<p>Reproduction of hand crafted 3D shape geometry is an important industrial concept design step employed for items ranging in size and function. Adding surface art work can extend concept design to include essential product information. This thesis describes an equipment and workflow implementation for reproducing both 3D shape and art work. The hand crafted sample shape is laser digitized to obtain the XYZ geometry coordinates simultaneously with the surface gray level. The resulting point cloud is processed and converted to an STL format for plastic rapid prototyping, while the surface gray level information is treated to fit the smoothed surface, and match the reproduction ink jet printing system resolution and specification. Developed software automatically calculates the dot pattern to reproduce the art work onto the correct prototyped surface location.</p> / Master of Applied Science (MASc)

<p>p.p1 {margin: 0.0px 0.0px 0.0px 0.0px; font: 11.0px Times; color: #2d2d2d} span.s1 {color: #4c4c4c} span.s2 {font: 11.0px Helvetica}</p> <p>p.p1 {margin: 0.0px 0.0px 0.0px 0.0px; font: 11.0px Times} span.s1 {font: 11.0px Helvetica} span.s2 {font: 10.0px Verdana} span.Apple-tab-span {white-space:pre}</p> <p>The aim of this research is to enhance performance and durability of the final PM component by improving spatial density homogeneity at die filling stage of powder metallurgy process. In this research, powder die filling processes has been studied using a novel laboratory experimental set-up, with a ring-shaped die, for assessing die fill characteristics of thin, high precision components of interest to Gates Canada.</p> <p>In this investigation, usefulness of incorporating a perforated plate at the bottom of the feed shoe to improve the density uniformity in the filling condition is assessed. With this arrangement, flow and distribution of powder during the delivery stage is monitored. The powder flow pattern observed through the transparent window is utilized for obtaining full-field displacement data using an optical measurement technique. In addition to the above, several powder flow characteristics during die filling have been studied through a series of high-speed camera recordings. The role of shoe speed, and powder properties in the development of density gradient have been experimentally assessed. A series of full-scale experiments with coloured salt as a powder medium to mimic the iron powder flow have been conducted to understand flow patterns, and segregation of powder during the filling process.</p> <p>Further, a novel method of density measurement of the part in die-fill condition by heating iron powder with a polymeric resin is explored. Qualitative density data obtained from the die filling experiments, and subsequent porosity data from powder sintering in the die have been compared, to understand the reasons for density gradient in the die-cavity.</p> <p><strong></strong></p> / Master of Applied Science (MASc)

<p>Pool boiling of nanofluids has been studied in the past decade and contradicting results have been found. Several parameters have been investigated, the most popular being the nanofluid concentration. The investigations in the literature have been carried out under different conditions. The effects of method of nanofluid preparation, pH value and boiling duration on the Heat Transfer Coefficient (HTC) and nanoparticle deposition have not been thoroughly investigated.<br /> An experimental investigation has been carried out to investigate such effects and the effect of nanofluids concentration on the HTC and nanoparticle deposition. A flat copper surface with a mirror-finish (Ra = 50 - 150 nm) has bee n used as the boiling surface. Using a nanofluid prepared from a ready-made suspension showed to have a similar HTC to a nanofluid prepared from dry nanoparticles at a neutral pH value. Reducing the pH value of the nanofluids prepared from dry particles gave different responses in HTC at different concentrations. At 0.01 vol. % concentration the HTC decreased due to change in base fluid properties, at 0.1 vol. % the HTC increased due to enhanced electrostatic stabilisation, and no change took place at 0.5 vol. % due to a high intensity of nanoparticle deposition. Increasing the concentration of the nanofluids resulted in a reduction in HTC, higher nanoparticle deposition as well as a faster rate of deposition on the surface.<br /> The effect of concentration on nanoparticle deposition has been studied by boiling water on nanoparticle deposited surfaces after boiling nanofluids. This approach has shown that nanoparticle deposition from boiling a higher concentration nanofluid gives a higher HTC, which is opposite to expectations. This approach has also shown that the surface condition depends on the intensity of the deposition as well as its uniformity.<br /> An analysis has been carried out using the Rohsenow correlation to quantify the effect of nanoparticle deposition on the heat transfer. Prediction of the boiling heat transfer of nanofluids may be used by adopting a transient surface factor in the Rohsenow correlation.</p> / Master of Applied Science (MASc)

