Different gap distances in radial and axial directions

If the material for rounded corners (e.g. quadrants) is removed with a cylindrical erosion tool, the problem usually occurs that different gap distances are set in the spark generator in the radial and axial tool directions. Therefore, the TCP of the erosion tool cannot be moved along a circular path.

In order to erode rounded corners, the point where the tool contacts the workpiece must be included when calculating the TCP path. The resulting path usually approximates an ellipse.

A reduced B-spline type is used to approximate the ellipse. This spline type is defined using the command #SPLINE TYPE REDBSPLINE.

This type allows a maximum of four programmed points in the NC program between #SPLINE ON and OFF, but this is sufficient to approximate the ellipse if the points are selected appropriately.

Programing Example

Using the reduced B-spline

%L sinking

N0240 #SPLINE TYPE REDBSPLINE

N0250 #SPLINE ON

(---- 1st B-spline half ellipse ----)

N0260 Y0.018078 Z-0.0127

N0270 Y0.057658 Z-0.009547

N0280 Y0.0767 Z-0.0029934

N0290 Y0.0767 Z0

N0300 #SPLINE OFF

N0310 #SPLINE ON

(---- 2nd B-spline half ellipse ----)

N0320 Y0.0767 Z-0.0029934

N0330 Y0.057658 Z-0.009547

N0340 Y0.018078 Z-0.0127

N0350 Y0 Z-0.0127

N0360 #SPLINE OFF

N0370 M17