“…When the motion is given to the tool, MR polishing fluid moves over the surface of the workpiece; it causes abrasion wear resulting in material removal in the form of microchips. The results obtained from the magnetostatic simulation in the form of numerical value of the magnetic field at the finishing cylindrical surface as well as flat-bottomed surface and the trend of variation of the magnetic field in the working gap satisfy the requirement for finishing the surfaces in the present work which can be validated from the other MR finishing processes [22,23]. Figure 3a shows the dimensions of the tool for finishing the internal cylindrical surface of the blind hole.…”
Section: Experimental Set-up With Tool Design and Finishing Mechanismsupporting
Permanent mould dies are used for various plastic injection moulding products. Most of the mould cavity is blind and henceforth difficult to finish. In this study, a novel magnetorheological fluid-based finishing process using permanent magnet tools has been developed for nano-finishing of cylindrical blind hole surfaces. Tools to finish the internal and flat-bottomed surfaces of the cylindrical blind hole are developed. The finishing performance of both tools is evaluated for finishing ferromagnetic material used in dies. The material of the die is P20 tool steel having 41 HRC hardness. Response surface methodology using a central composite design technique has been utilized for the plan of experiments and analysis of significant process parameters on the percentage change in surface roughness using newly developed tools. During finishing the internal cylindrical blind hole surface, the process parameters like rotational speed, reciprocation speed and abrasive mesh size are found to be significant. However, during flat-bottomed surface finishing of cylindrical blind hole workpiece, rotational speed, abrasive mesh size and abrasives volume percentage are found to process significant parameters. Experimentation at optimized parameters results in the final surface finish of 83 nm on internal cylindrical surface and 93 nm on the flat-bottomed surface of cylindrical blind hole workpiece.
“…When the motion is given to the tool, MR polishing fluid moves over the surface of the workpiece; it causes abrasion wear resulting in material removal in the form of microchips. The results obtained from the magnetostatic simulation in the form of numerical value of the magnetic field at the finishing cylindrical surface as well as flat-bottomed surface and the trend of variation of the magnetic field in the working gap satisfy the requirement for finishing the surfaces in the present work which can be validated from the other MR finishing processes [22,23]. Figure 3a shows the dimensions of the tool for finishing the internal cylindrical surface of the blind hole.…”
Section: Experimental Set-up With Tool Design and Finishing Mechanismsupporting
Permanent mould dies are used for various plastic injection moulding products. Most of the mould cavity is blind and henceforth difficult to finish. In this study, a novel magnetorheological fluid-based finishing process using permanent magnet tools has been developed for nano-finishing of cylindrical blind hole surfaces. Tools to finish the internal and flat-bottomed surfaces of the cylindrical blind hole are developed. The finishing performance of both tools is evaluated for finishing ferromagnetic material used in dies. The material of the die is P20 tool steel having 41 HRC hardness. Response surface methodology using a central composite design technique has been utilized for the plan of experiments and analysis of significant process parameters on the percentage change in surface roughness using newly developed tools. During finishing the internal cylindrical blind hole surface, the process parameters like rotational speed, reciprocation speed and abrasive mesh size are found to be significant. However, during flat-bottomed surface finishing of cylindrical blind hole workpiece, rotational speed, abrasive mesh size and abrasives volume percentage are found to process significant parameters. Experimentation at optimized parameters results in the final surface finish of 83 nm on internal cylindrical surface and 93 nm on the flat-bottomed surface of cylindrical blind hole workpiece.
