contour error are our primary concern thanaxial tracking errors. In this figure, the desired path is shown as solid linewhile the actual path taken is shown by dashed line. The figure also illustratean instance of time t when the desired position of the tool, as provided by theoutputs of the interpolator is at R.
While, because of axial tracking errors,the actual position of the tool is at P. From the figure it can be easily seenthat depending upon the relative magnitude of the axial tracking errors ,it iswell possible to have zero contour errors even for non- zero axial trackingerrors. I. CNC SYSTEM DESCRIPTIONControlling amachine tool by means of a prepared programme which contain numerical dataspecifying the desired motion of the machine’s axis is called as numericalcontrol (NC). NC is founded by US Air Force in the early 1950s, after thatcomputer numeric control was developed. In CNC monitor the movement of machinesbased on CAM/CAD programmes.
The machine can be milling, lathe, router, laseror waterjet cutter, robot etc. The CNC controller work together with aseries motors and drive components to move and control the machine axes, executingthe programmed motions. In CNC our desired model drawing using any type of CADprogramme in computer and at three axes there was thee different stepper motorfor each axis motion of this axis is based on the motion of the stepper motorsthe computer connect to the interface, it will help the signal from thecomputer to a form that the CNC machine can use. That mean our desired modeldrawing is decoded to G-code for CNC can read only G-code or ISO code.
The signalfrom the interface control the movement of the cutting tool A CNC machine tool is always a slide tableand spindle. The machine table is controlled the X and Y axis motion andspindle is controlled Z axis motion. The Fig.2 represent the 3 axes CNCrepresentation