| SiCp/Al composites have higher specific strength,specific stiffness,and lower density.SiCp/Al composites with different volume fractions are widely used in aerospace,automotive and other fields because of their different properties.As a kind of special processing,EDM can process some difficult-to-process materials with special structures,and will not produce macro cutting forces during the EDM process,so it has higher machining accuracy and higher surface quality.There are also some problems with EDM,such as low material removal efficiency and environmental pollution caused by this process.Therefore,this paper proposed magnetic field assisted EDM to improve the machining performance and solve above two aspects.This paper presented the removal mechanism of EDM of SiCp/Al composite material,further studied on the mechanism of magnetic field assisted electrical discharge machining and analyzed the effect of magnetic field on the plasma channel,which made the discharge channel confined and increased the energy density of charged particles and their collision probability.This violent process can release more energy and reduce the disturbance of charged particles on the electrode surface,which contributed to improve the machining efficiency,then the different effect of machining parameters on the electrical discharge machining were investigated.Based on Abaqus softwre,the EDM process of SiCp/Al composites were simulated to analyze the influence of current,pulse width,and magnetic field on the temperature field distribution and material removal rate(MRR)by FEM.The simulation results showed that current and pulse width are positively related to the rise of temperature,and the influence of the current was more significant,while magnetic field can gently increase MRR.Then a magnetic field assisted electrical discharge machining experiment platform was set up,and a large number of experiments were carried out to study the EDM process of different volume fraction of SiCp/Al composite materialsbased on Taguchi method,the experimental results showed that the increase of current and pulse width can increase the MRR and the concentration of aerosol emissions,the magnetic field can increase the MRR whereas reduce the surface roughness and concentration of aerosol emissions which leads to the reduction of edm pollution to the environment.By comparison of simulation and experimental results,the change trends of both were the similar and the relative errors were low,so the reliabilities of the simulation results were verified.Finally,BPNN model was used to optimize the EDM process of SiCp/Al composites,and the optimal parameter combinations were obtained to reduce the electrodewear rate and the concentration of aerosol emissions while increase MRR. |
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