Dissertations / Theses on the topic 'Precision Grinding'
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1
Ebbrell, Stephen. "Process requirements for precision grinding." Thesis, Liverpool John Moores University, 2003. http://researchonline.ljmu.ac.uk/5633/.
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Hekman, Keith Alan. "Precision control in compliant grinding via depth-of-cut manipulation." Diss., Georgia Institute of Technology, 1997. http://hdl.handle.net/1853/16627.
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Onwuka, Goodness Raluchukwu. "Ultra-high precision grinding of BK7 glass." Thesis, Nelson Mandela Metropolitan University, 2016. http://hdl.handle.net/10948/5203.
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With the increase in the application of ultra-precision manufactured parts and the absence of much participation of researchers in ultra-high precision grinding of optical glasses which has a high rate of demand in the industries, it becomes imperative to garner a full understanding of the production of these precision optics using the above-listed technology. Single point inclined axes grinding configuration and Box-Behnken experimental design was developed and applied to the ultra-high precision grinding of BK7 glass. A high sampling acoustic emission monitoring system was implemented to monitor the process. The research tends to monitor the ultra-high precision grinding of BK7 glass using acoustic emission which has proven to be an effective sensing technique to monitor grinding processes. Response surface methodology was adopted to analyze the effect of the interaction between the machining parameters: feed, speed, depth of cut and the generated surface roughness. Furthermore, back propagation Artificial Neural Network was also implemented through careful feature extraction and selection process. The proposed models are aimed at creating a database guide to the ultra-high precision grinding of precision optics.
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Orton, P. A. "Instrumentation and control for precision grinding machines." Thesis, Nottingham Trent University, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.278450.
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This thesis examines the present methods of centre less bearing grinding, with a view to applying IIDderncontrol nethods in order to reduce the distribution of output size variations and improve the quality of surface finish. Established rrodels of the grinding process shew that various inportant parameters describing the process can be derived, providing that the grinding power can be accurately rronitored. Several alternative control strategies based on paNer rronitoring are considered. The drive systems of a typical grinding machine are rrodelled as they react through the non-linear grinding wheel/work interface. A simplified computer simulation of the process is demonstrated. Suitable rrethods of instrumentation are evaluated including the optical shaft encoder as a source of high resolution data for the estimation of drive shaft dynamics. A method is devised for on line pararreter estimation of the drive system transfer functions. This enables the important grinding power to be estimated fran shaft dynamics and also al loes the rronitoring of the drive system parameters. The cpt.ica l shaft encoder is also assessed as the source of data for vibration detection. A development conputer with real tine multi-tasking operating system software and specialised shaft encoder interfacing has been established as a basis for an expandable control and rronitoring system. A plan for fee
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Tonnellier, Xavier. "Precision grinding for rapid manufacturing of large optics." Thesis, Cranfield University, 2009. http://dspace.lib.cranfield.ac.uk/handle/1826/4510.
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Large scale nuclear fusion and astronomy scientific programmes have increased the demand for large freeform mirrors and lenses. Thousands of one metre class, high quality aspherical optical components are required within the next five to ten years. Current manufacturing process chains production time need to be reduced from hundred hours to ten hours. As part of a new process chain for making large optics, an efficient low damage precision grinding process has been proposed. This grinding process aims to shorten the subsequent manufacturing operations. The BoX R grinding machine, built by Cranfield University, provides a rapid and economic solution for grinding large off-axis aspherical and free-form optical components. This thesis reports the development of a precision grinding process for rapid manufacturing of large optics using this grinding mode. Grinding process targets were; form accuracy of 1 m over 1 metre, surface roughness 150 nm (Ra) and subsurface damage below 5 m. Process time target aims to remove 1 mm thickness of material over a metre in ten hours. Grinding experiments were conducted on a 5 axes Edgetek high speed grinding machine and BoX R grinding machine. The surface characteristics obtained on optical materials (ULE, SiC and Zerodur) are investigated. Grinding machine influence on surface roughness, surface profile, subsurface damage, grinding forces and grinding power are discussed. This precision grinding process was validated on large spherical parts, 400 mm ULE and SiC parts and a 1 m Zerodur hexagonal part. A process time of ten hours was achieved using maximum removal rate of 187.5 mm 3 /s on ULE and Zerodur and 112.5 mm 3 /s on SiC. The subsurface damage distribution is shown to be "process" related and "machine dynamics" related. The research proves that a stiffer grinding machine, BoX, induces low subsurface damage depth in glass and glass ceramic.
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Thomas, David Andrew. "An adaptive control system for precision cylindrical grinding." Thesis, University of Liverpool, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.243279.
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Scagnetti, Paul Albert. "Design of an industrial precision ceramic grinding machine." Thesis, Massachusetts Institute of Technology, 1996. http://hdl.handle.net/1721.1/10918.
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Cai, Rui. "Assessment of vitrified CBN wheels for precision grinding." Thesis, Liverpool John Moores University, 2002. http://researchonline.ljmu.ac.uk/4972/.
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Basic, Saudin. "Magnetic Holding of Synthetic Quartz For Precision Grinding." BYU ScholarsArchive, 2014. https://scholarsarchive.byu.edu/etd/5615.
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The objective of this research work is to investigate the practicality of magnetic workholding of non-magnetic synthetic quartz during high-speed grinding. This research work is sponsored by Quartzdyne and will be used as the starting point to applying single-piece rounding of its quartz. Hypotheses were created that would permit the authors to conclude that magnets are in fact worthwhile workholders for non-magnetic materials. Designs of Experiments were used to reject or fail to reject the null hypotheses. Experiments were carried out using a custom HAAS lathe, modified into a grinding center with an NSK live spindle, and neodymium-iron-boron magnets used to obtain both the holding and shear forces. Lastly, purchased polyolefin foam bumpers were used to increase the shear force, values were obtained with the Starrett force measurement machine. Input variables for the Design of Experiments (DOE) comprised of the holding force, feed-rate, part rotation, and in-feed size of cuts. Sample rotation relative to the magnets was the singular output variable. Experimental results were fitted with the correct distribution and modeled. Once a statistically significant model was attained input settings that minimized quartz sample rotation were determined and used to create an optimized program. Two sets of experiments were needed before the data could be properly fitted with a model. Thirteen out of fifteen samples remained stationary during the optimized program, which was adequate in failing to reject the second null hypothesis; a static sample at 350 RPM will remain static when undergoing high-speed rounding of its outside perimeter. Comparison of cycle times was crucial in reaching this conclusion; in fact, the cycle time of 7 minutes and 58 seconds for the optimized program was substantially less than Quartzdyne's estimated batch flow per piece cycle time of around 15 minutes. Obtaining a model was not possible or needed for the first hypothesis due to all experiments having zero rotation, therefore the authors also failed to reject the first null hypothesis; a static sample sandwiched between two permanent magnets with adequate holding force will remain stationary during rotation (min 250 RPM) Larger in-feed size cuts are possible when the quartz is square in shape –interrupted cuts. As it becomes cylindrical, cuts were reduced to experimental levels. Also, due to the amount of material being removed, the resin bonded wheel required dressing, without it rotation is expected. Variation was noticed while quantifying the shear force; it is attributed to the polyolefin foam bumper with its inconsistent coefficient of friction. A more uniform material, which can provide repeatable shear force values, would lessen the variation. All optimized program samples turned out perfectly round- even the two that had slight rotation.
10
Milton, Gareth Edward Mechanical & Manufacturing Engineering Faculty of Engineering UNSW. "An automated micro-grinding system for the fabrication of precision micro-scale profiles." Awarded by:University of New South Wales. School of Mechanical and Manufacturing Engineering, 2006. http://handle.unsw.edu.au/1959.4/32285.
