| Single point diamond turning is a kind of processing technology which can be used to manufacture materials with nanometer surface roughness and submicron shape accuracy.It plays an important role in modern manufacturing industry.Magnetic field has been used in the preparation of single crystal materials and the magnetization of workpiece and cutting tool to improve the material properties and improve the cutting performance,and shows a very broad development prospect.In order to improve the strong plastic deformation in the cutting process of single crystal copper and suppress the generation of micro-surface defects such as tool marks and micro-burrs,the introduction of external magnetic field in the ultra-precision machining process was explored in this research.Firstly,a magnetic shielding device was designed according to the experimental conditions,and an experimental platform was built.Then,PCD tool was used to carry out static scratching experiments on single crystal copper workpiece,and the influence of magnetic field on cutting force,friction coefficient and chip deformation was explored,which provided support and reference for the follow-up ultra-precision turning experiments.Then,in order to explore the influence of magnetic field on surface quality and material deformation,a natural diamond tool was used for turning experiments,and the cutting force,surface roughness and chip shape changes were analyzed.The main research contents are as follows:(1)Design magnetic shielding device and build experimental platformAccording to the experimental conditions,Nd Fe B N35 permanent magnet was selected as the source of magnetic field,and the magnetic isolation effect of common materials such as aluminum,cast iron and 45 steel was discussed and the magnetic isolation fixture was designed.Maxwell simulation software was used to analyze the distribution of magnetic field lines and magnetic induction intensity of the selected permanent magnet,and the influence of the material placed in the magnetic field was analyzed.According to the required experimental conditions,the experimental platform was improved and built.(2)Magnetic field assisted static scratching experiment of single crystal copperThrough single factor experiment,the speed of brush stroke brush depth,strokes are thoroughly analyzed in the presence of the influence of magnetic field under the condition of single crystal copper processing,according to the knife before cutting force,surface friction coefficient,shear Angle and the change of the chip shape characteristics and laws,and based on the friction coefficient and friction Angle,the relationship between the shear Angle,reveals that the magnetic field effect on the deformation of material,found that the shear Angle will increase with the existence of the magnetic field,and suppress the material plastic deformation.(3)Experimental study on single crystal copper turning assisted by magnetic field and lubricatedBased on the single point diamond lathe,the experiment scheme of turning was designed,and the solution was put forward to solve the abnormal cutting problems such as force mutation and serious cutting mark.In-depth analysis of the cutting depth,feed velocity and linear velocity in the presence of the influence of magnetic field under the condition of single crystal copper processing,according to the change of cutting force,surface quality,chip shape characteristics and laws,reveals the influence of magnetic field on the surface quality and material deformation,found that the existence of the magnetic field can improve the surface quality,and reduce the material of plastic deformation. |
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