Dissertations / Theses on the topic 'Milling conditions'

The use of cutting fluids in machining process is very essential for achieving desired machining performance. Due to the strict environmental protection laws now in effect, there is a wide-scale evaluation of the use of cutting fluids in machining. Consequently, minimal quantity lubrication (MQL), which uses very small quantity of cutting fluids and still offers the same functionality as flood cooling, can be considered as an alternative solution. This thesis presents an experimental study of face milling of automotive aluminum alloy A380 under four different lubrication/cooling conditions: dry cutting, flood cooling, MQL (Oil), and MQL (Water). Experiments were design using Taguchi method for design of experiments. Empirical models for predicting surface roughness and cutting forces were developed for these four conditions in terms of cutting speed, feed and depth of cut. Optimization technique using Genetic Algorithms (GA) was used to optimize performance measures under different lubrication/cooling conditions, based on a comprehensive optimization criterion integrating the effects of all major machining performance measures. Case studies are also presented for two pass face milling operation comparing flood cooling condition with MQL. The comparison of the results predicted by the models developed in this work shows that the cutting force for MQL (Oil) is either lower or equal to flood cooling. The surface roughness for MQL (Oil) is comparable to flood cooling for higher range of feed and depth of cut. A comparison of the optimized results from the case studies, based on value of utility function, shows that the optimum point for two pass face milling operation having MQL (Oil) as finish pass has highest utility function value.

This thesis deals with manufacturing process of a front wheel hub carrier prototype for formula TU Brno Racing Dragon 5 series. The paper starts on foregoing work of design team leading to a proposed model and material. Both material and model are investigated form a manufacturing point of view. Cutting conditions and milling strategy are proposed based on final product analysis. Prototype was manufactured on CNC machining centre MCV 754 QUICK in company BOSCH DIESEL s.r.o. in Jihlava. Retrospective analysis of performed manufacturing process and critical risks is provided with a proposal of more effective manufacturing process. In the closure, there is technical-economical evaluation of chosen manufacture done by milling. Alternative manufacturing options including 3D print and welding are compared in technics and costs.

The current processing of electric motor feet and centering collars has been focusing on two main production methods. The production transfer from Germany allowed the introduction of a new enhanced technology. Cutting conditions values, cutting process operating forces , tool life criteria for a maximum productivity and a minimum costs were calculated. Control measurements of the required collar and stator pack concentricity provided the necessary feedback.

This study investigates the tool wear of advanced PVD TiALN/TiN multilayer coated end mill inserts when dry and semi-dry machining 4340 low alloy medium carbon steel. A factorial design of experiment setup consisting of two levels of speed, three levels of feed, two levels of depth of cut, and two levels of cutting conditions (semi-dry and dry) was used for the study. The combination of cutting conditions that gave the best response for different components of cutting force, cutting power, surface roughness and tool life were determined using MANOVA & ANOVA analysis and Tukey comparison of means test using MINITAB statistical software package. From a study of the Energy Dispersive X ray (EDX) analysis and primary back scatter images obtained from the worn out crater surface of the insert, it was observed that diffusion wear prevailed under both dry and semi-dry machining conditions. A tool life model was developed using multiple regression analysis within the range of cutting conditions selected. A model for flank wear progression was also developed using mixed effects modeling technique using S Plus statistical software package. This technique takes into account between and within work piece variations during end milling and produces a very accurate model for tool wear progression. This is the first time application of the mixed effects modeling technique in metal cutting literature.

Dans le processus de fabrication en fraisage à grande vitesse ‘FGV’, l’étude de la réaction de la machine au cours de l’usinage est une tâche très délicate et importante. En effet, l’identification du comportement de la machine nécessite la modélisation de la loi de mouvement des axes et de la trajectoire réelle aux niveaux des discontinuités. Le nombre important de discontinuités engendrent une instabilité de la vitesse de déplacement des axes, ce qui implique une augmentation du temps d’usinage et un non-respect de la vitesse d’avance programmée, se traduisant par des problèmes de productivité et une sous-estimation du coût de l’usinage pour l’industriel. L’objectif de cette thèse est de développer un outil informatique qui permet de calculer la vitesse d’avance et de faire une estimation précise du temps de cycle pour n’importe quelle trajectoire générée par un logiciel de FAO. Pour ce faire, nous avons déterminé un modèle qui permet d’identifier le comportement cinématique des axes d’un centre d’usinage en FGV pour toute forme de trajectoire. À partir de la modélisation de la variation de la vitesse d’avance, nous avons déterminé le temps réel selon les trajectoires et l’erreur imposée par le bureau des méthodes. Enfin, nous utilisons ces résultats pour mettre en place une méthodologie pour l’aide au choix du diamètre de l’outil et de la stratégie d’usinage. Afin de valider les modèles et les méthodologies développés, une étude expérimentale a été réalisée sur des applications didactiques et industrielles.

The work in this thesis comprehensively investigates the effects of non-uniform material behaviour exhibited by head-hardened Australian rail steel on ratcheting, wear and rolling-contact fatigue. As a result, this research develops novel approaches to characterising rolling-contact fatigue utilising wear debris and surface replication. Furthermore, calibration of material parameters was conducted to obtain a unified material model to elucidate the non-uniform mechanical behaviour of rail steel. All these methods draw attention to the need to refine track maintenance and re-railing practices related to Australian rail steel.

Diploma thesis deals with design and implementation of manufacturing technology of a part which was given by company Frentech Aerospace s.r.o. Manufacturing technology is prepared for conditions of workshop of Department of Machining FME Brno UT (laboratory C2). Acquired knowledges are used for design of innovative manufacturing technology with cutting tools from company Pramet Tools, s.r.o. Manufacturing technologies of gained part are designed for alloy blank EN AW 6082. Technical-economical assessment of all manufacturing technologies is part of this thesis. Both of manufacturing technologies designed for laboratory C2 are assessed together and manufacturing technology given by company Frentech Aerospace s.r.o. is assessed alone due to using different blank material.

This thesis discusses a change of an existing surface grinding technology for a more effective technology of face milling for the finishing operation of the jaw (for a hydraulic machine vise) in a tempered state with hardness of 53+4 HRC. The jaw is made of tool steel according to the Czech standard CSN41 9312. Two new versions are proposed for the new technology. Progressive cutting materials are listed for milling. A suitable tool is selected. Total production costs and machine times for cutting conditions of the chosen tool are predicted. In the experimental part, the cutting conditions are verified in practice.

The content of study is related to reducing the production times of milling of aluminum component of vacuum pump. The primary aim of the thesis is to experimentally verify the proposed cutting conditions when milling the rotor blades and then evaluate them according to predetermined parameters. The output is reducing machining time with respect to cost, tools and machine.

