BITS Faculty Publications
Permanent URI for this communityhttp://localhost:4000/handle/123456789/1867
Browse
6 results
Search Results
Item Experimental investigations of chemo-ultrasonic assisted magnetic abrasive finishing process(Inder Science, 2015-12) Kala, PrateekChemo-ultrasonic assisted magnetic abrasive finishing (CUMAF) is a compound finishing process, which integrates the use of chemo-mechanical polishing (CMP), ultrasonic vibrations and magnetic abrasive finishing (MAF), to finish surfaces up to nanometre order within a short span of time. The present work is focused on design and fabrication of experimental set up to perform CUMAF. Using the developed set up, experiments were conducted on copper alloy work piece and the effects of five process parameters on percentage change in average surface roughness value (ΔRa) was recorded. The experiments were planned using response surface methodology. Experimental data were analysed using analysis of variance to understand contribution of various process factors and interactions on process response. Regression model was developed to predict the percentage change in surface roughness in terms of significant process factors and interactions. Further the developed model was validated and optimised using genetic algorithm to maximise the performance of the developed processItem Understanding flexible abrasive brush behavior for double disk magnetic abrasive finishing based on force signature(Elsevier, 2017-08) Kala, PrateekThe Double disk magnetic abrasive finishing process (DDMAF) poses better finishing characteristics while finishing paramagnetic thin work piece, when compared to plain magnetic abrasive finishing. This is due to the significant change in the behaviour of the flexible magnetic abrasive brush (FMAB) formed in two cases under similar conditions. Observing and comparing the behaviour of FMAB in action visually is a difficult task. However, FMAB average behaviour can be understood by observing the force signature. Thus present work aims at developing a setup that can be used to capture force signature for the two cases and then understand the FMAB behaviour. The present work present the FMAB force signature obtained while performing finishing with MAF with single disk and double disk. The force signature and the basic magnetic principle have been used to understand the FMAB behaviour and thus understand implications on the finishing process.Item Surface roughness modelling for Double Disk Magnetic Abrasive Finishing process(Elsevier, 2017-01) Kala, PrateekMagnetic Abrasive Finishing (MAF) is a super finishing process having capability to produce surface finish in nano-meter level. The value of surface roughness obtained using MAF process depends upon the material properties of work piece and process factors. In the present work, a mathematical model has been proposed for Double Disk Magnetic Abrasive Finishing (DDMAF) process. DDMAF process is a process that can effectively finish even the flat paramagnetic work piece, which were considered ineffective to be finished by conventional MAF. In the present work, the surface roughness has been modelled as a function of workpiece material properties and process factors namely working gap, abrasive mesh number, percentage weight of abrasive, rotational speed and feed rate. The process model utilizes Lorentz force and Amperes law to estimate the finishing force experienced by an iron particle. The force so obtained has been used to calculate the finishing force transferred to the abrasive particle by using force equilibrium between iron and abrasive particle. The effect of normal distribution of abrasive particle size and the effect of frictional force on finishing forces have also been considered in this work. A MatLab code has been developed to include all the above aspects to determine the change in surface roughness. The model so obtained has been validated using experimental findings and thereafter used to study the effect of various process parameters.Item Experimental study on finishing forces in double disk magnetic abrasive finishing process while finishing paramagnetic workpiece(Elsevier, 2014) Kala, PrateekKnowledge of finishing forces is important in any manufacturing process as the surface integrity of the finished surface is being affected. In the present work finishing force and torque were measured for a recently developed double disk magnetic abrasive finishing process. Investigations have been made to understand the effect of process factors namely upper and lower working gap rotational speed, abrasive weight percentage on the normal finishing force and finishing torque. Experiments were planned and performed based on Taguchi L9 orthogonal array. Analysis of variance has been used to analyze the experimental data. The analysis of the experimental data showed that normal finishing forces is affected most significantly by lower and upper working gap and finishing torque is effected mostly by the lower working gap and rotational speed of the magnetic disk. The surfaces finished by DDMAF process are characterized by SEM and the surface morphology has been correlated to finishing force and torque values.Item Chemo Assisted Magnetic Abrasive Finishing: Experimental Investigations(Elsevier, 2015) Kala, PrateekIn modern industries with advancement of technology advanced engineering materials are needed to be used like Tungsten, Titanium alloys, ceramics, various composites etc. These materials possess some special characteristics such as high hardness, high wear resistance, high toughness, high strength etc. which make them preferred over conventional materials in modern industries. Due to the stringent properties these materials are difficult to process. Different conventional finishing processes like grinding, lapping, honing, buffing etc. are generally inefficient in finishing these materials. Although processes like abrasive flow machining, magnetic field assisted finishing processes and chemo-mechanical finishing may be used but these may be less productive. Therefore a new process which uses combination of chemical oxidation and magnetic field assisted abrasion (magnetic abrasive finishing) has been conceived in the present work for faster processing.Item Experimental investigations into internal magnetic abrasive finishing of pipes(Springer, 2016-05) Kala, PrateekSurface finish is one of the important parameters that affects functional aspects of an assembly like friction between mating parts and wear resistance. Magnetic abrasive finishing is one of the advanced finishing processes which has the ability to produce nano-finished surface by removing material in the form of microchips. The present paper introduces a novel tool based on magnetic abrasive finishing (MAF) principle for polishing holes, blind holes, grooves, and vertical surfaces. The tool designed and developed in the present study consists of two permanent magnets with their similar pole facing each other, such that a high magnetic flux density is achieved around the circumferential area between the magnets and the same has been simulated using Maxwell software. In order to evaluate the performance of the tool, experimentation based on central composite design (CCD) technique was performed to finish stainless steel (SS304) pipe. The results so obtained were analyzed to study the effect of process parameters like rotational speed, magnetic flux density, abrasive size, and abrasive weight percentage on percentage change in surface roughness. The analysis showed that the magnetic flux density was the most effective parameter while finishing the stainless steel (SS304) pipe followed by rotational speed. Experimentation at an optimized condition resulted in a surface finish of 56 nm. Further SEM images were taken to understand the surface morphology of finished surface.