Experimental Study of Material Removal Process of Fused Silica Glass Using MR Jet Polishing System

Recently,there has been an investigation of polishing processes that has considered new ultra-precision polishing technology for micro parts and optical parts such as those with aspheric and complex shapes.One suitable means of polishing complex shapes is to use a jet of abrasive fluid.However,aerodynamic disturbances and radial spreading are generated by the unstable polishing process of the jet on the surface of the workpiece when it is being polished.A method of jet stabilization has been proposed in which the original nozzle form of a jet of magnetorheological(MR)fluid contains abrasive particles that are magnetized using a magnetic.This paper details the design of an MR jet polishing system that uses an electromagnet,a nozzle,and a hydraulic unit to stabilize a slurry jet based on MR fluid, Second,for silica glass,the polishing spot and section profile are analyzed and the effect of the MR fluid jet polishing process is evaluated.The results of the experiment show that the removal profile is W-shaped and that,in this case,a stable can be proof of a distance of several tens of millimeters from the nozzle.Such results show the possibility of applying the proposed polishing method using MR fluids in ultra-precision micro and optical parts production processes. MR jet polishing shows great potential for use as a new type of precision surface polishing technology.In particular,this is a highly valuable process for the polishing of complex shapes such as micro parts,concaves parts,and cavities.

Rheological Properties and MR Polishing Characteristics of Core Shell-Structured Silica-Coated CI Particles

Recently,ultra-precision polishing processes using smart materials such as magnetorheological(MR)fluids have been used for optics parts such as aspheric lenses.The MR fluid applied in MR polishing is a phase controllable suspension comprising a mixture of CI particles and non-magnetic fluids such as mineral oil and water.The fluids are a kind of smart material that can be controlled according to their flow properties such as viscosity and stiffness. Water-based MR fluids are easily oxidized if the fluids are exposed and this oxidation can bring irregular polishing results. Also,this phenomenon is one of several factors that reduce the life time of MR fluids.In a previous work,CI particles were coated with a polymer or a composite for the improvement of dispersion stability and prevention of corrosion due to oxidation.From this study,the rheological properties such as viscosity and sedimentation of coated CI particles with silica were investigated with a rotational rheometer;MR polishing characteristics of BK7 glass were studied in order to investigate the surface roughness.The wheel speed and magnetic field intensity were chosen as variables.