Applied Research On CAD/CAE Of Automotive Fasteners Cold Heating Die

The cold heading process of automotive fasteners is a widely used production technic in the fastener industry in recent decades.During the cold heading process,the billet deformation and material flow are relatively complicated.So during the process of mold design and manufacturing,repeated trials and repairs are required,resulting in prolonging the production cycle of new products.With the popularization and application of CAD/CAE/CAM technology,that combining the experience of mold design and manufacturing with CAx technology has become an important research direction in industrial manufacturing.This paper uses cold heading theory and volume forming theory to study the cold heading process.Taking hexagon bolts as an example,two multi-station cold heading forming process for making hexagon bolts were developed.At the same time,by calculating and arranging the deformation of each step,the influence of various factors that have on the forming during these two processes was analyzed,and then the feasibility of the two processes was determined.Two finite element models of the process plan were established,parameters and boundary conditions were set,and then numerical simulation on each station of the two process plans through the finite element software and DEFORM-3D were performed.Via the post-processing function,the values of stress,strain,temperature field,crystal grain,and other parameters in each station in these two processes were analyzed.Then an optimal process for guiding the design of subsequent multi-station molds was selected.Then an orthogonal test with three-level four-factor was designed.Using the second-step extrusion method in the second process as an example,considering the four factors of the pressure,speed,coefficient of friction,die hardness,and die radius of the punch are important parameters,through range analysis and variance analysis,the optimal level is determined and the optimal combination then will be used in predicting the life of the mold,and at the same time the design of the mold will be guided.Through the design analysis,numerical simulation,process optimization of the process of cold heading die process,the cold heading is parameterized designed.This article also carries on the secondary development to UG NX,mainly includes designing NX interface menu,parameterized designing of the MFC dialog box,and establishing two-dimensional graphic template according to the expression.By writing a callback function and using a customized MFC dialog box,a parametric design of a cold head mold core,a cold head mold punch,a cold head mold,and a mold base are accomplished.According to the parametric design of the three-dimensional mold diagram,a two-dimensional drawing of the cold heading mold is generated,and the two-dimensional drawing of the cold heading mold is managed.By using AutoCAD's secondary developmenttechnology,information management,process management,and storage management of cold heading molds and cold heading molds areaccomplished.ObjectARX secondary development technology is used to accomplish the connection of chilled mold information and database in AutoCAD.At the same time,the function of automatically generating bar code and two-dimension code in AutoCAD is realized.It can be used for the processing and storage of cold heading molds and drawings,respectively.