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Dissertations / Theses on the topic 'Machining operations'
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1
Sekhon, Gurbachan S. "Monitoring and control of machining operations." Thesis, University of British Columbia, 2013. http://hdl.handle.net/2429/45025.
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The present Computer Numerical Controlled (CNC) machine tools can provide internal states of the machine (such as speed, feed, current, power, torque, and axis tracking errors) to external computers, which in turn can manipulate spindle speeds and feeds through Ethernet communication tools. This thesis presents on-line detection and avoidance of chatter vibrations, on-line prediction of cutting torque and its adaptive control during milling operations.
Chatter is detected by monitoring the frequency spectrum of sound signals during machining operations. The forced vibrations that occur at spindle and tooth passing frequencies are removed through a comb filter. The chatter frequency and its magnitude are predicted. The spindle speed is automatically changed to enter the process into the nearest stability pocket if it lies within the first five stability lobes. If the process cannot be stabilized due to missing lobes at low speeds, the spindle speed is harmonically varied without violating the power limit of the spindle drive. The algorithm is implemented on a five axis Mori Seiki NMV5000 Machining Center with a FANUC 30i controller. The communication with an external PC is handled through Ethernet and FOCAS command library of Fanuc.
The cutting torque is also predicted by monitoring the current of a three phase induction motor in real time. The cutting torque is estimated through Extended Kalman Filter from the steady state model of the motor after removing the friction component. The estimated torque is used to keep the cutting torque on the machine at desired and safe levels by manipulating the feed rate with adaptive pole placement controller.
The thesis shows that it is possible to add process monitoring and control functions to the machine without having to add costly and impractical sensors on the machine, leading to safer and more productive machining operations.
2
Polgar, Karch C. (Karch Christos). "Simplified time estimation for basic machining operations." Thesis, Massachusetts Institute of Technology, 1996. http://hdl.handle.net/1721.1/10929.
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Majeti, Viswanath. "Integration of milling operations into the intelligent machining workstation." Ohio : Ohio University, 2000. http://www.ohiolink.edu/etd/view.cgi?ohiou1172602307.
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Hagiwara, Masaya. "OPTIMIZATION OF MACHINING PERFORMANCE IN CONTOUR FINISH TURNING OPERATIONS." UKnowledge, 2005. http://uknowledge.uky.edu/gradschool_theses/341.
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Unlike straight turning, the effective cutting conditions and tool geometry in contour turning operations are changing with changing workpiece profile. This causes a wide variation in machining performance such as chip flow and chip breakability during the operation. This thesis presents a new methodology for optimizing the machining performance, namely, chip breakability and surface roughness in contour finish turning operations. First, a computer program to calculate the effective cutting conditions and tool geometry along the contour workpiece profile is developed. Second, a methodology to predict the chip side-flow for complex grooved tool inserts is formulated and integrated in the current predictive model for contour turning operations. Third, experimental databases are established and numerical data interpolation is applied to predict the cutting forces, chip shape and size, and surface roughness for 1045 steel work material. Finally, based on the machining performance predictions, a new optimization program is developed to determine the optimum cutting conditions in contour finish turning operations.
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Al-Habaibeh, Amin. "Rapid design of condition monitoring systems for machining operations." Thesis, University of Nottingham, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.326780.
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Owen, Geraint Wyn. "The buffering of transfer lines." Thesis, University of Bath, 1994. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.359242.
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Mgwatu, Mussa I. "Optimization of machining parameters with consideration of tool adjustment in turning operations." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1996. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp05/mq20936.pdf.
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Tennety, Chandu. "Machining Feature Recognition Using 2D Data of Extruded Operations in Solid Models." Ohio University / OhioLINK, 2007. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1181406949.
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Mgwatu, Mussa Iddi. "Optimization of machining parameters with consideration of tool adjustment in turning operations." Thesis, University of Ottawa (Canada), 1996. http://hdl.handle.net/10393/10431.
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This thesis presents six optimization models which are developed and solved in two stages in order to integrate tolerancing and machining parameters decisions. One model is developed in the first stage. The first-stage model is related to a design problem and provides better part tolerance to be used in the second stage to incorporate tool adjustment decisions into the optimization of machining parameters. Five models are developed in the second stage and are divided into single-machine and multi-machine turning operation problems. For single-machine turning operations, three models are formulated. The first is a single-product multi-pass model considering pass selection for determining optimum cutting speed, feed rate, depth of cut, dimension deviation and number of passes. The second is a single-product multi-pass model considering inventory and setup costs to find optimum cutting speed, feed rate, depth of cut, dimension deviation and batch size. The third is a multi-product multi-pass model considering inventory and setup costs for selection of optimum cutting speed, feed rate, depth of cut, dimension deviations and production cycle time. For multi-machine turning operations, two models are formulated. One is a multi-feature multi-pass model with the objective of minimizing total cost for determining optimum workload assignment, cutting speed, feed rate, depth of cut, and feature dimension deviations of machine-pass-feature combinations. The second is a multi-feature multi-pass model with the objective of minimizing cycle time which, once solved, will give optimum workload assignment, cutting speed, feed rate, depth of cut, and feature dimension deviations of machine-pass-feature combinations. A solution method and illustrative examples are given to test the feasibility of the developed optimization models. (Abstract shortened by UMI.)
10
Revere, Kelvin Mark. "A distributed decision support system for turning and milling operations using the internet." Thesis, Durham University, 2000. http://etheses.dur.ac.uk/4619/.
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The machine tool industry is highly dependent on the tooling which is needed to machine the components used to make the range of products seen in today's society. The range of tooling available to machinists is prolific and subject to continual growth. Those engineers faced with the task of process planning require advanced systems to support the decisions that need to be made for the production process to operate smoothly. The tooling data made available by these systems is a key factor in defining the efficiency with which the production processes can be carried out. This research examines the technical decision support systems made available to industrialists and highlights the scope to provide tooling engineers with up-to-date tooling performance and use data that can be used both in the planning stages as well as dealing with problems encountered during production. Specifically, this research identifies the role performed by widespread tool trials, associated with new tools or new materials, and goes on to show how the information obtained from tool trials can be collated in a structured manner and used to enhance the provision of data with which to carry out the process planning task. The goal of this research was to develop and implement a framework capable of collecting and disseminating data related to tool trials in a coherent and supportive fashion using distributed methods. This target resulted in the deployment of a system named JadeT, which is capable of receiving and analysing data from tool trials and subsequently enhancing the process planning task by basing cutting parameter selection on a combination of fundamental cutting parameter algorithms in parallel with using the approved data generated from tool trials. The JadeT system was tested via the creation of a database using actual tool trial reports, and the manner in which this data was used to provide cutting parameters was analysed. The JadeT system has been developed, deployed and evaluated. The opportunity to use data contained within tool trial reports to support process planning tasks has been identified and exploited. The testing of JadeT indicates that the system fulfils the initial goals and was able to provide suggestions for further research in this area.
11
Hansbrough, Andrew K. "Application of a Fabry-Perot interferometer for measuring machining forces in turning operations." Thesis, This resource online, 1993. http://scholar.lib.vt.edu/theses/available/etd-02132009-172658/.
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Stewart, Jeremy James Thomas. "An investigation of the use of inspection results in generative process planning for machining operations." Thesis, Queen's University Belfast, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.356973.
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Abbas, J. K. "Investigation into the effect of fixturing systems on the design of condition monitoring for machining operations." Thesis, Nottingham Trent University, 2013. http://irep.ntu.ac.uk/id/eprint/7/.