Vevaxeldeformation studeras i samband med uppspänning i en virvelfräsmaskin inför en skärande process. Syftet är att öka förståelse om deformationsbeteendet av vevaxelns viktiga funktionsytor genom analysering med Finita elementmetoden (FEM). Volvo Cars i Skövde hanterar i dagsläget oönskad vevaxeldeformation genom tidskrävande fysiska tester. Därför önskar företaget ta stöd av virtuell analysering. Detta arbete leder även till ett fastställande om FEM är ett tillämpbart verktyg att utgå ifrån för att upprätthålla snäva vevaxeltoleranser. Användning av virtuell analysering istället för fysiska tester skulle medföra tidsbesparing och ha positiv inverkan på miljön.  Programvaran Abaqus används för genomförande av deformationsanalyser vilka också utvärderas mot fysiska mätningar i en dragprovmaskin (Instron) för att därigenom säkerställa pålitligheten av använd FE modell.  Analyser genomförs huvudsakligen för deformationsuppkomst av vevaxeln i samband med uppspänning. Två olika typer av vevaxlar analyseras. Till respektive vevaxel skapas en FE modell med ansatta randvillkor och belastningsförhållanden utgående från en genomförd mekanisk analys av vevaxeln. Erhållna resultat visar att bricksidorna av vevaxeln deformeras med i storleksordningen  mm då vevaxeln belastas i samband med uppspänning med en hoptryckning på 0,2 mm. Denna deformation anses medföra risk att ett bearbetningsfel kan förorsakas. Analyserna visar även vilka ytor som deformeras mest/minst. Utvärdering mot dragprovning indikerar att riktning på vevaxeldeformation stämmer överens med analyserna, men att avvikelser på deformationsstorleken förekommer. Skillnaden kan möjligen förklaras med att E-modulen varierar inom den testade vevaxeln medan den definierade E-modulen i Abaqus antar ett konstant värde. Dessutom kan eventuella felkällor från dragprovningen ha inverkan på resultatutfallet av de fysiska mätningarna.  Genomförda analyser tyder på att FEM är tillämpbar för analysering av vevaxeldeformation och rekommendationer om en lämplig FE modell tillhandahålls. En potentiell lösning till deformationsproblemet anses vara beräkning av optimal klämkraft vid uppspänning.
Crankshaft deformation is studied in connection with clamping conditions in a whirl milling machine before a cutting process. The purpose of the project is to increase knowledge about the deformation behaviour of the crankshaft and its important functional surfaces by performing analyses using the finite element method (FEM). Volvo Cars in Skövde, Sweden is currently managing unwanted crankshaft deformation occurrence by using time consuming physical testing methods. Therefore, the company wish to use virtual analyses instead of physical tests. This work also leads to a determination if FEM is an applicable tool in order to maintain narrow tolerances of the crankshaft. Using virtual analyses instead of physical tests would be time saving and would also have a positive impact on the environment. The computer software Abaqus is used to implement the deformation analyses that are also evaluated against physical measurements done with a tensile testing machine (Instron) and thereby be able to ensure the reliability of the used FE model. FE analyses are mainly performed to evaluate the deformation of the crankshaft associated with clamping. Two different crankshaft types are being analysed. A FE model is created for each crankshaft along with applied boundary and load conditions according to performed mechanical analysis of the crankshaft. Obtained results show that the thrust bearing sides of the crank pins on the crankshaft deform in the range of  mm when the crankshaft is compressed during clamping with 0.2 mm. This deformation is considered to entail a risk for a processing error to occur. At the same time the analyses show which surfaces are most/least deformed. Evaluation according to the tensile testing indicates that the direction of the crankshaft deformation corresponds to the analysis but slight deviation of the deformation magnitude is present. The deviations can be explained by variations of the E-module within the crankshaft while the defined E-module in Abaqus has a constant value. Furthermore, there is a possibility that sources of error from the tensile tests can have an influence on the obtained results from the physical measurements. Conducted analyses indicates that FEM is applicable for crankshaft deformation analyses and recommendations of a suitable FE model are provided. A potential solution of the deformation problem is considered to be the calculation of optimal clamping force.

A very important requirement of modern machining systems in an 'unmanned' factory is to change tools that have been subjected to wear or damage in time. The old tool change strategies are based on conservative estimates from the past tool wear data, hence tools can be replaced too early or too late. This can increase the production cost or endanger the quality of the products. An integrated tool condition monitoring system composed of multi-sensors, signal processing methodology and decision-making plans is a crucial requirement for automtic manufacturing processes. An intelligent tool condition monitoring system for milling operations will be introduced in this report. The system is composed of four kinks of sensors, signal transforming and sampling apparatus and a microcomputer. By using intelligent pattern recognition techniques, different sensor signals are combined and the tool wear states can be recognised reliably. The efficient and effective orthogonal experimental design procedure is applied to comprehensively verify the monitoring system in a limited number of test runs. 50 signal features are extracted from time and frequency domain and they are found to be related to the development of tool wear values. A fuzzy clustering feature filter has been developed to remove less tool wear relevant features under different cutting conditions. multi-sensor signals reflect tool condition comprehensively and the sensor fusion strategy is used to provide reliable recognition results. Combining fuzzy approaching degree and fuzzy closeness provides a unique and overall fuzzy similarity index, the two-dimensional fuzzy approaching degree. A new type of fuzzy system, the fuzzy driven neural network has been established. The network can assign signal features suitable weights to make the tool wear state recognition process more accurate and robust. The advanced B-spline neurofuzzy networds are also successfully applied in the tool condiiton monitoring process. This powerful modelling system is established by combining the qualitative fuzzy rule representation with the quantitative adaptive numeric processing process. The fuzzy driven neural network and the B-spline neurofuzzy network can then be combined to build a neurofuzzy hybrid pattern recognition system, which is more reliable and accurate. Armed with the well- developed pattern recognition methodology, the established intelligent tool condition monitoring system has the advantages of being suitable for a wide range of machining conditions, robust to noise and tolerant to faults. As can be seen in the thesis, several innovations have been made in the research process of this project. The fuzzy clustering feature filter can significantly improve the efficiency and reliability of the tool wear state recognition process. The two-dimensional fuzzy approaching degree comprehensively characterises the similarity between two fuzzy sets. The fuzzy driven neural network indirectly solves the weight assignment problem of the conventional fuzzy system. The established neurofuzzy hybrid pattern recognition system obviously improves the system's recognition resolution and reliabilty

Thesis: S.M., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2018.
Cataloged from PDF version of thesis.
Includes bibliographical references (pages 81-84).
Tool wear is a major obstacle to realizing full automation in metal cutting operations. In this thesis, we designed and implemented a low cost Tool Condition Monitoring (TCM) system using off-the-shelf sensors and data acquisition methods . Peripheral end milling tests were done on a low carbon steel workpiece and the spindle vibration, cutting zone temperature and spindle motor current were recorded. Features from these data sources were used to train decision tree models in MATLAB with the aim of classifying the stages of tool wear. Results showed that the feature sets fusing information from all data sources performed the best, classifying the tool wear stage with up to 93% average accuracy.
by Deborah Ajilo.
S.M.

This thesis deals with design for manufacturing technology single part on machine FS, which is the connecting part. Work deals with the material of this component, therefore, cast iron with lamellar graphite, the properties of this material, primarily focusing on the machinability. Due to the shape and dimensions of the workpiece is also described problems cutting of box parts, the most common operations used in their manufacture, including cutting tools and materials. These findings are then applied in terms of the company TOS Kuřim - OS a.s. An analysis of current manufacturing technology and design is made for its amendment. In conclusion with the technical-economic evaluation.

Cutting tools with ceramic inserts are often used in the process of machining many types of super alloys, mainly due to their high strength and thermal resistance. Nevertheless, during the cutting process, the plastic flow wear generated in these inserts enhances and propagates cracks due to high temperature and high mechanical stress. This leads to a very variable failure of the cutting tool. Furthermore, in high-speed rough machining of nickel-based super alloys, such as Inconel 718 and Waspalloy, it is recommended to avoid the use of any type of coolant. This in turn, enables the clear visualization of cutting sparks, which in these machining tasks are quite distinctive. The present doctoral thesis attempts to set the basis of a potential Tool Condition Monitoring (TCM) system that could use vison-based sensing to calculate the amount of tool wear. This TCM system would work around the research hypothesis that states that a relationship exists between the continuous wear that ceramic SiAlON (solid solutions based on the Si3N4 structure) inserts experience during a high-speed machining process, and the evolution of sparks created during the same process. A successful TCM system such as this could be implemented at an industrial level to aid in providing a live status of the cutting tool’s condition, potentially improving the effectiveness of these machining tasks, whilst preventing tool failure and workpiece damage. During this research, sparks were analyzed through various visual methods in three main experiments. Four studies were developed using the mentioned experiments to support and create a final predictive approach to the TCM system. These studies are described in each thesis chapter and they include a wear assessment of SiAlON ceramics, an analysis of the optimal image acquisition systems and parameters appropriate for this research, a study of the research hypothesis, and finally, an approach to tool wear prediction using Neural Networks (NN). To carry out some of these studies, an overall methodology was structured to perform experiments and to process spark evolution data, as image processing algorithms were built to extract spark area and intensity. Towards the end of this thesis, these spark features were used, along with measured values of tool wear, namely notch, flank and crater wear, to build a Neural Network for tool wear prediction.

