Z-axis keeps going up

[cruz]

Hi everyone,

i'm new here on the forum,
i'm no sure wether this is a problem in sheetcam or mach so my apologies if it's not for this forum
i recently bought a cnc plasmatable and a hypertherm 105.
the problem i now have is when i load part in mach3 and hit start,
the torch goes to its starting possiotion but then the Z axis start going slowly up and it doesn't stop doing this until it is out of travel.
thc is on and in sheet cam the correct parameters are giving for the part

any help would be highly appreciated

[djreiswig]

Try it with THC disabled. If it cuts fine then your THC is running the Z backwards. It is probably trying to lower the torch to drop the volts to match the setting, but the torch is going up instead causing the volts to increase.

[Les Newell]

It sounds like the homing direction is configured wrong in Mach3. If your torch height switch is configured as a home switch go to Config->Homing/limits. Click the 'Reversed' box for the Z axis. If it had a cross it will now become a tick or vice-versa. That should fix it.