摘要 |
PCT No. PCT/JP84/00484 Sec. 371 Date Jun. 10, 1985 Sec. 102(e) Date Jun. 10, 1985 PCT Filed Oct. 12, 1984 PCT Pub. No. WO85/01683 PCT Pub. Date Apr. 25, 1985.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. Straight lines (L1-L14) connecting the centroids (Wi) of the convex polygons and the apices (P1-P10) of the convex polygons, and straight lines (BL1-BL4) connecting the mid-points (M1, M2) and the two ends (P1, P4; P4, P7) of the boundary lines bisected by the mid-points are partitioned into a predetermined number of partitions. A tool is moved along plural closed paths (CPT1, CPT2, . . . ) obtained by connecting partitioning points (Pa1, Pa2, . . . Pa18; Pb1, Pb2, . . . Pb18), which correspond to the straight lines (L1-L14, BL1-BL4), in such a manner that the base line (BL) is enclosed. The tool is moved along the base line (BL) and along the offset curve (OFC).
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