Fundamental Studies on Wheel Wear in ELID Grinding

Ph.DDOCTOR OF PHILOSOPH

Elid superfinishing of spherical bearings

Driven by a requirement to extend the lifespan of self-aligning lined spherical bearings, this research investigates the use of Elid (electrolytic in-process dressing) as a method of improving ball surface finish. Elid is a continuous and self-regulating electrochemical dressing process that modifies the surface of a grinding, lapping, or superfinishing wheel. It provides improved grit protrusion, impedes wheel loading / glazing and promotes effective cutting. The characteristics of the newly-developed Elid superfinishing process are in many ways fundamentally different to conventional superfinishing. The main difference is that the use of super-abrasives prevents the wheel from self-sharpening; the normal mechanism by which dulled conventional abrasives are removed and a wheel’s surface refreshed. Because the wheel’s performance and condition is continually maintained inprocess by the Elid system, metal resin bonded (MRB) wheels containing very small super-abrasives can be used. It is the utilization of these fine abrasives (30 to 0.12 μm) that enables surface roughness values below 5 nm Ra to be consistently produced on the spherical surface of corrosion-resistant steel balls. This research provides an in-depth understanding of the Elid spherical superfinishing process; investigating the most effective use of the Elid system, wheel dressing requirements and process performance. Optimisation is provided in terms of evaluating the critical operating parameters, the most effective superfinishing cycle and the implications to the complete ball production chain. A range of techniques are used to evaluate processing performance and ball output quality. These include in-process monitoring of Elid and wheel spindle power levels, analysis of wheel condition, rates of ball surface generation and material removal, ball finish and form. Although predominantly concentrated on corrosion-resistant steel, testing is also conducted on titanium and various ball coatings. In investigating various ways of using the Elid system, this work considers electrodischarge truing, pre-process dressing, Elid 1, Elid 2, Elid 3, and Elid combined with electrolytically assisted superfinishing. The initial process solution of Elid 3 (electrodeless) superfinishing provides the capability of working on all standard size balls, however the dressing system lacks stability. The development of a fixturing system that has a small separate electrode enables Elid 1 (conventional) to be used on the majority of ball sizes. Elid 1 allows more aggressive and consistent dressing, a faster rate of ball material removal and thus a substantially reduced processing time. Results with a #12,000 wheel show that surface quality is vastly improved through the use of Elid whilst maintaining current production standards of form accuracy. Surface finishes of 2nm Ra are achieved, which is an order of magnitude better than balls currently produced using barrelling / polishing. Processing times are equivalent or faster when using Elid 1. Alternatively, consistently sub 10 nm Ra finishes can be reached with a #2,000 wheel using Elid 2 (interval dressing). Generally MRB-CBN wheels provide a more effective carbide cutting action than conventional superfinishing wheels. Controlling wheel condition and achieving full and even ball to wheel conformity are the two most significant contributory factors to the success of Elid spherical superfinishing. Insufficient control of these factors results in poor output quality. Monitoring of wheel spindle and Elid power usage provides useful information in assessing the condition of the wheel and identifying potential problems. High spindle power correlates with fast material removal and is a result of high loads and a free cutting action. Elid processing can be employed for improving surface finish after the conventional honing stage, or after cylindrical grinding for improving both ball form and finish.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Modeling and analyses of electrolytic in-process dressing (ELID) and grinding

Ph.DDOCTOR OF PHILOSOPH

Remanufacturing and Advanced Machining Processes for New Materials and Components

"Remanufacturing and Advanced Machining Processes for Materials and Components presents current and emerging techniques for machining of new materials and restoration of components, as well as surface engineering methods aimed at prolonging the life of industrial systems. It examines contemporary machining processes for new materials, methods of protection and restoration of components, and smart machining processes. • Details a variety of advanced machining processes, new materials joining techniques, and methods to increase machining accuracy • Presents innovative methods for protection and restoration of components primarily from the perspective of remanufacturing and protective surface engineering • Discusses smart machining processes, including computer-integrated manufacturing and rapid prototyping, and smart materials • Provides a comprehensive summary of state-of-the-art in every section and a description of manufacturing methods • Describes the applications in recovery and enhancing purposes and identifies contemporary trends in industrial practice, emphasizing resource savings and performance prolongation for components and engineering systems The book is aimed at a range of readers, including graduate-level students, researchers, and engineers in mechanical, materials, and manufacturing engineering, especially those focused on resource savings, renovation, and failure prevention of components in engineering systems.

Remanufacturing and Advanced Machining Processes for New Materials and Components

"Remanufacturing and Advanced Machining Processes for Materials and Components presents current and emerging techniques for machining of new materials and restoration of components, as well as surface engineering methods aimed at prolonging the life of industrial systems. It examines contemporary machining processes for new materials, methods of protection and restoration of components, and smart machining processes. • Details a variety of advanced machining processes, new materials joining techniques, and methods to increase machining accuracy • Presents innovative methods for protection and restoration of components primarily from the perspective of remanufacturing and protective surface engineering • Discusses smart machining processes, including computer-integrated manufacturing and rapid prototyping, and smart materials • Provides a comprehensive summary of state-of-the-art in every section and a description of manufacturing methods • Describes the applications in recovery and enhancing purposes and identifies contemporary trends in industrial practice, emphasizing resource savings and performance prolongation for components and engineering systems The book is aimed at a range of readers, including graduate-level students, researchers, and engineers in mechanical, materials, and manufacturing engineering, especially those focused on resource savings, renovation, and failure prevention of components in engineering systems.

