Hög produktkvalitet och låg tillverkningskostnad är avgörande för den ekonomiska framgången för en produkt, och för att uppnå en sådan framgång används metoden tillverkningsanpassad konstruktion (DFM). DFM är en väldigt integrativ metod och kräver ett tvärfunktionellt arbete mellan experter så som produktionstekniker, produktionsberedare och tillverkningspersonal (Ulrich & Eppinger, 2014). Volvo CE har ett kontinuerligt arbete med DFM och det utförs idag genom många iterationer och direkt kontakt mellan tillverknings- och utvecklingsavdelningen. Trots det kontinuerliga arbetet med DFM eftersöker nu avdelningen Driveline Systems Product Improvement en metod för detta arbete, eftersom att ingen metod används idag. Metoder för DFM finns beskrivna på flera olika sätt och av flera olika författare, och i detta arbete undersöks metoder av Ulrich & Eppinger (2014), Dalton et al. (2016) and O’Driscoll (2002). En standardiserad metod och ett överskådligt arbete med DFM kan skapa bättre förutsättningar för kunskapsåterföring för att se och lära från tidigare arbeten kopplat till tillverkning av produkterna. Samtidigt som en DFM-metod efterfrågas undersöks Volvos nuvarande produktutvecklingsprocess, DMAIC, på den aktuella avdelningen, som idag är anpassad till utveckling och förbättringar av befintliga artiklar. För det aktuella ärendet är orsaken att öka beläggningen och genomförandet föregås således inte av någon förbättring eller utveckling av artiklarna. Därför ska det aktuella insourcing-ärendet jämföras mot Volvos egna process. För att knyta an det aktuella ärendet till vedertagna produktutvecklingsprocesser används en teoretisk produktutvecklingsprocess, och ärendet jämförs även mot denna process. I arbetet utförs fältarbete, inklusive fallstudier och intervjuer, samt en kompletterande litteraturstudie runt metoden DFM och insourcing. I fältarbetet undersöks två externt tillverkade artiklar som två fall som väljs ut genom ett projektval, vari totalt sex artiklar ingår från början. För att genomföra projektvalet och vidare utveckling av artiklarna tillämpades i huvudsak Ullmans (2010) produktutvecklingsprocess med tillhörande metoder (relevanta för detta arbete), med något inslag av Ulrich & Eppingers (2014) process. Utifrån den eftersökta metoden för arbete med DFM, och aktuella fallstudier och processer ska följande frågor besvaras:   Hur korrelerar en insourcing-process med teoretiska produktutvecklingsprocesser och Volvos produktutvecklingsprocess? I vilka steg i insourcing-processen är det relevant att inkludera DFM?   Aspekter kopplat till tillverkningsanpassad konstruktion, och således DFM, är aspekter som påverkar tillverkningskostnaden. Vid insourcing är förädlingskostnaden och skiftgraden de mest relevanta och kanske viktigaste aspekterna, som bör adresseras redan i projektvalet. Både förädlingskostnaden och skiftgraden är aspekter som påverkar tillverkningskostnaden. Vid insourcing är det dessutom viktigt att beakta orsaker till outsourcing, som inte framgår i varken processen DMAIC eller Ullmans (2010) process. Kopplat till processerna jämfört med insourcing-ärendet så förekommer vissa skillnader mellan både Ullmans (2010) produktutvecklingsprocessen och Volvos process DMAIC, även om en del likheter också finns. / High product quality together with low manufacturing cost are vital aspects of the economic success of a product. To achieve such success the method Design for Manufacturing (DFM) is used. DFM is a highly integrative method and demands a cross-functional team consisting of experts such as production engineers, pre-process engineers and manufacturing personnel (Ulrich & Eppinger, 2014). Volvo CE has a continuous work with DFM and it is done through many iterations and direct contact between the manufacturing- and design department. Although the overall work with DFM is continuous the department Driveline Systems Product Improvement is requesting a method for this work, due to the lack of any methods used today. It is discovered that there are many different methods for DFM described by many authors, and in this thesis methods by Ulrich & Eppinger (2014), Dalton et al. (2016) and O’Driscoll (2002) are investigated. A standardized way may increase the quality of the DFM work and may help create a more holistic view. A holistic view over the work with DFM can help create better conditions for re-use of previous knowledge related to manufacturing of the parts. In addition of the requested method for DFM the current product development process used, DMAIC, is investigated. The process is today mainly used and adapted for the development and improvement of existing products. The reason of the current case studies is to increase the utilization level at the current manufacturing department, and thus no improvement or development is initially present. Therefore, the current insourcing case studies are compared to the Volvo process DMAIC. To connect the current case to established product development processes the case studies are also compared to a theoretical product development process.   