Newbie- Calibration

[metalfixer]

Hi,
I did a search on "Calibration" and the 7 results did not answer my question.
I operate a plasma cutter using Mach 3, THC-1000 and Sheetcam. I am having trouble calibrating the machine, the motors are belt driven, and have gear racks. If the machine is set for 25" it will travel the 25", but anything below this distance gradually looses accuracy, 6 inches will be 5 7/8 inches.
If increasing over 25", I gain , 72" will be 72 5/8 inches. The machine is used about 32 hours a week, and is 3 years old. I am thinking the plastic or fiber wheels, spur gears or something must be wearing out. To compensate, I offset the drawing center and other features 5/32" on the Y axis, this has been increasing over the years. Any help will be appreciated.
Thanks, Larry

[blackbeard52]

I would seem that if the pinion were wearing it would not be gaining and losing in the same path. Try removing Mach and reloading it. Sometimes alternate programs loaded on the system will cause funky results i.e. antivirus or spyware or cute screensavers.........delete them and try again.

[metalfixer]

Thanks Blackbeard52, I will give it a try. It is a standalone computer, no anti-virus, no internet connection, just what is needed for the plasma cutter. I also wanted to add that the entire 5' X 10' cutting area is normally used, not just the first 2 or 3 feet.
Thanks, Larry

[blackbeard52]

Before removing Mach...save the xml file to another location so you dont have to reconfigure the Mach setup or at least the setting screen shots.

Bob

[Big John T]

You might get a more informative answer over on the mach forum. I don't know anything about mach except it was a pain to remove after testing.

The problem doesn't sound like a calibration issue but a software issue. Having the the wrong steps per inch would be same offset ie more all the time or less all the time from programmed.

You could always use EMC2! That is what I use on my plasma cutter...

John

[metalfixer]

UPDATE
The problem was that the pinion gear on the Y-axis motor was loose, and would move, ever so slightly, in each direction.
Hope this helps anyone else having the same problem. A drill point was drilled on the shaft to prevent this from happening again.
Larry