Abstract: The present invention relates to a surface cutting method for cutting a surface within an area (AR) bounded by a predetermined closed curve (CCL) by moving a tool (TL) along a cutting path (PT.sub.i) in a predetermined direction (direction of arrow A) to cut the surface within the area, thenceforth moving the tool along an adjacent cutting path (PT.sub.i+1), obtained by a shift of a predetermined amount, to cut the surface, and repeating these surface cutting operations.

Abstract: The invention relates to a surface cutting method for back-and-forth surface cutting of the interior of an area (AR) bounded by a closed curve.The surface cutting method includes repeating the following steps:a step of obtaining points of intersection P.sub.i, Q.sub.i between an i-th cutting path (PT.sub.i) and an offset curve offset (OFC') by (T+C+R) to the outer side of the closed curve, as well as points of intersection P.sub.i+1, Q.sub.i+1 between the offset curve and an (i+1)th cutting path (PT.sub.i+1), where T, C and R represent excess thickness, amount of clearance and tool radius, respectively;a step of obtaining a coordinate value, in the cutting path direction, of an outermost point R.sub.i on the offset curve (OFC') between the points of intersection Q.sub.i, Q.sub.i+1, where Q.sub.i is a point of intersection on a cutting end point side of the i-th cutting path (PT.sub.i) and Q.sub.i+1 is a point of intersection on a cutting starting point side of the (i+1)th cutting path (PT.sub.

Abstract: The present invention provides an area cutting method for cutting the interior of an area (AR) bounded by a closed curve (OFC'). The area cutting method includes the steps of: (1) calculating a centroid (W) of an area bounded by the closed curve; (2) determining whether each line segment (L1-L10) connecting the centroid with each vertex (P1-P10) of the area intersects the closed curve; (3) partitioning each line segment into a predetermined number of partitions if the line segment does not intersect the closed curve, and (4) performing area cutting by moving a tool along plural closed paths (CPT1, CPT2 . . . ) each of which is obtained by connecting corresponding ones of the partitioning points of respective line segments.

Abstract: A method of approach in area cutting includes giving in advance an angle .theta. between a workpiece plane (WPL) and a straight line (SL) connecting an approach starting point (P.sub.A) and a cutting starting point (P.sub.i), and a distance dz between the approach starting point (P.sub.A) and the cutting starting point (P.sub.i) in a direction perpendicular to the workpiece plane. Coordinate values of the approach starting point (P.sub.A) are calculated using the angle .theta. and the distance dz in such a manner that a projection (SL') of the straight line (SL) on the workpiece plane (WPL) is brought into orientation with a direction of a normal line at the cutting starting point (P.sub.i) on a curve (OLC) of the external shape. A tool (TL) is positioned at the approach starting point (P.sub.A) in a rapid-traverse mode, and the tool is subsequently moved to the cutting starting point (P.sub.i) in a cutting-feed mode. Thereafter, cutting is started.

Abstract: An area cutting method for cutting the interior of an area (AR) bounded by an external shape curve (OLC) including a number of straight lines (S1, S2, . . . S6) and a circular arc (A1). The method includes linearly approximating a circular arc portion (A1') of an offset curve (OFC) which is offset a predetermined amount from the external shape curve. Then an area bounded by the linearly approximated offset curve is divided into a plurality of convex polygons (PG1-PG3). The centroid (Wi) of each convex polygon and the mid-points (M1, M2) of boundary lines (B1, B2) of two mutually adjacent convex polygons are calculated, and a base line (BL) is generated by successively connecting each centroid and each mid-point.