Remanufacturing and Advanced Machining Processes for New Materials and Components

Remanufacturing and Advanced Machining Processes for Materials and Components presents current and emerging techniques for machining of new materials and restoration of components, as well as surface engineering methods aimed at prolonging the life of industrial systems. It examines contemporary machining processes for new materials, methods of protection and restoration of components, and smart machining processes. • Details a variety of advanced machining processes, new materials joining techniques, and methods to increase machining accuracy • Presents innovative methods for protection and restoration of components primarily from the perspective of remanufacturing and protective surface engineering • Discusses smart machining processes, including computer-integrated manufacturing and rapid prototyping, and smart materials • Provides a comprehensive summary of state-of-the-art in every section and a description of manufacturing methods • Describes the applications in recovery and enhancing purposes and identifies contemporary trends in industrial practice, emphasizing resource savings and performance prolongation for components and engineering systems The book is aimed at a range of readers, including graduate-level students, researchers, and engineers in mechanical, materials, and manufacturing engineering, especially those focused on resource savings, renovation, and failure prevention of components in engineering systems

Remanufacturing and Advanced Machining Processes for New Materials and Components

Remanufacturing and Advanced Machining Processes for Materials and Components presents current and emerging techniques for machining of new materials and restoration of components, as well as surface engineering methods aimed at prolonging the life of industrial systems. It examines contemporary machining processes for new materials, methods of protection and restoration of components, and smart machining processes. • Details a variety of advanced machining processes, new materials joining techniques, and methods to increase machining accuracy • Presents innovative methods for protection and restoration of components primarily from the perspective of remanufacturing and protective surface engineering • Discusses smart machining processes, including computer-integrated manufacturing and rapid prototyping, and smart materials • Provides a comprehensive summary of state-of-the-art in every section and a description of manufacturing methods • Describes the applications in recovery and enhancing purposes and identifies contemporary trends in industrial practice, emphasizing resource savings and performance prolongation for components and engineering systems The book is aimed at a range of readers, including graduate-level students, researchers, and engineers in mechanical, materials, and manufacturing engineering, especially those focused on resource savings, renovation, and failure prevention of components in engineering systems

Experimental Investigation of Process Parameters in Electrochemical Machining

Electrochemical machining is a non-conventional machining process worked with a principle of Faraday’s law. It is one of the best alternatives for producing complex shapes in advanced materials used in aircraft and aerospace industries. However, the reduction of the stray material removal continues to be a major challenge for industries in addressing accuracy and improvement. It is very difficult to appliance a high strength, heat-resistant material into complex shapes by conservative techniques, but such materials can be effectively machined by electrochemical machining (ECM) method. This experiment highlights features of the development of a comprehensive mathematical model for correlating the interactive and higher-order influences of various machining parameters on the dominant machining criteria, i.e. the metal removal rate and the surface roughness phenomena, through Taguchi method and RSM method using the pertinent experimental data as obtained by experiment

Machining and grinding of ultrahigh-strength steels and stainless steel alloys

Machining and grinding of ultrahigh-strength steels and stainless steel alloy

Metal Matrix Composites with Diamond for Abrasion Resistance

Abstract Metal matrix composites (MMCs) have been used in many applications (such as automotive, aerospace and construction) for many decades. Recently, there have been interesting developments in this type of composite, applying them in electronic and thermal applications such as with semiconductors, in electronic packaging and heat sinks. This is particularly the case for composites of a metal matrix with diamond which are considered a modern sub-class of metal matrix composites. However, while the thermal properties are exceptional, this class of composites has not been extensively examined for mechanical and tribological behaviour, and it may be possible to apply these composites in practical applications, especially those that require extreme mechanical and tribological strength, for example cutting resistance for security applications. Therefore, this research looks for a composite material consisting of metal matrix and diamond particles, which resists abrasive cutting. This progresses through a series of steps, developing methods to process the material, understanding the mechanics of abrasive behaviour and optimizing the composite structure to resist abrasive cutting. Gas Infiltration (GI) casting under gas pressure has been applied to metal matrices with relatively low melting point (aluminium (Al) and tin (Sn)) to obtain a significant penetration of the metal into a preform of diamond particles. Different diamond particle sizes (63-75, 212-250, 420-500 μm) were used to strengthen the Al matrix and diamond coated with a thin Ti layer was used to attempt to enhance the bonding forces between the aluminium matrix and diamond. Al-1 wt. % Mg as a matrix alloy was utilised to investigate the possible effect of Mg on bonding phases and to reduce the surface tension of molten aluminium during the infiltration process. Epoxy was also used as a matrix with diamond in this research by gravity infiltration. Tribological and microstructural tests were performed on the samples, and the results show that the surface modification (Ti coating) of diamond particles has an important role for enhancing the bonding between the aluminium matrix and diamond reinforcement as is apparent under SEM observation, thus improving wear resistance. The coating layer works to either catalyse the graphitisation of diamond surfaces to then dissolve carbon in the metal, or reacts at the diamond surfaces to form carbide crystallites at the interface. This may be one of the reasons contributing to the bonding between the different matrices and diamond. The presence of some of these phases was indicated with XRD patterns and Raman spectra. The principal characterization method was by abrasion cutting tests, which have been carried out on all the samples made. One particle size range, 420-500 μm, of diamond coated by Ti, has been used to manufacture composites with different matrices (titanium (Ti), nickel )Ni(, copper)Cu(, tin)Sn) and epoxy) using different production methods (PM and SPS) for the transition metal matrices due to their high melting points. The abrasion cutting tests of these composites showed that the bonding between the metal matrix and diamond reinforcement and the processing temperature, have an important role in enhancing the abrasion wear resistance of composites, rather than the hardness of matrices