Machinists are skilled tradespeople responsible for running a variety of machine tools to produce precision components for end-users or use in other manufacturing. This project identifies the current and future change in the number of machinists in the Tri-Cities area, especially the five-county service area of Northeast State Community College. Using an industry survey, the need for machinists is identified and evaluated to understand local employers’ needs. The results indicate industry needs more machinist to keep up with demand, as 6 out of 14 companies have open positions and, 8 reported difficulty filling openings. Furthermore, most companies are growing or stable overall, but have an average 15% of their machinists eligible to retire. The survey results show a need for more students to enroll in programs, such as the Machine Tool degree, or even for regional policy changes to encourage more young people to pursue machining.

Titanium alloys support a wide range of practical applications due to their excellent mechanical properties. These include high strength-to-weight ratio, high mechanical strength at elevated temperatures and remarkable oxidation resistance. Machinability investigations so far have been intentionally focused on Ti-6Al-4V, which is commonly used in the aerospace research and development. However, a new classes of titanium alloys are also being developed for these applications. Ti-5Al-5Mo-5V-3C, also known as Ti5553, is included in this new category of titanium grade alloys. It corresponds to a near beta titanium alloy and generally it is employed on the production of high strength parts. Its high tensile strength combined with low weight (compared to Ti64) makes Ti5553 a suitable choice for landing gear parts and advanced structural components. However, due to the previously mentioned mechanical properties of Ti5553, machining processes can be difficult. During the cutting tests, the cutting zone experiences high cutting temperatures, and combined with a low rate of heat transfer, it generates stress and premature tool failure. By using several distinct experimental approaches, this work presents a comparison between different machining conditions (combinations of tools and coolants) to diagnose wear processes and identify better cutting parameters. The main objective of this research is to establish an understanding of how these parameters affect tribological aspects when machining Ti5553. The results of machining studies demonstrate different wear behaviour for CBN and PCD tools under various cutting environments (different coolant modes). These operating conditions can considerably affect the cutting forces leading to an increased tool life and improved surface integrity by decreasing, the residual stress and roughness, as well as work of hardening the workpiece during machining operations. / Thesis / Master of Applied Science (MASc)

Ultraprecision, single point diamond turning (SPDT) is a tool based machining technology that allows the ability to produce high quality surface finishes on the order of nanometers while meeting tight form tolerances on the order of micrometers. It is generally agreed that surface finish in SPDT is primarily affected by four factors: Tool edge quality, relative vibration between the tool and workpiece, material properties and microstructure, and tool geometry (nose radius and machining parameters) machining. To the author’s knowledge, no work has been done to combine all the factors to study their effect on surface generation in SPDT. This is important given that the factors are highly interdependent. Two diamond tools with nose radius of 12mm were used; however, one of them was chemically honed. Results suggest that the honed tool provides a much better surface finish with a significantly reduced amount of running-in stage tool wear. The cutting edge radius of the diamond tools was measured using a novel 3D confocal laser microscope to analyze the chemical honing process and to measure tool wear. The presence of built-up edge (BUE) is more prominent on the honed tool earlier in its life which results in unpredictable surface roughness to appear sooner than on the regular tool. To understand the dynamics of the machine, a redesign of the tool holder bracket was done to increase stiffness. Modal tests were then performed on it to verify performance improvement. With an understanding of the vibration and its effect on the cutting force, a 400Hz disturbance frequency was detected in the cutting forces. From a 3D scan of the surface, a total of 24 undulations on the surface of the part were observed when the spindle speed was set to 1000RPM The machine was instrumented and a rotordynamic investigation was carried out to determine the cause and nature of the vibration in an effort to reduce it and in so doing improve surface form accuracy. / Thesis / Master of Applied Science (MASc)

