CNC Interpolations

Interpolations are completed to execute contouring tool paths. This produces a series of intermediate data points among given coordinate positions and computes the axial velocity of an individual axis along the contour path. Today, all of CNC controls are equipped with linear & circular interpolations, some provides helical interpolation, and an extremely few provides parabolic & cubic interpolations.

 (a) Linear Interpolation

This moves tool from beginning point to the target point along with a straight line. It might be implemented in a 2-D plane or 3-D space. The programming command must indicate X, Y, Z coordinates of target point, and feed rate.

 (b) Circular Interpolation

This is programmed to cut circular arcs in three principal planes; such as XY, YZ, ZX. Direction, target position, cutting plane, arc radius, and feed rate should be specified in the program.

 (c) Helical Interpolation

Helical interpolation joins the two-axis circular interpolation along with a linear interpolation in third axis.

 (d) Parabolic Interpolation

It utilizes three non-collinear points to approximate curves that are of free forms. This decrease the number of programmed points by as much as 50 times the number needed by the linear interpolation mode. This is mainly used in mold and die making.

 (e) Cubic Interpolation

Cubic interpolation approximates the surfaces described by third-order geometry. This involves the motion of three axes to machine complicated shapes such like automobile sheet metal dies.