Ronnie,
First off, you need to check the native units in mach to see that you are in inches.
If so, you need to make sure that you when you tell the machine to move one inch that the machine actually moves that distance. Chances are your machine configuration is set wrong. meaning your motor tuning needs to be configured to your machines hardware configuration. If your machine moves the correct distances, then you need to check which post processor you are using in artcam.