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Production of micro-scale components is an important emergent field. One underdeveloped area is the production of micro-scale 3D surfaces, which has important applications in micro-optics and fibre optic sensors. One particular application is the production of micro-lenses. With scales of less than 200 ??m these lenses can improve light coupling efficiencies in micro-optic systems. However, current lens production techniques have limitations in accuracy and versatility. Creating these surfaces through mechanical micro-grinding has the potential to improve the precision and variety of profiles that can be produced, thus improving transmission efficiencies and leading to new applications. This work presents a novel micro-grinding method for the production of microscale asymmetric, symmetric and axisymmetric curved components from brittle materials such as glasses. A specialised micro-grinding machine and machining system has been designed, constructed and successfully tested and is presented here. This system is capable of producing complex profiles directly on the tips of optical fibre workpieces. A five degree of freedom centring system is presented that can align and rotate these workpieces about a precision axis, enabling axisymmetric grinding. A machine vision system, utilising a microscope lens system and sub-pixel localisation techniques, is used to provide feedback for the process, image processing techniques are presented which are shown to have a sensing resolution of 300 nm. Using these systems, workpieces are centred to within 500 nm. Tools are mounted on nanometre precise motion stages and motion and infeed are controlled. Tooling configurations with flat and tangential grinding surfaces are presented along with control and path generation algorithms. The capabilities and shortcomings of each are presented along with methods to predict appropriate feed rates based on experimental data. Both asymmetric and axisymmetric flat and curved micro-profiles have been produced on the tips of optical fibres using this system. These are presented and analysed and show that the system, as described, is capable of producing high quality micro-scale components with submicron dimensional accuracy and nanometric surface quality. The advantages of this technique are compared with other processes and discussed. Further development of the system and technique are also considered.
11
Bibler, Jared Evan. "Effects of imbalance and geometric error on precision grinding machines." Thesis, Massachusetts Institute of Technology, 1997. http://hdl.handle.net/1721.1/43428.
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Nguyen, Thai. "Development of New Cooling Methods for Grinding." Thesis, The University of Sydney, 2005. http://hdl.handle.net/2123/1689.
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This research aimed to develop new cooling methods to replace, or at least minimise, the use of currently used grinding coolants which are known to be harmful to the environment. The methods used involved the application of a cold air and vegetable oil mist mixture (CAOM), and the use of liquid nitrogen as cooling media. Allied research focused on the development of a segmented grinding wheel equipped with a coolant chamber. The feasibility of a grinding system using CAOM was assessed on the surface grinding of plain carbon steel 1045. It was found that at low material removal rates, ground surfaces were obtained with a quality comparable to that from grinding with a conventional coolant in association with a reduction of grinding forces. There was no significant difference in the subsurface hardness of the components using CAOM, although the latter method showed a stronger dependence of surface residual stresses on the depth of cut due to the limit in cooling capacity of CAOM. The effects of using liquid nitrogen as a cooling medium on the microstructure of quenchable steel were explored. It was found that a martensite layer was induced on the ground surface. The microstructure featured a dispersion of very fine carbides within the martensite lattice, resulting in a remarkable increase in hardness and high compressive residual stresses within the layer. The topography of the ground surfaces indicated that the material was predominantly removed by brittle fracture. Furthermore surface oxidisation was suppressed. In the interest of coolant minimisation, a segmented wheel equipped with a pressurized coolant chamber was developed. A higher quality ground surface was obtained in conjunction with a coolant saving of up to 70%. In addition, the adhesion of ground chips on the wheel surface largely disappeared. Furthermore, surface tensile residual stresses caused by thermal deformation were minimised. The mechanism of coolant disintegration to form mists using this type of wheel system was studied. The Weber theory for Newtonian jet instability was applied to quantitatively determine the contribution of coolant flow rate to mist and ligament modes. A semi-analytical model was then developed to predict the mist flow rate by taking into account both grinding parameters and coolant properties. The model prediction was in agreement with experimental measurements. Based on the principles of fluid motion and the mechanisms of spin-off and splash, analytical models for both conventional and segmented wheels were established to provide a physical understanding of the mechanisms of coolant penetration into the grinding zone. Coolant minimisation was evident using the segmented wheel where the coolant pumping power into the grinding zone increased with wheel speed, but for the conventional wheel it decreased. A quantitative analysis was developed that accounted for the coolant properties and system design characteristics governing the penetration mechanism revealed by the theory established above. In conjunction with the mist formation analysis, the developed model offers a practical guideline for the optimal use of grinding coolants in achieving a balance between the demands of productivity and care for the environment.
13
Nguyen, Thai. "Development of New Cooling Methods for Grinding." University of Sydney, 2005. http://hdl.handle.net/2123/1689.
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Doctor of PhilosophyThis research aimed to develop new cooling methods to replace, or at least minimise, the use of currently used grinding coolants which are known to be harmful to the environment. The methods used involved the application of a cold air and vegetable oil mist mixture (CAOM), and the use of liquid nitrogen as cooling media. Allied research focused on the development of a segmented grinding wheel equipped with a coolant chamber. The feasibility of a grinding system using CAOM was assessed on the surface grinding of plain carbon steel 1045. It was found that at low material removal rates, ground surfaces were obtained with a quality comparable to that from grinding with a conventional coolant in association with a reduction of grinding forces. There was no significant difference in the subsurface hardness of the components using CAOM, although the latter method showed a stronger dependence of surface residual stresses on the depth of cut due to the limit in cooling capacity of CAOM. The effects of using liquid nitrogen as a cooling medium on the microstructure of quenchable steel were explored. It was found that a martensite layer was induced on the ground surface. The microstructure featured a dispersion of very fine carbides within the martensite lattice, resulting in a remarkable increase in hardness and high compressive residual stresses within the layer. The topography of the ground surfaces indicated that the material was predominantly removed by brittle fracture. Furthermore surface oxidisation was suppressed. In the interest of coolant minimisation, a segmented wheel equipped with a pressurized coolant chamber was developed. A higher quality ground surface was obtained in conjunction with a coolant saving of up to 70%. In addition, the adhesion of ground chips on the wheel surface largely disappeared. Furthermore, surface tensile residual stresses caused by thermal deformation were minimised. The mechanism of coolant disintegration to form mists using this type of wheel system was studied. The Weber theory for Newtonian jet instability was applied to quantitatively determine the contribution of coolant flow rate to mist and ligament modes. A semi-analytical model was then developed to predict the mist flow rate by taking into account both grinding parameters and coolant properties. The model prediction was in agreement with experimental measurements. Based on the principles of fluid motion and the mechanisms of spin-off and splash, analytical models for both conventional and segmented wheels were established to provide a physical understanding of the mechanisms of coolant penetration into the grinding zone. Coolant minimisation was evident using the segmented wheel where the coolant pumping power into the grinding zone increased with wheel speed, but for the conventional wheel it decreased. A quantitative analysis was developed that accounted for the coolant properties and system design characteristics governing the penetration mechanism revealed by the theory established above. In conjunction with the mist formation analysis, the developed model offers a practical guideline for the optimal use of grinding coolants in achieving a balance between the demands of productivity and care for the environment.
14
Zervos, Charilaos. "The Application of electrolytic in-process dressing to precision grinding processes." Thesis, Cranfield University, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.444868.
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Arai, S. "Surface integrity control of piezoelectric materials in ultra precision grinding on the basis of machine design assessment." Thesis, Cranfield University, 2004. http://dspace.lib.cranfield.ac.uk/handle/1826/10441.
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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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Jourdain, R. P. "Ultra-precision grinding of piezoelectric ceramic thick films for fabrication of pre-stressed bimorph microactuators and development of new numerical models to assess induced thermal stress in multilayer structure." Thesis, Cranfield University, 2005. http://dspace.lib.cranfield.ac.uk/handle/1826/11000.
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The research programme aims to develop a novel 2.5 dimensional fabrication process for
multilayer piezoelectric microactuators. Ultra-precision grinding was used in conjunction
with standard micro-fabrication techniques and adhesive bonding technology to create a
powerful bimorph structure. The multilayer structure forms the heart of a microvalve
device and it comprises piezoelectric ceramic layers joined to a metal shim at relatively
low
temperature (200° Celsius). I contrast with existing thick deposition techniques this
new fabrication technique does not adversely affect the electro-active properties of the
ceramic material and it has the further advantage that it is not substrate sensitive making
it
compatible with the wide range of materials available for micro-scale device
construction. The objectives of this project were twofold:
> To investigate the mechanism of the material removal process for piezoelectric
ceramics using a ultra-precision grinding machine tool on four different piezoelectric
materials. The research work investigated both planarization and surface integrity.
> To develop different models using the definite element analysis technique to
analyse and assess the thermally induced stress due to the bonding process. Direct and
initial stress loading conditions were analysed and applied to a multilayer structure.
This work ends with a fully characterized symmetric structure for bimorph cantilevers.