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The global market competition has drawn the manufacturer’s attention on automated manufacturing processes using condition monitoring systems. These systems have been used for improving product quality, eliminating inspection, and enhancing manufacturing productivity. Fixtures are essential devices in machining processes to hold the tool or workpiece, hence they are influenced directly by the stability of the cutting tool. Therefore, tool and fixturing faults play an important part in the inaccuracy of the machining processes causing deterioration of surface roughness. For the above mentioned reasons, and the limited work in this domain, this thesis develops an experimental investigation to evaluate the effect of fixturing quality on the design of condition monitoring systems. The proposed monitoring system implements multisensors and signal processing methods able to analyse the sensory information and make an appropriate decision. Therefore, several sensors namely force, vibration, acoustic emission, eddy current, power, strain and sound, are combined with a newly suggested approach, named Taylor’s Equation Induced Pattern (TIP), and neural networks to detect tool wear and tool breakage. It also evaluates the monitoring system to provide valuable data to show the effect of fixturing quality. Surface roughness of the workpiece has been measured and compared with the sensitivity of the monitoring system, which reflects the state of tool and fixturing conditions. A novel approach, termed ASPSF, (Automated Sensor and Signal Processing Selection for Fixturing) has been implemented to select the most sensitive sensors and signal processing method. The aim is to reduce the number of sensors needed in the overall system and reduce the cost. New automated detection methods (Principal Component Analysis (PCA), Fuzzy logic, correlation coefficients) have been implemented to prove the capability of the approach. A cost reduction is performed based on removing least utilised sensors without losing the performance of the condition monitoring system. The results prove that the ASPSF is capable of detection the effect of fixturing quality on the design of the condition monitoring system and the trend in surface roughness. Consequently, the findings of this thesis prove that the change in the fixturing quality could have significant effect on the design of the condition monitoring system and the behaviour of the system. Therefore, continuous condition monitoring design process will be needed regularly for every machine, to allow compensation in the change in the characteristics.
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Заблоцький, В. Ю. "Аналіз можливостей спрямованого формування показників якості деталей на механообробних операціях." Thesis, Сумський державний університет, 2017. http://essuir.sumdu.edu.ua/handle/123456789/61361.
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Послідовність етапів технологічних процесів їх склад і використані
технологічні підходи характеризуються технологічною історією
виготовлення деталі. Вона, в свою чергу, визначається рядом новоутворених
показників якості деталі. Знаючи закономірності їх утворення, стає
можливим вже на етапі технологічної підготовки виробництва передбачити
заходи для забезпечення регламентованих значень, тобто передбачити
спрямоване формування показників якості.
15
Gupta, Shelly Bagchi Amit. "A sensor based fixturing system to determine the minimum required clamping force for unte[n]ded machining operations /." Connect to this title online, 1988. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1094830578.
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Arezoo, Behrooz. "The application of intelligent knowledge based systems to the selection of cutting tools and conditions for machining operations." Thesis, University of Sheffield, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.267598.
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Gupta, Shelly. "A sensor based fixturing system to determine the minimum required clamping force for unte[n]ded machining operations." The Ohio State University, 1988. http://rave.ohiolink.edu/etdc/view?acc_num=osu1094830578.
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Teixidor, Ezpeleta Daniel. "Contribution to laser milling process parameters selection for process planning operations." Doctoral thesis, Universitat de Girona, 2013. http://hdl.handle.net/10803/124506.
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Nontraditional manufacturing processes (NTM) appeared to answer the growing demands of market productivity. Needs of higher quality products in less time and new demands such as new exotic work materials, innovative geometric designs as well as much smaller dimensions justify laser processes insight. Laser machining is a NTM which presents several unique advantages in material processing that makes it suitable to solve these demands. However, laser machining is a complex process, because the type of laser, the combination of process parameters, the material and the configuration of the process among other variables, could affect the performance of the process. This thesis focuses on increasing knowledge about the laser milling, establishing relationships between the process parameters and the key process aspects (quality, dimensional accuracy and productivity)Els processos de mecanitzat no tradicionals van aparèixer per donar resposta a la creixent demana del mercat productiu. A la necessitat de productes d’alta qualitat en el menor temps possible s’hi afegeixen noves demandes com nous materials exòtics, dissenys amb geometries innovadores així com dimensions molt petites. El mecanitzat làser és un procés no tradicional que presenta un seguit d’avantatges únics que el fan adequat per donar solució a aquestes demandes. Tot i això, el mecanitzat làser és un procés complex. El tipus de làser, la combinació dels paràmetres de procés, el material i la configuració, entre d’altres variables, poden afectar l’execució del procés. Aquesta tesi pretén ampliar el coneixement sobre el fresat làser, establint relacions entre els paràmetres de procés i els aspectes rellevants de procés (qualitat, precisió dimensional i productivitat)
19
Mohammed, Anwaruddin. "ACHIEVING ULTRAFINE GRAINS IN Mg AZ31B-O ALLOY BY CRYOGENIC FRICTION STIR PROCESSING AND MACHINING." UKnowledge, 2011. http://uknowledge.uky.edu/ms_etds/1.
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This thesis presents results from the application of cryogenic cooling on multiple-pass friction stir processing and the subsequent orthogonal machining on friction stir processed and as-received Mg AZ31B-O disks, and shows their combined effects on microstructure and microhardness values. A simple friction stir tool, a specially designed fixture and liquid nitrogen are used to perform multiple-pass friction stir processing experiments on Mg AZ31B-O alloy. The friction stir processed and as-received sheets are then made into disks for the orthogonal machining experiments. This study analyzes the microhardness, microstructure changes by cryogenic friction stir processing and the effect of machining conditions such as dry, MQL and cryogenic and cutting parameters on the Mg AZ31B-O alloy. Four different speeds and three different feed rates are used for the orthogonal machining experiments. The effects of stirring parameters such as the translational feed, rotational speed, cooling conditions and the machining parameters are studied. The resulting microstructure and microhardness from these processes hold a key to the mechanical properties of the alloy. This analysis would help to understand and evaluate the specific aspects of grain size and microhardness that influence the fatigue life of a component.
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Wroblewski, Adam C. "Model Identification, Updating, and Validation of an Active Magnetic Bearing High-Speed Machining Spindle for Precision Machining Operation." Cleveland State University / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=csu1318379242.
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Machinini, Mazondeki Andreas. "The impact of six sigma on operational efficiency / Andreas Machinini." Thesis, North-West University, 2010. http://hdl.handle.net/10394/4462.
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Globalisation of markets has brought about enormous challenges and
opportunities for business organisations. The prevailing business environment
propels organisations to improve and create value in order to remain
competitive. Improvement and value creation begin internally and get reflected
externally in the form of value added propositions to the market. Six Sigma is
a methodology known for creating value within organisations, in all industries,
through process improvement which translates into enormous savings for the
organisation. Six Sigma is widely used globally and it has been in existence
for many years, yet it is not so prevalent in the South African business
environment. This research explores the principles and approach adopted,
which distinguish the Six Sigma methodology from other improvement
programs. In the manufacturing industry, operational efficiencies are essential
to enhance value creation and profitability.
The study begins by discussing the origin, history and evolvement of Six
Sigma into a methodology recognisable and espoused by leading world class
organisations. The technique used to effect Six Sigma is entrenched and
enforced by adherence to stipulated basic principles, breakthrough strategy
and Six Sigma tools in identification and elimination of variation. The study
later models some of Six Sigma tools by application on the operational entity
in verification and testing of theoretical knowledge into practical knowledge
that can be exploited for process improvement consequently enhancing
operational efficiencies. The impact of Six Sigma on operational efficiencies
underlie on the ability to positively change process effectiveness and
capability to near perfection as expressed by defect rate of not more than 3.4
defects per million opportunities.Thesis (M.B.A.)--North-West University, Potchefstroom Campus, 2011.