A model for optimizing the assignment of maintenance actions for a piece of equipment is developed in the thesis. The model considers the detectability and the criticality of component failure in order to assign a maintenance instruction. The thesis also develops the framework for an integrated maintenance management system. The system consists of three modules. The first module is work control. It is used to prepare, schedule, and insure the execution of maintenance instructions. The second module is the equipment condition control module which monitors maintenance effectiveness and accordingly updates the maintenance instructions. The third module is cost control. This is the tool used to monitor the economical performance of the maintenance function. An equipment information system is also presented, and two futuristic maintenance proposals are introduced. The model and the integrated maintenance management system, constitute a strong tool, that equipment managers can use to optimize the maintenance function, and improve the mechanical, operational, and economical performance of equipment. / Master of Science

The increasing demands for precision and efficiency in machining call for new control strategies for machining systems based on the identification of static and dynamic characteristics under operational conditions. By considering the machining system as a closed-loop system consisting of a machine tool structure and a machining process, the join system characteristics can be analyzed. The capability of a machining system is mainly determined by its static and dynamic stiffness. The goal of this thesis is to introduce some concepts and methods regarding the identification of machining system stability. Two methods are discussed, one for the static behaviour analysis of a machine tool, and one for dynamic stability of a machining system. Preliminary results are indicating unambiguous identification of capabilities of machining systems static and dynamic characteristics. The static behaviour of a machine tool is evaluated by use of a loaded double ball bar (LDBB) device. The device reproduces the real interaction between the join system, the machine tool elastic structure and the cutting process. This load is not equivalent to real cutting forces, but it does have a similar effect on the structure. This has been investigated both trough simulation and experimental work. It is possible to capture the process – ­machine interaction in a machining system by use of the model-based identification approach. The identification approach takes into consideration this interaction and can therefore be used to characterize the machining system under operational conditions. The approach provides realistic prerequisites for in-process machining system testing. The model parameters can be further employed for control and optimization of the cutting process. Using different classification schemes, the model-based identification method is promising for the detection of instability. Furthermore, it is the author’s belief that a model-based stability analysis approach is needed to exploit the full potential of a model driven parts manufacturing approach. / QC 20101103

This thesis presents the investigations of femtosecond laser machining on three different dielectric materials, namely quartz, sapphire and diamond. The laser micromachining experiments were performed with a Titanium:Sapphire solid state laser with a repetition rate of 1 kHz, centered at a wavelength of 800 nm and pulse duration of 150-200 femtoseconds (fs). A 5x microscope objective for surface micromachining and a 50x microscope objective for subsurface micromachining. The 50x microscope objective was used to obtain a smaller spot size and a shorter confocal parameter. The purpose of this research was to study the interaction between the femtosecond laser pulses and quartz, sapphire and diamond which have bandgap energies of 8.4 eV (λ=148 nm), 9.9 eV (125 nm), and c)· diamond 5.5 eV (225 nm) respectively. Since the photon energy of the laser was below the wide bandgap energies of the aforementioned dielectrics, the materials were essentially transparent to the incident laser. In order to study the behavior of the dielectric materials under femtosecond laser irradiation, several experiments with varying type and number of pulses (N) were performed, such as single pulse ablation, plural pulse ablation (N ≤ 100 pulses), multiple pulse ablation (N ≤ 100 pulses), and continuous lines micromachining on the surface and in the sub-surface of materials were performed. The features, damage, and structural changes introduced by femtosecond laser irradiation on the materials studied were characterized through examination of both the plan and cross-section views. The characterization process was carried out using optical microscopy (operated in the Nomarski mode), scanning electron microscopy, focused ion beam, atomic force microscopy, and transmission electron microscopy. The laser micromachining demonstrated distinct behaviors of the three wide bandgap materials. Quartz was very prone to cracking and showed nearwavelength alternating crystalline and amorphous sub-structure with the orientation parallel with respect to the electric field direction. Sapphire showed sub-wavelength ripples formation in lower fluences. Finally, diamond showed a strong tendency for ripples formation from near- to sub-wavelength spacing with the orientation of the ripples perpendicular and parallel with respect to electric field polarization. / Thesis / Master of Applied Science (MASc)

