Structure Optimize Of The Ring Scanner Based On Finite Element Method

This dissertation use a ring scanner as an example,from the view of the product design and using finite element method,finite volume method and the test to simulate and test the structure of ring scanner,then according to the simulation results and test results to optimize the structure of ring scanner.Firstly,introduced the history of bar code technology and bar code scanner technology development and the current situation of domestic and foreign,and introduced the FEM(Finite Element Method)which is used in this dissertation.At the same time,introduced the design challenge from the environmental testing requirements of the ring scanner.Next,using FEA(Finite Element Analysis)to evaluate the fatigue performance of the ring scanner's trigger.The analysis results show that the weakest region of the fatigue life of the trigger is in the elastic plate bending part,this minimum fatigue life meet the product design requirement.Fatigue test results also show that the trigger can meet the product design requirement.Secondly,this dissertation also studies the temperature field of the scanner.On the one hand,using the finite volume method to analyze the scanner's temperature field,and analysis results shows that the temperature of SENSOR and AIMER_VLD over the allowed temperature of these two product,this will affect the scanner performance.On the other hand,the temperature field test was carried out on the scanner,and the results were basically consistent with the analysis results.Based on the analysis results and test results,this dissertation proposes the optimization design of temperature field from the improvement of thermal conductivity of materials,and verifies the feasibility of the optimization schemes.Thirdly,this dissertation also use the dynamic FEA and drop test method to study the drop performance of the ring scanner.First using the dynamic FEA to simulate the drop from the height of 1.5m,and evaluating the stress level and acceleration level.Analysis results show that top cover and bottom cover all appear high stress regions,these regions may occur crack risk;the acceleration response on scanner engine is lower than the impact acceleration specification of the production,the failure risk is low.Using the fixed direction method with the two drop direction of FEA to do drop test for ring scanner production,there are two failures from the test result,one failure is the bolt hole on bottom cover appears crack,the other failure is the copper nut on top cover was pulled out.This study from the process and the structure to optimization the design of the failure regions and using FEA and testing to verifies the feasibility of the proposed design.