The aim of this thesis is shortening of standard mechanical time of work piece from aluminium casting alloy. . The shortening can be reached by linear programming of cutting conditions of cutting conditions during machining holes. This method is defined both theoretically and is applied to given setting and by the calculation by the Simplex method. Another method is exchange of tools at machined threads, it’s exchange of used tools for the new one, that makes more operations at a time. The result is shortening of mechanical time, augmentation of productive dose, capacities of workplace and productivity work.

[ES] La calidad superficial en las piezas mecanizadas depende del acabado superficial, resultado de las marcas dejadas por la herramienta durante el proceso de corte. Las aproximaciones teóricas tradicionales indican que estas marcas están relacionadas con los parámetros de corte (velocidad de corte, avance, profundidad de corte...), el tipo de máquina, el material de la pieza, la geometría de la herramienta, etc. Pero no todos los tipos de mecanizado y selección de materiales pueden dar un resultado ambiguo. Hoy en día, de manera progresiva, se están utilizando las técnicas de fresado de Alta Velocidad sobre materiales de difícil mecanizado cada vez más. El fresado de Alta Velocidad implica a un considerable número de parámetros del proceso que pueden afectar a la formación topográfica 3D de la superficie. La hipótesis de que los parámetros de rugosidad superficial dependen de las huellas dejadas por la herramienta, determinadas por las condiciones de trabajo y las propiedades del entorno, condujo al desarrollo de una metodología de investigación personalizada. Este trabajo de investigación muestra como la combinación de los parámetros, inclinación del eje de la herramienta, deflexión geométrica de la herramienta y comportamiento vibracional del entorno, influencian sobre el parámetro de rugosidad superficial 3D, Sz. El modelo general fue dividido en varias partes, donde se ha descrito la influencia de parámetros del proceso adicionales, siendo incluidos en el modelo general propuesto. El proceso incremental seguido permite al autor desarrollar un modelo matemático general, paso a paso, testeando y añadiendo los componentes que más afectan a la formación de la topografía de la superficie. En la primera parte de la investigación se seleccionó un proceso de fresado con herramientas de punta plana. Primero, se analiza la geometría de la herramienta, combinada con múltiples avances, para distinguir los principales parámetros que afectan a la rugosidad superficial. Se introduce un modelo de predicción con un componente básico para la altura de la rugosidad, obtenida por la geometría de la herramienta de corte. A continuación, se llevan a cabo experimentos más específicamente diseñados, variando parámetros tecnológicos. Esto empieza con el análisis de la inclinación del eje de la herramienta contra la mesa de fresado. Los especímenes de análisis son muestras con cuatro recorridos de corte rectos con corte en sentido contrario. Las trayectorias lineales con diferentes direcciones dan la oportunidad de analizar la inclinación del husillo de fresado en la máquina. Un análisis visual reveló diferencias entre direcciones de corte opuestas, así como marcas dejadas por el filo posterior de la herramienta. Considerando las desviaciones de las marcas de corte observadas en las imágenes de rugosidad superficial obtenidas a partir de las medidas, se introdujo un análisis sobre el comportamiento dinámico del equipo y de la herramienta de corte. Las vibraciones producen desviaciones en la mesa de fresado y en la herramienta de corte. Estas desviaciones fueron detectadas e incluidas en el modelo matemático para completar la precisión en la predicción del modelo. Finalmente, el modelo de predicción del parámetro de rugosidad Sz fue comprobado con un mayor número de parámetros del proceso. Los valores de Sz medidos y predichos, fueron comparados y analizados estadísticamente. Los resultados revelaron una mayor desviación de la rugosidad predicha en las muestras fabricadas con diferentes máquinas y con diferentes avances. Importantes conclusiones sobre la precisión del equipo de fabricación han sido extraídas y de ellas se desprende que la huella de la herramienta de corte está directamente relacionada con los parámetros de la topografía de la superficie. Además, la influencia de la huella está afectada por la geometría de la herramienta de corte, la rigidez de la herramienta y la precisión del equipo. La geometría de la herramienta conforma la base del parámetro Sz, desviación de la altura de la superficie. Las conclusiones alcanzadas son la base para recomendaciones prácticas, aplicables en la industria.
[CA] La qualitat superficial en les peces mecanitzades depèn de l'acabat superficial, resultat de les marques deixades per l'eina durant el procés de tall. Les aproximacions teòriques tradicionals indiquen que aquestes marques estan relacionades amb els paràmetres de tall (velocitat de tall, avanç, profunditat de tall...), el tipus de màquina, el material de la peça, la geometria de l'eina, etc. Però no tots els tipus de mecanitzat i selecció de materials poden donar un resultat ambigu. Avui en dia, de manera progressiva, s'estan utilitzant les tècniques de fresat d'Alta Velocitat sobre materials de difícil mecanització cada vegada més. El fresat d'Alta Velocitat implica un considerable nombre de paràmetres del procés que poden afectar la formació topogràfica 3D de la superfície. La hipòtesi que els paràmetres de rugositat superficial depenen de les empremtes deixades per l'eina, determinades per les condicions de treball i les propietats de l'entorn, va conduir al desenvolupament d'una metodologia d'investigació personalitzada. Aquest treball de recerca mostra com la combinació dels paràmetres, inclinació de l'eix de l'eina, deflexió geomètrica de l'eina i comportament vibracional de l'entorn, influencien sobre el paràmetre de rugositat superficial 3D, Sz. El model general va ser dividit en diverses parts, on s'ha descrit la influència de paràmetres addicionals del procés, sent inclosos en el model general proposat. El procés incremental seguit permet a l'autor desenvolupar un model matemàtic general, pas a pas, testejant i afegint els components que més afecten a la formació de la topografia de la superfície. En la primera part de la investigació es va seleccionar un procés de fresat amb eines de punta plana. Primer, s'analitza la geometria de l'eina, combinada amb múltiples avanços, per distingir els principals paràmetres que afecten la rugositat superficial. S'introdueix un model de predicció amb un component bàsic per a l'altura de la rugositat, obtinguda a través de la geometria de l'eina de tall. A continuació, es duen a terme experiments més específicament dissenyats, variant paràmetres tecnològics. Això comença amb l'anàlisi de la inclinació de l'eix de l'eina contra la taula de fresat. Els espècimens d'anàlisi són mostres amb quatre recorreguts de tall rectes amb tall en sentit contrari. Les trajectòries lineals amb diferents direccions donen l'oportunitat d'analitzar la inclinació del fus de fresat en la màquina. Una anàlisi visual revelà diferències entre direccions de tall oposades, així com marques deixades pel tall posterior de l'eina. Considerant les desviacions de les marques de tall observades en les imatges de rugositat superficial obtingudes a partir de les mesures, es va introduir una anàlisi sobre el comportament dinàmic de l'equip i de l'eina de tall. Les vibracions produeixen desviacions en la taula de fresat i en l'eina de tall. Aquestes desviacions van ser detectades i incloses en el model matemàtic per completar la precisió en la predicció de el model. Finalment, el model de predicció de el paràmetre de rugositat Sz va ser comprovat amb un major nombre de paràmetres del procés. Els valors de Sz mesurats i predits, van ser comparats i analitzats estadísticament. Els resultats van revelar una major desviació de la rugositat predita en les mostres fabricades amb diferents màquines i amb diferents avanços. Importants conclusions sobre la precisió de l'equip de fabricació han estat extretes i d'elles es desprèn que l'empremta de l'eina de tall està directament relacionada amb els paràmetres de la topografia de la superfície. A més, la influència de la empremta està afectada per la geometria de l'eina de tall, la rigidesa de l'eina i la precisió de l'equip. La geometria de l'eina conforma la base del paràmetre Sz, desviació de l'altura de la superfície. Les conclusions assolides són la base per recomanacions pràctiques, aplicables en la indústria.
[EN] Surface quality of machined parts highly depends on the surface texture that reflects the marks, left by the tool during the cutting process. The traditional theoretical approaches indicate that these marks are related to the cutting parameters (cutting speed, feed, depths of cut...), the machining type, the part material, the tool geometry, etc. But, different machining type and material selection can give a variable result. In nowadays, more progressively, High Speed milling techniques have been applied on hard-to-cut materials more and more extensively. High-speed milling involves a considerable number of process parameters that may affect the 3D surface topography formation. The hypothesis that surface topography parameters depends on the traces left by the tool, determined by working conditions and environmental properties, led to the development of a custom research methodology. This research work shows how the parameters combination, tool axis inclination, tool geometric deflection, cutting tool geometry and environment vibrational behavior, influence on 3D surface topography parameter Sz. The general model was divided in multiple parts, where additional process parameters influence has been described and included in general model proposed. The incremental process followed allows the author to develop a general mathematical model, step by step, testing and adding the components that affect surface topography formation the most. In the first part of the research a milling procedure with flat end milling tools was selected. First, tool geometry, combined with multiple cutting feed rates, is analyzed to distinguish the main parameters that affect surface topography. A prediction model is introduced with a basic topography height component, performed by cutting tool geometry. Next, specifically designed experiments were conducted, varying technological parameters. That starts with cutting tool axis inclination against the milling table analysis. The specimens of analysis are samples with 4 contrary aimed straight cutting paths. Linear paths in different directions give a chance to analyze milling machine spindle axis topography, as well as marks left from cutting tool back cutting edge. Considering the deviations of cutting marks observed in the images of the surface topography obtained through the measurements, the milling equipment and cutting tool dynamical behavior analysis were introduced. Vibrations produce deviations in the milling table and cutting tool. These deviations were detected and included in the mathematical model to complete the prediction model accuracy. Finally, the prediction model of the topography parameter SZ was tested with increased number of process parameters. Measured and predicted SZ values were compared and analyzed statistically. Results revealed high predicted topography deviation on samples manufactured with different machines and with different feed rates. Relevant conclusions about the manufacturing equipment accuracy have been drawn and they state that cutting tool's footprint is directly related with surface topography parameters. Besides, footprint influence is affected by cutting tool geometry, tool stiffness and equipment accuracy.
Logins, A. (2021). High speed milling technological regimes, process condition and technological equipment condition influence on surface quality parameters of difficult to cut materials [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/164122
TESIS