Methods used within this thesis are field work, with interviews and case studies, and a complementary literature study to investigate methods and to increase the understanding of DFM and insourcing. In the field work two parts for insourcing are investigated as two case studies. The parts are initially selected through a project selection, where a total of six parts are included. To perform the selection and further development of the current case studies Ullmans (2010) design process were applied, with use of relevant methods and tools for this work. Also, some elements of the product development process according to Ulrich & Eppinger (2014) were applied. Based on the requested method for DFM and the current case studies the following research questions were raised:   How does an insourcing process correlate with theoretical design processes and with Volvo’s product development process? Where in the insourcing process is it relevant to include DFM?   Aspects of DFM are aspects that affect the manufacturing cost. When insourcing processing of parts and labour shift rate are the most relevant and important aspects and should be addressed when selecting and evaluating project. Both processing of parts and labour shift rate are aspects that affect the manufacturing cost. When insourcing it is also important to include aspects connected to outsourcing, and this fact cannot be identified in the DMAIC process nor the design process of Ullman (2010). Compared to the current insourcing case studies there are some differences between both the design process of Ullman (2010) and the Volvo process DMAIC, even if there also are some similarities.

This master thesis deals with the manufacturing process of oil distribution transformers. Firstly, the thesis devotes to the design arrangement of the magnetic circuit and its manufacturing technology. The procedure of cutting laminations for core and their building into the core. Subsequently, the thesis describes technologies used for manufacturing primary and secondary windings including procedures on winding machines. Then it deals with the production of the tank and the final assembly of the transformer into one unit. The next part of the thesis discusses the design procedure of the assigned distribution oil transformer with a numerical calculation while respecting the requirements of the standards. Finally, the costs of the material of the designed transformer are determined.

The modern manufacturing world has been driven to compete in a more international and interconnected system. This has led to increased focus upon frameworks and architectures to guarantee quality, high market acceptance, and reduce cost. Modern manufacturing design processes evolved largely from Henry Ford at Ford Motor Company, and Alfred Sloan at General Motors. Their structures embody two different focuses on quality and value engineering which have influenced many recent design frameworks. In the 1970s a heavy emphasis was placed upon Design for Manufacturing, which uses group technology, commonality of processes, and continual focus to reduce part count. Some companies have desired a design process that better accounts for new market needs and Voice of the Customer changes, allowing them to break out of the old processes by using a new framework called Design for Six Sigma. Contextual and survey analysis contrasting DFSS and DFM showed these systems have different definitions of what creates value; which causes a different focus on how to improve value. As the market frequently errs at knowing when to apply DFM or DFSS, using a simple case study of a product with high part and assembly cost, teams were challenged to create a better flashlight using both DFM for part reduction, and DFSS for function improvement. The aim was to increase value. Value has been defined by the formula: value = (performance + capability) / cost or as value = function/cost. Results from the case study combining DFM and DFSS constructs demonstrate a total value engineering construct. It was also shown that DFM indicated effectiveness for a slow-changing market with cost reduction focus, and DFSS demonstrated effectiveness for analyzing continually changing market needs. Disruptive innovations can replace a formerly lull market, for which DFM can be completely unprepared; while DFSS is not effective in slow product-change markets. Incorporating the best of DFSS and DFM creates a Total Value Engineering framework.