The study of factors governing cutting tool performance and life is driven by manufacturers’ need to increase economic efficiency in their production facilities. Tooling and process optimization represent an ongoing opportunity for realizing substantial improvements, thus manufacturers continue to focus on promoting design and development of cutting tools and surface treatment technology relevant to machining. The central goal of cutting tool technology is to increase productivity while simultaneously reducing cost and meeting the quality targets of the machined parts. This thesis considers a nano-tribological approach to explain some of the past performance improvements in cutting tools used in dry machining applications and to look for opportunities to make further improvements in this field. The approach considers tribofilms, which are often described as tribo-oxides composed of either the base cutting tool material or freshly cut workpiece material transferred to the tool that have formed on the friction surface through interaction with the environment (air or cutting fluids) and a tribo-oxidation process. In general, the formation of tribofilms plays an important role in friction and wear behaviour by offering thermal protection and/or in-situ lubrication, which is especially important during dry machining of hard workpiece materials. The formation of various tribofilms on cutting tools have been reported through: 1) cutting tools with surface modification and further tribo-oxidation during the cutting process; 2) mass transfer from freshly cut workpiece material due to tool/chip contact in machining; and 3) interaction between the cutting tool surface and the cutting environment. This dissertation presents a novel method to control the formation of tribofilms on the cutting tool surface during machining of hard materials such as Inconel DA 718 and hardened steels (AISI T1 and AISI D2), with coated and uncoated tools. In particular, the frictional conditions experienced by the cutting tool during the initial period of cutting (the running-in stage) are shown to strongly influence whether or not beneficial processes related to adaptability will trigger. Employing a more aggressive cutting speed during the running-in stage noticeably enhances the generation of protective/lubricious tribo-ceramic films on the friction surface. When the cutting speed is subsequently reduced, the accelerated formation of beneficial tribofilms previously initiated is not fully removed and therefore the rate of tool wear is considerably less than if the tool is run at the lower cutting speed for its entire life. In addition, preliminary results are presented regarding tribofilms formation under the influence of the cutting environment, specifically the nature of the cooling medium used, which demonstrates an entirely different avenue to explore in terms of fine-tuning of tribofilms generation. The overall objective of this dissertation is to highlight different approaches to control the tribofilms formed on the cutting tool surface in order to benefit the machining process and to improve cutting tool life, material remove rate and the machined surface quality. Additionally, little work has been found demonstrating the formation of tribofilms on the tool surface through mass transfer from the workpiece material or through interaction with the cooling medium. Thus a secondary objective of this work is to demonstrate the formation of tribofilms through these different means and to investigate the effect of cutting parameters on their formation. / Thesis / Doctor of Philosophy (PhD)

The availability of sophisticated machine tools, together with advanced cutting tool designs and high performance coatings has allowed machining to meet many challenges. A significant remaining challenge is the competitive milling of hardened steels at moderate to high cutting speeds. This is of particular importance for the die and mould making industry. Despite the necessity to achieve higher production rates and improved surface finish, cutting speeds above the range of 300-600 m/min are still not possible. This limitation is due to the combination of high mechanical, thermal and chemical interactions that are taking place on the tool surface during cutting. To address this situation, an extensive amount of research has been focused on developments associated with hard coatings such as nano-multilayered hard PVD coatings that exhibit novel mechanical and thermal properties. The development of methodologies for designing a cutting tool with a strong cutting edge micro-geometry has set guidelines for selecting proper cutting edge preparation for specific cutting applications. The results indicate that, the development of new hard coating designs is the most effective way to improve the service life of coated carbide tools for hard high speed milling applications. The developments of both robust and rigid substrate designs with adaptive cutting edge micro-geometries assist the cutting tool performance by favoring the surface adaptability of the deposited coating. The developments of different strategies for dry air cooling that provide a "soft-cool" environment seem to have a beneficial impact on cutting performance and tool life improvement. Dry air cooling is found to be more effective than chilled-air cooling and minimum-quantity-lubrication (MQL). Therefore, the utilization of a cutting environment tailored to meet the requirements of both the tool and the coating while providing sufficient air flow to remove chips from the cutting zone will complement the adaptability of the whole tool-workpiece-chip system. / Thesis / Master of Applied Science (MASc)