The goal of this thesis project was to digitize a milling machine. To achieve this, a data collection system was created using current sensors connected to a PLC external to the machine's CNC control to measure the phase currents of the machine's motors. During a period of observation, in which the machine exhibited only healthy behavior, data on the motor currents were collected by running a diagnostic cycle between the normal production cycles. This data was then processed to develop a condition monitoring PLC application for the motors. The application allows the user to determine how similar the signals recorded are to those recorded during the collection period and in this way determine if any anomalies are present. To determine the presence of anomalies, the signals are processed using three different approaches: first they are compared to a nominal signal in the time domain, then through a classifier obtained by machine learning techniques, their harmonic content is analyzed; finally, an autoencoder is used and the reconstruction error is evaluated. Combining the results of these approaches, the final judgment on the executed diagnostic cycle is then produced. In addition, a mobile human-machine interface has been created to allow the machine operator to visualize the produced diagnostic data, to update the production data and to monitor the machine operation through a mobile device.

Milling is a widely used cutting process, most commonly applied to machining external surfaces of workpieces. When machining operations are required within hard to reach areas of components, or deep within the bore of components, alternative methods of metal removal are generally employed. Typically when milling at extended reaches, difficulties may increase exponentially when trying to achieve distances several meters into a component. Essentially every topic of the milling process becomes difficult and more convoluted. Firstly to generate a stable cutting condition, and ultimately for an operator to be able to understand the cutting conditions, when all normal senses to interpret the machining stability are removed. The aim for the research is, to enable the operation of high slenderness ratio internal milling operations to become a viable technology, by detailing the measures required, to obtain a stable cutting condition. The process needs to be monitored for degradation of the tooling due to wear, and to prevent catastrophic machine damage from tool breakage or machine component failure. This research addresses the lack of knowledge available for milling with extended reaches, and the knowledge gained to overcome the real difficulties that exist for this process. Initial experiments are conducted on a prototype machine to gain experience of the internal machining operation and the many issues that it faced. Establishing requirements of the process via investigation of the tooling and necessary auxiliary equipment, it becomes possible to consider countermeasures to address the errors generated by torsional twisting of the milling arm. A system for applying a counter torque to reduce torsional deflection errors has been employed to successfully reduce the unavoidable issue over such long distances. For the process to become manageable for an industrial operator without a high level of specialist knowledge, the application of tool condition monitoring (TCM) and process condition monitoring (PCM) had to be applied. This addresses a void in available literature and research with respect to internal machining, and enables the process to become practical for an industrial environment. For this reason the research project will concentrate on the application of TCM and PCM onto the machining system. The completion of the research resulted in the process becoming satisfyingly stable, and with a resulting accuracy that satisfies the requirements of the component. Performance of the final system rivalled or achieved better results than had been experienced by the project sponsor.

Condition monitoring of critical machine tool components and machining processes is a key factor to increase the availability of the machine tool and achieving a more robust machining process. Failures in the machining process and machine tool components may also have negative effects on the final produced part. Instabilities in machining processes also shortens the life time of the cutting edges and machine tool.

The condition monitoring system may utilise information from several sources to facilitate the detection of instabilities in the machining process. To avoid additional complexity to the machining system the use of internal sensors is considered. The focus in this thesis has been to investigate if information related to the machining process can be extracted directly from the internal sensors of the machine tool.

The main contibutions of this work is a further understanding of the direct response from both linear and angular position encoders due the variations in the machining process. The analysis of the response from unbalance testing of turn tables and two types of milling processes, i.e. disc-milling and slot-milling, is presented. It is shown that operational frequencies, such as cutter frequency and tooth-passing frequency, can be extracted from both active and inactive machine axes, but the response from an active machine axis involves a more complex analysis. Various methods for the analysis of the responses in time domain, frequency domain and phase space are presented.

QC 20100518

This work documents an investigation of the degradation of a variety of different tools whilst conducting milling operations on a computer numerical controlled (CNC) milling machine. The potential of a range of sensors to detect tool degradation has been investigated and the outputs have been incorporated into a monitoring system. Progressive degradation under nominal rough and finish face milling and rough groove milling has been investigated using a two point grooving tool and four and eight point face milling tools on En8, En24 and En24T workpiece materials. Rapid degradation of the cutting tool has also been observed under rough milling conditions using four and eight point face milling tools, whilst machining n8 and En24T materials in a variety of simulated and actual tool breakage situations. A limited investigation of the effect of the individual wear geometries associated with both progressive and instantaneous tool degradation has been conducted by simulating these geometries and carrying out rough miffing tests using a four point face milling tool on a workpiece of En8 material. Similarly, a limited investigation of the effect of machining on different machines has also been undertaken. A number of different sensing technologies have been used, including conventional sensors such as spindle current and cutting force but also novel sensing techniques such as Acoustic Emission. These have been combined using artificial intelligence techniques to provide automatic recognition of the tool wear state. Similarly, the feasibility of breakage detection/prediction has also been demonstrated.

In a fully automated manufacturing environment, instant detection of condition state of the cutting tool is essential to the improvement of productivity and cost effectiveness. In this paper, a tool condition monitoring system (TCM) via machine learning (ML) and machine ensemble (ME) approach was developed to investigate the effectiveness of multisensor fusion when machining 4340 steel with multi-layer coated and multi-flute carbide end mill cutter. Feature- and decision-level information fusion models utilizing assorted combinations of sensors were studied against selected ML algorithms and their majority vote ensemble to classify gradual and transient tool abnormalities. The criterion for selecting the best model does not only depend on classification accuracy but also on the simplicity of the implemented system where the number of features and sensors is kept to a minimum to enhance the efficiency of the online acquisition system. In this study, 135 different features were extracted from sensory signals of force, vibration, acoustic emission and spindle power in the time and frequency domain by using data acquisition and signal processing modules. Then, these features along with machining parameters were evaluated for significance by using different feature reduction techniques. Specifically, two feature extraction methods were investigated: independent component analysis (ICA), and principal component analysis (PCA) and two feature selection methods were studied, chi square and correlation-based feature selection (CFS). For various multi-sensor fusion models, an optimal feature subset is computed. Finally, ML algorithms using support vector machine (SVM), multilayer perceptron neural networks (MLP), radial basis function neural network (RBF) and their majority voting ensemble were studied for selected features to classify not only flank wear but also breakage and chipping. In this research, it has been found that utilizing the multisensor feature fusion technique under majority vote ensemble gives the highest classification performance. In addition, SVM outperformed other ML algorithms while CFS feature selection method surpassed other reduction techniques in improving classification performance and producing optimal feature sets for different models.