No description available.

Thesis (PhD)--Stellenbosch University, 2011. / ENGLISH ABSTRACT: The knee is the largest, most complicated and incongruent joint in the human body. It sustains very high forces and is susceptible to injury and disease. Osteoarthritis is a common disease prevalent among the elderly and causes softening or degradation of the cartilage and subcondral bone in the joint, which leads to a loss of function and pain. This problem can be alleviated through a surgical intervention commonly termed a “knee replacement”. The aim of a knee replacement procedure is to relieve pain and restore normal function. Ideally, the knee replacement prosthesis should have an articulating geometry similar to that of the patient’s healthy knee, and must allow for normal motion. Unfortunately, this is often problematic since knee prostheses are supplied in standard sizes from a variety of manufacturers and each one has a slightly different design. Furthermore, commercial prostheses are not always able to restore the complex geometry of an individual patient’s original articulating surfaces. This dissertation shows that there is a significant variation between knee geometries, regardless of gender and race. This research aims to resolve the problem in two parts: Firstly by presenting a method for preoperatively selecting the optimal knee prosthesis type and size for a specific patient, and secondly by presenting a design procedure for designing and manufacturing patient-specific unicompartmental knee replacements. The design procedure uses mathematical modelling and an artificial neural network to estimate the original and healthy articulating surfaces of a patient’s knee. The models are combined with medical images from the patient to create a knee prosthesis that is patient-specific. These patient-specific implants are then compared to conventional implants with respect to contact stresses and kinematics. The dissertation concludes that patient-specific implants can have characteristics that are comparable to or better than conventional prostheses. The unique design methodology presented in this dissertation introduces a significant advancement in knee replacement technology, with the potential to dramatically improve clinical outcomes of knee replacement surgery. / AFRIKAANSE OPSOMMING: Die knie is die grootste, mees komplekse en mees ongelyksoortige gewrig in die liggaam. Osteoarthritis is ’n siekte wat algemeen by bejaardes voorkom en die versagting of agteruitgang van die kraakbeen en subchondrale bene in die gewrig tot gevolg het, wat tot ’n verlies van funksionering en pyn lei. Hierdie probleem kan verlig word deur ’n chirurgiese ingryping wat algemeen as ’n “knievervanging” bekend staan. Die doel van ’n knievervangingsprosedure is om pyn te verlig en normale funksionering te herstel. Ideaal gesproke behoort die knievervangingsprostese ’n gewrigsgeometrie te hê wat soortgelyk aan die pasiënt se gesonde knie is, en normale beweging moontlik maak. Ongelukkig is dit dikwels problematies aangesien knieprosteses in standaardgroottes en deur ’n verskeidenheid vervaardigers verskaf word, wat elkeen se ontwerp effens anders maak. Verder kan kommersiële prosteses nie altyd die komplekse geometrie van ’n individuele pasiënt se oorspronklike gewrigsoppervlakke vervang nie. Hierdie proefskrif wys dat daar ’n betekenisvolle variasie tussen knieafmetings is, afgesien van geslag en ras. Hierdie navorsing is daarop gemik om die problem op tweërlei wyse te benader: Eerstens deur ’n metode aan te bied om die optimal knieprostesetipe en -grootte vir ’n spesifieke pasiënt voor die operasie uit te soek, en tweedens om ’n ontwerpprosedure aan te bied vir die ontwerp en vervaardiging van pasiëntspesifieke unikompartementele knievervangings. Die ontwerpprosedure gebruik wiskundige modellering en ’n kunsmatige neurale netwerk om die oorspronklike en gesonde gewrigsoppervlakke van ’n pasiënt se knie te bepaal. Die modelle word met mediese beelde van die pasiënt gekombineer om ’n knieprostese te skep wat pasiëntspesifiek is. Hierdie pasiëntspesifieke inplantings word dan met konvensionele inplantings vergelyk wat kontakstres en kinematika betref. Daar word tot die slotsom gekom dat die pasiëntspesifieke inplantings oor eienskappe kan beskik wat vergelykbaar is met of selfs beter is as dié van konvensionele prosteses. Die unieke ontwerpmetodologie wat in hierdie proefskrif aangebied word, stel beduidende vordering in knievervangingstegnologie bekend, met die potensiaal om die kliniese uitkomste van knievervangingsoperasies dramaties te verbeter.