<p>p.p1 {margin: 0.0px 0.0px 0.0px 0.0px; font: 11.5px Times; color: #292929} span.s1 {color: #3e3e3e} span.s2 {color: #575757}</p> <p>The significance of online process monitoring of discrete part manufacturing usmg multivariate analysis is its ability to help the Canadian manufacturing industry compete in the global market. Process monitoring can accomplish this by: assessing the state of a machining system for unusual occurrences, moving the part quality prediction upstream, and producing higher volumes of in specification parts for improved profits.</p> <p>The focus of this research was discrete process monitoring of a turning operation in a laboratory at the McMaster Manufacturing Research Institute (MMRI) and an industrial machining cell at Glueckler Metal Incorporated (GMI). Both applications involved instrumentation of a lathe with current sensors, an accelerometer and thermocouples. Serial port communication between the machine control panel and computer was established to allow for online automated data acquisition. The multivariate latent model applied was principal component analysis to develop correlations among the machining process information. Principal component analysis was successful in identifying the occurrence of an out of balance spindle, unusual surface finish, changes in depth of cut, and a worn tool in laboratory tests, through the use of simple control plots. Industrial results validated the ability of the system to differentiate machining data from one day to another, and to isolate an unusual piece of barstock that led to slightly below average part dimensions.</p> <p>The difficulties experienced in the transitioning from laboratory conditions to industrial testing were discussed. This information will allow future researchers to continue adding new process monitoring sensors to the system.</p> <p>In conclusion, this research demonstrated the ability of online process monitoring of discrete part manufacturing in a laboratory setting; and brings the MMRI and GMI closer to having a fully implemented process monitoring system for part quality prediction and machine maintenance.</p> / Master of Applied Science (MASc)

<p>p.p1 {margin: 0.0px 0.0px 0.0px 0.0px; font: 12.0px Times} span.s1 {font: 11.5px Helvetica}</p> <p>Using an integrated Tuned Liquid Damper (TLD)-Structure in-house developed numerical algorithm that has been validated against recent rigorous experimental tests, the TLD performance was analyzed when coupled with a vibrating Single Degree of Freedom (SDOF) body representing a civil structure. The numerical algorithm solves the full two dimensional Navier-Stokes equations with no linearization assumptions. It uses the Volume of Fluid method to reconstruct the free surface, and the Partial Cell Treatment method to model the effect of any obstructions. This study investigated the structure response when coupled to a TLD with and without a screen under harmonic excitations. Structure sway was found to decrease by 71 % in the case of a TLD without a screen, and 80% in the case of a TLD with one screen. The best screen configuration was then determined for the TLD-Structure coupling under non-hmmonic excitations, taking minimal structure sway and acceleration as the deciding criteria. Eighteen different cases considering different screen locations and solidities were investigated, and the case with one screen placed in the middle with a solidity of 0.4 proved to be the best.</p> <p>The study also investigated the effect of fluid height on structure sway under a p.p1 {margin: 0.0px 0.0px 0.0px 0.0px; font: 12.0px Times}</p> <p>wide range of excitation amplitudes. Harmonic Excitations with amplitudes up to 3% of the tank length and fluid heights up to 40% of tank length were considered. The results showed better structure response with lower fluid heights in the case of low to moderate excitation amplitudes. With high excitation amplitudes, the results confirmed an opposite trend where higher fluid heights resulted in better structure response.</p> <p>The numerical code was then modified to model a Sloped Bottom (SB) TLD using the Partial Cell Treatment method. The numerical model for the SB TLD has been validated against experimental data to ensure accuracy. Numerous cases have been considered to investigate structure response under the new configuration, and to analyze how a SB TLD compares to a standard TLD. The results showed an increased damping ratio and better structure response for SB TLDs, and a significant softening spring behaviour that is important upon excitation cessation.</p> / Master of Applied Science (MASc)

<p>There is currently a lack of quality sensing techniques that can provide the required spatial and temporal resolution for use in microfluidic devices. The development of such micro sensors will allow real time monitoring and control of many processes at the micro level, and play a crucial role in expanding microfluidics to novel applications. For example, integration of sensors within the microfluidic device itself will allow active control of processes within these devices. The overall objective of this study was to develop a micro temperature and micro flow sensor for use in microfluidic devices. The specific objectives were to develop, design and micro fabricate a micro thermocouple and micro heater, and integrate these within a microchannel to show proof of concept of a micro thermal pulse flow sensor. A platinum-constantan (PT-NiCu) micro thermocouple was developed and fabricated using a three mask process. The micro fabrication protocols and procedures were developed for potentiostatically electroplating the constantan leg of the micro thermocouple. The thermocouples were characterized and the Seebeck coefficient (sensitivity) was found to be 39.04 μV/゜C and 41.75 μV/゜C for non compensated and a compensated thermocouple arrangement respectively.</p> <p>A meandering resistive type micro heater was developed. The power consumption for the 400 Å thick gold micro heaters on the silicon oxide and on the glass substrates was compared. The power required for the glass substrate was 46mW, 112mW and l60mW for 5V, 8V, 10V respectively, while for the silicon oxide was 499.5 mW, 1.27 W and 1.943 W respectively.</p> <p>The thermal flow sensor was developed by integrating the micro heater and micro thermocouple within a microchannel to show proof of concept of the sensor. The flow sensor was operated in three modes; time of flight, temperat1ll'e difference and pulsed thermotransfer calibration mode. Essentially the thetmotransfer principle occurs as the heat loss from the micro heater source to the fluid will increase with the flow rate, thereby giving greater voltage amplitude of the thetmocouple response with increasing flow velocities.</p> <p>The flow sensor performance was characterized using methanol/water as the working fluid for mass flow rate in the range of no flow to 0.7 ml/min. The device has several unique operating and physical characteristics, including the novel pulsing scheme developed that compensates against temperature drift, resulting in high repeatability.</p> <p>The flow sensor was calibrated using the thermotransfer principle for three pulse modes; single, multiple pulses with change in input voltage and multiple pulses with change in pulse duration. The comparative results showed that the multiple pulse modes generated a more detectable signal than the single pulse mode. The multiple pulse regimes allowed for a larger dynamic flow range. The flow sensor can be duplicated relatively easily so that multiple sensors can be distributed within a microfluidic device to allow simultaneous flow measurements at different locations within the device.</p> / Master of Applied Science (MASc)