The arid interior of South Africa lacks long, continuous and well-dated climate and environmental proxy records that can be compared with cultural sequences and with broader global climate records. This thesis develops the first substantial terrestrial environmental sequence for the interior of southern Africa at the site of Wonderwerk Cave, spanning two million years of prehistory. Changes in vegetation and humidity over time were investigated by means of carbon and oxygen stable isotope analysis on fossil herbivore enamel and ostrich eggshell, creating two independent proxy datasets. The Holocene record was used as a baseline for comparing the Pleistocene sequence, but required chronological tightening. Therefore, nine new radiocarbon dates were obtained, and calibrated and modelled with existing dates to provide a firmer chronology. The ostrich eggshell isotope record suggests arid but variable conditions, with distinct phases of increased humidity in the Early Pleistocene and mid-Holocene. Enamel stable isotope results show clear differences in local resource availability between the Early and Mid-Pleistocene, and then between the Pleistocene and Holocene, with an overall trend of increasing aridity. In particular, the onset of dietary specialisation in grazers at 0.8Ma is linked to expanding C4 grasslands. Aridity was not the driver behind the increase in C4 grasses, but changing pCO2 levels at the Mid Pleistocene transition were identified as a possible key factor. The presence of C3 and C4 grasses in the Early Pleistocene, when compared to the domination of C4 grasses today, was fostered by reduced rainfall seasonality. Regional independent developments have to be considered, as other regions in South and East Africa show C4 dominated diets in herbivores at earlier times than at Wonderwerk Cave. In the Holocene, higher temporal resolution indicates phases of environmental change coinciding with changes in the cultural record.

Today’s buildings are responsible for 40% of the world’s energy use and also a substantial share of the Global Warming Potential (GWP). In Sweden, about 21% of the energy use can be related to the heat losses through the climatic envelope. The “Million Program” (Swedish: Miljonprogrammet) is a common name for about one million housing units, erected between 1965 and 1974 and many of these buildings suffer from poor energy performance. An important aim of this study was to access the possibilities of using Vacuum Insulation Panels (VIPs) in buildings with emphasis on the use of VIPs for improving the thermal efficiency of the “Million Program” buildings. The VIPs have a thermal resistance of about 8-10 times better than conventional insulations and offer unique opportunities to reduce the thickness of the thermal insulation. This thesis is divided into three main subjects. The first subject aims to investigate new alternative VIP cores that may reduce the market price of VIPs. Three newly developed nanoporous silica were tested using different steady-state and transient methods. A new self-designed device, connected to a Transient Plane Source (TPS) instrument was used to determine the thermal conductivity of granular powders at different gaseous pressure combined with different mechanical loads. The conclusion was that the TPS technique is less suitable for conducting thermal conductivity measurements on low-density nanoporous silica powders. However, deviations in the results are minimal for densities above a limit at which the pure conduction becomes dominant compared to heat transfer by radiation. The second subject of this work was to propose a new and robust VIP mounting system, with minimized thermal bridges, for improving the thermal efficiency of the “Million Program” buildings. On the basis of the parametric analysis and dynamic simulations, a new VIP mounting system was proposed and evaluated through full scale measurements in a climatic chamber. The in situ measurements showed that the suggested new VIP technical solution, consisting of 20mm thick VIPs, can improve the thermal transmittance of the wall, up to a level of 56%. An improved thermal transmittance of the wall at centre-of-panel coordinate of 0.118 to 0.132 W m-2K-1 and a measured centre-of-panel thermal conductivity (λcentre-of-panel) of 7 mW m-1K-1 were reached. Furthermore, this thesis includes a new approach to measure the thermal bridge impacts due to the VIP joints and laminates, through conducting infrared thermography investigations. An effective thermal conductivity of 10.9 mW m-1K-1 was measured. The higher measured centre-of-panel and effective thermal conductivities than the published centre-of-panel thermal conductivity of 4.2 mW m-1K-1 from the VIP manufacturer, suggest that the real thermal performance of VIPs, when are mounted in construction, is comparatively worse than of the measured performance in the laboratory. An effective thermal conductivity of 10.9 mW m-1K-1 will, however, provide an excellent thermal performance to the construction. The third subject of this thesis aims to assess the environmental impacts of production and operation of VIP-insulated buildings, since there is a lack of life cycle analysis of whole buildings with vacuum panels. It was concluded that VIPs have a greater environmental impact than conventional insulation, in all categories except Ozone Depilation Potential. The VIPs have a measurable influence on the total Global Warming Potential and Primary Energy use of the buildings when both production and operation are taken into account. However, the environmental effect of using VIPs is positive when compared to the GWP of a standard building (a reduction of 6%) while the PE is increased by 20%. It was concluded that further promotion of VIPs will benefit from reduced energy use or alternative energy sources in the production of VIP cores while the use of alternative cores and recycling of VIP cores may also help reduce the environmental impact. Also, a sensitivity analysis of this study showed that the choice of VIPs has a significant effect on the environmental impacts, allowing for a reduction of the total PE of a building by 12% and the GWP can be reduced as much as 11% when considering both production and operation of 50 yes. Finally, it’s possible to conclude that the VIPs are very competitive alternative for insulating buildings from the Swedish “Million Program”. Nevertheless, further investigations require for minimizing the measurable environmental impacts that acquired in this LCA study for the VIP-insulated buildings.
Dagens byggnader ansvarar för omkring 40% av världens energianvändning och  står också för en väsentlig del av utsläppen av växthusgaser. I Sverige kan ca 21 % av energianvändningen relateras till förluster genom klimatskalet. Miljonprogrammet är ett namn för omkring en miljon bostäder som byggdes mellan 1965 och 1974, och många av dessa byggnader har en dålig energiprestanda efter dagens mått. Huvudsyftet med denna studie har varit att utforska möjligheterna att använda vakuumisoleringspaneler (VIP:ar) i byggnader med viss fokus på tillämpning i Miljonprogrammets byggnader. Med en värmeledningsförmåga som är ca 8 - 10 gånger bättre än för traditionell isolering erbjuder VIP:arna unika möjligheter till förbättrad termisk prestanda med minimal isolerings tjocklek. Denna avhandling hade tre huvudsyften. Det första var att undersöka nya alternativ för kärnmaterial som bland annat kan reducera kostnaden vid produktion av VIP:ar. Tre nyutvecklade nanoporösa kiselpulver har testats med olika stationära och transienta metoder. En inom projektet utvecklad testbädd som kan anslutas till TPS instrument (Transient Plane Source sensor), har använts för att mäta värmeledningsförmågan hos kärnmaterial för VIP:ar, vid varierande gastryck och olika mekaniska laster. Slutsatsen blev att transienta metoder är mindre lämpliga för utföra mätningar av värmeledningsförmåga för nanoporösa kiselpulver låg densitet. Avvikelsen i resultaten är dock minimal för densiteter ovan en gräns då värmeledningen genom fasta material blir dominerande jämfört med värmeöverföring genom strålning. Det andra syftet har varit att föreslå ett nytt monteringssystem för VIP:ar som kan användas för att förbättra energieffektiviteten i byggnader som är typiska för Miljonprogrammet. Genom parametrisk analys och dynamiska simuleringar har vi kommit fram till ett förslag på ett nytt monteringssystem för VIP:ar som har utvärderats genom fullskaleförsök i klimatkammare. Resultaten från fullskaleförsöken visar att den nya tekniska lösningen förbättrar väggens U-värde med upp till 56 %. En förbättrad värmegenomgångskoefficienten för väggen i mitten av en VIP blev mellan 0.118 till 0,132 W m-2K-1 och värmeledningstalet centre-av-panel 7 mW m-1K-1 uppnåddes. Detta arbete innehåller dessutom en ny metod för att mäta köldbryggor i anslutningar med hjälp av infraröd termografi. En effektiv värmeledningsförmåga för 10.9 mW m-1K-1 uppnåddes. Resultaten tyder även på att den verkliga termiska prestandan av VIP:ar i konstruktioner är något sämre än mätvärden för paneler i laboratorium. En effektiv värmeledningsförmåga av 10.9 mW m-1K-1 ger dock väggkonstruktionen en utmärkt termisk prestanda. Det tredje syftet har varit att bedöma miljöpåverkan av en VIP-isolerad byggnad, från produktion till drift, eftersom en livscykelanalys av hela byggnader som är isolerade med vakuumisoleringspaneler inte har gjorts tidigare. Slutsatsen var att VIP:ar har en större miljöpåverkan än traditionell isolering, i alla kategorier förutom ozonnedbrytande potential. VIP:ar har en mätbar påverkan på de totala utsläppen av växthusgaser och primärenergianvändningen i byggnader när både produktion och drift beaktas. Miljöpåverkan av de använda VIP:arna är dock positiv jämfört med GWP av en standardbyggnad (en minskning med 6 %) medan primärenergianvändningen ökade med 20 %. Slutsatsen var att ytterligare användning av VIP:ar gynnas av reducerad energiförbrukning och alternativa energikällor i produktionen av nanoporösa kiselpulver medan användningen av alternativa kärnmaterial och återvinning av VIP kärnor kan hjälpa till att minska miljöpåverkan. En känslighetsanalys visade att valet av VIP:ar har en betydande inverkan på miljöpåverkan, vilket ger möjlighet att reducera den totala användningen av primärenergi i en byggnad med 12 % och utsläppen av växthusgaser kan vara minska, så mycket som 11 % när det gäller både produktion och drift under 50 år. Avslutningsvis är det möjligt att dra slutsatsen att VIP:ar är ett mycket konkurrenskraftigt alternativ för att isolera byggnader som är typiska för Miljonprogrammet. Dock krävs ytterligare undersökningar för att minimera de mätbara miljöeffekter som förvärvats i denna LCA-studie för VIP-isolerade byggnader.