Grinding is shown to be a suitable machining technique to prepare the surface of
piezoelectric ceramic discs. The required surface quality is fully achieved for the target
microsystems application. Surface flatness and roughness have been scientifically
investigated through a experimental plan. The infinite element analysis reveals some
valuable results relating to stress intensity and explores the effect of changes due to
thermal expansion coefficient mismatch and the influence of adhesive bond thickness in
a multilayer structure. Use of initial stress loading allows simulation of complex
processes of fabrication leading to optimization of the structure. h this way a improved
fabrication process has been established which avoids any profile deformation. Finally
the
performance of the bimorph cantilevers is predicted through analytical and numerical
modelling and a correlation is established.
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Blackburn, Travis Lee. "Electro-kinetically enhanced nano-metric material removal." Thesis, Atlanta, Ga. : Georgia Institute of Technology, 2008. http://hdl.handle.net/1853/26600.
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Thesis (M. S.)--Mechanical Engineering, Georgia Institute of Technology, 2009.Committee Chair: Danyluk, Steven; Committee Member: Butler, David; Committee Member: Hesketh, Peter; Committee Member: Yoda, Minami. Part of the SMARTech Electronic Thesis and Dissertation Collection.
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Fiocchi, Arthur Alves. "Ciência e tecnologia da manufatura de ultraprecisão de cerâmicas avançadas: Lapidorretificação Ud de superfícies planas de zircônia tetragonal policristalina estabilizada com ítria." Universidade de São Paulo, 2014. http://www.teses.usp.br/teses/disponiveis/18/18146/tde-30032015-094410/.
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O presente estudo aborda a fronteira da manufatura de ultraprecisão (UP) da zircônia tetragonal policristalina estabilizada com 3 mol% de ítria (3Y-TZP), realizado por meio da lapidorretificação Ud. A crescente demanda por produtos de cerâmicas avançadas com: elevado acabamento e integridade superficial; alta exatidão de forma; e menor custo de fabricação, tem fomentado pesquisas em diversas áreas da nanociência e nanotecnologia (N&N), visando sobrepujar as limitações ou agregando as principais vantagens dos tradicionais processos de retificação, lapidação e polimento. Em decorrência das excepcionais propriedades mecânicas, a cerâmica 3Y-TZP tem sido extensivamente aplicada na indústria. A 3Y-TZP, entretanto, pode apresentar a desestabilização da sua fase tetragonal em diferentes situações e condições, por exemplo, tendo início na própria manufatura, durante sua usinagem, podendo comprometer seu desempenho. Dessa forma, a 3Y-TZP pode ser considerada um material chave para avaliar e qualificar os processos abrasivos que visam padrão ouro de qualidade que, portanto, não devem suscitar a transformação martensítica. Em meio à pluralidade de processos, destaca-se a lapidorretificação Ud. A presente pesquisa estudou a manufatura UP de superfícies planas de zircônia TZ-3Y-E lapidorretificadas com rebolos de SiC de liga epóxi, almejando rugosidade nanométrica e integridade superficial sem danos microestruturais. Discos de TZ-3Y-E foram prensados isostaticamente a 200 MPa e sinterizados a 1400°C por 2 horas. Os discos foram caracterizados por meio de ensaios de: microdureza; perfilometria de contato e óptica; MEV-FEG; espectroscopia Raman; DRX; e microscopia confocal de epi-fluorescência. Os projetos mecânico e eletroeletrônico da Lapidorretificadora Fiocchi foram evoluídos na direção da retificação cerâmica UP. Os resultados demostraram que o projeto evolutivo da lapidorretificadora Fiocchi foi bem sucedido. A execução e controle das etapas de processamento cerâmico foram fundamentais para obter corpos cerâmicos densos e homogêneos, compatíveis com o acabamento aspirado. Os parâmetros de usinagem que se destacaram foram: profundidade de dressagem de 0,1 mm; pressão de lapidorretificação de 100 kPa; 100 rpm do rebolo e porta-peça; e emulsão (1:40) aplicada por MQF. A aspiração dos resíduos sobre o rebolo melhorou em 21,6% o acabamento, todavia a associação de abrasão dois (rebolo) e três corpos (abrasivos soltos) reduziu em 57,15% a rugosidade. O macroefeito foi visível nos rebolos de #800, #600 e #300 dressados com Ud = 1. A menor rugosidade, Ra = 60,63 nm, proveio do rebolo #300 dressado com Ud=5. O menor desvio de planeza, 0,308 μm, foi obtido com o rebolo de #800 e Ud = 3. O processo alcançou condições de plasticidade da zircônia que apontam para o predomínio dos mecanismos de remoção de microcorte e pulverização de material, sem ocorrência de microtrinca. Segundo ensaios de DRX e Espectroscopia Raman, a lapidorretificação Ud não provocou transformação martensítica. Todavia, o rebolo de #300 gerou alargamento assimétrico dos picos tetragonais nas proximidades de 2θ = 35° e 39° e a reversão das intensidades dos picos tetragonais a 40° e 41°. A reversão foi atribuída a mudança do domínio ferroelástico e a reorientação de planos cristalográficos em nível de cristalito. Os estudos sugerem que a usinagem introduziu tensão residual de compressão que pode ter estabilizado a fase romboédrica. Não há relato de processo capaz de alcançar acabamento nanométrico similar com mesmo tamanho e tipo de abrasivo. A lapidorretificação Ud pode substituir o engajamento da retificação, lapidação e polimento de cerâmica avançada.The present study focuses on the border of ultra-precision (UP) manufacturing of 3 mol% yttria tetragonal zirconia polycrystal (3Y-TZP), carried out by Ud-lap grinding. The increasing demand for advanced ceramic products with: high surface finish and integrity; high form accuracy; and lower manufacturing cost, has encourage research in several areas of nanoscience and nanotechnology (N&N), to overcome the limitations or adding the main advantages of traditional grinding, lapping, and polishing processes. 3Y-TZP ceramics has been extensively applied by industry due to its exceptional mechanical properties. The 3Y-TZP, however, can present destabilization of its tetragonal phase in different situations and conditions. In the beginning of its manufacture, during its machining for instance, which may compromise its performance. Thus, the 3Y-TZP can be considered a key material to evaluate and qualify abrasive processes aiming gold standard quality that, therefore, should not raise the martensitic transformation. In the midst of plurality of processes, it is noteworthy the Ud-lap grinding. This research studied the UP manufacture of flat TZ-3Y-E zirconia surfaces lap ground with epoxy binder SiC grinding wheels, aiming to nanometer roughness and microstructural integrity without damage. Discs of TZ-3Y-E were isostatically pressed at 200 MPa and sintered at 1400 °C for 2 hours. The discs were characterized by tests of: microhardness; contact and optical profilometry; FEG-SEM; Raman spectroscopy; XRD; and confocal epi-fluorescence. Mechanical and electric-electronic designs of Fiocchi lap grinder were developed toward the UP ceramic grinding. Results showed that the developmental design of Fiocchi lap grinder was successful. The accomplishment and control of ceramic processing stages were essential for dense and homogenous ceramic bodies, compatible with the finish aspired. The machining parameters that stood out were: 0.1 mm depth of dressing; 100 kPa lap grinding pressure; 100 rpm grinding wheel and workpiece-holder; and emulsion applied by MQF. Suction of debris on the grinding wheel has improved finishing in 21.6%, however the combination of two-body abrasion (grinding wheel) and three-body abrasion (loose abrasives) decreased roughness in 57.15%. The macroeffect was visible on #800, #600, and #300 dressed with Ud = 1. The best finishing, Ra = 60.63 nm, came from #300 grinding wheel dressed with Ud = 5. The smallest flatness deviation, 0.308 μm, was obtained with the #800 grinding wheel and Ud = 3. The process has achieved zirconia plasticity conditions pointing towards predominance of microcutting and pulverization material removal mechanism without causing microcrack. According to XRD and Raman spectroscopy, the Ud-lap grinding caused no martensitic transformation. However, #300 grinding wheel has generated asymmetric broadening of the tetragonal peaks close to 2θ = 35° e 39° and reversal of the intensities of 40° and 41° tetragonal peaks. The reversal was attributed to ferroelastic switching and reorientation of crystallographic planes into crystallite level. Studies suggest that the machining has introduced compressive residual stress that may have stabilized rhombohedral phase. There is no report of an abrasive process capable of achieving similar nanometric finish with same grit size and type of abrasive. The Ud-lap grinding can replace the engagement of grinding, lapping, and polishing of advanced ceramics.
