Design And Optimization Of An Electronically Controlled Permanent Magnet All-Steel High-Temperature Resistant Chuck

Electronically controlled permanent magnetic chucks with the advantages of energy saving and environmental protection,magnetic force can be controlled,safe and reliable control the working state by transient pulse current,widely used in machinery fields,marine fields,lifting fields and other fields.However,the existing chucks cannot clamp,grip and carry high-temperature workpieces as they are not resistant to high-temperature.Therefore,in order to ensure that the chucks work reliably in a high-temperature environment,a new type of high-temperature resistant electronically controlled permanent magnetic chuck is designed.It can meet market demand,strengthen the ability of enterprises to develop new products and promote the further development of new technologies.The main research content of the thesis is as follows:The theory that the magnetic suction force of an electronically controlled permanent magnetic chuck can be adjusted is analysed.Variable magnetic suction force control of allsteel high-temperature resistant chucks is achieved by varying the parameters of the current in the excitation coil to dynamically magnetise the Alnico reversible magnets,causing them to demagnetise.The formula for calculating the magnetic suction force is derived and three methods for calculating the magnetic circuit are given.The dimensional parameters of the components in the all-steel high-temperature resistant chuck were initially determined.Sm Co material was chosen as the main permanent magnet,Al Ni Co material as the reversible magnet and Fe-Si alloy soft magnetic material as the chuck body.The dimensions of the components of the chuck were verified by the equivalent circuit method,and the magnetic circuit was designed to meet the requirements of the magnetic field strength of the working air gap.The structural dimensions of the all-steel high-temperature resistant chucks were initially optimised by single factor analysis and then by multi-factor optimisation based on the Response Surface Optimisation module.The optimal dimensions of the chucks were obtained with the objective of maximising the magnetic suction force per unit area,which is in accordance with the design requirements.A three-dimensional model of the chuck was established.The static magnetic field and transient field in the finite element software are used to analyse the chuck charging and demagnetising operating conditions to further verify the feasibility.A combined thermal and magnetic field simulation of an all-steel high-temperature resistant chuck was done.The steady-state thermal simulation shows that the magnetic suction force of the chuck is reduced by 16.0% compared to the ambient temperature when the temperature is 300°C.The transient thermal simulation simulates the handling of a hightemperature steel plate workpiece by a chuck.The magnetic suction force at high temperatures at different times is no more than 16% less than at room temperature.The simulation results illustrate that temperature has an effect on the magnetic properties of the permanent magnet material,but has little effect on the magnetic suction force of the chuck.All-steel high-temperature resistant chucks were developed and the magnetic suction force was measured in an experimental system at ambient and high-temperatures.The magnetic suction force of the chuck on the workpiece at room temperature was 3234 N.When the workpiece was heated to 300°C,the magnetic suction force of the chuck was measured to be 2303 N,a reduction of 28.8%.Comparing the experimental data with the finite element simulation results,the error is 5.3% for the ambient temperature condition and 4.0% for the high temperature condition.The experiments have proven that the all-steel high-temperature resistant chucks can meet the high-temperature working requirements.