“…Corresponding to the stationary and the rotating workpiece cylinder, an active abrasive particle forms the helical path over the workpiece's internal surface of the pitch length P st and P rt respectively. The pitch length of the helical path formed by an active abrasive particle on the stationary workpiece (P st ) is calculated using the equation (3). Whereas, the pitch length of the helical path formed by an active abrasive particle on the rotating workpiece (P rt ) is calculated using equation (4).…”
Section: Effect Of Particle's Motions On the Finishing Performance During R-mrh Process Through The Path Covered On Internal Cylindrical mentioning
confidence: 99%
“…The MRP fluid is comprised of magnetic electrolytic iron particles (EIPs) and non-magnetic abrasive particles and the base fluid. 3,4 The micron-sized abrasive particles of the MRP fluid play an important role in the finishing mechanism due to their motion along with the motion of the tool and workpiece. Due to the finishing operation performed by the micron-sized abrasive particles, the mechanism of finishing is found invisible.…”
The particles used in magnetorheological polishing (MRP) fluid are the key components of the magnetorheological (MR) finishing processes. The rotational magnetorheological honing (R-MRH) process is recently developed as a highly productive MR finishing process which is used for finishing the internal surface of the industrial cylindric components. The involvement of micron-sized abrasive particles of MRP fluid in the finishing operation results in the invisible observation of the finishing mechanism which enables the urge of analyzing the motion of the particles during the present R-MRH process. Therefore, the effect of motions of the MRP-fluid’s particles is analyzed for nano-finishing performance on the inside surface of the cylindric workpieces. The motions performed by active abrasive particles on the inside surface of the rotating hollow cylindric workpiece cause a higher finishing rate. The effects of particle motions on the reduction in surface roughness and improvement in surface morphology confirm the usefulness of the R-MRH process. The surface finish with the effect of the particles' motions of the MRP-fluid in the R-MRH process on the stationary workpiece’s inner surface is achieved upto 100 nm from 420 nm of the initial ground surface in 60 min of finishing. Whereas, the same aforementioned surface of the rotating workpiece is finished upto 50 nm from the same initial ground surface in only 40 min of finishing with the effect of the particles' motions of the MRP-fluid. The improvement in the surface finish is also noticed through the scanning electron micrographs in this work. The significant change in surface finish obtained in experimentations confirms the integrity of the analytical study conducted for understanding the effects of motions of particles while finishing with the R-MRH process.
“…The indentation diameter ( d i ) as indented by the active abrasive due to the indentation force ( F in ) is calculated using the Brinell hardness model. The model of Brinell hardness number ( H BHN ) is given by equation (35) 28,31 where the active abrasive’s diameter is denoted as d sic in m. The indentation diameter as indented by the AAP is denoted as d i in m. For F in = 4.0698 × 10 −7 N, H BHN = 400 kgf/mm 2 (H13 steel) and d sic = 19 × 10 −6 m, the value of d i from equation (35) is calculated as d i = 1.5786 × 10 −8 m. Figure 9.Schematic of single active abrasive indenting into the external surface roughness peaks during the MR finishing due to the indentation force ( F in ).…”
Section: Surface Roughness Theoretical Model For Magnetorheological Fmentioning
Fine finishing entails increased percentage contact area, less friction, and less wear. The magnetorheological finishing is a precision process to obtain the fine finishing on the workpiece surface for improved functional applications. So, the rotary rectangular core-based magnetorheological finishing process is utilized for the precise finishing of the cylindrical external surfaces. The rotary-rectangular shaped tool core tip surface provides the uniformly magnetic flux concentration that further benefit to offer the uniform fine finishing on the cylindrical work-part's external surface. In this work, a theoretical model is developed to predict the reduction in the surface asperities during the magnetorheological finishing of the external cylindrical surfaces. The rotational speed of the rectangular tool core on the rotating cylindrical work-part enhances the relative speed of active abrasives, which decreases the pitch, helix angle, and increases the helical path length. These results enhance the uniform precise finishing on the cylindrical work-parts and also enhances the process performance. For validation of the theoretical roughness model, the experiments have been performed on the cylindrical external surface of the H13 die steel workpiece. The percentage error between the experimentally obtained Ra value and theoretical Ra value is found to be −4.76% to 3.06%, which shows the good agreement between the theoretical model and experimental results. It also shows the practicality and accuracy of the present process while finishing the H13 die steel and it is useful for many industrial applications.
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