Parameterized Curve Wireframe Modeling Method For Local Feature Of Automobile Panel Process

In the process of automotive panel mold surface design,a large number of complex local features need to be designed to change the flow law of sheet metal,absorb excess material to avoid micro-corrugation,wrinkling and cracking forming defects,and to improve the surface quality of parts.Traditional design methods use curve and surface commands in mainstream modeling software to create.This process is complicated and inefficient,and requires repeated modification of the position and shape and size of local features to continuously optimize the process plan,modeling and design changes.It is very large,so the development of a set of modules that can quickly create and edit complex local features has important theoretical and practical significance for the design of automotive panels.Based on the development project of a company’s "Automotive Die Surface Intelligent Design System",this paper develops a parametric design module with complex local features based on the NX platform.The module includes four types of complex features: Convex hull,Strengthened-bead,water drop,and overdrawn surface.The parameterized design function allows designers to control the shape and position information of complex local features through parameters,and realizes the rapid creation and editing of local features by parameterization.Compared with the manual creation method,the design time is significantly shortened and the repeatability is reduced.Work to improve the design efficiency of the die surface.This paper puts forward a modeling method of applying parametric curve wireframes,and introduces the general method of constructing parametric curve wireframes.Three different creation ideas are proposed for the three types of curves that make up the wireframe.After that,the method is applied to the four types of complex local features that are common in die surface design,and the construction method of the parametric curve wire frame of each type of feature is introduced in detail.Aiming at the problem that the designer randomly inputting parameters may cause creation failure,for the Convex hull features,an algorithm for calculating the parameter value range is proposed,which depends on the constraint relationship between the curves,and calculates the limit range of the parameter that needs to be adjusted through the existing parameters.So that the input parameters create local features within a reasonable range.For Strengthened-bead features,in view of the problem that input parameters within a reasonable range may still cause creation failure,an automatic parameter adjustment algorithm is proposed,and the parameters are adjusted according to certain rules to ensure the successful creation of complex local features under different control parameters.At the end of the paper,the developed parametric design module was verified,showing the different types of local features created by this module.Through a large number of tests on different types of automobile covering parts,it was compared with the method of manually creating a curved surface.The efficiency and flexibility of parametrically creating surface modules.