Non-retraction toolpath generation for irregular compound freeform surfaces with the LKH TSP solver

  • Zhiwei Lin
  • Jianzhong Fu
  • Yangfan Sun
  • Qing Gao
  • Guanhua Xu
  • Zhengtuo Wang


Toolpath planning for irregular-shaped compound freeform surfaces remains a challenge. This work presents a new approach for compound surface finishing by treating the toolpath planning task as a traveling salesman problem (TSP). The concept of curvature map is proposed. With this concept, the curvatures of the surface patches are recorded to corresponding cells of the map and then the path intervals are determined. The CC points as well as the normal vectors are calculated on the mesh model of the compound surface with a linear algorithm. The obtained CC points are linked as cities in LKH, in which the distance function is redefined to cope with the illegal linking problems. With LKH, tool retractions are no longer necessary. The resulted toolpath is capable of covering the whole compound surface with only one pass. The proposed toolpath generation method is more forgiving on the input. It does not require the surfaces to be perfectly conform on the joining boundaries. Several compound surface examples have been used to verify the feasibility of the proposed method.


Non-retraction toolpath Curvature map Compound surface TSP LKH 


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Copyright information

© Springer-Verlag London 2017

Authors and Affiliations

  • Zhiwei Lin
    • 1
    • 2
  • Jianzhong Fu
    • 1
  • Yangfan Sun
    • 2
  • Qing Gao
    • 2
  • Guanhua Xu
    • 1
    • 3
  • Zhengtuo Wang
    • 1
  1. 1.State Key Laboratory of Fluid Power and Mechatronic Systems, College of Mechanical EngineeringZhejiang UniversityHangzhouChina
  2. 2.Key Laboratory of 3D Printing Process and Equipment of Zhejiang Province, College of Mechanical EngineeringZhejiang UniversityHangzhouChina
  3. 3.Zhejiang University Kunshan Innovation InstituteKunshanChina

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