QC 20151109

Simulations of heat and moisture conditions in a retrofit wall construction with Vacuum Insulation Panels
Textural and thermal conductivity properties of a low density mesoporous silica material
A study of the thermal conductivity of granular silica materials for VIPs at different levels of gaseous pressure and external loads
Evaluation of the thermal conductivity of a new nanoporous silica material for VIPs – trends of thermal conductivity versus density
A comparative study of the environmental impact of Swedish residential buildings with vacuum insulation panels
ETICS with VIPs for improving buildings from the Swedish million unit program “Miljonprogrammet”

碩士
國立成功大學
機械工程學系碩博士班
94
This thesis investigates the effect of milling conditions and tool geometry on cutting coefficients. The cutting coefficients are identified by using the Least Square method with the milling force in time domain. The Least Square method has smaller errors than mean force method and harmonic force method to identify the cutting coefficients. The experiment investigates cutting coefficients by choosing different materials (Al 6061-T6, SUS 304 and Inconel 718), milling configuration (up milling, down milling), conditions (different radial of depth), and tool Geometry (rake angle, clearance angle, helix angle). The results of experiments on Al6061 show that the diversity of down milling and up milling can be ignored for the same mean chip thickness. In milling SUS 304 by different tool factors, the results show that a large helix angle, results is smaller specific coefficients; the bigger rake angle, the smaller specific coefficients. The clearance angle has less effect on specific coefficient. In different cutting speed experiments, on using Al 6061 and SUS 304, the results of experiment show specific coefficients decrease with increase cutting speed, on the contrast, the specific coefficients of Inconel 718 increase with cutting speed.

碩士
逢甲大學
機械與電腦輔助工程學系
106
The main purpose of this thesis is to investigate the influence of machining parameters and milling path on the machining accuracy in the deep groove end-milling for the offset angle of the cylindrical material (SNCM220). The machine used in this study is a turning-milling machine. The milling path includes contour milling (positive and negative milling) and linear reciprocating milling. The machining parameters include spindle speed, feedrate, and feed per edge. In this experiment, Taguchi method was used to conduct experimental analysis to find out the key parameters, and then get the best combination of parameters. Through the experimental analysis, the optimal parameter combination is: milling path = contour positive milling, spindle speed = 2400rpm, feedrate = 300m/min, feed rate per blade = 0.629mm. This study confirms that this combination of parameters can effectively improve the deep groove machining accuracy of the offset angle, and thereby meet the experimental design goals.

碩士
國立臺北科技大學
製造科技研究所
102
In this paper, an investigation of counterbore milling conditions by using end mill cutters was performed. Using the measured milling forces and the machined counterbore quality (diameter accuracy and its roundness) to predict the ideal milling conditions for counterbore machining. A variety of milling conditions including the used end mill diameter, the interval of step type feeding method, the helical angle or pitch of helical type feeding method and the feed per tooth were planned. In contrast to the step type method, the experimental results show that the helical type feeding method can stabilize the cutting forces and reduce the lateral cutting force during milling process and improve the machined counterbore accuracy. As well as the appropriate end mill diameter of counterbore milling is between about 70% to 80% of the counterbore hole diameter.

碩士
國立虎尾科技大學
機械與電腦輔助工程系碩士班
105
NAK80 mold steel is a high-performance, high-precision, and advanced plastic mold steel with mirror surface and hence is a specific material commonly used for plastic die manufacturing currently. The machined surface may exhibit fine pattern and artistic appearance in electrical discharge machining, and is also featured by good mirror surface quality in grinding. Recently, the demand of surface quality for mold steel is getting more stringent, but the machined surface after milling operation is usually rougher. Therefore, most manufacturers solved these problems by grinding followed by polishing subsequently. However, the time wasted and cost for grinding and polishing procedures are considerable. If the surface quality machined by milling only may be promoted to a certain degree through different assisted ways, the time and cost for these machining operations can thus be reduced. As a result, the same standard of surface quality may be attained in replacement of grinding operation eventually and the grinding procedure may be omitted directly. It is expected that some machining processes for surface quality enhancement can be omitted based on the advantages of different assisted ways, which can serve as a reference for mold manufacturing to save the time wasted in some intermediate machining procedures, and enhance the production efficiency. In this study, five different assisted ways, including without assistance, laser assisted, cutting fluid assisted, MQL assisted and cold air assisted were employed for NAK80 mold steel milling. The assisted effect on cutting performance could be verified and the difference, merit and drawback among them may be compared. Milling experiments without assistance were conducted, followed by laser assisted, cutting fluid assisted, MQL assisted and cold air assisted milling experiments subsequently. The 18 set experiments were performed in each assisted way but 27 sets were executed in the first situation. Under each assisted milling circumstance, the effects of process parameters on the variations of surface roughness, cutting force, tool wear and surface morphology of workpiece are thus investigated. It is expected that the cutting performance of the NAK80 mold steel could be promoted through these assisted ways. Before the use of laser assistance, the laser preheating time related to the workpiece surface should be tested in advance for a proper spacing distance setting between laser-spot and cutting-tool. In this study, milling experiments of NAK80 mold steel by cutting-tool of extra-fine particle tungsten carbide with TiSiN coating were conducted. And the experiments of process parameter combinations such as spindle speed, feed rate and radial depth of cut were also planned. During the experiments, dynamometer is used to monitor the variation of cutting forces. Flank wear of cutting-tool and machined surface morphology of the NAK80 mold steel were measured by tool-microscope off-line. Surface roughness measurement through a probe contact type instrument is also performed. The results show that, under the same milling conditions, the surface roughness and cutting force are decreased as the spindle speed is increased, but both of them is increased as the feed rate and radial cutting depth are increased. In addition, the maximum flank wear of cutting-tool is increased as the spindle speed, feed rate and radial cutting depth are increased. In terms of cutting assisted, the cutting performance exhibited in the cold air assisted milling prevails over that in milling without assistance as well as with the other each assisted way. As a result, the cutting-tool flank wear, surface roughness and cutting force are all better than the other assisted ways. The better result obtained in this study was achieved by using the cold air assisted in NAK80 mold steel milling under the conditions of the spindle speed of 15000 rpm, feed rate of 300mm/min and radial cutting depth of 0.1 mm. The cutting force of 40.31N and surface roughness could be reduced to 0.216μm accompanied by these process parameter combinations.

