Experimental Research On Magnetic Fieldassisted Micro-EDM Machining Of Small Holes

Micro-EDM mainly relies on the instantaneous high temperature generated by the discharge between the two electrodes to remove the workpiece material.It has good machining ability for some difficult-to-cut materials such as titanium alloys and composite materials.It plays a great role in the machining of micro-holes.However,traditional microEDM has problems such as low machining efficiency and poor machining quality,which limit its application in related fields.In order to solve the problems in micro-EDM and improve its machining performance,this paper combines the magnetic field with the microEDM method,and conducts an experimental study on the magnetic field-assisted microEDM machining,and analyze the influence of the magnetic field on the machining efficiency and machining quality of micro-holes.The main research contents are as follows:First,the principle of magnetic field-assisted micro-EDM is analyzed,based on the effect of the magnetic field on the discharge channel,analyzes the force of the charged particles in the discharge channel,and derives the motion trajectory equation of the charged particles,and obtains the influence of the magnetic field on the motion state of the charged particles,at the same time,it analyzes the influence of the magnetic field on the current density,the oscillation of the discharge channel and the dielectric solution,and lays the theoretical foundation for the magnetic field-assisted micro-EDM.Secondly,the test of magnetic field-assisted micro-EDM machining of micro-holes is carried out.First,the magnetic field-assisted micro-EDM device is built,and use the principle of magnetic field generation of the three-phase electromagnetic coil to design the magnetic field auxiliary device,design and select parts such as coil fixtures,workpiece fixtures,and complete the construction of the magnetic field auxiliary device,then uses the peak voltage,peak current,and pulse width as the test parameters for micro-holes machining.The test results before and after applying the magnetic field were compared,and analyzes the influence of the apply magnetic field on the material removal rate,electrode wear rate,surface roughness and surface morphology of micro-holes machining.The test results found that: compares with conventional micro-EDM,magnetic field-assisted micro-EDM increases the material removal rate and electrode wear rate,reduces the surface roughness of the microholes,and improves the surface quality of the micro-holes.Finally,the experiment of machining micro-holes with special-shaped electrodes combined with magnetic fields was carried out.The magnetic field was combined with tube electrodes,groove electrodes and spiral electrodes respectively,and analyzes the influence of the three special-shaped electrodes on the electro-erosion debris and the machining process.Then uses the electrode speed as the test parameter to perform micro-holes machining,and studies the influence of the magnetic field special-shaped electrodes composite machining method on the machining performance and machining quality.The test results found that:under the combined action of the magnetic field and the special-shaped electrodes,the material removal rate and electrode wear rate of the micro-holes machining is further increased,the surface roughness of the micro-holes is further reduced,and the surface quality is further improved.