19
Анциферова, Олеся Олександрівна. "Технологічне забезпечення точності та якості поверхонь зубчастих коліс при удосконаленні методу зубошліфування." Thesis, НТУ "ХПІ", 2018. http://repository.kpi.kharkov.ua/handle/KhPI-Press/38013.
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Дисертація на здобуття наукового ступеня кандидата технічних наук за спеціальністю 05.02.08 – технологія машинобудування. – Національний технічний університет "Харківський політехнічний інститут", Харків, 2018.
Дисертацію присвячено вирішенню проблеми підвищення продуктивності процесу зубошліфування на основі досягнення високої необхідної точності і якості поверхневого шару з оцінкою комплексного впливу конструктивно-технологічних факторів на процес формування поверхневого шару зубів зубчастих коліс з метою підвищення їх зносостійкості, а також продуктивності технологічного процесу в оптимальних виробничих умовах. Отримала подальший розвиток теоретико-експериментальна залежність формоутворення якості поверхневого шару та способу переривчастого зубошліфування, яка відрізняється врахуванням геометричних параметрів переривчастого кругу, що дозволило прогнозувати експлуатаційні властивості зубчастих коліс. Удосконалені технологічні засоби стабілізації оптимальних режимів переривчастого зубошліфування, які дозволяють підвищити якість обробки зубчастих коліс. Встановлена закономірність зменшення засалювання переривчастого зубошліфувального кругу та температури у зоні контакту, яке впливає на забезпечення експлуатаційних властивостей поверхонь зубів.Thesis for scientific degree of Candidate of Technical Sciences on speciality 05.02.08 − Manufacturing Engineering. − National Technical University "Kharkiv Polytechnic Institute", Kharkiv, 2018. The dissertation is devoted to solving the problem of increasing the productivity of the process of grinding on the basis of achieving the high required accuracy and quality of the surface layer with an assessment of the complex influence of structural and technological factors on the formation of the surface layer of teeth of gear wheels in order to increase their wear resistance, as well as the productivity of the technological process in optimal production conditions. The theoretical and experimental dependence of the formation of the quality of the surface layer and the method of intermittent gear grinding has been further developed, which differs from the geometric parameters of the discontinuous circle, which allowed predicting the operational properties of the gears. Improved technological means of stabilizing optimal modes of intermittent gear grinding, which allow to improve the quality of machining of gear wheels. The regularity of reduction of salting of intermittent gear grinding wheels and temperature in the contact zone is established, which affects the maintenance of the operational properties of tooth surfaces.
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Анциферова, Олеся Олександрівна. "Технологічне забезпечення точності та якості поверхонь зубчастих коліс при удосконаленні методу зубошліфування." Thesis, НТУ "ХПІ", 2018. http://repository.kpi.kharkov.ua/handle/KhPI-Press/37888.
Full textAbstract:
Дисертація на здобуття наукового ступеня кандидата технічних наук за спеціальністю 05.02.08 – технологія машинобудування. – Національний технічний університет "Харківський політехнічний інститут", Харків, 2018.
Дисертацію присвячено вирішенню проблеми підвищення продуктивності процесу зубошліфування на основі досягнення високої необхідної точності і якості поверхневого шару з оцінкою комплексного впливу конструктивно-технологічних факторів на процес формування поверхневого шару зубів зубчастих коліс з метою підвищення їх зносостійкості, а також продуктивності технологічного процесу в оптимальних виробничих умовах. Отримала подальший розвиток теоретико-експериментальна залежність формоутворення якості поверхневого шару та способу переривчастого зубошліфування, яка відрізняється врахуванням геометричних параметрів переривчастого кругу, що дозволило прогнозувати експлуатаційні властивості зубчастих коліс. Удосконалені технологічні засоби стабілізації оптимальних режимів переривчастого зубошліфування, які дозволяють підвищити якість обробки зубчастих коліс. Встановлена закономірність зменшення засалювання переривчастого зубошліфувального кругу та температури у зоні контакту, яке впливає на забезпечення експлуатаційних властивостей поверхонь зубів.Thesis for scientific degree of Candidate of Technical Sciences on speciality 05.02.08 − Manufacturing Engineering. − National Technical University "Kharkiv Polytechnic Institute", Kharkiv, 2018. The dissertation is devoted to solving the problem of increasing the productivity of the process of grinding on the basis of achieving the high required accuracy and quality of the surface layer with an assessment of the complex influence of structural and technological factors on the formation of the surface layer of teeth of gear wheels in order to increase their wear resistance, as well as the productivity of the technological process in optimal production conditions. The theoretical and experimental dependence of the formation of the quality of the surface layer and the method of intermittent gear grinding has been further developed, which differs from the geometric parameters of the discontinuous circle, which allowed predicting the operational properties of the gears. Improved technological means of stabilizing optimal modes of intermittent gear grinding, which allow to improve the quality of machining of gear wheels. The regularity of reduction of salting of intermittent gear grinding wheels and temperature in the contact zone is established, which affects the maintenance of the operational properties of tooth surfaces.
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Rossi, Moacir Aparecido. "Método prático para otimização do ciclo de retificação transversal de precisão." Universidade de São Paulo, 2009. http://www.teses.usp.br/teses/disponiveis/18/18145/tde-04052009-112707/.
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Este trabalho descreve uma forma prática para planejamento do ciclo de operação de retificação por mergulho, em função da especificação dimensional da peça e da rigidez da máquina. Essa otimização é estendida além do ciclo, envolve produzir lotes de peças com dispersão das dimensões dentro de limites especificados. O tempo de set-up, que normalmente não está incluído no tempo de processo, aqui é incluído e considerado. A primeira atividade de laboratório teve como objetivo confirmar a relação entre a quantidade de material removido em função do tempo de spark-out. A segunda atividade comprovou a existência de uma relação linear entre a velocidade de avanço radial do rebolo e o diâmetro final da peça. A terceira atividade confirmou a existência de uma relação entre a velocidade de avanço radial e o índice de capabilidade especificado para o processo. Ainda, foi sugerida a inclusão deste processo proposto num programa CNC da máquina, de forma a se obter automaticamente o set-up. Concluiu-se que o método aqui apresentado reduziu significativamente o tempo de set-up da máquina conferindo um incremento de produtividade aos processos que fizerem uso deste princípio.This work shows a practical way to design the cycle of a plunge grinding process as a function of workpiece dimensional specification and the machine stiffness. This optimization is extended beyond the cycle, it\'s included make batch of parts with dispersion within the specification limits. The set-up time, that usually isn\'t in the process time, here it was included and focused. The first activity of laboratory had an objective to confirm the relation of the amount of material removed as a function of spark out time. The second activity has been confirmed the linear relationship between the infeed velocity of the grinding wheel and the final diameter of the workpiece. The third activity has been confirmed the relation of the infeed velocity and the capability of the process. Yet, it was suggested to include this procedure in a CNC set of the machine to allow a faster and automatic set up. So, this work shows a conclusion that the set up time can be reduced a lot, allowing higher productivity for who use this procedure.
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Huang, Hung Yi, and 黃弘毅. "Ultra Precision Grinding of Silicon Wafers." Thesis, 2003. http://ndltd.ncl.edu.tw/handle/15301360032924188148.
Full textAbstract:
碩士國立臺灣大學
機械工程學研究所
91
Abstract Silicon wafers are most extensively used materials for IC substrates. A single crystal silicon ingot before taking the form of wafers must go through a series of machining processes including slicing, lapping, surface grinding, edge profiling, and polishing. A prime requirement of the processes is to produce extremely flat surfaces on workpieces up to 350 mm diameter. A total thickness variation (TTV) of less than 15 micrometers is strictly demanded by the industry for 0.18μm IC process. Further the surfaces should be smooth (< 10 nm Ra) and have minimum subsurface damage (< 10μm) before the final touch by etching and polishing. The end products should be crack free mirror surfaces with mico-roughness less than 1.8Å. However subsurface damages are usually accompanied in the grinding and lapping processes, which result in reduced strength of substrates and give adverse effects on IC properties. In this thesis, experimental observations are conducted to investigate various parameters on the surface and subsurface damage of ground silicon wafers. Different methods are attempted to examine and measure the subsurface damages. The initial results indicate that grit size of the grinding wheel, feedrate applied in the grinding process, and the rotational speed of the wafer are the key factors. It is suggested that the surface and subsurface damage can be reduced by controlling the grain depth of cut. In addition, a new method is proposed to investigate the critical depth of cut of wafer grinding and it was shown that the critical depth of cut is about 30 nm. The subsurface damage of lapped wafer is also investigated. Finally, the article made a comparison between wafer grinding and lapping in economical aspect.
