Study On Tool System And Control Technology Of The Blade Polishing Machine

Turbine blades is a key component, is also one of the most sophisticated and the most important part. It is responsible for transforming the kinetic energy of the steam into the mechanical energy. The surface design and manufacturing level of blades will affect greatly the working efficiency of the steam turbine. In order to adapt it to have a good running in high temperature, high-pressured, the huge centrifugal force, the steam strength, the corrosion and the vibration as well as wet steam area waterdrop eroding combined, the materials of manufacturing blades usually have the following special combinational properties:stretch, durable and anti-high temperature fatigue fracture performance; high tissue stability; the good performance of thin-walled; good process performance; high resistance to corrosion and heat resistance of gas; high anti-vibration attenuation ability. The leaf blade is made by 1Crl3,2Crl3 and other difficult-to-machine materials. At present, the final processing of blade's surface still remains in the hand-polishing stage, the worker labor intensity is big, the processing efficiency is low, the leaf blade production cycle is long, and the leaf blade's quality cannot obtain the safeguard. With the development of nuclear power equipment manufacturing, large-size turbine blades on the demand for high quality will continue to rise, and the traditional manual polishing can not meet the requirements of blade production. Therefore, seeking the automated polishing equipment for leaf blade is imperative.In this paper, based on blade polishing machine, a set of blade belt polishing system is developed innovatively, which can well adapt to blade curvature, and make full use of processing flexibility, high precision and good processing technology of parallel mechanism. Adopting sand belts polishing equipment and machine's parallel mechanism manufacturing leaf blade together, the quality and efficiency of polishing are improved, the working environment of workers is improved and labor intensity is reduced too. Facing the increasingly competitive market environment, only by constantly developing and innovating sand belts inquiry, increasing development depth of the polishing theory for cutting-edge technology and high precision end product, can realize from technology introduction, digestion, profound changes to the independent innovation, gradually get rid of domestic sand belts polishing technology with a high dependence on foreign passive situation.In this paper, the overall frame of the blade polishing machine is introduced. The blade polishing machine is divided into five parts, which are the slideable table,3-SPS Steward table, clamp, variable contact wheeled tool system and gantry in this paper. Technical parameters of the machine are given. Combined with the steam turbine blade structure and processing technology requirements, taking into account the kinematic characteristics of the blade polishing machine, sand belts cast processes of the machine are designed, which include the way of polishing belt, the contact form of belt with leaves, polishing process parameters, etc.The frame of the tool system is constructed. Fully considering the leaf blade profile characteristic and the processing technological requirement, and taking into account the form of constant pressure polishing, this paper proposes the solution about variable wheeled tool system, determinate the polishing systems and devices for changing wheel, and finishs various modules'design, assembly and interference checking in CATIA. Based on the mechanism of sand belts polishing and comparison of polishing type, the author determines tool system by using the contact wheel abrasive belt behind closed developed ways; Considering the performance of the machine and blade material characteristics, the author determines belt polishing technological parameter as follows:The range of sand belts linear velocity varies between 15m/s and 30m/s; The speed of workpiece feeding range between 0 and 0.2m/min; The depth of polishing is about 0 to 0.1mm; Polishing pressure range between 10 and 120N.Carring on the finite element analysis with ANSYS to the tool system. The static and modal analysis of tool system and key components are done in ANSYS environment with the right three-dimensional solid elements. The results of static analysis show that tool system overall mechanics performance meets the design requirements, small deformation of the tool board does not affect the accuracy of polishing; Through modal analysis about the exchange wheel mechanism, it concludes that the inherent frequency of wheel mechanism is no longer working in commonly operating frequency scope used of the stepper motor. Avoid the resonance and make change wheel mechanism damage or influence polishing precision, and has further confirmed rationality of the tool system design.Research on control technology of the tool systems is done. According to the tool system's structural features, this paper establishs the mathematical model about grinding pressure, indirectly control grinding pressure by adjusting the cylinder pressure value and finally realize constant force polishing; Then hardware structure of electric control system and pneumatic control system has been building. The control system's overall solution uses the IPC and PMAC motion controller to realize, IPC is responsible to control air cylinder's movement, the motion controller achieve two electrical machinery's real-time controls. Finally, this paper establishs the main parts of the mathematical model of the pneumatic control system.