碩士
中興大學
機械工程學系所
95
selected tools were calculated using F.W. Taylor’s tool life equation. We hypothesized that by manipulating these independent variables, the surface roughness, the chip shape, and the relationship between the cutting conditions and cutting resistances would vary. The results of this study indicated that with high cutting speed and low feed rate, the chips were long and thin with no spiral shape, and are accompanying with small chips. The surface roughness was good. With an increase in feed rate without changing cutting speed, the shape of the chips became spiral with hook-shape slices. The surface roughness was not good. The change in surface roughness associated with the change in feed depth was far less than the change associated with feed rate. With the same feed rate and feed depth, the cutting resistance increased proportionally to the increase in cutting speed.

碩士
國立虎尾科技大學
機械與電腦輔助工程系碩士班
101
In the recent year, the glass substrate has become gradually the most important material of the development in the information technology enterprise, its demanding quantity is increasing higher and higher, the quality of various processing have been requested more severer. For the time being, the enterprise of glass processing is mainly on cutting and edge seaming, the process flow is complicated and the cost is higher, therefore , the important topics of the current processing technology are seeking for the breakthrough of short process and the efficient cost saving . Because the glass possesses the quality of high intensity, high stiffness and low thermal conductivity, it is easy to make the cutting tool have the fast abrasion in the processing period and have imperfections like cracks and edge/corner collapse on the processing surface. To improve the above problems, the high rotation speed and low cutting depth and cooling fluild are employed in this study, also collocates the suitable feed rate and proceed the side milling/cutting, control the tough and brittle milling/cutting transformation model hopefully, thus, improve the processing efficiency of the glass substrate. The study employs large and medium water- soluble cutting fluid and green Production technique MQL and uses the diamond Tungsten Carbide (WC) cutting tool to proceed the milling/cutting experiment of the glass substrate. During the milling/cutting experiment, dynamometer and spectrum analyzer are employed to monitor the cutting force and vibration quantity, respectively. Also, observing the quality of edge surface of glass and the abrasion of cutting tool under different experiment parameters by tool-microscope off-line. The experimental data are analyzed under numerical analysis. Results show that the comparison between the traditional medium quantity of pouring wet milling/cutting and MQL, large quantity of pouring wet milling/cutting provide a good quenching effect on processing zone, thus, reduce the abrasion of the cutting tool and contribute to lower the cutting force. Observing from the cutting dynamic vibration quantity reveals that adding the water- soluble cutting fluid will contribute to improve and lower the cutting vibration and provide the stable action of cutting. Another observing from the damage of the raw material edge reveals that the better surface quality of the glass edge is obtained under high cutting speed, low feed rate and shallow path cutting. Adding the water- soluble cutting fluid can lower effectively the large amount of heat which is generated in the processing period of the glass surface. The high temperature difference between the surface and the inner layer of the glass is avoided, thus, the internal stress of the glass increases and over the limited intensity of the glass itself, then, leads to the break of the glass. Observing from the abrasion quantity of the cutting tool reveals that adding the water- soluble cutting fluid in the milling/cutting period, when increasing the cutting depth, the apparent dent damage will appear on the abdomen part of the cutting tool as the feed rate is increasing. Applying the MQL processing will make the cutting tool collapse the edge and shell off on its front end. Making a comprehensive survey of all the performance of milling/cutting, raising the cutting speed, lowering both of the cutting depth and the feed rate will reduce the occurrence of damage of glass substrate edge effectively, upgrade the cutting tool life and obtain the better quality of edge surface.

碩士
輔仁大學
食品科學系
98
Rice bran is the byproduct of rice milling. It is rich in lipid, protein, fiber, and functional components. Obtaining the rice bran with high amount of functional components could be achieved by screening from the rice variety. Moreover, the functional property of rice bran is poor, resulting in the limitation of its application. With proper milling and sieving process, the hull and broken rice in the bran could be separated, and a bran fraction with special functional property could be screened. Therefore, the objectives of this research were to investigate and compare the content of functional components in different rice mutant bran, and to study the effects of milling cycle and sieving on the physicochemical properties of rice mutant bran. The results showed that the order of rice mutants in two crop years (2007II and 2008I) based on their functional component contents were the same except α-tocopherol. This result indicated that the rice mutants used in this study were well cultivated. Moreover, the alpha type tocopherol and the gamma type tocotrienol represented highest proportion in the rice mutant brans. According to the literature, α-tocotrienol had the best antioxidant activity among the tocotrienol derivatives. Thus, the rice mutants, SA402 and SA419 with the highest and the lowest content of α-tocotrienol were screened and used for analyzing the physicochemical property of rice bran treated with different milling and sieving process. SA402 rice bran obtained from the second milling cycle had higher ash, lipid, and protein contents than the bran obtained from the first milling cycle, but SA419 rice bran had the opposite results. The water-holding and oil-holding capacities of the rice bran decreased with particle size. The results also showed that the lower the total starch in rice bran, the higher the insoluble dietary fiber, and the better the water-holding and oil-holding capacities. In conclusion, rice bran with high amount of functional components and special functional property could be prepared by the combined selection of rice variety, milling and sieving.

碩士
淡江大學
水資源及環境工程學系碩士班
96
Since municipal solid waste incinerator (MSWI) fly ash contains a lot of heavy metals, which exceed the regulatory limits of hazardous waste usually, and the disposal of fly ash has presented a significant problem. Consequently, the stabilizing and recovering of MSWI fly ash is the majority trend, and sintering is a potentially technology in the future. In the study, the characteristics of heavy metals volatilities of MSWI fly ash handled by water-extraction and then high energy ball milling with different stabilizers were investigated. The particle size analyzer, X-ray diffraction (XRD) and scanning electron microscope (SEM) were used to exam the properties after milling. The hydrofluoric acid digestion was applied to evaluate the heavy metals volatilities of the ashes. The results showed that, the addition of 30% Al2O3 with 0.8 M phosphoric acid ball milling, the volatility of Zn and Pb could be controlled within 20-30% in the sintering temperature of 800 and 1,000 oC, which can also control the volatility in 41% and 22%at 1200 oC relatively. The compression strength of regenerated aggregate was increased with the elevation of temperature gradually, reached 344 kg/cm2 at 1,200 oC, which reached the criteria of constructional aggregate. Key words: MSWI fly ash, high energy ball milling, heavy metals, stabilization, sintering, regenerated aggregate.

Chan Kai Yiu.
Thesis (M.Phil.)--Chinese University of Hong Kong, 1992.
Includes bibliographical references.
Chapter 1. --- Introduction: Big Business Financing in Modern China --- p.1
Chapter 2. --- The Demand for Capital and Credit --- p.18
Chapter 3. --- Internal Financing --- p.30
Chapter 3.1. --- Shareholders' Initial Investment
Chapter 3.2. --- Accumulated Capital
Chapter 4. --- External Financing --- p.56
Chapter 4.1. --- Economic Background and Rationale behind External Financing
Chapter 4.2. --- Loans and Credits from Qianzhuang
Chapter 4.3. --- Loans from Modern Chinese Banks
Chapter 4.4. --- Loans from the Foreign Banks in China
Chapter 4.5. --- Credits in Machinery Buying
Chapter 5. --- Attempts of Closed Financing --- p.110
Chapter 5.1. --- Guangsheng Qianzhuang: The First Attempt
Chapter 5.2. --- Gechang Wanglai: A Channel of Closed Financing
Chapter 5.3. --- The Headquarters Company: An Institutional Device
Chapter 5.4. --- Staff's Savings Department: One Step Further
Chapter 6. --- "Conclusion: Entrepreneurship, Social Networking, and Economic Rationalization" --- p.136
Chapter 6.1. --- Entrepreneurship
Chapter 6.2. --- Social Networking
Chapter 6.3. --- Economic Rationalization
Appendix --- p.148
Glossary --- p.150
Selected Bibliography --- p.157

Thesis (M.S.)--University of Wisconsin--Madison, 1988.
Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 149-156).

Thesis (Ph. D.)--University of Wisconsin--Madison, 1987.
Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 201-208).