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Chen, Shen-Hang, and 陳聖航. "Studies on the Grinding Mechanism of New Ultra-Precision Ball Grinding Machine." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/38960765473220417585.
Full textAbstract:
碩士國立中山大學
機械與機電工程學系研究所
92
The ceramic ball bearing has been used to exact machine for its good properties such as heat-resistant, corrosion-resisting, and wear-resisting. The old grinding methods of ball bearing spend much time and power. Although the magnetic fluid grinding method economizes time, but cost much money. This study research the effects of spindle speed, grit size, load, and the material of float-ring and fixed-ring on the grinding characteristics by using a new ultra-precision ball grinding machine which developed by our lab. Search the optimum operating conditions of this machine for the requirement of industrial circles. Experimental results show that the converge rate of the saturated value for the sphericity, surface roughness (Ra), and the removal rate are increased with increasing spindle speed, grit size, or load. The sphericity and surface roughness (Ra) are increased when spindle speed, grit size, or load is increased. The sphericity and surface roughness (Ra) are increased with increasing removal rate in using the same grit size and load. Under a certain operating parameter of grinding process, the mean diameter and removal rate are decreased with increasing grinding time. The sphericity and surface roughness (Ra) are better when using the plastic than the float-ring and fixed ring of aluminum, but its removal rate is lower than aluminum’s. First, let the average sphericity achieve saturated value by using diamond grind disk to grinding the Al2O3 ceramic ball. Then, the optimum sphericity can achieve 0.7μm and the surface roughness (Ra) can achieve 0.1μm by using the B4C grits of 0.5μm to grinding.
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Horng, Yeh Jenq, and 葉政宏. "Studies on the Grinding Characteristics of New Ultra-Precision Ball Grinding Machine." Thesis, 1999. http://ndltd.ncl.edu.tw/handle/67419070273340804680.
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碩士國立中山大學
機械工程學系
87
This study develops kinematic analysis of ball grinding process, to realize the skidding mechanism. The effects of grit size, load, and spindle speed on the grinding characteristics is investigated by using a new ultra-precision ball grinding machine to search the optimum operating conditions of this machine. For the Al2O3 ceramic ball made in Taiwan, experimental results show that the converge rate to a saturated value for the sphericity and the removal rate increase with increasing grit size, load, or spindle speed. The sphericity increases when grit size or spindle speed increase, but is doesn’t depend on load. The surface roughness increases with increasing grit size, but it is independent of load or spindle speed. The sphericity increases with increasing removal rate using the same grit size and load. Under a certain operating parameter, the mean diameter decreases with increasing grinding time, but surface roughness and removal rate don’t change with increasing grinding time. Experimental results show that the best sphericity can achieve 1.5 μm. For Al2O3 ceramic ball made in Japan, the grinding characteristics are the same as Al2O3 ceramic ball made in Taiwan in qualitative analysis. However, the higher removal rate, the higher sphericity, and the higher surface roughness can be qualitatively obtained for Japanese ceramic’s ball by using the present machine.
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Lu, Yi-Wun, and 陸怡妏. "Subsurface Damage in Precision Grinding of Zerodur." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/79145667979053937846.
Full textAbstract:
碩士國立臺灣大學
機械工程學研究所
100
Zerodur is a glass-ceramic made by Schott AG. With its very low coefficient of expansion, it can be used to produce mirrors which retain acceptable figures in extremely cold environments such as satellite. The primary subject of this study is to reach the characteristics of subsurface damage (SSD) in diamond wheels precision grinding of Zerodur, and establish the model of SSD in Zerodur using different grinding parameters, e.g. depth of cut, speed, feed rate, and different grinding wheel conditions, e.g. grain size and wheel bond. The research results about the grinding parameters show that to reduce the depth of cut or work speed would be effective in reducing SSD, and increase the wheel velocity can reduce SSD. However, above a certain wheel velocity, the SSD increases due to high temperature. The results about the wheel conditions show that the metal bond wheel induces slightly larger SSD than the resin bond wheel. Using wheel with larger abrasive size will cause deeper SSD. The abrasive sizes have a decisive impact on the SSD, which is much larger than the grinding parameters. Experiments on #600 metal wheel with the depth of cut 5μm, work speed of 30mm/min and wheel speed of 10 m/s, the subsurface micro-crack is 2.91μm. If all variables remain the same but with work speed of 10mm/min, it will achieve subsurface micro-crack less than 2.91μm. The results of this study match the theoretical formula, and the empirical formula from curve fitting could predict the subsurface micro-crack depth after grinding within a certain grinding conditions in which the error is less than 24 %.
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Sun, Houng. "Precision gear grinding using self-learning control strategy." 1986. http://catalog.hathitrust.org/api/volumes/oclc/15361948.html.
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Wang, You-min, and 王佑敏. "Studies on the Grinding Characteristics of Ball by Using Eccentric Ultra-Precision Ball Grinding Machine." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/98537592010037933961.
Full textAbstract:
碩士國立中山大學
機械與機電工程學系研究所
93
ABSTRACT The ceramic ball bearing has been used to exact machine for its good properties such as heat-resistant, corrosion-resisting, and wear-resisting. Now, the produced expense of ceramic ball is hundred of steel ball because the grinding process must spend much time and money. This study research the effects of eccentricity (e: the distance is between the center of the ball circulation and the center of the spindle), spindle speed, and load on grinding characteristics of ball by using eccentric ultra-precision ball grinding machine which developed by our lab, under saving cost and time, search the optimum operating conditions of this machine, it’s good for industrial circles in the future. Experimental results show that the converged rate of the saturated value for the sphericity is increased with increasing eccentricity. Saturated value of sphericity is sphericity reduced to a steady state. The saturated value of the sphericity is not fully proportional to eccentricity. The relation between eccentricity and saturated value of sphericity are divided two region by one rb, the first region is that sphericity is proportional to eccentricity when eccentricity is 0~rb, and the second region is that sphericity is inverse proportional to eccentricity when eccentricity is rb~2rb. The converged rate of surface roughness (Ra) are negative with increasing eccentricity and the saturated value of the surface roughness (Ra) is higher. The volume removal rate is increased with increasing eccentricity. The converged rate of the saturated value for the sphericity and surface roughness (Ra) are increased with increasing spindle speed and load, and the saturated value are higher. The volume removal rate is also increased with increasing spindle speed and load.
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Chang, Chih-Neng, and 張智能. "study on the internal gear precision grinding using EDM." Thesis, 1995. http://ndltd.ncl.edu.tw/handle/69786294973860340915.
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Hsu, Chang-Lin, and 徐彰嶺. "Theoretical Studies on Grinding Trajectories on Precision Ball Surface." Thesis, 2003. http://ndltd.ncl.edu.tw/handle/89554327913127815916.
Full textAbstract:
碩士國立中山大學
機械與機電工程學系研究所
91
A ball bearing is widely used in the precision machine, and the ball is its major component. The sphericity and the surface roughness of the ball significantly influence the bearing per-formance and reliability. First, this study considers the gyro-scopic effect and modifies the theoretical model of magnetic fluid grinding to analyze the kinematics characteristics of ball grinding process. According to the apparent changes in the spin angle and the shaft angular speed, the theoretical analysis qualitatively predicts the onset of skidding between contacts. Moreover, the gyroscopic effect is helpful to the randomizing for the ball motion. Second, the grinding trajectory on ball is theoretically analyzed for the new self-developed grinding machine to ob-tain the high efficiency and high precision grinding of balls. Results show that the grinding trajectory is uniform when the spin angle stably changes from 0 to 2p periodically.
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Chiu, Shaowei, and 邱紹維. "The CAM grinding program for precision non-metal cutting." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/ycq593.