Este trabalho trata da usinagem em verde aplicada ao projeto de corpos cerâmicos, quanto a sua morfologia e propriedades requeridas e inclui estratégia de usinagem para seleção do processo, parâmetros de corte e ferramentas. A usinagem em verde é uma técnica estruturada na filosofia do near-net-shape e vem sendo amplamente aplicada na fabricação de peças cerâmicas de formatos variados e complexos, a exemplo de implantes ósseos. Por ser aplicada em compactos de baixa resistência mecânica exige precauções e controle sobre as forças aplicadas na usinagem. O trabalho objetiva a elaboração de uma matriz de decisão para estratégia de usinagem em verde para a seleção e tomada de decisões, que baseada em um produto, possa direcionar aspectos relativos à formulação de ligantes cerâmicos, tratamentos pós-conformação, ferramentas, equipamentos e parâmetros de usinagem. Foram preparados grânulos de aluminas, baseados em ligantes PVAl, PVB e acrílicos B-1022 e B-1007, compactados na forma de cilindros, blocos e de cones. Na usinagem foram empregadas ferramentas com abrasivos de diamante, CBN e alumina eletrofundida com ligante metálico, resinoide e vitrificado. Operações representativas da usinagem foram selecionadas e aplicadas na geração de cilindros, barras e furos. Seletivamente foram realizadas medidas de torque de usinagem e forças tangenciais desenvolvidas durante o corte em verde. A resistência mecânica à flexão foi medida em verde e após sinterização, enquanto a rugosidade foi medida após a sinterização. Os resultados mostram uma forte correlação entre resistência em verde dos compactados brutos e esforços de corte e foram observadas particularidades para cada ligante cerâmico aplicado e para cada tipo de abrasivo e ligante utilizado nas ferramentas. Como melhores resultados, de peças usinadas com rebolo de alumina eletrofundida, foram encontradas resistência mecânica em verde de 7,8 MPa em peças com ligante acrílico B-1022, resistência mecânica após sinterização de 342,6 MPa em peças com ligante de PVB, potência consumida de 192,2 W em peças com ligante PVAl, rugosidade de 0,761 μm em peças com o ligante acrílico B-1007, e com ferramenta de diamante uma força de corte de 0,222 N foi obtida em peças com ligante PVAl. É concluído que há um forte compromisso entre todas as variáveis estudadas e que o formato e dimensão do produto, bem como seu acabamento e propriedades requeridas, podem ser fortemente influenciadas pelas condições do compactado e da usinagem empregada. Como solução mais notável, se tem o uso do ligante acrílico B-1007 prensado a 200 MPa, ferramenta com abrasivo de diamante de granulometria #80 mesh com ligante metálico, onde foi observado o compromisso de alta resistência em verde (para suportar os esforços), baixo empastamento de rebolo, baixa força de corte, baixa potência consumida, acabamento superficial e integridade das bordas. A matriz de decisão para estratégia de usinagem em verde desenvolvida foi aplicada na fabricação de um implante dentário conceitual free-form e foi validada pelo sucesso da obtenção desta peça. / This paper deals with the green machining applied to the project of ceramic parts, specifically with its morphology and required properties and includes machining strategy to the selection of the process, cutting parameters and tools. Green machining is a structured near-net-shape technique philosophy and has widely been applied in the ceramic parts manufacturing with varied and complex shapes such as bone implants. For being applied in low mechanical strength compacts parts it requires precautions and control over the forces used during the machining process. This work aims the development of a decision matrix for a machining green strategy to provide a selection and a decision-making that, based on a product, will direct aspects relating to the ceramic binders formulation, post-forming treatments, tools, required equipment and machining parameters. Alumina granules were prepared based on binders such as PVAl, PVB, acrylics B-1022 and B-1007, compacted in the form of cylinders, blocks and cones. In the machining itself it was applied tools with diamond, CBN and eletrofused alumina abrasives with metal, resinoid and vitrified binders. Representing machining operations were selected and applied in order to form cylinders, bars and holes. Were made selectively measures of machining torque and tangential forces, developed during the green cutting. The flexural mechanical strength was measured in green and after sintering while the surface roughness was measured after the sintering. The results demonstrate a strong correlation between only the green strength of the rough compacted parts and the cutting forces and it was observed the particularities of each ceramic binder applied and each kind of the abrasive and binder used in the tools. As best results, machining using eletrofused alumina grinding wheel obtained green strength up to 7.8 MPa in parts with B-1022 acrylic binder, mechanical strength after sintering up to 342.6 MPa in parts with PVB binder, power consumption up to 192.2 W in parts with PVAl binder, surface roughness up to 0.761 μm in parts with B-1007 acrylic binder and with diamond tool a cutting force up to 0,222 N was obtained in parts with PVAl binder. As a conclusion, it can be said that there is a strong commitment between all the studied variables and the format and size of the product, as well as its finishing and required properties can be strongly influenced by the conditions of the compacted parts and the machining used. The most remarkable solution, has been the use of B-1007 acrylic binder compacted at 200 MPa, diamond abrasive tool with grain size of #80 mesh with metal binder, where was observed a high green strength commitment (to withstand the stresses), low grinding wheel clogging, low cutting force, low power consumption, surface finishing and edges integrity. The developed decision matrix for the strategy of a green machining was applied for a free-form conceptual dental implant manufacturing and has been validated by the obtainment of this part with success.

