Browsing by Author "Arai, S."

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    Surface integrity control of piezoelectric materials in ultra precision grinding on the basis of machine design assessment
    (Cranfield University, 2004-11) Arai, S.; Whatmore, Roger W.
    The target of this research work was to establish a surface integrity control methodology in ultra precision grinding for piezoelectric materials, taking into account the interaction between the material removal manner and the machine design contributions. Whilst there are many respective research works concerning the microscopic material removal behavior on brittle materials and the design characterization of individual machine components, it was necessary to identify the design characteristics in order to ensure a consistent and fine surface integrity ( i.e. surface roughness, surface atness, textural damage ) in contact machining. For example, in a thermal analysis of a machine structure, the considerable inuences of internal and external heat sources were observed, which resulted in heat ows in aerostatic and hydrostatic components. After identifying several thermal error modes, a substantial improvement of thermal stability was applied successfully onto the machine structure. However, the major contributions arising from this research work are considered to be the following. ( i ) Suggestion of a method to achieve optimized grinding conditions for piezoelectric materials ( ii ) Identification of a link between material removal behavior and the machine design contribution (iii)Development of a novel tooling component Following a static and dynamic assessment of three grinding machine structures, it was conciuded that an enhanced damping performance at the loop distance, between the grinding wheel and work tooling, is beneficial to obtain a fine surface finish together with a at surface, whereas past researchers have claimed that static stiffness and high resonant frequencies should be the prime aim.
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    Ultra-precision grinding of PZT ceramics--Surface integrity control and tooling design
    (Elsevier, 2009-10) Arai, S.; Wilson, Stephen A.; Corbett, John; Whatmore, Roger W.
    A comprehensive statistical analysis of the factors controlling surface quality and form in ultra-precision grinding of polycrystalline lead zirconate titanate (PZT) ceramics has been conducted. The work focuses on practical grinding conditions and it includes an assessment of the interactions that exist between the method of material removal and the machine design. In the first phase of experimentation, defects including porosity and the fractural damage induced in the subsurface area were investigated. Machining trials were then conducted which were used to highlight the significant technical factors or combinations of technical factors that influence surface roughness, surface flatness and textural damage. A model for the systematic material removal mechanism which suggests that a relatively large depth of cut and ‘soft contact’ can be used to achieve improved surface integrity is proposed. In order to verify the suggested model, a series of design modifications to the tooling structure were made and the nature of the contact at the material removal interface was studied. Dramatic improvements in surface quality were achieved by incorporating a compliant polymer layer into the vacuum chuck used to hold the ceramics during grinding.