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碩士國立虎尾科技大學
機械與機電工程研究所
96
The main goal of this paper is investigation on geometrical relationships of the woodcutter. The procedure and grinding path of woodcutters also have been analyzed. By Visual Basic, CAM systemof tool grinding for woodcutters is developed. The mathematical correlation of geometrical dimensions would be droved by CAM system software. The geometrical relationship between grinded side and grinding wheel can be obtained by mathematical functions. With the integration of three dimensional equations of grinding angles, grinding process and displacement control of cutter, and logical control of NC code, the control program for grinding path of cutters would be schemed Then this system will be applied for setting the fitting parameters and determining the optimal grinding point and procedure. Finally, by 3D motion simulation of tool and machine, a safe cutting path could be gained and a precision cutter grinding could be achieved.
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He, Tao-Yu, and 何燾羽. "Analysis and Prediction of Thermal Deformation for Precision Grinding Machine." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/gdm94u.
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碩士中原大學
機械工程研究所
93
This study uses the heat sources of regulation and randen types to simulate thermal deformations and temperatures from one direction and multiple directions by finite element method. Using the analyzed results of finite element method to build the prediction model which by feed-forward Neural Network input as temperatures and output as thermal deformations. After modeling, the other analyzed results add with white noise which are 0.5%, 1%, 2%, 5%, 10%, 15%, 20%, 25% and 30% for the original temperatures, to discuss the predicted accuracy of Neural Network.
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Chang, Ming-Tsan, and 張明燦. "The Engineering Anlysis of Ultra Precision Grinding of Silicon Wafers." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/94023933575063174970.
Full textAbstract:
碩士國立臺灣大學
機械工程學研究所
93
In the semiconductor industry, the grinding process is recently introduced in a wide variety of fields such as the fabrication of silicon wafer, the silicon wafer recycling process, and the silicon wafer thinning process due to its high yielding rates and the resulting qualities of the products. The superior characteristics of the ground wafer are usually produced through its excellent physical properties. However, the warp of ground silicon wafer, which is one of the most serious problems, should be carefully controlled. In this thesis, the physical properties of ground wafer are analyzed to find the factors which affect the results. The residual stress of the silicon wafer is measured and estimated by reciprocal lattice unit of X-ray diffraction measure. The grinding parameters which decide the residual stress and physical properties of ground silicon wafers are analyzed through design of experiments and the optimum grinding conditions are then sought. Also, the correlation between the grinding temperature, residual stress and the warp of ground wafers is investigated. Finally, the residual stress and physical properties are measured and compared to investigate the effects of the polishing process which follows the grinding process.
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Chang, Shih-Yen, and 張世彥. "The thermal error simulation and analysis of precision grinding machine." Thesis, 1999. http://ndltd.ncl.edu.tw/handle/86515403558150003250.
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碩士國立臺灣大學
機械工程學研究所
87
Improvement on product accuracy is one of the main objectives in the mechanical industry. Recent research has applied experimental technique in combination with multi-variable regressive analysis for on—line compensation during machining. Though significant improvement has been achieved, tremendous efforts and time have to be devoted in constructing the compensation model. The finite element method (FEM), on the other hand, can be equally efficient in solving the problems with complicated geometry and boundary conditions, either linear or non-linear. In this study, focus has been placed on the analysis of CNC surface grinder. The results include the deformed machine tool under gravity and various mode shapes. The FEM model has been applied to simulate various machining conditions and corresponding experiments arranged for verification. Two significant factors in regards to thermal errors have been found by the analysis of variation.
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Chen, Jo-Han, and 陳若翰. "A study of grinding glass using precision electroplated diamond tools." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/46180461570549575510.
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碩士華梵大學
機電工程學系
103
The purpose of the paper investigated the grinding chipping of the glass substrates using the electroplated diamond tools. Using four kinds of different diamonds and two diamond sizes; the strength of the diamonds was a low strength of YK-JQ-SMB and YK-JQ, a high strength of PK-5, and a middle strength of P5Y-J. Comparing the different (1) diamond types and size, (2) feed rate, and (3) up grinding and down grinding would be studied to analyze the effect of diamond protrusion and working particles of the tools on the chipping of glass grinding edge, drilling holes, and slot processing. The experiment results showed that (1) For glass edge grinding, when the smaller grit size and the narrower particle size distribution of the diamond grinding tools were used during dry grinding, the smaller diamond protrusion obtained can produce a smaller chipping size of the glass substrates. The tools containing the larger size of 40-50 μm with a lower diamond strength of YK-JQ after grinding glass can get a smaller chipping than that of a higher strength of P5Y-J with a grit size of 36-54 μm. For a smaller diamond size, the tool using a higher diamond strength of P5Y-J of 20-30 μm can obtain a relatively smaller chipping than that of a lower strength of diamond YK-JQ of 22-36 μm. In addition, the tool containing a higher strength of P5Y-J with an irregular shape can produce a smaller chipping of glass than that of PK-5 with a regular shape. Furthermore, when an up grinding and a faster feed rate employed during dry grinding glass can obtain a smaller edge chipping. (2) For glass drilling holes and slots processing, drilling depth and the amount of cooler fluid have greatly effected on wet grinding glass holes and slots. Using a tool with a smaller grit size, and a low strength diamond of YK-JQ 22-36 μm can obtained a smaller glass chipping than that of a larger size, a larger difference of grit protrusion and a higher strength diamond of PK-5 36-54 μm.
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Lin, Shin-Shian, and 林信憲. "A study for the vitrified bond of precision grinding wheels." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/35532669546141082382.
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碩士華梵大學
機電工程學系博碩專班
96
The paper is to investigate the moderate design of the vitrified bond compositions, and thereafter, the selection of raw materials, mixing and fusing to get the frits. Then the frits and alumina abrasives were mixed and fired to the desired mixture. The following analysis of the fired mixtures was discussed: (1) the relationship of the flow ability of the frit bonds and temperature; (2) the reaction of the frit bonds and the alumina abrasives; (3) physical properties such as the three-point bending strength and dynamic Young’s modulus; (4) the fracture structure; (5) thermogravimetric analysis (TGA). The experiment results showed that a less amount of B2O3 and a higher amount of ZrO2 caused the frit bond to lower fusing ability and reduce flow ability. The frit bond containing a higher amount of MgO had a better fusing ability, thereby causing a better flow ability. Besides, the bending strength obtained for the fired mixture of frit bond was higher than that of raw bond. The flow ability test for the raw bond showed that the raw materials with the lower melting point first fused and then mixed with powders of higher melting point, and then cover the alumina abrasives, forming a shorter bond bridge among the alumina grits or disappearing. Hence, the resulting poorer bending strength for raw bond was obtained. Using frit bond of moderate flow ability combined the grits to form a solid and strong bond bridge with a good wetting contact angle, which displays a better bending strength among the abrasives. From the TGA analysis, the different bond compositions would affect two temperature variations, showing a lower temperature of 350-450℃ and a higher temperature of above 600℃, which produces a mass loss.
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Lin, Sing-Min, and 林賜民. "Studies on Precision Grinding Characteristics of Chromium - Molybdenum Alloy Steel." Thesis, 1994. http://ndltd.ncl.edu.tw/handle/29588365628656821941.
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碩士國立成功大學
機械工程研究所
82
This thesis investigates the grinding characteristics of chromium-molybdenum alloy steel with the vitrified bonded CBN (cubic boron nitride) and Al2O3 wheel. The grinding forces, surface roughness and wheel wear were measured under various grinding conditions, and an optimum grinding condition was obtained. Using the 3-axis machining center, dynamometer and surface roughness testing machine, the grinding force and the surface roughness of the specimem under various grinding conditions for both alumina oxide and cubic boron nitride wheel. The experimental results showed that te grinding performance with cubic boron nitride is superior to that with alumina oxide. Based on the experimental results of this study, an optimum grinding condition was applied to the grinding of variable pitch lead screw with conical meshing elements. Then, the surface quality of the screw was measured.
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Chen, Cheng-Li, and 陳正理. "Researches And Designs Of Special High-Precision Grinding Forming Tools." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/03704084725236533677.