<p>A turbulent impinging slot jet is a device which is used in various industrial applications such as glass tempering, heating of complex surfaces, cooling of turbine blades, cooling of electronic devices and in the continuous hot-dip galvanizing line, which is the focus of this study. An impinging slot jet is used to control the zinc film thickness on the sheet substrate to reach uniform product coating thickness by applying a pressure gradient and shear stress distribution on the moving substrate, after immersion in a bath of molten zinc. The impinging jet wipes the excess molten zinc from the steel strip through the combined effects of a pressure gradient and shear stress distribution on the steel strip.</p> <p>In this study, the fluid flow of three multiple-impinging slot jet configurations discharging air at high velocity on a moving substrate were investigated numerically. Computational fluid dynamics was used to determine the wall pressure results and wall shear stress distributions due to the multiple impinging slot jets, and these results were used as boundary conditions in an analytical model to estimate the final liquid zinc thickness on the substrate. The standard k - ε turbulence model with non-equilibrium wall treatments was used to capture the turbulence parameters in the flow field.</p> <p>The knowledge of using multiple-impinging slot jets in the hot-dip galvanizing line process as a wiping actuator is quite limited. There is not any systematic work available in using these devices as a wiping actuator. In this study, three models of multiple slot jets were developed numerically with the goal of estimating the coating weight on the moving sheet substrate. The conventional model of a single-impinging slot jet was used as a base case for comparing the wall pressure results, wall shear stress distributions and consequently the coating weight data on a moving substrate with different multiple-impinging slot jet configurations. Adjusting the various process parameters such as main slot jet Reynolds number (Re_m), auxiliary slot jet Reynolds number (Re_a), plate-to-nozzle ratio (z / d) and sheet substrate velocity (V_substrate) allows the producers to control the coating weight on a moving sheet substrate.</p> <p>For this study, the numerical simulations were solved using FLUENT commercial code. A comprehensive set of numerical modeling over a wide range of process variables was performed for all configurations in order to present a broad summary of the coating weight trends in the wiping process. A full analysis of the wall pressure distributions and wall shear stress results, as well as coating weight estimation generated under different impinging slot jets have been presented in this study.</p> / Master of Applied Science (MASc)

<p>The stability behaviour of a thin clamped-ended pipe with an internal flow is determined. Classical potential flow theory is used to determine the unsteady fluid forces and the motion of the pipe is represented by the Flugge-Kempner equation. The solution is obtained using Fourier integral theory and the method of Galerkin.</p> <p>Theoretical results are compared with experiments as well as previous work.</p> / Master of Engineering (ME)

<p>During metal removal operations, friction occurs at the interface between the rake face of the cutting tool and the chip. Tool rake face friction adversely influences the chip formation process and consumes about 25% of the total cutting energy. Friction in cutting can be controlled and reduced by introducing a lubricant into the tool-chip interface, however the effectiveness of this is a function of the cutting speed and uncut chip thickness, among other factors. Lubricant penetration was determined in the 1970's to be a result of capillary action through channels resulting in part from the roughness of the tool rake face and the mating chip face. Recent investigations have looked at increasing the penetration and effectiveness of lubrication by engineering the tool surface to promote and retain lubricants by introducing a texture on the tool rake face.</p> <p>This thesis details methods used for surface engineering the rake face of cutting tools focusing on the novel application of electrical discharge machining (EDM) to obtain the desired texture, with a view to facilitating lubricant penetration and retention. A significant enhancement in machining performance consequent to such tool face texturing is demonstrated. The functionality of such surfaces is discussed as well as the texturing process, application areas and limitations.</p> / Master of Applied Science (MASc)

<p>Statistical Process Control (SPC) provides tools to monitor process quality and productivity. When coupled with closed loop control theory, SPC algorithms can be utilized to compensate for various error sources in stable, high volume, discrete part manufacturing processes. These error sources include environmental effects, tool wear, measurement, and material errors.</p> <p>Closed loop machining cells must be analyzed from both Quality and Manufacturing Engineering perspectives for efficient and successful implementation. Discrete, stochastic, time event manufacturing simulation is used to analyze process organization, data flow and control system performance. SPC and Engineering Process Control (EPC) control algorithms are compared using data gathered from a high volume machining process involving steel turned components with a critical machined surface.</p> / Master of Applied Science (MASc)