Research On The Key Technologies On Feeding System For Floating-mandrel Drawing Machine Of Thin-walled Copper Tube And The Influence Of Drawing Process

The existing thin-wall copper tube drawing with floating plug machine adopts manual feeding,which has great labor intensity and low production efficiency,and it has been unable to meet the needs of modern engineering.There are two technical difficulties in the automatic feeding of thin-wall copper tube drawing with floating plug machine,the first one is high precision positioning of core head,the other is that copper tube single sorting difficulties caused by long size and large deflection.At the same time,the surface quality defects of copper tube and drawing parameters have great influence on the drawing forming.Therefore,the research has great research value and application prospect.In this paper,the following work has been done by the combination of theoretical research,numerical simulation and experimental analysis: In order to solve the problem of the assembly of the core through the copper tube,the assembly dimension chain is established and solved through the analysis of the drawing space error,and the core piercing technology is determined.According to the problem of large deflection of a single tube sorting,based on the dynamic simulation of copper separation;in the conventional drawing machine on the basis of complete material on the structure and control system design of mechanical system;combined with the actual production,by moving core floating plug drawing process of finite element simulation.After the research,primary results can be obtained as follows:(1)the space assembly system composed of tube billet,plug rod and plug head are analyzed,The positioning error of plug piercing is described quantitatively,The clearance between the plug and the copper tube is used as closing link,The spatial dimension chain of copper tube assembled with plug piercing is established,The solution of assembly dimension chain is illustrated by large number exchange method,determining the method for the plug positioning and the coring technology,That is,using V block positioning combined with self-centering ping mechanism(mainly composed of double screw and nut pair)to complete the plug positioning and coring.(2)After analyzing the characteristics of the single copper tube sorting,the establishment of ADAMS model based on tube sorting,To sort Φ106mm thin-walled copper tube as an example,to investigate the influence of the process parameters(sorting speed,inclination angle,copper tube deflection)to single tube sorting technology index(the height of rise,sorting completion time,contact force),At the same time,multiple tube sorting model was established based on ADAMS,to explore the effects of process parameters(sorting speed and inclination angle)on the sorting efficiency(sorting rate,sorting time and overlap ratio)of copper tube,The sorting speed of copper tube sorting device is better at 400mm/s~800mm/s,and the inclination angle is better at 35°~40°,The rationality of the simulation model is verified by experiments.(3)on the basis of the conventional drawing machine,The simulation results of the plug piercing technology and the copper tube sorting device,The feeding system is divided into 5modules: sorting,conveying,positioning and penetrating,double shifting and feeding,Structural design and material selection are made for each module and the control system design of the feeding system is completed on the basis of PLC.(4)In view of the problem of copper tube,such as uneven wall thickness,Take H62 copper alloy as an example,Based on the uniaxial tensile test of H62 copper alloy,the constitutive model of H62 copper alloy was established by using Elastic-viscoplasticity model,Numerical simulation of drawing process of thin wall copper core with MARC software,Quantitative analysis of the influence of wall thickness fluctuation and friction coefficient on drawing process(drawing force,equivalent effect force,axial movement of plug head),By comparing and analyzing the floating plug drawing and fixed plug drawing,it is found that the floating plug drawing is helpful to improve the product quality.Through the above research,it has well application value and guiding significance for the development of the feeding system of the copper tube drawing machine.At the same time,it has done the preparatory work for the experimental verification of the process analysis of the drawing forming process.