Full textAbstract:
碩士遠東科技大學
機械工程研究所
100
Forming tool is according to the needs of the workpiece design with high efficiency, high precision, reducing the process and the cost of equipment. Suitable for the final finishing with a large number of manufacturing, it can shorten the manufacturing process and time. The forming tools have many types such as composite forming tools and so on. This paper researches of the designs and grinding for the high-precision forming turning tools, reamers and helical involute cutters and uses software such as CAD and VERICUT for simulation and verification. The toroid-shaped helical cutter with an involute generator is a precision tool used in the machining of involute helical gears with side milling. This kind of helical milling cutters is a high quality and high efficiency cutter in the NC machining. This paper presents a precise mathematical model and a systematic modeling procedure for design and manufacturing the revolving involute milling cutters. The detailed models of cutting edge, flute shape, grinding wheel profile are derived and presented. The procedure for employing NC machines simulation for producing such cutters is addressed. The produced cutters are further evaluated and verified by illustrative numerical examples and NC manufacturing. Some major researches of this project are cited as follows: 1.By employing the theory of envelope, this paper designs the forming wheel grinding the high precision forming lathe tool. 2. By employing the methods of CAD, this paper designs the forming wheel grinding the high precision forming reamer. 3. Calculate the cutting edges curve of involute helical cutter. 4. By employing the methods of CAD, this paper designs the forming wheel grinding special groove. 5. Grind the involute helical cutter using standard wheel and simulation by VERICUT. Keywords: helical angle; groove; envelope; reverse envelope;
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Lin, Yu-Wei, and 林育緯. "The Study of Precision Compensation System for Grinding End-mills." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/jbr3j2.
Full textAbstract:
碩士國立虎尾科技大學
創意工程與精密科技研究所
99
In recent years, the machining technology in high speed milling and cutting for hard materials or fine shapes develops fast. Due to the development of new engineering materials and components miniaturization and precision, there is a great demand for high value-added and high productivity cutting tools. Therefore, manufacturers are actively developing high-performance cutting tools for a variety of processing applications and expand their production capacity. This thesis establishes a precision compensation system for grinding end mills based on a five-axis tool grinder. Owing to the wear of grinding wheels, this leads to the geometric error of cutting tools. Thus, it needs to adjust the grinding parameters to compensate the parameters of grinding wheels. We measured the tool images as input values, and derived mathematical modules and analyzed the grinding processes. Then the offset of grinding point can be obtained for the wear of grinding wheel. The experimental results show that the developed system in this study can improve the geometric accuracy, quality, production efficiency of cutting tools and reduce production costs. Furthermore, it also can achieve the standard processes for grinding end mills.
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Liu, Michael, and 劉應進. "The Study of Electrolytic In-process Dressing Grinding in Precision Ceramic." Thesis, 2000. http://ndltd.ncl.edu.tw/handle/00774291231013003995.
Full textAbstract:
碩士國立海洋大學
機械與輪機工程學系
88
Abstract The demand of industry of high technology for precision parts made from brittle and hard materials has risen and continues to rise and they ask for high level in surface roughness. The electrolytic in-process dressing grinding is capable of performing ductile machining on brittle and hard materials to ensure good machining accuracy, reduce the extent of damage layer and improve the surface roughness. In this study, we adopted Response Surface Methodology of Statistical Experimental Design to plan the experiment of ELID grinding. The results of the regression analysis using the statistical software can be applied to mode the mathematical relationship between machining factors with surface roughness and material removal rate. The results associated with the analysis of the variance can be judged the mathematical mode and practiced to assess the prominence among experiment factors. Finally, an optimum method ─ Simulated Annealing Method was adopted to search the optimal grinding conditions.
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Arthur, Song, and 宋俍宏. "Preliminary Research and Development of New Ultra-Precision Ball Grinding Machine." Thesis, 1998. http://ndltd.ncl.edu.tw/handle/53514785278455995071.
Full textAbstract:
碩士國立中山大學
機械工程研究所
86
The purpose of this study is to develop a new ultra-percision ballgrinding machine. First, the kinematic characteristics of ball and removal mechanism for various ball grinding machines are theoretically investigated. This new float-ring ball grinding machine combines thee design advantages of those ball grinding machines previously developed. The effects of gritsize, abrasive material, the angle of float-ring, spindle speed and load on the grinding characteristics of machine are investigated experimentally. Experimental results show that when spindle speed increases to 1200rpm under low load, the removal rate increases because of the sliding between driving shaft and ball. When the speed increases to 1800 rpm, the remmoval rate achieves a saturated value. When load increases to 1.5 N/ball under the speed of 1200 rpm, the highest removal rate can be obtained. To obtainthe better sphericity and removal rate it is suggested to decrease the angle of float-ring and to increase the spindle speed. When the abrasive gritsize # increases, the better sphericity and surface roughness can be achieved,but with lower removal rate. It is also found that the diamond can obtain the better removal rate, but the rougher surface. However, it is not suitablefor the carborundum to grind ceramic balls due to the severe wear. In this preliminary test, the present ball grinding machine can achieves the sphericityof 6.32 um.
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Chien, Sheng-Hsien, and 簡聖憲. "Study on Optimization Process of Ultra-Precision Grinding of the Tungsten Carbide." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/92862489727756343840.
Full textAbstract:
碩士明新科技大學
機械工程系精密機電工程碩士班
103
This study analyzed variation of workpiece form accuracy (Peak to Valley Value) and surface roughness on Ultra-Precision Grinding process parameters during manufacture of Tungsten Carbide-Co profiles. The experimental plan was based on a Taguchi orthogonal array table. A hybrid method includes the response surface methodology (RSM), and back-propagation neural network (BPNN) integrated simulated annealing algorithm (SAA) are proposed to determine an optimal parameter setting of the Ultra-Precision Grinding process. In addition, an analysis of variance (ANOVA) was implemented to identify significant factors influencing for the Ultra-Precision Grinding process parameters. By regression analysis, a mathematical predictive model of the Ultra-Precision Grinding process parameters of the response surface equation was developed in terms of the process parameter. The combining BPNN/SAA optimization method can be obtained for the appropriate combinations of the optimal setting. In addition, the result of BPNN integrating SAA was also predictive by BPNN approach. By verification results show the proposed algorithm of SAA approach has better prediction result than the RSM method.
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CHIANG, PO-HUI, and 江柏輝. "Structural Analysis and Experimental Verification of Moving Column High-precision Grinding Machine." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/c2a74f.
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Shih, Sheng-Yu, and 施勝禹. "Development of a high-precision CNC grinding machine and study of a monocrystalline diamond probe grinding for measurement of surface roughness." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/34594753407232781838.
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Hsiao, Wen-chi, and 蕭文奇. "The Study of Machining Precision on Flute Grinding Process by Response Surface Methodology." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/86031654191225391316.
Full textAbstract:
碩士國立雲林科技大學
機械工程系碩士班
99
The diamond wheels which are made by foreign companies are about 4~10 times better than those are made by native companies according to the industrial experience. The specific grinding conditions were set for comparing the efficiency of grinding wheels which made in overseas and native companies, then the surface quality and shape accuracy were measured, also the wheel life could be assessed. For testing the performance of each diamond wheel in this study, the sintered tungsten carbide-based hard metals (HRA 92.3 and referred to as tungsten carbide or WC hereinafter) are set as the workpiece. We grooved four flutes in the end mill, which is an application of creep feed grinding. The grinding resistance and the consumption power which spindle made could considered as the cutting performance, surface roughness could considered as the shape accuracy, and grinding ratio could considered as the wheel service life. This paper analyzed the wheel grinding resistance, surface quality of the tool, and the grinding wheel service life through different diamond wheels which with specific combined conditions. When the basic characteristics of the groove grinding are obtained, further we analysis the surface roughness of a grinding groove by response surface methodology (RSM), grinding depth, tangential speed of wheel, and feed rate are chose as the controllable factors, the analysis result by RSM shows we could get the best grinding conditions to obtain finest groove roughness, or a range of fine roughness of groove, also the grinding depth and wheel tangential speed affect flute roughness more than the feed rate by engineering statistics analysis.
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Kao, Pei-Huang, and 高培晃. "Study on Surface/sub-surface damage induced by Precision grinding of Silicon Wafers." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/czj2v3.
