Research On Automation Design Method Of Lifter Core-pulling Mechanism Of Injection Mold

Many products have internal undercut features,which need the help of lifter corepulling mechanism in injection molding.The design process of lifter is tedious,which not only requires designers to have rich design knowledge and experience,but also has low efficiency and is error-prone.In addition,after the design,there is a lack of efficient motion simulation system to analyze and verify the design results.Therefore,this paper takes the automatic design of lifter core-pulling mechanism as the goal,conducts in-depth research on the process and method of lifter automatic design,and explores the automatic motion simulation method of lifter.The lifter core-pulling mechanism is composed of a forming head and a driving component.The driving component is a combination standard part with complex structure,many parameters and strong correlation.In this paper,the composition and structure of lifter are analyzed,and the 3D model of each driving component is established by using key technologies such as parametric design technology and correlation technology,and the related datas are stored and managed by using engineering database technology.Finally,we constructed the model library of lifter driving components.The premise and key step of the automatic design of lifter is to recognize the undercut features.In this paper,the definition and classification of undercut features are given.We used a method which based on surface visibility and positive-negative characteristic to identify the undercut features of products automatically,and the key information of undercut features,such as location,direction and size are extracted.Then,the type and parameter values are determined and calculated automatically by using the theoretical knowledge and engineering experience of lifter design.Finally,the forming head is generated by using a method of clipping body,and the driver component is called and updated from the model library.Through motion simulation,the actual operation process of the mechanism can be simulated,and the problems existing in the design can be found in advance.The key of motion simulation is to create the motion analysis model of the mechanism,which is tedious and inefficient to create manually.In this paper,the motion characteristics of injection mold and lifter are analyzed,and the motion relation table is established.Then the motion simulation analysis model was created automatically according to the general process of motion simulation.Finally,the reliability of lifter movement process is analyzed and verified according to the simulation results.Based on the above research work,this paper has developed an automated design system for lifter on the UG NX platform,and verified the feasibility and effectiveness of the system through application cases.