A constante evolução de métodos, tecnologias e ferramentas associadas na área de projeto fornece maior capacidade para o projetista. Entretanto, ela também aumenta os requisitos de interfaces e controle do conjunto de componentes de projeto consideravelmente. Tipicamente, este aspecto está presente na área de Projeto Orientado para a Manufatura (DFM) onde existem diversos distintos componentes. Cada um dos componentes existentes, ou futuros, pode ter foco diferente, consequentemente com requisitos de informação, utilização e execução distintos. Este trabalho propõe a utilização de padrões conceituais flexíveis de informação e controle de forma abrangente em uma arquitetura de Projeto Orientado para a Manufatura (DFM). O objetivo principal é auxiliar a análise e resolução de DFM, bem como dar suporte à atividade de projeto estruturando e propondo uma solução em relevantes aspectos em DFM: estruturação do contexto das informações (ou conhecimento) em DFM. A arquitetura utiliza as seguintes atividades de projeto em processos de usinagem: Tolerância, Custo, Acessibilidade da ferramenta, Disponibilidade de máquinas e ferramentas e Análise de materiais para demonstrar a relevância da correta contextualização e utilização da informação no domínio DFM . Sob forma geral, concomitantemente, as amplas necessidades de compreensão dos distintos tipos e formas da informação em DFM demandam que uma arquitetura de projeto tenha capacidade de gerenciar/administrar diferentes contextos de informações de projeto. Este é um tópico relevante tendo em vista que existem diferentes atividades DFM que eventualmente devem ser incluídas no ato de projetar. Tipicamente, cada uma delas tem requisitos distintos em termos de dados e conhecimento, ou contextualização do projeto, que idealmente poderiam ser gerenciados através da arquitetura de informação atual – STEP.Aarquitetura proposta gerencia contextos de informações de projeto através de ontologias direcionadas no domínio DFM. Através dela, será possível compreender e utilizar melhor as intrínsecas interfaces existentes nas informações deste domínio, além de, através disto, aumentar a flexibilidade e eficácia de sistemas DFM. / This work proposes the use of industry standards to support the utilization of Design for Manufacturing (DFM) techniques in a comprehensive scale in the design field. The specific aspect being considered in an architecture is the definition and structure of DFM information context. In order to demonstrate the research concepts, some design activities are implemented the framework (which is focused in machining processes): Tolerancing model, Cost model based on material remove processes, Tool Accessibility model taking into consideration the part being designed, Availability of Machines and Tools model, and Material analysis. The broad needs of design–based frameworks, in general, require that its architecture must have the capabilities to handle di erent framework design information utilization contexts, or information context concepts. This is a relevant aspect since there are severalDFMcomponents/activities that preferably should be included in the design process. Traditionally, each one of them might have distinct data & knowledge requirements, which can be handled by the current information architecture – STEP – only in part. Additionally, each one of them might have, or need, di erent forms of understanding DFM information (information context). The framework handles information context concepts through the use of the ontologies targeted to the DFMfield. It is expected that a better comprehension and usage of the intrinsic information interfaces existent in its domain be achieved. Through it, more flexible and e ective DFM systems information-wise can be obtained.