Full textAbstract:
碩士淡江大學
機械與機電工程學系碩士班
106
This research aims to investigate the surface/subsurface damage of silicon wafer induced by precision diamond grinding. Effort has been made to clarify the effect of spark out on surface integrity of the obtained surface. It is found that the damaged layer of precision ground silicon wafer are typically composed of defects such as amorphous layer, dislocation and micro-cracks. The machining parameters have profound effect on the extent and distribution of these defects. Based on the results of this study, surface generated by applying moderate spark out (5-6 revolutions) can effectively reduce the thickness of the damaged layer. Very little improvement can be obtained when spark out are pushed to 12-24 revolutions. 12" silicon wafers of Ra better than 11 nm and 5 nm and thickness of the damaged layer smaller than 180nm and 70nm are obtained by rough and fine grinding respectively in this research.
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Chen, Run-Yuan, and 陳任垣. "Ball Nuts Cutting Tool Geometry Design of Precision Grinding and Optimization of Machining Parameters." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/53gaq7.
Full textAbstract:
碩士國立虎尾科技大學
機械設計工程研究所
101
Ball screw drive with low friction and high efficiency characteristics is widely used in machine tools and high-speed precision feeding system of industrial applications. Its machining precision directly affects the vibration, noise and positioning accuracy of transmission. Therefore, key factors for grinding wheel geometry design of ball nuts, tool holder mechanism design and grinding parameters are affecting the machining precision. To meet the demand for precision machining, the geometric parameters mathematical model of grinding wheel profiles is established based on the theory of conjugate meshing surfaces to produce precision grinding wheel geometry to grind a variety of screw and ball-nut. An innovative mechanism design of inclined tool for grinding high-lead of the ball nut to prevent interference in the internal spiral grooves is developed. The finite element analysis of the inclined straight tool grind including dynamic stress, strain, contact pressure, grinding wheel deflection and natural frequency is presented. Finally, the actual grinding machining verification and confirm the grinding wheel geometry correctness is also been investigated.
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HUANG, BO-SIANG, and 黃柏翔. "Studies of the properties for the low sintering temperature vitrified bond of precision grinding wheels." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/81765103247401786941.
Full textAbstract:
碩士華梵大學
機電工程學系博碩專班
97
The purpose of the paper investigated the proportion of lithium oxide and sodium oxide of the vitrified bonds, the selection of raw materials, mixing sequence, etc. to fuse and get the powder mixture. The obtained mixture and alumina grits were mixed and fired to the desired samples and the grinding wheels. The following analysis of these fired samples were studied: (1) porosity and density, (2) flowability, (3) three-point bending strength and rupture strain, (4) SEM observation of the fracture structure, (5) XRD analysis, (6) thermogravimetric analysis (TGA), (7) grinding performance. The experiment results showed that the vitrified bond containing a higher proportion of lithium oxide reduced the flowability, causing its bending strength to be lower. The bond containing the compound raw materials didn’t obtain a higher bending strength than that of pure raw materials. The frit bond containing a fused alumina after a higher fire temperature displayed a better bending strength, but, in a lower fire temperature, its strength was lower than the frit bond that didn’t contain alumina in advance. From the SEM observation of the fracture structure, alumina powders of the bond in a lower fire temperature showed a little exposure on the bond surface. With a higher fire temperature used alumina powders progressively fused into the bond, thereby leading a higher bond strength obtained. From the XRD analysis, the frit bond showed an amorphous structure. From the TGA analysis, the vitrified bond containing the compound raw materials reduced a fire temperature by about 30 ºC. Besides, the frit bond containing extra added alumina displayed a lower fire temperature by about 80 ºC. From the results of the grinding hardened steel, the wheel fired at a higher temperature with larger bond strength showed a better grinding ratio and a larger grinding force.
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Yu, Hsiang-Chih, and 游祥志. "Application of ELID and Vibratory Machining on the Analysis and Planning of Precision Grinding Processes." Thesis, 2003. http://ndltd.ncl.edu.tw/handle/56815855676305291046.
Full textAbstract:
碩士國立海洋大學
機械與輪機工程學系
91
This research incorporated “Electrolytic In-process Dressing (ELID)” and vibratory machining mechanism into the conventional grinding process and established a series of experiments. A full set of experimental data was gathered and compared for surface roughness on four types of grinding processes: normal grinding process, ELID grinding process, vibratory grinding process, and ELID & vibratory grinding process. A result of vibratory machining didn''t increase the complexity of machinery, and it required little power consumption. Furthermore, it is easy to be built and set up on a conventional grinding machine. If the results show that vibratory machining mechanism improved the grinding procedures to become more efficient and cost-effective, we can then utilize the advantages of vibratory machining to obtain and maintain fine surface roughness in creep feed grinding processes. S45C carbon steel was used in the experiments of this research and their results were used to evaluate the effects to the part surface roughness in the above four different processing environments. Finally, based on the statistics analysis and experiment planning methods, the analysis on data regression was conducted to investigate the influence of each process parameter on the surface roughness and the feasibility of the regression mathematical model.
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Huang, Shih-Wei, and 黃士瑋. "Use Electrophoretic deposition combined with micro ultrasonic grinding to enhance the precision of micro holes." Thesis, 2003. http://ndltd.ncl.edu.tw/handle/22369974407893326508.
Full textAbstract:
碩士國立中央大學
機械工程研究所
91
Drilling micro hole with micro-electric discharge machining (Micro-EDM) is an economic machining method. However, because of the electrode wearing, the precision of micro hole is not well enough. For solving this problem, we combined Micro-EDM, electrophoretic deposition (EPD) and ultrasonic vibration grinding to get high precision shaft with better inner surface. Before experiment, we searched the best parameters of EPD first. Because loose abrasive grains are attracted to grinding tool (electrode) and fixed on the tool surface by EPD, this phenomenon will increase the ultrasonic vibration grinding efficiency, and we found 6 min(deposition time), pH8, 30V(potential), SiC 15wt%(concentration of slurry), 50rpm(electrode rotation rate) are the best parameters. After the process above, we modified the electrode shape with WEDG and drilled the micro hole on titanium alloy by the electrode that had made. Then improved the precision of micro hole by combination of EPD and ultrasonic vibration grinding. As the result, when we set amplifier to be 5μm, electrode rotation rate to be 50rpm, and use stepped or breached electrode, the improvement of straightness will be up to 56%. And the inner surface roughness will be 0.449μm(Rz). Besides, using stepped electrode will get the best roundness. So this composite machining process was efficient method to improve the precision of micro holes.
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Wu, Dong-Chen, and 吳東晨. "Application of Acoustic Emission Signals for Surface Roughness of Zirconia Ceramic in the Precision Grinding." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/43744148639906484300.
Full textAbstract:
碩士國立中興大學
機械工程學系所
102
Due to advances in the technology industry, subtle manufacturing technology continues to improve, zirconia such brittle materials used in high-precision parts more extensive and grinding technology also needs to follow the high-precision, high efficiency working in high-precision grinding improve processing efficiency, quality, and reduce processing costs is seen as key to improving competitiveness, so the precision grinding of automation and intelligent systems is one of the conditions. This study aimed to analyze investigate AE (Acoustic Emission) signal in the application of the grinding surface roughness characteristics.This experiment in Taguchi method, AE signals interception zirconia grinding processing, the AE signals do Fourier transform, and root mean average (RMS) , the zirconia surface with grinding message after the signal correlation of roughness for the final will have relevance AE signal input neural network to predict the zirconia surface roughness. In the experimental analysis of acoustic emission signals , the surface roughness of the assessment made the following points, primarily to determine the roughness of the grinding poor basis: First, most of the high frequency(200kHz-320kHz) has peaks, and the second is high frequency(200kHz-320kHz) has high energy, and finally in the low frequency(50kHz-100kHz) with high energy. The experimental results show that AE signals for neural network to predict the surface roughness 10μm wheel,10-10-1 network architecture with the greatest difference is 0.0124μm, the minimμm difference is 0.0007μm, an average difference of 0.0061 μm, MSE (mean square error) is 0.0001, MAPE (Mean absolute percentage error) is 0.04%, R (Sample Correlation Coefficient) of 0.6988, with the wheel 10μm AE signal is applied to the neural network to predict the surface roughness MAPE 0.04% to reach a very low error. In 25μm wheel of 4-4-1 network architecture with the greatest difference is 0.0144μm, the minimμm difference is 0.0015μm, the average difference was 0.0086μm, MSE is 0.0001, MAPE is 0.11%, R is 0.6194, at 25μm wheel with AE signals for neural network to predict the surface roughness is 0.11% MAPE error value is quite low, observed that AE signals for grinding surface roughness prediction is a high correlation.