Study On The Mechanical Coupling Stiffness Of Workpiece-Die-Equipment System

Based on the theory and the process requirement of precision plastic forming, the thesis did the study on static analysis and pre-tightening analysis and modal analysis of workpiece- die-equipment system, then, advanced the coupling method of designing, analyzing and comprehensively optimizing workpiece-mould-equipment system.Precision plastic forming is the important orientation of technological development of plastic processing. Process system is the precondition of precision plastic forming, which includs precision plastic forming process, moulds and equipments. And, in which, the moulds and equipments play a key role in the precision of formed parts. The frame is the key component of hydraulic press. The bearing capacity, the deformation and the dynamic performance of press frame determine the precision of products and the service life of moulds are impacted.Thus, it is necessary to take the product precision as restriction condition to design, analyze and comprehensively optimize the coupling stiffness of workpiece-mould-equipment system, so as to reach the precision requirement of products at the reasonable costs of moulds and equipments, which make the production hardware of plastic forming process system superior. In the paper, the study on plastic processing system has been done by using the moulds in the production line of containment of nuclear power reactor and the frame of THP22-4000 hydraulic press.Based on actual production, the each mould in the production line and the frame of THP22-4000 hydraulic press was modelled by coupling method. By using the FEA software ANSYS Workbench, freedom degrees of the nodes in contact surfaces between the every assembled component are coupling by node-coupling method, in order to make models tally with real equipments, and get actual and scientific simulation results. The coupling analyzing results as follows: with the increase of mould's assembly area or mould's close-height, the coupling stiffness improves, which results in the higher deformation of coupling model and the higher machining accuracy of equipment.The dynamic parameters of the frame such as previous six natural frequencies and corresponding modes are obtained through modal analyzing the frame of THP22-4000 hydraulic press. The simulating results indicate as follows:(1)THP22-4000 hydraulic press has reasonable modal parameters. No sympathetic vibration or noise pollution will occur. The press meets the design requirements.(2)The frame has not only fore and after,up-down and left-right bending vibration, but also twisting vibration. These vibrations will affect the strength and stiffness of the frame, affect the precision or forge piece and decrease the service life of die and press machine, so the effects of those vibrations should be prevented by increasing partial stiffness and damp.In this study, the multi-components and combined frame is studied in integrated whole. And the method is the key to the components contacting problems. And the problems caused by the traditional, independent and segregated designs of press frame and mould, such as high production costs and big assembly tolerance of press and mould, low precision, are also solved in this paper.The study on design method of the mechanical coupling stiffness of workpiece- die-Equipment System guides the design and optimization of mould and hydraulic press. Under the prerequisite of ensuring the forming precision of containment, it would be possible to configure and optimize scientifically and rationally the structure of forming molds and equipments, lower the costs of productions, and obtain higher economic benefits.