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Du, Plessis Lukas Johannes. "Design and optimum operation of a re-configurable planar Gough-Stewart machining platform." Thesis, Pretoria : [s.n.], 2001. http://upetd.up.ac.za/thesis/available/etd-10312005-140405/.
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Lemaitre, Benard Paul Jean Pierre Daniel. "Automatizace obráběcích operací." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2017. http://www.nusl.cz/ntk/nusl-364600.
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Úvod Vzhledemke zvyšování počtu objednávek leteckých součástek se společnost ArianeGroup rozhodla zintenzívnit svoji činnost, aby uspokojila tuto poptávku. Objem jejích součástí vyrobených za jeden rok se výrazně zvětšil, a tedy výrobní servis musí být funkčně optimalizován. Cílem uvedené optimalizace je snížit počet stop machines. Existuje nepřeberné množství řešení, která se potýkají s problémem, jak snížit počet stop machines, nicméně je velmi obtížné implementovat tato řešení přímo na stroji. Situaci určitě nelze řešit zastavením výroby a následnou implementací nějakých technických řešení. Avšak je naopak možné implementovat technická řešení už v samotném průběhu kvalifikační fáze. Kvalifikační fáze probíhá tehdy, když je součást poprvé na stroji. Tři části byly kvalifikovány a nějaká technická řešení byla aplikována právě v průběhu těchto kvalifikací. Bezpečnost procesu Prvním aspektem, na který bych se rád zaměřil, je bezpečnost samotného procesu. Nesmí dojít k vysouvání součásti z upínacích čelistí. Právě proto je požadován výpočet upínacího tlaku disku D. Druhým aspektem práce je nedeformování součásti. Díky vysokému upínacímu tlaku je přítomna geometrická deformace. Z tohoto důvodu bylo důležité provést výpočty upínacích tlaků pro disky D a B. Cílem je zjištění, zda je možné snížit upínací tlak a zároveň respektovat podmínku, že se součást nebude vysouvat z čelistí. Za třetí je důležité zaručit bezpečnost procesu. Někdy se stává, že obslužní pracovníci zapomenou odstranit příruby. Z tohoto důvodu sem byl umístěn automtický detektor, který upozorní na to, že externí příruby nebyly odstraněny. Automatická sekce pomáhá vyvarování se kolizím. Jak je možno vidět na obr. 1, sonda detekuje vnitřní příruby. Objeví se zpráva, dveře se otevřou a obslužný pracovník je upozorněn. Odolnost procesu . Robustní process je process s nízkým počtem rozbíjení nástrojových destiček. Existuje technické řešení. Skládá se z iplementace a monitorování opotřebení nástroje. To vše je možné díky sondě a aBLUM laseru. Během vyhodnocení disku D, soustružnické nástroje jsou kontrolovány pomocí sondy a nástroje frézovací pomocí BLUM laseru. Výkonnost procesu Inovativním přístupem ke zlepšení řezných podmínek je integrace vysokého tlaku. Ten byl použit pro některé ze součástí. Dalším řešením je integrování tool sisters do procesu. Během kvalifikace disku D, byly přidány tools sisters. Navíc, byla provedena studie pro zvládnutí nástroje a jeho zablokování poté, co byl použit. Nové technologie destiček byly využity pro zlepšení řezných podmínek a snížení času. Automatizace operací ve strojírenské výrobě Zásadním důvodem pro stop machines je prostorová kontrola pomocí obslužných pracovníků. Technicky je totiž možné nahradit tyto činnosti automatickými kontrolami, přičemž zmíněné automatické kontroly se provádí pomocí automatických sond. Proces může být zkreslený, pokud je měření nepřesné. Byly provedeny pokusy pro kalibraci řešení. Aktualní provedení kalibrací nebylo dostačují
24
Bothner, Rose. "An optimization model for selecting the economical cutting parameters in an external forward turning operation /." Online version of thesis, 1990. http://hdl.handle.net/1850/10592.
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Udayshankar, Siddharth. "Statistical process control (SPC) in a high volume machining center : value of standard operating procedures." Thesis, Massachusetts Institute of Technology, 2015. http://hdl.handle.net/1721.1/101527.
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Thesis: M. Eng. in Manufacturing, Massachusetts Institute of Technology, Department of Mechanical Engineering, 2015.Cataloged from PDF version of thesis.
Includes bibliographical references (pages 84-85).
Statistical process control is implemented in a high volume machining center to reduce scrap and improve the quality of production. New hires are working in a complex production environment with excellent metrology resources that can be used for real time inspection but there is a lack of standard operating procedures to help them use these resources. A methodology for implementation of statistical process control is developed and evaluated by implementing it in a section of the machining center which has the biggest benefit. Gages are evaluated and control charts are established in that section. Operators are trained in the standard operating procedures related to the different components of SPC. The standard operating procedures are developed to be portable such that SPC can be used in various sections of the machining center. Findings include cost saving benefits and scrap rate reduction of approximately 50% can be achieved for the entire machining center by the implementation of statistical process control. A training matrix is developed to train different people of the company on the concepts of SPC. Implementing SPC in a high volume machining center has proved to deliver value in reduction of scrap, quality improvement, ability to react to changes for the new hires and other benefits. Standard operating procedures have made a difference in the quality inspection of parts and in maintaining high quality standards that can make the machining center a world class manufacturer.
by Siddharth Udayshankar.
M. Eng. in Manufacturing
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Österlind, Tomas. "Estimation of Machining System Dynamic Properties - Measurement and Modelling." Doctoral thesis, KTH, Maskin- och processteknologi, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-204579.
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Dynamic characteristics of machining systems are analysed for improved understanding of both structural and process properties. The thesis stresses the use of testing methods under operational like conditions as these are more representative of closed loop systems, such as machining systems, as compared to conventional testing methods. The test instrument proposed is a contactless excitation and response system, developed for testing of machine tool spindles under load and with rotating spindle. The instrument uses electromagnetic excitation and displacement sensors for analysis of rotating milling tools subject to load. A graphical tool for displaying and analysing rotor displacement was developed in conjunction with this. A modelling procedure for both off-line and on-line estimation of dynamic properties of mechanical structure and process information is presented. The proposed auto-regressive moving average models enable calculation of operational dynamic parameters and they can be estimated in a recursive manner, thus enabling real-time monitoring. The discrimination between stable and unstable processes, both in turning and milling, was performed by analysing the damping obtained from the operational dynamic parameters.QC 20170330
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Sádlo, Dominik. "Racionalizace obrábění skříní převodovek." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2020. http://www.nusl.cz/ntk/nusl-417111.
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Content of the thesis is the proposal of new technology using machining centres, including five controlled axis. Benefit of implementation the new nechnology is investigated at machining example, which is the gear housing of a single stage gearbox, manufactured in the company. In the first part of the thesis, the general properties of gearboxes and their housings are analyzed, as well as the procedure of the current proces of the machining representative. In practical part of the thesis is proposed necessary tool equipment and jig equipment, needed for machining of the part. After that are analyzed and filled in time studies, provided by manufacturers of machining centres. On the bases of these studies, were calculated operating times and operating costs per one piece of the housing. In the part of technical and economical evaluation is calculated the return of initial investment, including costs for byuing new machining cente and cutting tools equipment. Finaly are evaluated the overal benefits of the new technology, given the needs of the company.