Product tolerancing decisions made in product design have a significant effect on manufacturing environmental and cost performances by strongly influencing both the selection and operation of processing machinery. These decisions however are typically made without quantitative knowledge of their effects in manufacturing. With estimates of environmental and cost performances of manufacturing processes required to achieve specific part designs earlier in the product design cycle, designers may make more informed, and potentially better, design decisions with respect to manufacturing environmental and cost performance goals. In this thesis a method for quantifiably relating product tolerancing decisions to environmental and cost performances in manufacturing in order to provide decision support for cost and environmentally conscious design for manufacturing is developed. The method is instantiated as an Excel-based tool and exercised by two illustrative examples of increasing complexity, as well as a study of the manufacture of automotive transmission pinion gears with differing tolerance requirements. Uncertainty analysis is performed through the use of @RISK software; the uncertainty of parameters associated with manufacturing operations and machinery is captured through the use of probability density functions and Monte Carlo simulation is performed. Simulation results provide insight into the uncertainty of performance estimates and the risks associated with ensuing decision making. This method may be useful to product designers, as well as process planners, to support decision making efforts related to cost and environmental consciousness in the manufacturing phase of the product life cycle.

Standard cells are fundamental circuit building blocks designed at very early design stages. Nanometer standard cells are prone to lithography proximity and process variations. How to design robust cells under variations plays a crucial role in the overall circuit performance and yield. This dissertation studies five related research topics in design and manufacturing co-optimization in nanometer standard cells. First, a comprehensive sensitivity metric, which seamlessly incorporates effects from device criticality, lithographic proximity, and process variations, is proposed. The dissertation develops first-order models to compute these sensitivities, and perform robust poly and active layout optimization by minimizing the total delay sensitivity to reduce the delay under the nominal process condition and by minimizing the performance gap between the fastest and the slowest delay corners. Second, a new equivalent source/drain (S/D) contact resistance model, which accurately calculates contact resistances from contact area, contact position, and contact shape, is proposed. Based on the impact of contact resistance on the saturation current, robust S/D contact layout optimization by minimizing the lithography variation as well as by maximizing the saturation current without any leakage penalty is performed. Third, this dissertation describes the first layout decomposition methods of spacer-type self-aligned double pattering (SADP) lithography for complex 2D layouts. The favored type of SADP for complex logic interconnects is a two-mask approach using a core mask and a trim mask. This dissertation describes methods for automatically choosing and optimizing the manufacturability of base core mask patterns, generating assist core patterns, and optimizing trim mask patterns to accomplish high quality layout decomposition in SADP process. Fourth, a new cell characterization methodology, which considers a random (line-edge roughness) LER variation to estimate the device performance of a sub-45nm design, is presented. The thesis systematically analyzes the random LER by taking the impact on circuit performance due to LER variation into consideration and suggests the maximum tolerance of LER to minimize the performance degradation. Finally, this dissertation proposes a design aware LER model which claims that LER is highly related to the lithographic aerial image fidelity and the neighboring geometric proximity. With a new LER model, robust LER aware poly layout optimization to minimize the leakage power is performed. / text

Metal foams have many attractive properties such as light weight, low relative density, energy absorption capability etc. One of the main advantages of metal foam is that the foam inherits several properties of the parent metal, at the same time, at a fraction of the weight. Metal foams are basically of two types; closed pore and open pore. In the open pore configuration the highly porous structure with large surface to volume ratio is attractive in thermal applications such as heat exchangers, small scale refrigeration, diesel exhaust cooling and heat sink for electronics. Large surface area to volume ratio of the heat transfer area is an important parameter in design of heat exchangers. Application of open cell metal foam as a heat exchanger involves production of the metal foam, cutting/drilling the metal foam to required dimensions