Automatic design for trimming die insert of automotive panel

Trimming inserts with complicated geometric features are widely used in the manufacture of automotive panels. The number of trimming inserts for a typical automotive panel is usually more than 20, even up to 100. The design of trimming inserts is a complex and time-consuming process, which significantly affects the development period and quality of automotive panels. However, the design of trimming insert needs to handle a lot of complex geometrical problems, such as 3D curve offset problems. The current commercial CAD software cannot provide a complete and effective solution to the problem, where a lot of tedious human-intersections are needed. This paper presents a systematic methodology which includes the automation of trimming lines division and trimming inserts design. An automatic-decomposition algorithm is presented to divide the trimming lines into short segments. Then the trimming insert is designed for each divided trimming segment. In order to automate the design of trimming insert, a bulking-fairing algorithm is introduced to fair planar curves to meet physical constraints, and a robust 3D curve offset method is proposed to generating 3D offset curves to overcome the main limitation of existing methods. Lastly, the path-interference-check algorithm is presented to check if the interference occurs during the trimming process. This system is implemented and has applications in industry. Case studies and industrial applications have demonstrated the system's powerful ability in design trimming inserts of automotive panel, and the efficiency for insert design could be improved by 80% at least.