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Deane, Erick Johan. "Multi-sensor optimization of the simultaneous turning and boring operation." Master's thesis, University of Central Florida, 2011. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/4751.
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To remain competitive in today's demanding economy, there is an increasing demand for improved productivity and scrap reduction in manufacturing. Traditional manufacturing metal removal processes such as turning and boring are still one of the most used techniques for fabricating metal products. Although the essential metal removal process is the same, new advances in technology have led to improvements in the monitoring of the process allowing for reduction of power consumption, tool wear, and total cost of production. Replacing used CNC lathes from the 1980's in a manufacturing facility may prove costly, thus finding a method to modernize the lathes is vital. This research focuses on Phase I and II of a three phase research project where the final goal is to optimize the simultaneous turning and boring operation of a CNC Lathe. From the optimization results it will be possible to build an adaptive controller that will produce parts rapidly while minimizing tool wear and machinist interaction with the lathe. Phase I of the project was geared towards selecting the sensors that were to be used to monitor the operation and designing a program with an architecture that would allow for simultaneous data collection from the selected sensors at high sampling rates. Signals monitored during the operation included force, temperature, vibration, sound, acoustic emissions, power, and metalworking fluid flow rates. Phase II of this research is focused on using the Response Surface Method to build empirical models for various responses and to optimize the simultaneous cutting process. The simultaneous turning and boring process was defined by the four factors of spindle speed, feed rate, outer diameter depth of cut, and inner diameter depth of cut. A total of four sets of experiments were performed. The first set of experiments screened the experimental region to iii determine if the cutting parameters were feasible. The next three set s of designs of experiments used Central Composite Designs to build empirical models of each desired response in terms of the four factors and to optimize the process. Each design of experiments was compared with one another to validate that the results achieved were accurate within the experimental region. By using the Response Surface Method optimal machining parameter settings were achieved. The algorithm used to search for optimal process parameter settings was the desirability function. By applying the results from this research to the manufacturing facility, they will achieve reduction in power consumption, reduction in production time, and decrease in the total cost of each part.ID: 030646229; System requirements: World Wide Web browser and PDF reader.; Mode of access: World Wide Web.; Thesis (M.S.M.E.)--University of Central Florida, 2011.; Includes bibliographical references (p. 88-91).
M.S.M.S.E.
Masters
Mechanical and Aerospace Engineering
Engineering and Computer Science
Mechanical Engineering; Mechanical Systems Track
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Archenti, Andreas. "A Computational Framework for Control of Machining System Capability : From Formulation to Implementation." Doctoral thesis, KTH, Maskin- och processteknologi, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-48824.
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Comprehensive knowledge and information about the static and dynamic behaviour of machine tools, cutting processes and their interaction is essential for machining system design, simulation, control and robust operation in safe conditions. The very complex system of a machine tool, fixture and cutting tools during the machining of a part is almost impossible to model analytically with sufficient accuracy. In combination with increasing demands for precision and efficiency in machining call for new control strategies for machining systems. These strategies need to be based on the identification of the static and dynamic stability under both the operational and off-operational conditions. To achieve this it is necessary to monitor and analyze the real system at the factory floor in full production. Design information and operational data can then be linked together to make a realistic digital model of a given machining system. Information from such a model can then be used as input in machining simulation software to find the root causes of instability. The work presented in this thesis deals with the static and dynamic capability of machining systems. The main focus is on the operational stability of the machining system and structural behaviour of only the machine tool, as well. When the accuracy of a machining system is measured by traditional techniques, effects from neither the static stiffness nor the cutting process are taken into account. This limits the applicability of these techniques for realistic evaluation of a machining system’s accuracy. The research presented in this thesis takes a different approach by introducing the concept of operational dynamic parameters. The concept of operational dynamic parameters entails an interaction between the structural elements of the machining systems and the process parameters. According to this concept, the absolute criterion of damping is used to evaluate the dynamic behaviour of a machining system. In contrast to the traditional theory, this methodology allows to determine the machining system's dynamic stability, in real time under operating conditions. This framework also includes an evaluation of the static deformations of a machine tool. In this context, a novel concept of elastically linked system is introduced to account for the representation of the cutting force trough an elastic link that closes the force loop. In addition to the elastic link which behaves as a static element, a dynamic non-contact link has been introduced. The purpose is to study the non-linear effects introduced by variations of contact conditions in joints due to rotational speed.QC 20111123
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Zhong, Yu Mechanical & Manufacturing Engineering Faculty of Engineering UNSW. "A study of the cutting performance in multipass abrasive waterjet machining of alumina ceramics with controlled nozzle oscillation." Publisher:University of New South Wales. Mechanical & Manufacturing Engineering, 2008. http://handle.unsw.edu.au/1959.4/41216.
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An experimental investigation has been undertaken to study the depth of cut in multipass abrasive waterjet (AWJ) cutting of an 87% alumina ceramic with controlled nozzle oscillation. The experimental data have been statistically analysed to study the trends of the depth of cut with respect to the process parameters. It has been found that multipass cutting with controlled nozzle oscillation can significantly increase the depth of cut. Within the same cutting time and using the same cutting parameters other than the jet traverse speed, it has been found that multipass cutting with nozzle oscillation can increase the depth of cut by an average of 74.6% as compared to single pass cutting without nozzle oscillation. Furthermore, a multipass cutting with higher nozzle traverse speeds can achieve a larger depth of cut than a single pass cutting at a low traverse speed within the same cutting time. A recommendation has been made for the selection of appropriate process parameters for multipass cutting with nozzle oscillation. In order to estimate the depth of cut on a mathematical basis, predictive models for the depth of cut in multipass cutting with and without nozzle oscillation have been developed using a dimensional analysis technique. The model development starts with the models for single pass cutting which are then extended to multipass cutting where considerations are given to the change of the actual standoff distance after each pass and the variation of kerf width. These predictive models has been numerically studied for their plausibility by assessing their predicted trends with respect to the various process variables, and verified qualitatively and quantitatively based on the experimental data. The model assessment reveals that the developed models correlate very well with the experimental results and can give adequate predictions of this cutting performance measure in process planning.
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Mejri, Seifeddine. "Identification et modélisation du comportement dynamique des robots d'usinage." Thesis, Clermont-Ferrand 2, 2016. http://www.theses.fr/2016CLF22688/document.
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La robotisation des procédés d’usinage suscite l’intérêt des industriels en raison du grand espace de travail et le faible coût des robots par rapport aux machines-outils conventionnelles et la possibilité d’usiner des pièces de formes complexes. Cependant, la faible rigidité de la structure robotique favorise le déclenchement de phénomènes dynamiques liés à l’usinage sollicitant le robot en bout de l’outil qui dégradent la qualité de surface de la pièce usinée. L’objectif de ces travaux de thèse est de caractériser le comportement dynamique des robots en usinage. Ces travaux ont suivi une démarche en trois étapes : La modélisation d’un premier modèle considéré de référence où le robot est au repos. Ensuite l’identification du comportement dynamique du robot en service. Enfin, l’exploitation des modèles dynamiques du robot en vue de prédire la stabilité de coupe. L’originalité de ces travaux porte sur le développement des méthodes d’identification modale opérationnelles. Elles permettent d’intégrer les conditions réelles d’usinage et d’élaborer des modèles plus précis que le premier modèle de connaissance sans être biaisés par l’effet des harmoniques de rotation de l’outil. Enfin, des préconisations sur le choix de configurations du robot et sur la direction des forces d’excitation sont proposées pour assurer la stabilité de la coupe lors de l’usinage robotiséMachining robots have major advantages over cartesian machine tools because of their flexibility, their ability to reach inaccessible areas on a complex part, and their important workspace. However, their lack of rigidity and precision is still a limit for precision tasks. The stresses generated by the cutting forces and inertia are important and cause static and dynamic deformations of the structure which result in problems of workpiece surface. The aim of the thesis work is to characterize the dynamic behavior of robots during machining operation. This work followed a three-step approach : Modeling a first model considered as a reference where the robot is at rest. Then the identification of the dynamic behavior in service. Finally, the prediction of the cutting stability using the robot dynamic model. The originality of this work is the development of new operational modal identification methods. They integrate the machining conditions and result into a more accurate model than the first model of reference without being biased by harmonics. Finally, guidlines of robot’s configurations and excitation forces’ direction are proposed to ensure the robotic machining stability
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Dostálová, Markéta. "Optimalizace operačních nákladů obráběcího procesu." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2013. http://www.nusl.cz/ntk/nusl-230505.