and attaching it to a substrate or duct. Foams are cut by various methods such as by using circular saw, band saw, abrasive sawing wire or electrical discharge machining. Cutting or drilling operations plastically deform the struts and affect the surface roughness of the struts and hence, the contact area between the foam and the substrate. The foam and the substrate are then joined to get the final product. Various techniques are adopted to join the foam and substrate that includes, press fit, welding, soldering, brazing and use of epoxy adhesives or thermal glue. These methods either deform the foam plastically or involve a bonding material which involves an additional step in manufacturing and is generally necessary to reduce the thermal resistance at the interface. Every secondary step involved in machining the foam and joining it to substrate/duct add to the energy, time and cost of the component. Significant amount of materials wastage occurs during the production and machining steps of the metal foam. Bonding material used for attaching foam to the substrate makes the recycling of the heat exchangers difficult. In the present research work the above issues were rectified by introducing a novel method of fabricating the heat exchanger in a single step. This can be done by producing open cell foam, bonded to the substrate in a single step to get the ready to use heat exchanger. The uniqueness of the method/ process is that it provides an advantage of manufacturing heat exchangers consisting of open cell aluminium foam both inside and outside the aluminium duct/substrate. Here open cell metal foam is metallurgic ally bonded to the aluminium duct without producing any distortion in the aluminium duct. The present method avoids the secondary cutting and joining operations, hence reducing material and energy wastage. This heat exchanger does not need a bonding material at the foam duct interface which makes the product completely recyclable without even having to separate the aluminium foam and, many-at-times, the copper substrate. Further, in the present process no hazardous material is involved in the fabrication process of the heat exchanger and all the materials used for the foam production can be recycled. Another unique advantage of this process is that the foam can also be cast inside and outside the tube in a single step. This helps increase the heat transfer area per unit volume inside the tube increasing the effectiveness significantly. First, an attempt was made to cast aluminium foam over a Cu substrate. Spheres made of Plaster of Paris (PoP) were used as space holders to create pores in the foam. First, a dough of PoP was prepared by mixing sufficient amount of water with the powder of PoP. Small pieces of PoP were taken from the dough and were rolled by hands to prepare spherical balls. Next, a casting setup was made where a die made of stainless steel was placed in a crucible whose bottom was filled with sand. A tube/duct made of copper was placed at the centre of the die and PoP balls were dropped around the duct. This setup was then placed in a furnace and was preheated to remove all the moisture from the PoP. Molten aluminium at around 700 °C was poured into the preheated die. After solidification, the die was opened and cast was allowed to cool in ambient air. PoP balls were removed by using a sharp needle and by dipping the casting in acetic acid. After removal of PoP from the cast, interconnected holes/cavities formed in the place of space holders/PoP balls, forming pores in the foam. There are some limitations of this method such as removal of PoP was tedious and needed chemicals that need to be discarded, PoP cannot be recycled and creates waste, small amount of moisture present in PoP balls can cause an explosion. The bonding between aluminium foam and Cu substrate obtained was not good, giving rise to thermal contact resistance. Due to the above limitations further implementation of this process using PoP was not explored further. There was a need of space holder material which can withstand the temperature of molten Al and also can be removed easily from the cast without any use of chemicals. Obtaining metallic bonding between foam and Cu substrate was difficult due to the corrosion layer formation at the interface of Al and Cu substrate due to preheating. If preheating was not carried out full penetration of the molten aluminium did not take place in the space available in between the spheres. Therefore, it was decided to cast Al foam over Al substrate. The main challenge and difficulty was to cast open cell Al foam inside and outside the tube/duct made of the same material (Al) without distorting the tube/duct as well as achieving consistent metallic bonding between the two. This has been successfully done by gravity casting method a single step manufactured and ready to use open cell Al foam heat exchanger were fabricated. A casting setup was prepared, which consisted of a commercially pure aluminium tube placed in the middle of a stainless steel split die. The gap between the tube and die was filled with the