碩士
國立中興大學
機械工程學系所
105
A number of studies have been reported for the development of tool wear monitoring system based on the vibration and acoustic emission signal. However, few study focus on the machining of nickel based material. In addition, due to the variation of the collected signals with the change of cutting parameters, tool geometry, the clamper force, and the other system variation, it is not easy to directly transfer the developed system to industry in past decades. To study the relationship between tool wear and collected spindle vibration and vise AE signals, analyze the effect of system variation on the collected signals, and develop the robust tool wear monitoring system, an experiment has been implemented to collected signals during cutting process. The effect of the number of tool tooth and the clamping force on collected signals was studied as well. To improve the robustness of developed system, an SOM filter is designed for feature extraction to remove the unreliable features for monitoring system. In experimental setup, two accelerometers were installed on an adaptor attached to the spindle in X and Z direction, respectively, along with an AE signals installed on the vise. Three kinds of cutting tool with various numbers of teeth were implemented in experiments. Three setup of clamping forces with 50 NM, 60Nm, and 100Nm were also implanted to study their effect on collected signals. The results show that the change of the number of tooth in cutting tool will not affect the energy distribution over frequency for both spindle vibration signals. For AE signal, the energy of AE signal increase dramatically when the number of tooth increase from two to three. With the change of clamping force, the change of the energy distribution over the frequency for X direction vibration signal can be observed. However, the same phenomenon will not be observed for Z direction vibration signal. Moreover, the increase of clamping force will increase the level of the AE signal on vise. For the evaluation of developed system, the 93% and 90% classification rate can be reached, respectively, with Z and X direction spindle vibration signals without adopting SOM filter. The classification rate can be improved to 95.2% and 94.5%, respectively, with the application of designed SOM filter. For the AE-signal based monitoring system, only 65% of classification rate can be obtained, and no improvement can be observed when applying the SOM filter to the system.

碩士
國立中興大學
機械工程學系所
106
The Inconel-718 is the key material for the aero industry, but the serious tool wear always make it a challenge to improve the quality and machining efficiency. The tool condition monitoring provides a solution to optimize the tool exchange time and machining efficiency. However, the uncertainty of system and material variation make the system not easy to implement the developed system in the laboratory to the industrial site. Therefore, how to improve the robustness of the system plays an important role to implement the tool wear monitoring system in the production line. In this research, a modified Recurrent Hidden Markov Model (RHMMs) is proposed to improve the robustness of the monitoring system. In the system development and evaluation, the variation of system is designed by changing the clamping force on the vise and the diameter of cutting tool. Finally, multi-sensor feature and decision fusion was adopted to improve the overall performance of the monitoring system. In experiments, the vibration signals in the X and Y directions were collected simultaneously during the machining of the straight line, along with the Acoustic Emission (AE) signals. The results show that the classification rate of tool wear monitoring with the constant clamping force in machining is improved from 85% to 94.8% with the implement of the modified RHMMs comparing to the one with traditional HMMs. With the varying clamping force setup, the classification rate is improved from 86.39% to 90.83%. In the analysis of applying the feature and decision fusion to the BPNN, HMMs, and RHMMs classifiers, the improvement of system robustness is also observed for the system with the RHMMs classifier. Although no clear difference of the classification rate between applying three classifiers is observed by evaluating the system by signals with the constant clamping force, the classification rate could be improved from 92.78% and 94.4% to 97.78%, respectively, by adopting the feature fusion integrated with RHMMs classifier comparing to the integration with BPNN and HMMS classifiers. With the implementation of decision fusion integrated with RHMMs, the classification rate could be improved from 93.96% and 90.83% to 96.39% comparing to the BPNN and HMMs classifiers.

碩士
國立成功大學
機械工程學系
88
The heat generated during metal cutting process will degrade the dimensional accuracy and surface integrity including residual stresses, micro-structural changes and cracks etc. First, the work temperature beneath the surface in an end milling process is analyzed with the moving heat source theory and the results are verified with experiments. In order to investigate the influences of the tools geometry and cutting conditions on the temperature on work surface, the cutting simulation software “AdvantEdge” in combination with Taguchi method is used to identify the significant parameters that affect the surface temperature of AL7075-T6. Further investigation shows how to maximize the metal removal rate under the constrained of maximum surface temperature.

碩士
國立高雄應用科技大學
化學工程與材料工程系碩士在職專班
105
Nowadays the MLCC industry is heading to the technologies of small size, thinner film, and higher stacking layers. Due to the difficulties of the process technology, the products are frequently have low yield rate and quality issues while manufacturing. This research will discuss the front process of a MLCC, slurry making. By introducing the different milling speed to find out the influence to MLCC characteristics, and finalize the optimal milling condition from the results of the MLCC electrical properties measurement and accelerated life test. From the results, it showed that the milling speed of 8 m/s gets the more homogeneous particle size distributed slurry, and there is no abnormal particle growth after sintering the samples. From measuring the properties of the capacity (Cap.) and the dissipation factor (Df), the stats were better and well-distributed. And from measuring the properties of the insulation resistance (I.R.) and breakdown voltage (BDV), it also performed better than that by other milling conditions, which obviously improved the product reliability, and raise the yield of MLCC electrical properties to 91.5 % from it was originally, 79.6 %.

A dissertation submitted to the Faculty of Engineering and the Built Environment, University of the Witwatersrand, in fulfilment of the requirements for the degree of Master of Science in Engineering. Johannesburg 2016
The quantity and particle size distribution of pulverised coal supplied to combustion equipment downstream of coal pulverising plants are critical to achieving safe, reliable and efficient combustion. These two key performance indicators are largely dependent on the mechanical condition of the pulveriser. This study aimed to address the shortfalls associated with conventional time-based monitoring techniques by developing a comprehensive online pulveriser condition monitoring philosophy. A steady-state Mill Mass and Energy Balance (MMEB) model was developed from first principles for a commercial-scale coal pulveriser to predict the raw coal mass flow rate through the pulveriser. The MMEB model proved to be consistently accurate, predicting the coal mass flow rates to within 5 % of experimental data. The model proved to be dependent on several pulveriser process variables, some of which are not measured on a continuous basis. Therefore, the model can only function effectively on an industrial scale if it is supplemented with the necessary experiments to quantify unmeasured variables. Moreover, a Computational Fluid Dynamic (CFD) model based on the physical geometry of a coal pulveriser used in the power generation industry was developed to predict the static pressure drop across major internal components of the pulveriser as a function of the air flow through the pulveriser. Validation of the CFD model was assessed through the intensity of the correlation demonstrated between the experimentally determined and numerically calculated static pressure profiles. In this regard, an overall incongruity of less than 5 % was achieved. Candidate damage scenarios were simulated to assess the viability of employing the static pressure measurements as a means of detecting changes in mechanical pulveriser condition. Application of the validated pulveriser CFD model proved to be highly advantageous in identifying worn pulveriser components through statistical analysis of the static pressure drop measured across specific components, thereby demonstrating a significant benefit for industrial application.
MT2016

碩士
國立中興大學
機械工程學系所
102
Micro-mechanical machining holds the advantage of machining complex feature in micro scale with various types of material and draws much more attention recently due to the increase demand in micro device with various types of material. However, the high tool wear rate in machining brittle material such as silicon and PZT limits its application in mass production. 　　The development of tool wear and surface quality monitoring in machining PZT/Si wafer with the diamond thin film deposited micro mill was focused in this study. The system includes the acoustic emission signal collection, feature selection, and classification models. The class-mean scatter criteria were used in the feature selection, and the back propagation neural network was used for the classifier design. In order to collect the data for the system development and verification, an experiment was conducted on a PMC micro machining center with the diamond film deposited micro mill. In machining, the AE signal and cutting force was collected and analyzed for the delamination of the diamond thin film from tool and tool wear, as well as the quality change on the bottom surface of machined slot. 　　The results show that the close relationship between the AE signal and the tool condition was confirmed, as well as the surface quality of machined slot. With the proper selection of features and number of training samples, higher than 94% classification rate can be obtained for the film delamination and tool wear with the developed system in machining the PZT/Si wafer with the thin film deposited micro tool. Moreover, 100% classification rate can be obtained for the quality monitoring.