Milling machine and methods of milling and menu selection

Abstract

Determining the intersection line of a plane Z=Z1 perpendicular to the axial direction of an end mill and a design surface, determining equal pitch offset-curves as path elements inside a material and outside the intersection line, determining intersection points crossing a material boundary from outside to inside as cutting start and end points and reverse respectively when going along the path, determining a tangent to the path element at the cutting start point and determining the intersection point of the tangent and a material boundary offset line outside the materials as the end mill approach start point. Determining a point at a minimum height on a design surface and determining such a ball end mill that a mill model does not interfere with the design surface when aligning the tip of the mill model with the point. When performing offset milling by a thickness .delta., making a mill model by reducing the outline of a rotating end mill by the thickness .delta., placing the model on the design surface to determine a path and actually cutting with the end mill along the path. Displaying a tree-type hierarchical menu and selecting one item of the lowest layer in the menu, resulting in selecting all related items in the hierarchical layers above it automatically.