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This work deals with operating production costs in machining process and further optimalization. In the first chapter, individual costs items which are related to machining process are specified. These cost items are quantified and total production costs are acquired. Optimalization of operation production costs are described for criterion of minimal production costs and criterion of maximal productivity are described in next chapter. Practical part of this work is focused to apply each individual criterion in practical example. There is CD with programs attached to this work. The goal is to find optimal combination of cutting speed, sufficient life time of cutting tool and suitable cutting technology so that chosen criterion can be acceptable.
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Šikula, Josef. "Analýza operačních nákladů obráběcího procesu." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2017. http://www.nusl.cz/ntk/nusl-318157.
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This master’s thesis deals with the operating production cost in machining process and further optimalization. Individual costs items which are related to machining process are specified. Attention is paid to the time consumption of individual machining methods. The aim of the thesis is to find an optimal combination of cutting speed and durability in order to meet the minimum cost criteria and maximum productivity. The calculations are used for turning the outer cylindrical surface and the face surfaces at a constant cutting speed. The work is accompanied by tables and calculations in Microsoft Excel.
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Dib, Marcel Henrique Militão. "Fundamentos do fresamento: uma aplicação em microfresamento." Universidade de São Paulo, 2013. http://www.teses.usp.br/teses/disponiveis/18/18145/tde-31102013-165527/.
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Nos últimos anos, o estudo do microfresamento tem recebido grande atenção devido a seu uso na fabricação de microcomponentes como células de combustível, microatuadores ou sensores, circuitos integrados, etc. O objetivo deste trabalho é apresentar os fundamentos do fresamento aplicados ao microfresamento. Para isto foi investigado, em escala reduzida, o comportamento de alguns princípios fundamentais da usinagem convencional, tais como espessura de corte instantânea, espessura de corte média, força de corte, pressão específica de corte, potência de corte, entre outros. A importância deste trabalho justifica-se pela necessidade de se entender como estes princípios comportam-se em escalas reduzidas. Inicialmente foi realizada uma investigação da literatura a fim de mostrar a origem de alguns destes princípios fundamentais. Em seguida, uma análise critica destes fundamentos foi apresentada e experimentos foram realizados com o intuito de confrontar o levantamento teórico com os resultados práticos. Para isso foram realizados testes de microfresamento com duas microfresas de metal duro constituídas de dois dentes cada uma com diâmetro de 0,8 mm. O raio da aresta de corte de cada ferramenta foi medido usando um microscópio confocal e os valores variaram de 1,8 \'mü\'m a 3,3 \'mü\'m. O material usado nos experimentos foi um alumínio liga (RSA 6061) de grãos ultrafinos (valor médio de 1 \'mü\'m). O fresamento adotado foi o frontal parcial (não engajado) com penetrações de trabalho de 0,2 mm e 0,4 mm. Os avanços por dente usados foram de 5 \'mü\'m e 10 \'mü\'m a uma profundidade de usinagem de 50 \'mü\'m. A máquina usada foi um centro de usinagem CNC de três eixos com potência nominal de 18 kw e rotação máxima de 24000 RPM. A máxima velocidade de corte alcançada foi de 50 m/min. Para coletar o sinal das forças de usinagem um dinamômetro piezoelétrico modelo 9256 C2 (Kistler) foi usado. Os resultados experimentais mostraram que o comportamento da variação da força de corte, o aumento da pressão específica de corte com o decréscimo da espessura de corte, energia de corte, potência de corte e representação da energia e potência de corte com base na força de corte média durante a formação do cavaco, são semelhantes ao comportamento destes parâmetros durante a usinagem convencional. Com base nestes resultados, foi mostrado que os fundamentos do fresamento podem ser aplicados em microfresamento para explicar o comportamento da microusinagem.Recently, micro end milling is a subject that has received a large contribution due to its feasibility to be applied to the manufacturing of micro components such as fuel cells, micro actuators and sensors, integrated circuits, etc. The objective of this study is to present fundamental principles of machining of end milling operation applied to the micro end milling operation. It will be investigated the behavior at small scale of some known conventional machining parameters such as instantaneous thickness of cut, average thickness of cut, cutting force, specific cutting pressure, cutting power among others. The relevance of this study is justified by the need of understanding how those cutting parameters behave when the machining scale is reduced. Firstly, a review of the literature was carried out in order to show the origin of some fundamental principles of machining of materials. Thereafter, a critical analysis was held on these fundamentals and experimental cutting tests were designed and carried out aiming to comparing the experimental results with the expected trend shown by those parameters in conventional machining scale. The micro end milling tests used two carbide two teeth micro end mills with a diameter of 0,8 mm. The cutting edge of each tool was measured using a confocal optical profiler and the values ranged from 1,8 \'mü\'m up to 3,3 \'mü\'m. The workpiece material used in the cutting experiments was an ultra fine grain (average 1 \'mü\'m) aluminum alloy (RSA 6061). The machining operation was partial (not engaged) end milling with radial depths of cut of 0,2 mm and 0,4 mm. The feed per tooth used were 5 \'mü\'m and 10 \'mü\'m at constant depth of cut of 50 \'mü\'m. The machine tool used was a three axis CNC machining center with 18 kw nominal power and maximum spindle speed of 24000 RPM. At the maximum spindle speed the maximum cutting speed reached was 50 m/min. A mini piezoelectric dynamometer multicomponent model 9256 C2 (Kistler) was used to gather the cutting forces signals during machining. Therefore, the experimental results showed that the cutting force variation behavior, the increase of specific cutting pressure with the decrease of thickness of cut, cutting energy, cutting power, representing the energy and cutting power representation based on the average cutting force during chip formation are similar to the behavior of these parameters during conventional machining. Based upon that it is shown that the fundamental principles may well be applied to explain the machining behavior at very reduced scales during micro end milling operation.
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Kalnaši, Radoslav. "Ekonomická analýza obráběcího procesu." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2012. http://www.nusl.cz/ntk/nusl-230219.
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This master’s thesis focuses on analysis of time consumption of machining process, the basic units of operating costs of production,optimization and subsequen tapplication to specific part. It is a turning shaft in two operations, named roughing and finishing turning. The aim is to find the optimum combination of life time of cutting tool and cutting speed, which is the main criterion for optimization in terms of minimum production cost or a maximum of productivity.
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Maamar, Asia. "Identification modale opérationnelle des robots d'usinage en service." Thesis, Université Clermont Auvergne (2017-2020), 2019. http://www.theses.fr/2019CLFAC013/document.
