Vibration Analysis And Structure Optimization Of High-speed Precision Crosscutting Machine

Compared with corrugated board,honeycomb board has the advantages of material saving,large volume,stable structure and so on.It is widely used in industry,pack-aging,construction and other fields.With the rapid development of honeycomb paperboyard industry,the processing efficiency of honeycomb paperboard has been put forward higher and higher requirements.As the key equipment in honeycomb paperboard production,the cutting speed of crosscutting machine is the key factor affecting the production efficiency of honeycomb paperboard.However,with the increase of cutting s-peed,on the one hand,the vibration of crosscutting machine is obviously aggravated,which seriously affects the service life and cutting quality of equipment.On the other hand,it will affect the deformation of the tool carrier,so that the cutting gap between the upper and lower knives becomes smaller,and it will also cause the phenomenon o-f "biting the knife",which will aggravate the tool wear and even produce a gap.In order to improve the cutting speed of the crosscutting machine,and reduce the vibration of the fuselage and the deformation of the tool rest,this paper takes the crosscutting machine with a width of two meters as an example to carry out the following research:Firstly,by analyzing the working principle of the power system of the crosscutting machine,based on the L-N contact force model and Hunt-Crossley friction model,the dynamic model of the crank slider mechanism considering the clearance between the connecting rod pin and the bearing motion pair was established,and the virtual simulation model of the power system of the crosscutting machine was established based on the ADAMS simulation software.The simulation results verified the correctness of the dynamic model.On this basis,the finite element simulation analysis of the tool rest was carried out by COMSOL to obtain the deformation of the tool rest in the working process.The simulation results were compared with the experimental results to verify the correctness of the simulation results.Based on the dynamics model,the effects of the length,mass,centroid distance and tool rest mass of the connecting rod on the external load of the connecting rod pin are analyzed.The results show that the external load of the connecting rod pin is proportional to the mass,length of the connecting rod and the mass of the tool rest,and inversely proportional to the centroid distance of the connecting rod.Secondly,based on the influence analysis of external load of connecting rod pin,the length,mass,distance between the center of mass and the quality of tool rest were taken as design variables,the horizontal and vertical forces at the center of crank rotation were taken as constraints,and the deformation of tool rest was minimized as optimization objective.The sequential quadratic programming method(NLPQL)was adopted to conduct the ADAMS/ISIGHT/COMSOL multi-platform joint optimization design.The optimal structural parameters with the minimum tool rest deformation were obtained,and the optimization results were analyzed.The results show that the deformation of the tool rest decreases from 39.6?m to 20.3?m before optimization.In addition,in order to ensure the strength of the optimized connecting rod,the finite element analysis of the connecting rod shows that the maximum stress of the optimized connecting rod is 182.7MPa,less than the yield stress of the material,which meets the strength requirements.Thirdly,based on the quality of the substitution model,the establishment of crosscutting machine equivalent inertia force analysis model,quantitative analysis of the transverse between inertial force and rotational speed,the change rule of crosscutting machine through COMSOL software simulation analysis was made on the deformation of roof in the working process,revealing the crosscutting machine work process of inertia force is the main cause of crosscutting machine vibration.In order to reduce the cutting vibration,on the basis of the existing inertia force balance method,put forward a counterweight to balance shaft structure inertia force balance method,equilibrium condition is derived,and by establishing balance of crosscutting move system ADAMS simulation model of inertial force before and after contrast balance,The results show that the force on the fuselage roof is greatly reduced.Finally,according to the optimization results of structural parameters such as connecting rod length,mass,centroid distance and tool rest mass as well as the new balance mechanism,a prototype of high-speed crosscut machine power system was manufactured.Virtual instrument technology based on Lab VIEW was used to carry out vibration comparison experiments on the crosscut machine system before and after optimization.The results show that after the inertial force of the power system of the optimized crosscutting machine is balanced,the vibration of the machine body is effectively controlled.