Hello Guest it is April 18, 2021, 03:00:35 PM

Author Topic: Mach3 Z Axis drilling problem  (Read 119 times)

0 Members and 1 Guest are viewing this topic.

Mach3 Z Axis drilling problem
« on: February 09, 2021, 05:35:52 AM »
Hi All,
I have the latest version of Mach3 running on a Windows XP Pro PC.
I am using a Gecko G540 stepper controller, using the parallel port for my mini-mill.
I have some G-Code that I generated with VCarve Desktop for drilling holes - it looks fine to me but when I run it the Z axis doesn't drill down far enough - all the X and Y axes run fine.
As far as I can see the Z axis is -2.5mm short of where it should be for every hole (it doesn't stay there long enough to be sure of the DRO reading). However, the strange part is that if I run the code in Single Block mode the Z axis depth is always correct for each hole.
I have Windows XP Pro and same Mach3 running on my Mac under Parallels as a test bed and it does the same thing - even though there is no hardware connected, so it isn't the hardware, the only thing common is Mach3 and the G-Code.

I have attached one of my G-Code programs (they all have the same problem). Can anyone explain what's going on and give me a fix?

Many thanks,
Davo.
« Last Edit: February 09, 2021, 05:45:45 AM by Pompey Dockyard »

Offline Graham Waterworth

*
  • *
  •  2,305 2,305
  • Yorkshire Dales, England
    • View Profile
Re: Mach3 Z Axis drilling problem
« Reply #1 on: February 09, 2021, 09:36:11 AM »
Add line

N185 G61

and line

N2905 G64

and try it.
Without engineers the world stops
Re: Mach3 Z Axis drilling problem
« Reply #2 on: February 10, 2021, 05:04:31 AM »
Add line

N185 G61

and line

N2905 G64

and try it.

Thanks Graham, that fixed it.
I had a sneaking suspicion it was somehow tied up with constant velocity but it threw me when it worked OK in Single Block mode.
I assume Mach3 defaults to Exact Stop mode when in Single Block.
I've changed all my other drilling code to suit and all work fine now.

Cheers,
Davo.  ;D
Re: Mach3 Z Axis drilling problem
« Reply #3 on: February 10, 2021, 06:53:33 PM »
Further reading:
Last night I watched two very good YT videos by Peter Passuello, who has the CNCnutz channel, in which he discusses constant velocity and its downfalls and ways around it.
I am now much the wiser and know why I had the problem. ::)

Cheers,
Davo.