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L’identification des paramètres modaux des machines-outils et des robots d’usinage, en service, constitue un levier d’optimisation des performances de coupe. En effet, la connaissance en continue du comportement dynamique d’une machine permet une prédiction fine des conditions de stabilité, bases d’un pilotage intelligent des paramètres du procédé. Cependant, la présence de fortes excitations harmoniques, dues à la rotation de la broche et de l’outil coupant, rend les techniques classiques d’Analyse Modale Opérationnelle (AMO) inapplicables. Le premier objectif de cette thèse consiste à déterminer une méthode d’AMO adéquate pour une application en présence des harmoniques. Une étude comparative des méthodes existantes est conduite, à savoir : la méthode de décomposition dans le domaine fréquentiel (EFDD), la méthode d’identification dans le sous-espace stochastique (SSI), la méthode PolyMAX et la méthode basée sur la fonction de transmissibilité (TFB). La méthode TFB est choisie afin de réaliser une identification modale opérationnelle des robots d’usinage. Cette technique est tout d’abord investiguée sur une machine-outil cartésienne. Cette étape est justifiée par le fait qu’une machine-outil est une structure plus rigide qui présente moins de variations des propriétés dynamiques par rapport à un robot d’usinage. Les résultats montrent la pertinence de la méthode TFB pour identifier les paramètres modaux de la machine-outil en usinage, même en présence des composantes harmoniques fortement dominantes. Ensuite, l’identification modale opérationnelle du robot d’usinage ABB IRB 6660, qui présente une structure moins rigide par rapport à une machine-outil, est menée sur une trajectoire d’usinage. Les résultats obtenus permettent d’établir une base modale du robot montrant l’évolution de son comportement modal en service. L’originalité des travaux présentés réside dans le développement d’une procédure robuste d’identification modale opérationnelle qui permet de suivre l’évolution du comportement modal du robot en cours d’usinage dans son espace de travailThe identification of the modal parameters of machining robots in service has a significant adverse influence on machining stability, which will, therefore, decrease the quality of the workpiece and reduce the tool life. However, in presence of strong harmonic excitation, the application of Operational Modal Analysis (OMA) is not straightforward. Firstly, the issue of choosing the most appropiate OMA method for an application in presence of harmonic components, is handled. For a comparison purpose, the modified Enhanced Frequency Domain Decomposition (EFDD) method, the Stochastic Subspace Identification (SSI) method, the PolyMAX method and the Transmissibility Function Based (TFB) method are investigated. The obtained results lead to the adoption of the Transmissibility Function Based (TFB) method for an OMA of machining robots. For an accurate modal identification procedure, the OMA of a machine tool is, initially, conducted. It is a preparation step in order to verify the performance of the chosen method under machining conditions as well as a machine tool is a rigid structure, thus, it has less variation in its dynamic behavior compared to a machining robot. Results demonstrate the efficiency of the TFB method to identify the machine tool modal parameters even in the presence of preponderant harmonic components. Finally, the OMA of the machining robot ABB IRB 6660, which has a flexible structure compared to a machine tool, is carried out for a machining trajectory. The obtained results allow the identification of a modal basis of the machining robot illustrating the evolution of its modal behavior, in service. The main novelty of this thesis lies in the development of a robust procedure for an operational modal identification of machining robots, in service, which makes it possible to continuously follow the variations in the modal parameters of machining robots
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Ganet-Mattei, Florent. "Fabrication additive de matériaux électroactifs pour applications à la mécatronique." Thesis, Lyon, 2018. http://www.theses.fr/2018LYSEI011/document.
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La Fabrication Additive (FA) est un procédé de fabrication qui a commencé à se développer dans les années 80 et qui atteint actuellement une maturité qui lui permet d’être utilisé de manière rentable et fonctionnelle par les industriels. La fabrication additive est définie comme étant le procédé de mise en forme d’une pièce par ajout de matière, à l’opposé de la mise en forme traditionnelle par enlèvement de matière (usinage). Cette nouvelle technologie est une réelle révolution et permet de relever de nouveaux défis technologiques sans précédent. Que ce soit sur un axe matériau ou plus largement dans le cadre de l’usine du futur, la fabrication additive est un réel levier de croissance, mais de nombreux travaux de recherche sont encore à mener afin de perfectionner cette nouvelle technologie. C’est autour de cette problématique que les travaux de thèses se sont focalisés avec un accent sur l’intégration de matériaux électroactifs pour la réalisation de fonction mécatronique tirant profit des procédés de Fabrication Additive. Les actions de recherche montrent que la fabrication additive de matériaux électroactifs sera de plus en plus employée pour la réalisation de fonctions mécatroniques hybrides qui combineront à la fois la structure mécanique, des circuits intégrés en silicium, des pistes conductrices et des matériaux couplés imprimés, intégrant ainsi des fonctionnalités, telles que des capteurs, des affichages ou des sources d’énergie. Les travaux montrent le potentiel applicatif autour du contrôle de santé des structures en composites, mais aussi du contrôle de forme d’instrument pour la chirurgie. Pour arriver au développement de ces dispositifs, les points suivants ont été développés autour des matériaux électroactifs et de leurs règles d’intégrations et d’optimisationAdditive Manufacturing (FA) is a manufacturing process that began to develop in the 1980s and is now mature enough to be used in a cost-effective and functional way by manufacturers. Additive manufacturing is defined as the process of shaping a part by adding material, as opposed to traditional shaping by material removal (machining). This new technology is a real revolution and enables us to meet new unprecedented technological challenges. Whether on a material axis or more widely as part of the plant of the future, additive manufacturing is a real growth driver, but many research work is yet to be conducted to perfect this new technology. It is around this issue that the work of theses focused with a focus on the integration of electroactive materials for the realization of mechatronics function taking advantage of Additive Manufacturing processes. Research shows that additive manufacturing of electroactive materials will be increasingly used for the realization of hybrid mechatronic functions that will combine both the mechanical structure, silicon integrated circuits, conductive tracks and printed coupled materials, integrating as well as features, such as sensors, displays or power sources. The work shows the potential application around the health control of composite structures, but also the instrument shape control for surgery. To arrive at the development of these devices, the following points have been developed around electroactive materials and their integration and optimization rules
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Do, Van Dong. "Usinage à grande vitesse efficace basé sur l'identification opérationnelle du comportement dynamique et l'optimisation du support de pièce." Thesis, Université Clermont Auvergne (2017-2020), 2020. http://www.theses.fr/2020CLFAC036.
