Inconsistent Z for 3D cutting

[nick]

Im starting to cut multiple parts on a full sheet instead of using 0,0 for everything.

I am seeing different Z height's all over the place.

I am running a PRS Standard with no vacuum table.

Is the tolerance buildup my enemy or vacuum table.

Absolutly no slop in Z.

Appreciate your help.

[cnc_works]

If you are running a spindle, it is possible that enough RF is being generated to give you spontaneous stepper movement. Check your grounding and check if your Z stepper cable is laying closest to the power cable in your wire loom.

Donn

[magic]

I too have the same problem occasionally on fine work. It only happens on the y axis.

If I'm cutting a raster at 0 angle, there are hills and valleys on complete passes that should be flat.

[ljdm]

If you aren't using vac for hold down, is the sheet bowed in some spots, causing deeper cuts in those areas?

[khalid]

I second LOU..

[nick]

Its my base sheet not my work material.

I am resurfacing as we speak...The ends of my sub are bowed...about .010"

[dray]

Before I do any 3d work, I always machine table down 1/32. The differences in heat/cold/moisture will slightly distort table from one day to the next.