Reliability Study On Kinematic Accuracy In Bottled Bottom Sealing Mechanism

With the rapid development of the pharmaceutical industry,the degree of automation is becoming increasingly higher.The bottom sealing mechanism is an important part of the medicament bottling automation equipment,and its key point of good working and reliable operation in expected life is the comprehensive evaluation between reliability for displacement accuracy and key factors.During real working process of the equipment,multi factors will result in the end position error and the failure of the system.Thus,with the vertical packing machine for ampoule and vial bottles as object,this paper makes an analysis of the motion accuracy and reliability for the bottom sealing mechanism.The research is mainly on following aspects:(1)The cam contour is generated by the software of cam profile design.According to a series of points belonging to the contour,3D model is established on the basis of Creo modeling module,then kinematics simulation of mechanism is made by Creo simulation module.At the same time,the united moving position of end pieces is extracted out and analyzed for obtaining the failure case in the actual operation.The mathematical model is established with the analytical method and reverse design method according to the requirements of end component given by the project.(2)Due to the research object is two stage transmission system and multi-factors like geometric dimension tolerances,clearance and cumulated factors like wear,output state equation is established by the use of dividing the two level and above transmission mechanism into a plurality of single stage complete function parts.The qualitative and quantitative analysis is carried out according to the error simulation result.According to reliability simulation with Monte Carlo method,it can be got that error model under total differential method are more conservative and safe than the direct error state equation in different allowed errors of the given working hours.(3)Run-time reliability curve of different allowable errors is got by taking 90% as the reliability index of running well for a batch of bottom sealing equipment during the set time.Based on the clearance of key points,the corresponding curve of allowable error 1mm is extracted to make fitting analysis,which finds that the initial accuracy reliability of the mechanism are low and it is vital to pay close attention to equipment monitoring and maintenance work after 24000 hours running time.At the same time,the reliability simulation of the cam with different revolving speed shows that the speed has much influence on reliability.So that the necessity of kinematics accuracy takes the flexible rod ofmechanism into account is proposed.(4)Multi rigid body model of the bottom sealing system is established by the use of ADAMS,then,flexible file of rocking beam is generated by the use of ANSYS,which is used to replace the corresponding ones to get the rigid flexible coupling model in ADAMS.Based on the two models,the kinematics displacement simulation concerning the flexible rocking beam is made under different driving speed of cam,it can be found that when the driving revolving speed is 480 degree per second,the design can not only meet the requirements of good and reliable operation,but also meet the requirements of packaging efficiency of enterprise equipment.