Hoping someone can help me. Trying to setup my 6040 cnc. Instructions that came with the system for mach3 setup are as follows

Steps per on all AXis  640
Velocity X&Y            2500
Velocity z                800
Acceleration X&Y     200
Acceleration Z         150
Step Pulse              5
Dir Pulse                 1
This caused jobs to miss many steps doubled the job size and was generally Crap.

Changed steps to 320 x 2000 x 200 XY
This eliminated most problems.

Jobs are now correct size. Although job is perfect for approx first 50% after that Z axis seems to start going deeper. Cchecked that tool was properly tightened and work flat)
Job im doing is the Bullshead sign from vectric.


Any help greatly appreciated

Probably the best suggestion would be to half your Velocity and Acceleration settings (in motor tuning) for the Z axis and see if that cures the issue.

Tweakie.

Thanks Tweakie.cnc

Changed Z axis to Velocity 400 and Acceleration to 75 Exactly the same. Noticed when job finished and unit returned to home position z axis set to 12.7mm(1/2") above as per VCarve settings Bit is only approx 9.7 mm above home.

The next (in my opinion) most likely cause is mechanical - perhaps check the grub screws / coupling etc. for tightness on the Z axis.

Tweakie.

Have checked all screws, Bolts etc everything nice and tight.

Could you attach your .xml file (mach3 folder - the profile you are using .xml)
Rename it to jagman.xml and use the additional option in the reply page to attach it.

I will check your settings here and see if I can spot anything that may be causing the problem.

Tweakie.

Seems the couplers are slipping after few minutes of running, Think ive fixed problem by moving couplers further down motor shaft, so they have better grip on Axis Shaft. Did one run seemed perfect then X axis did same thing unfortunately coupler broke when attempting to move stepper motor. Have ordered new Coupler will Keep you updated.

Having more problems with the couplers, Using aluminium 30mm couplers with a 8mm shaft. They dont seem to grip ball screw shafts tight enough. Also think the couplers might be a little short 30mm(1.2") need be about 35mm(1.38"). Any suggestions on better couplers greatly appreciated.

One possibility, perhaps, would be to drill & tap a small grubscrew hole in each end of the existing couplers then grind a small flat on the screw and motor shafts. ?

Tweakie.