Research On The Contact Wheel Exchangeable Tool System Of Parallel Polishing Machine

Blades are the key parts of the steam turbine.Capability and efficiency of Steam turbine mainly depend on design and machining of blade surface.The material used for making blades has many excellent performances such as high intensity,corrosion resistance and temperature resistant.So,1CR13 which is very difficulty to be machining is used to manufacture steam turbine.Blades's surface is complex free surface and is very difficult to machining.But the surface quality of turbine blade is very important,it will affect the yield stress,wearing capacity,rigidity and so on.surface is complex free surface.Coated abrasive belt grinding,as an important branch of grinding technology,has many excellent performances,like high efficiency,little vibration and low temperature,and it is widely used in the grinding,lapping and polishing of many kinds of metal and nonmetal material.Belt grinder can manufacture all kinds of materials and complex surface now.At present,steam turbine blades are all grinded by handcraft of workers at last working procedure in our country.The turbine blade is frequently polished manually,this way is repetitive,time-consuming and requires experience.Furthermore,the usual polishing equipment is relatively out-of-date,working conditions are poor and harmful to workers' health.Meanwhile,the polishing efficiency is low and the polishing effect is varied with the different proficiency of workers.5-axis blade NC polishing machine and robots polishing has been developed and used to grind blades abroad.Therefore,it's pressed for developing a sort of high precision and efficiency steam turbine blade belt grinding machine,using advanced process to substitute handwork grinding.Firstly,according to modularization principles,blade parallel polishing machine is divided into three parts,which are the slideable table,3-SPS Steward table,clamp,contact wheel exchangeable tool system and gantry in this paper.By means of the analyze of the configuration character of the blade,it is proposed an elementary design to the polishing machine based on CATIA software.Sequentially,,the characteristics of belt grinding on steam turbine blades are analyzed and researched,along shape and material of blades,and speciality of abrasive belt grinding. Based on analyzing of grinding movement on blades,the structural configuration of the machine tool is determined,the kinematic model of blade belt grinding is built,contact wheel exchangeable tool system is designed.According to the actual demand of workpiece to be processed,the structure of wheel train,such as contact wheel,driving wheel,idle wheel and jockey wheel,is designed and arranged,and the strainer structure of abrasive belt is also designed.When the tool system is designed,this article refers to some diminutive,simple machine,confirming reasonable parameter of tool system.Analyzing the intervene and error at working,it is the base of manufacturing the parallel polishing machine.The three-dimensional modeling of every part made by CATIA software is virtually assembled and then the machining system is made to interfere examining.So the designed machining system is rational.After introducing the structure of the tool system,the author establish the simplified model of grind force.In order to constant force polishing,I have designed a pneumatic control system to control the polishing pressure.In order to ensure that the Mathematical model is right and to do further research on the dynamic characteristics of the pneumatic control system,we used Matlab software on the model dynamic simulation analysis.Finally,this thesis makes PATRAN analysis of the Tool system.Then this paper chooses the material of the tool board,reduce the weight.at last,the mechanics ability of the belt grinding machine is verified.This thesis makes ABAQUS analysis of contact of abrasive belt polishing.The paper analyzes the relation of abrasive belt velocity and press force which have an effect on maximal stress between contact wheel and workpiece.The analysis instruct the choice of polishing parameter,which makes a basis for the design of polishing machine.