to the universal mounts and re-adjusted spindle perpendicularity to the waste board and have much improved the surface quality of the sides of my parts and my z depth of cut is more accurate now. Tabs had nothing to do with this as I suggested in an earlier post.
Shapeoko2 #3702:
DW611, arduino uno, gshield v5, NEMA23's on X & dual Y, NEMA17 on Z with ACME rod, 9mm belts, Mean Well NES-350-24V power supply, re-inforced gantry rails.
Soon to have inventables spindle mount and 1M X axis.

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