In the last two decades, energy is becoming one of the main issues in the manufacturing industry as it contributes substantially to production cost, CO2 emissions, and other destructive environmental impact. Due to rising energy costs, environmental concerns and stringent regulations, manufacturing is increasingly driven towards sustainable manufacturing which needs to address the associated environmental, social and economic aspects simultaneously. One common approach is to achieve sustainability and to implement energy-resource efficient production management systems that enable optimisation of energy consumption and resource utilisation in the production system. However, by reducing energy consumption, the product quality and production cost may be compromised. To remain competitive in the dynamic environment, the energy-efficient management system should not only concern energy consumption but also maintain product quality and production efficiency. This thesis presents a development of the Energy-smart Production Management (e-ProMan) system which provides a systematic, virtual simulation that integrates manufacturing data relating to thermal effect and correlation analysis between energy flow, work flow and data flow for the heating, ventilation and air conditioning (HVAC) system and production process. First, the e-ProMan system comprises of the multidimensional analysis between energy flow, work flow and data flow. The results showed that the product quality is significantly affected by ambient temperature in CNC precision machining. Product quality appears to be improved at lower temperatures. This research highlights the significance of ambient temperature in sustainable precision machining. Second, the simulation experiment was modelled at the production process due to it being the main source of energy consumption in manufacturing. An up-hill workload scenario was found to be the most energy and cost-efficient production processes. In other words, energy consumption, CO2 emission and total manufacturing cost could be reduced when workload capacity and operating machine increase incrementally. Moreover, the e-ProMan system was modelled and simulated using the weather forecast and real-time ambient temperature to reduce energy consumption of the HVAC system. The e-ProMan system results in less energy consumption compared to the fuzzy control system. To conclude, the e-ProMan demonstrates energy efficiency at all relevant levels in the manufacturing: machine, process and plant. For the future research, the e-ProMan system needs to be applied and validated in actual manufacturing environments.