Research On High Efficiency Magnetorheological Planazation Processing Technology Using Permanent Magnetic Yoke With Straight Air Gap

The popularity of mobile phone,tablet personal computer and digital cameras promotes the extensive use of optical glass in civilian field,which leads to strong demand for planar high-precision lenses.Traditional method can be used to polish flat glass material,but its machining efficiency and precision is very difficult to meet market demand.Therefore,it is urgent to develop new types of polishing technology with high efficiency and high quality.Magnetorheological finishing technology(MRF)is a new type of optical finishing machining technology which has been developed over the past twenty years.It has incomparable advantages than the traditional machining method in optical machining.It is able to process super-smooth surface without subsurface defects,and it is also a kind of flexible and controllable polishing way.The tranditional magnetorheological polishing adopts the method of wheel polishing,where polishing contact is point contact,which is easy to control,compensate and achieve high surface accuracy,but it is poor in machining efficiency and expensive in cost.With the growing demand for flat glass material workpiece and the size of part tending to be larger and larger,the current magnetorheological machining method is hard to meet market demand.In order to solve this problem,this paper studies a kind of magnetorheological finishing processing technology with surface contact to improve machining efficiency.The main research work is as follows:(1)By making the contrastive analysis of electromagnetic and permanent magnet excitation mode,and combining the design requirement of planar MRF machine with the actual situation,the author designs and fabricates excitation system based on permanent magnet yoke.(2)The author uses ANSYS software to do the simulation analysis of the permanent magnet yoke system.The excitation system of the planar MRF polishing machine is designed and manufactured after optimization design.And experiments are done to testify the effect before and after optimization.(3)The author usesthe planar magnetic rheological prototype developed by the research group and permanent magnet yoke designed by himself to do technology experimental research with singal factor variable changing during the experiment.With the result of the experiment data,the author discusses the influence of technology parameters on the results of the experiments both on removal rate and surface roughness.The technology parameters studied in this paper included workpiece speed,polishing disk rotational speed,excitation gap,working gap,yoke clearance,the concentration of iron powder,and the concentration of polishing powder and so on.