salt spheres. An uncommon and new approach was adopted to produce NaCl salt spheres. NaCl salt balls (spherical and ovoid) of different diameters were processed by casting route. The casting step of NaCl is necessary as the moisture present in NaCl can be completely removed during the melting of NaCl. NaCl was chosen as it had a melting point higher than aluminium. The casting setup was placed in a furnace and was preheated to various temperatures up to 550 °C. Commercially pure aluminium was melted separately in a crucible and was poured into the steel die at 700oC. The liquid metal flows through the die and fills the cavities between the salt balls. The die was opened immediately after solidification of molten Al and cast was allowed to cool in ambient air. The salt (NaCl), which was still solid, was dissolved in water to get the foam structure. With proper control of the preheat temperature and temperature of liquid aluminium no distortion of the aluminium duct was observed throughout the length of the heat exchanger. Consistent and complete fusion/ metallic bonding was observed at the interface of Al foam and Al substrate/duct. Several heat exchangers with different porosity and pore geometry with the aluminium foam cast outside the tube and both inside and outside of the tube were fabricated. The beauty of the designed method is that it is simple and cost effective and eliminates the major issue of thermal contact resistance since the foam and the duct are made of the same material and are bonded in the liquid state leaving no interface between the foam and the duct. Further, foam can also be cast inside the duct in the same step while casting the foam outside the tube, giving an integral heat exchanger which has higher heat transfer surface area to volume ratio inside and outside the duct. This is expected to further improve the efficiency and effectiveness of the heat exchanger An added advantage of this method is that the heat exchanger can be recycled easily in a single step re-melting route. Further, the heat exchanger does not use any hazardous material during manufacture that needs attention during recycling. After the production and fabrication of the heat exchangers, the thermal performance or effectiveness of the heat exchangers was assessed, to evaluate its usefulness and suitability for heat transfer application. An experimental test setup was fabricated in the laboratory to perform the heat transfer tests. The experimental test setup consists of the following major components;1) A test chamber whose function was to insulate the heat exchangers from the surroundings and to avoid any heat loss to the surroundings, 2) An air blower used to supply cold fluid (air) to the test chamber, 3) A constant temperature bath was used to supply the hot fluid, which was water in this case, in the duct of the heat exchanger, 4) A rotameter was used to measure the volumetric flow rate of the cold fluid and 5) A pressure gauge having the pressure measurement range between 1 mbar to 160 mbar to measure the pressure drop across the test chamber. K-type chromel – alumel thermocouples having temperature measurement range between -270 °C to 1,260 °C were used to measure the temperature of hot and cold fluids during the experiments. By aid of the data logger system and computer, temperature readings were recorded during the tests and were used further for the heat transfer calculations. For testing the aluminium foam heat exchangers was placed in the insulated test chamber. Hot water was supplied inside the duct of heat exchanger whereas air at room temperature was supplied around the foams at varying flow rates during the tests. During the tests, temperature readings were taken at steady state condition. NTU-Effectiveness method was used to evaluate the thermal performance of heat exchangers. Overall results obtained by this experimental study are as follows • As the inlet temperature difference between hot and the cold fluids increases the heat transfer rate and the effectiveness of the heat exchangers also increases. • At a constant flow rate of hot fluid, heat exchangers exhibits significantly better thermal performance at lower flow rate of cold fluid compared to higher flow rate. As the flow rate of cold fluid increases, the velocity of the fluid increases and consequently, reduces the optimum interaction time between hot and the cold fluids required for the efficient heat transfer. • At a constant and low flow rate of cold fluid the effectiveness of the heat exchanger increases as the porosity of the foam increases. But when the flow rate of cold fluid was increased further after a certain limit, the effectiveness value of the heat exchanger decreases. • Heat exchanger consisting of foam of higher porosity exhibits higher effective. • Heat exchanger having foam inside and outside of the duct/tube exhibits significantly higher effectiveness compared to Al duct, Cu duct and other heat exchanger tested. • At a higher flow rate of the cold fluid, the heat exchangers consisting of foams of higher porosity, experience more drop in effectiveness