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L’usinage à grande vitesse joue aujourd’hui un rôle très important dans l’industrie mécanique. Cependant, les phénomènes vibratoires en usinage peuvent être néfastes à la qualité des pièces usinées, à la productivité et à la durabilité des accessoires, etc. La maîtrise du comportement dynamique du système couplé (machine-outil/broche/outil/pièce/porte-pièce) est la clé primordiale pour la réussite de l’usinage à grande vitesse. Le premier objectif de la thèse a consisté à appliquer des techniques existantes d’identification modale opérationnelle et à proposer de nouvelles techniques d’identification mieux adaptées en tenant compte des spécificités de l’usinage à savoir : la présence des harmoniques très prépondérants, l’excitation aléatoire non contrôlée et non-mesurée, et les réponses seules enregistrées. Trois nouvelles procédures d’identification modale opérationnelle ont été proposées : la méthode de transmissibilité (PSDTM-SVD) (i) combinée avec les valeurs de kurtosis et les histogrammes, (ii) ou hybridée avec les fonctions d’autocorrélation, (iii) et la nouvelle méthode SCA-FDD basée sur la séparation aveugle de sources. L’efficacité des méthodes proposées a été validée par des exemples numériques et un test expérimental. Le deuxième objectif de la thèse a consisté à proposer une nouvelle conception du support de pièce en utilisant des matériaux innovants, afin de rendre le comportement dynamique optimal vis-à-vis de la stabilité d’usinage. Pour augmenter les performances d’usinage, le nouveau support en matériau composite doit posséder une raideur au moins égale à celle du support existant en aluminium tout en ayant un taux d’amortissement plus élevé. Un nouveau composite stratifié hybride renforcé par des fibres de carbone et des fibres de lin est alors proposé. Cette combinaison permet d’allier les avantages des deux types de fibres dans un même composite. Des supports de pièce en composite stratifié hydride carbone-lin avec différentes séquences d’empilement ont été fabriqués pour des essais de validation. Dans le cas d’usinage avec les supports de pièce en composite, la stabilité d’usinage est fortement augmentée par rapport au support initial en aluminium. Parmi les différentes séquences d’empilement, le support de pièce en composite hybride carbone-lin [C6/L8/C6] est la solution optimale en termes de performance d’usinage et d’impact environnemental. Cette solution permet d’augmenter la stabilité d’usinage de 283 % avec un taux de fibres végétales de 14 %High-speed machining plays a very important role in the engineering industry today. However, vibration phenomena during machining process can be detrimental to the quality of machined workpiece, the productivity and the durability of accessories, etc. Mastering the dynamic behavior of the coupled system (machine tool/spindle/tool/workpiece/workpiece holder) is the primordial key to successful high speed machining. The first objective of the thesis consisted in applying existing techniques of operational modal identification and proposing new identification techniques better adapted to take into account the specificities of machining: the presence of very predominant harmonics, the uncontrolled and unmeasured random excitation, and responses only recorded. Three new operational modal identification procedures have been proposed: the transmissibility method (PSDTM-SVD) (i) combined with kurtosis values and histograms, (ii) or hybridized with autocorrelation functions, (iii) and the new SCA-FDD method based on blind source separation. The effectiveness of the proposed methods has been validated by numerical examples and an experimental test. The second objective of the thesis was to propose a new design of the workpiece support using innovative materials, in order to make the dynamic behavior optimal with respect to machining stability. To increase the machining performance, the new composite workpiece holder must have a stiffness at least equal to that of the initial aluminum workpiece holder while having a higher damping ratio. A new hybrid composite laminate reinforced by carbon and flax fibers is then proposed. This combination enables to combine the advantages of two fiber types in a composite. Workpiece holders in carbon-flax hybrid composite laminates with different stacking sequences were fabricated for validation tests. In the case of machining with the composite workpiece holders, the machining stability is greatly increased compared to the initial aluminum workpiece holder. Among the different stacking sequences, the carbon-flax hybrid composite workpiece holder [C6/L8/C6] is the optimal solution in terms of machining performance and environmental impact. This solution increases machining stability by 283 % with a vegetable fiber volume ratio of 14 %
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An, Libao. "Optimization of machining parameters in multi-pass turning and milling operations." Thesis, 2003. http://spectrum.library.concordia.ca/2128/1/MQ77696.pdf.
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The primary objective in machining operations is to produce products with low cost and high quality. Machining parameter optimization plays an important role in achieving this goal. Machining parameter optimization in multi-pass machining operations usually involves the optimal selection of cutting speed, feed rate, depth of cut and the number of passes. In this thesis, the parameter optimization problem for multi-pass machining operations is studied. Mathematical programming models for both multi-pass turning and face-milling operations with single-tool applications are developed based on the minimum production cost criterion. Maximum and minimum cutting speeds, feed rates and depths of cut, as well as tool life, surface roughness, cutting force and cutting power consumption are considered as constraints. Optimal values of machining parameters are found by two methods. One involves using integer programming and the other using nonlinear programming. When solving the optimization problem by the method using integer programming, two steps are adopted. The first step is to minimize the costs for individual finishing and roughing passes for various possible depths of cut. In the second step, an optimal combination of depths of cut for the finishing and roughing passes, the optimal number of passes and corresponding cutting speeds and feed rates, based on minimum total unit cost, are determined using an integer programming model. Examples are presented to illustrate the effectiveness of the optimization models and the solution methods developed. The effect of tool replacement time on the optimization results is evaluated. Certain conclusions related to the problem are made.
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Congden, Steven Wayne. "An empirical examination of the relationship between competitive strategy and process technology in the tooling and machining industry." 1991. https://scholarworks.umass.edu/dissertations/AAI9132832.
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A considerable segment of the business literature has espoused the importance of appropriately using process or manufacturing technology to support competitive strategy. This literature implicitly and explicitly suggests the importance of "fit" between a firm's business level strategy and its process technology. Three gaps remain with respect to the "fit" assertion: (1) The nature of fit is insufficiently specified. (2) No empirical research has attempted to statistically validate the existence of fit within an industry. (3) No empirical research has attempted to statistically link fit to firm performance. To address these issues, this dissertation surveys firms in the U.S. tooling and machining industry to test hypotheses on the nature, existence, and impact on performance of fit. Strategy is assessed as membership in one of six strategic groups derived from clustering eight strategy factors. Factor analysis results in four technology factors, Dedicated Automation, Non-Dedicated Automation, Range of Capabilities, and Computer Aided Design. Performance comprises ROS and average annual sales growth. Findings regarding the nature of fit suggest: (1) Dedicated and non-dedicated automation relate positively to new and existing product stability. Broad product range (products very different from each other) relates negatively to dedicated automation, but does not relate to non-dedicated automation. (2) Linkages may be obscured because multiple capabilities are often bundled in a given technology so that different strategies use the same technology for different reasons. (3) Process technology appears to relate primarily to strategic dimensions concerning physical product characteristics, and very little to service dimensions. The existence of fit is demonstrated by highly significant differences in technology between groups, combined with the qualitative plausibility with which these differences appear to correspond to each strategic group. Although insufficient support was found for fit linked to performance (technology moderating strategic group membership's impact on performance), results suggest that performance advantage from a technology is gained not in the group where it is most appropriate or a given, but in a group where it is also appropriate, but less widespread.
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chen, Gu-Meng, and 古孟晨. "Implementing adaptive machining parameters for quality control system of surface roughness in end milling operations." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/65953185651398091695.
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碩士中原大學
工業與系統工程研究所
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As the tendency to industry automation, to increase the competitiveness of the industry, the factory are not only maintain the productivity, but also to enhance the quality of product for customers. Quality is affected by different types. One important index that can represent quality characteristic is the surface roughness. Many studies were proposed to improve the surface roughness of processing work-pieces by predicting. But they would cause the stop of continuous production, and were too hard to find a balance between quality and productivity. Therefore, the purpose of this study is to have a good control of surface roughness by adjusting the parameters of CNC machine, and to meet the client’s requirements and maintain the productivity simultaneously. In order to produce qualified work-pieces, this research not only takes processing parameter into consideration, but also uses force sensors to detect influences from uncontrolled cutting force and vibration that can affect the surface roughness during cutting process, to achieve the system can accurately control the surface roughness. Data is collecting from Surftest QP1620 CNC machine and then trained by neural network to build a decision making system that investigate the relation between processing parameter and surface roughness. This intelligent surface roughness quality control system is consist of four sub-systems. The first subsystem is to make a forecasting machine parameters of the processing condition. The second one is a forecasting of the surface roughness. The third subsystem is to adjust the parameter of spindle speed. And the fourth subsystem is to adjust the feed rate. Every subsystem uses neural network as decision making system. To decrease the training time, the Taguchi method to find the best network parameter combination. Surface roughness quality indicated by clients was asked as a starting point for system implementation, and use the indicators to predict the processing condition in the first subsystem, adding the second subsystem to predict the surface roughness under this condition. Then, two major parameters (spindle speed, feed rate) of the machine CNC can be adjusted through the subtraction of the results between the first and second system. The surface roughness can be controlled in an acceptable quality range. In this study, a intelligent surface roughness quality control system. The analysis of the error function are less than 0.0011 for subsystems, 30 data was used to validate the system, the results of the experiment model adjust the processing parameters can be found up to 87% data to meet customer requirements.
