Research On Automated Design Of Trimming Block For Automotive Panels Driven By Parameters And Sketch

Trimming block is one of the key parts of trimming die,which has a great influence on trimming quality and design periods.Traditional design methods not only have high professional quality requirements for designers but also are difficult to ensure the design quality,which cannot meet the requirements of intelligent manufacturing development of automotive stamping die manufacturing enterprises.At present,many scholars have studied the automated die design,but the research on the automated design of the trimming block is still less,and the market urgently needs a robust and reliable automated design system of the trimming block.Therefore,the thesis has carried out in-depth research on the automated design method and system of the trimming block.This paper analyzes the key and challenging problems in the automated design of trimming block: curve offset,surface construction,installation flange uncertainty,etc.,and proposes the automated design method of trimming block based on full parameters and sketch drive.In this method,curve offset and surface construction are the key techniques.Five criterions of three-dimensional(3D)offset of trimming curve are put forward.Through pre-offset distance calculation and point direction calculation,it filters the bad points to get valid sample points,and it eliminates the offset sharp angle.The method identifies the feature inflexion points of the curve from t he curvature direction and deflection direction,and constructs the B-spline curve as the offset datum point to get the 3D offset curve of the trimming curve.To construct high-quality 3D surfaces of trimming block,we propose a segmented design method based on NURBS mesh surface supplemented by filling surface.It uses NURBS mesh surface in the smooth segment with slight curvature change,while it uses filling surface in the sharp segment with concave curvature change.It guarantees the continuity and smoothness between different surfaces.In considering of the diversity and uncertainty of the installation flange of trimming block,this paper introduces an interactive sketch method for flange outline design.In the full process of curve offset,surface construction and sketch design with parametric driving,coupled with the serial design process of trimming block,an automated design system of trimming block is established,and through the trimming block design example of an automotive fender panel verified the effectiveness of the system,performed the high quality automated block design of onetime successful,design efficiency contrasted with the traditional method has been improved.To manage the non-model information in the design process of trimming insert steel,This paper presents a non-model information management method for designers,developed the integrated information management system,receive the diversification and visual description of design information improve the use value of trimming block design information and product design quality.