compared to the heat exchanger having foams of low porosity. • Pressure drop across the length of the foam/fin increases as the volumetric flow rate of the cold fluid (m3/s) increases. • Surface area per unit volume and effectiveness values for bare Al tube is very low compared to Al foam heat exchangers resulting in the bare Al tube exhibiting much lower effectiveness compared to heat exchanger made of Al foam. • For a certain flow rate of fluids, the effectiveness of the heat exchanger increases up to a certain thickness of the Al foam. • Regardless of the thickness of the foam, the effectiveness of the heat exchangers is low at higher flow rate of cold fluid compared to lower flow rate. • These foam based heat exchanger had a much higher effectiveness when compared to that of other heat exchangers, data of which were got from literature. The present experimental study concludes that fuse bonding open cell aluminium foam over an Al duct or Al substrate can improve the thermal performance of the heat exchanger significantly. The thesis includes five chapters. Chapter 1 gives a detailed introduction about the metal foam, heat exchangers, thermal contact resistance and its effect on the heat transfer rate has been explained. This chapter also includes the overall aim and motivation for the research work. Chapter 2 covers the literature available on production methods of metal foam and its limitations has been listed out. And conventional methods of manufacturing open cell metal foam heat exchangers and its disadvantages have been explained in detailed. Chapter 3 covers in detail the novel method of production and fabrication of open cell metal foam heat exchangers. Chapter 4 includes an experimental study, where thermal performance of heat exchangers has been assessed through heat transfer experiments. Chapter 5 is the conclusions and future works.

Product designers address the costs of assembly during the design process. Design process can be more efficient if assembly issues could be addressed early in its design process. Doing this requires the ability to assess assemblability among others. Assemblability refers to the ease of assembling the final product from its parts. Assemblability evaluation is applied by product designers for quantitatively estimating the degree of difficulty of the assembly. This helps in identifying areas of improvement, so as to reduce process time and production costs. This work focuses on assessing assemblability in a manual assembly and its importance in the earlier phases of design. Literature contains various methods for assessing assemblability (e.g. Boothroyd-Dewhurst method, the DFA house, Sturges DFA calculator and Sony DFA method). These methods are typically rule-based and their use requires insight and knowledge on the part of the designer. Further, the designer has to interpret and apply them differently in each specific and unique case. Literature also contains methods for ergonomic assessment of manual work and its link with assemblability. Both observation based ergonomic assessment such as RULA, REBA, VIDAR, LUBA and OWAS and instrumentation based ergonomic assessment using electro-goniometer and accelerometer are the techniques reviewed in this thesis for their suitability in assembly assessment. The most recent trend in the area is automation of the evaluation process. This thesis proposes an approach to automated assessment of assemblability using electromagnetic trackers. In spite of advances in industrial automation, manual assembly tasks continue to be an important feature of many industrial operations. The method proposed in the thesis is for the assessment of assemblability of manual assembly that combines both time and postural analysis. The tool used for the static analysis is called Rapid Upper Limb Assessment (RULA); for dynamic analysis a new method of time analysis is proposed that is based on the ratio of time spent in fine and gross motions carried out in an assembly process. The difficulty of assembly of a series of manual assembly tasks are carried out in a laboratory setting. Then by correlating this assessment with the feedback on the difficulty of these assembly task obtained from the subjects who carried out these tasks. The remaining work carried out as a part of this thesis is focussed on automating the process of carrying out the above assessment in an automated manner. Suitability of electromagnetic trackers as a means for automated capture of data necessary for executing the proposed assessment method is studied. Electromagnetic trackers have been used to capture postural data for various limbs of the assembly operators. Data from the limbs are then analysed to identify, to which limb movement signifies which sources of difficulty (i.e. reach, visibility, etc.) in assembly; for example reach difficulty is indicated by torso movement. Finally, the thesis proposes as a part of the future work in possible improvement of the assessment method. Also, its application using a virtual reality (VR) platform assesses in ascertaining ease or difficulties in assembly and many.