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Chiang, Shiuh-Tarng, and 蔣旭堂. "Optimization of Machining Operations Using Neural Networks and Suppression of Chatter by Fuzzy Control in End Milling." Thesis, 1994. http://ndltd.ncl.edu.tw/handle/55103589787663463242.
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Wu, Chung-Chieh, and 吳仲傑. "Optimized Operation Planning in Free Form Machining with Geometric Decomposition." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/99250213615077111992.
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LIN, CHIAN-YONG, and 林千用. "The flexibility and economic analysis of the Japanese work organization--applied in machining operation." Thesis, 1992. http://ndltd.ncl.edu.tw/handle/83093159903036309164.
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Wang, Jheng-Jie, and 王政捷. "Optimization of Operation Conditions and Tool Wear Investigation of Direct-Coupled Rotary Ultrasonic Machining." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/57479601688359142053.
Full textAbstract:
碩士國立高雄應用科技大學
模具工程系碩士班
103
This thesis is aimed at optimization of operational conditions of Rotary Ultrasonic assisted Machining (RUM) spindle applied to the milling and drilling of ZrO2 and sapphire crystal. The key experiment quality includes brittle collapse length (BCL), surface roughness (SR), and material removal rate (MRR) and abrasive tool’s life. Control parameters involve spindle speed, feed rate, cutting depth per layer, tool type, grit size and amplitude of RUM (denoted by excitation power). By using Taguchi methods, milling tests by traditional linear and cycloidal milling paths, and drilling by pecking cycles are conducted. The qualities experiments reveal the tool type and grit size of diamond tools dominate the processing quality. Three types of tools are designed in this study, in which, helical abrasive tool and straight flute tool are designed for milling and taper tool is for drilling, respectively. It is found helical tool is more suitable to ZrO2 milling, and the finest SR 0.04 μm Ra is achieved with optimized conditions and cycloidal milling. But straight tool is better for lateral milling of sapphire; the finest BCL of 36.68 μm is achieved with optimized conditions. Compared to those severe drilling BCL conducted by commercial cylinder tool or ball-head tool, the novel proposed 0.8 mm taper tool improves to better BCL of 20.5μm. With the optimized combination of federate 15 mm/min and cut depth 0.1 mm/layer, only 15 seconds is needed for drilling through each single hole of 1.0 mm thick of sapphire crystal. Three sacrificial materials are investigated, and it is concluded harder sacrificial can improve BCL more significantly. Furthermore, this study investigates RUM’s milling resistance and the drilling thrust by a 6-axes load cell. Long term milling path reveals cutting force arise gradually as the tool wears, in which the increasing rate of Z force presents the largest one resulting from worn-out of diamond grits at tool end and succeeded by friction. It is also found cutting force of cycloidal path presents intermittent fluctuation and smaller resistant than conventional linear path, therefore, the tool life is prolonged with sufficient coolant flushing. In this study, milling force without vibration assistance (No-RUM), with self-tracking ultrasonic vibration RUM(19~21kHz), and with high frequency vibration HRUM (29~31kHz) are also compared. Self-tracking RUM resulted in the smallest cutting force, while No-RUM presents the biggest milling resistance. Moreover, various sacrificial can effectively suppressed drilling force from 47.5 N to 23.5 N according to their hardness. Finally, the proposed designs and quality experiments confirm that the optimization conditions for roughing and finishing of brittle materials by direct-coupled RUM are effective. Combining with the force study and suggestion means for prolonging tools life, the consuming time and machining cost can be significantly reduced through this investigation.
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林津民. "Characteristic Representation of the Grinding Surface Before and After the Machining Operation of a Steel Workpiece." Thesis, 1999. http://ndltd.ncl.edu.tw/handle/12243017850660059909.
Full textAbstract:
碩士國立中興大學
機械工程學系
87
Abstract For a SS40 steel undergoing the grinding process, the geometric texture of the engineering surface is investigated by examining the variations of its roughness parameters. The fractal nature of the surface profile is examined by the analysis of the power spectrum and hence the fractal simulation of the surface profile is proposed. The quantitative data on the surface texture are obtained from three-dimensional surface profilometry. The measurement results show that (1) the surface heights of the SS40 steel before grinding can be described by an isotropic, Gaussian distribution, (2) the average roughness and RMS roughness remain nearly constant after thoroughly removing the engineering surface of the workpiece by the grinding operation, and (3) the surface texture is non-isotropic after the grinding on the SS40 steel.
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Lin, Chin-Hung, and 林錦鴻. "The Study on Operation for Cultural Publishing Machinism in Lienchiang County：The Perspective of Cultural Policy." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/22p7my.
Full textAbstract:
碩士銘傳大學
公共事務學系碩士在職專班
102
The purpose of this research is to analyze the the operational machnism of cultural publication, exploring the current operating results and the subsequent development of this cultural policy. Through the comparison of the ideas and the value judgements between the public and private sectors to survey the cultural publication in Lienchiang County. With the method of in-depth interview, interviewees divided into four groups : Group A consisting of three Cultural Affair Bureau members, Group B,three cultural workers, Group C ,three public readers, Group D ,one expert. By interviewing on the problems which needs solving, consulting the interviewees opinions respectively, confirming the ideas recorded and reach a consentient results. Directions on Research; Focus on the interviews with the Cultural Affair Bureau members of Lienchiang County and cultural workers. The reaserch shows that in order to have a functional publication machenism, the emphisis has to be put on both academic tradition and diversity and innovation, and make it function well throuhgh the cooperation of Government of Lienchiang County and civial sector. I suggest that we keep promoting the excellent experience in cultural asministration in Lienchiang County Government. The residents of Lienchiang county develop their own cultural publishing industry, the government actively supports; Every and each of the residents in Lienchiang County is all in to shape the cultural image of Matsu and promote Matsu. The study results not only can be used as a reference for local cultural affairs but also can be used by the central government as a reference when making cultural policy on remote island development.
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WU, CHIH-FENG, and 吳峙葑. "Exploring the Influence of ISO 9001:2015 Quality Management System on Operating Performance A Case Study of Metal Machining Industry in Tainan." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/fhnq8e.
Full textAbstract:
碩士國立高雄科技大學
工業工程與管理系
107
Quality is one of the important competitiveness of enterprises. In response to the needs of globalization, how to establish a quality management system to strengthen organizational processes is the direction of the industry. There have been many documents in the past for the ISO 9001 quality management system, but the ISO 9001 quality management system has been revised in 2015, and there are still few studies on the new version. The purpose of this study is to investigate the impact of the quality management system on operational performance and whether there is an impact between the quality management system and operational performance through the intermediary variable human quality. A cross-sectional questionnaire survey is used for the metal machining industry in Tainan. The results of this study show that the quality management system has a significant impact on human quality, human quality has a significant impact on operational performance, quality management system has a significant impact on operational performance, and human quality has a significant intermediary between quality management system and operational performance effect. Keywords：ISO 9001:2015 Quality Management Systems,Qualityof Workforce,Metal Machining Industry,Operating Performance