Just In CNC router having frequent X axis offsets

Hi Friends,

I am new to CNC operation, we are designing molds for some parts of hobby planes in our machine. Last week we got a 3-Axis router, it was working well then what happened is, the tool started cutting the workpiece at the centre of the platform bed. When i reset the tool position in my software to workpiece origin, the software traces the tool to be at origin, but in the machine the tool has moved to some distance in the x direction.

This has happened at three different locations at three different machine run times. I use NC studio for my controller drivers and ArtCAM to make the CAM codes(reliefs or toolpaths) from the solidworks part file.

I am losing precious material and production time because of this.
Please help me out.

Thanks in advance.

Cheers,
Karthik