La intenció d'aquest projecte de recerca és anar més enllà de l' aconseguit pels sistemes existents de selecció i comparació de processos de Prototipat Ràpid, mitjançant la introducció d'una nova metodologia que tingui com a únic fi la 'Fabricació Final' de components. El sistema desenvolupat incorpora algunes de les eines més recents del camp de Intel·ligència Artificial, de manera que sigui possible aconseguir una metodologia concurrent que inclogui: · Sistemes experts, que s'executen durant el procés de presa de decisions amb alternatives múltiples. Els sistemes experts utilitzen típicament estructures del tipus: IF-THEN-ELSE o CASE, de manera que les opcions puguin ser 'cribrades' especialment durant les primeres etapes de la selecció. · Lògica difusa per a la presa de decisions. Normalment en l'àmbit de la fabricació, alguns termes lingüístics o paràmetres de tipus qualitatiu són utilitzats per definir estats o propietats. Per exemple és comú trobar termes qualitatius com ara: 'bones propietats mecàniques "o" alta taxa d'absorbència', en lloc de xifres i números puntuals. Per tant és necessari comptar amb un mètode per traduir i gestionar aquesta informació. La lògica difusa ha estat adoptada com a mitjà per traduir termes d'ordre qualitatiu a informació quantitativa de manera que a partir d'aquestes dades es pugui construir un sistema de classificació i rànquing de processos.· Presa de decisions Multi-criteri, agrupació (sumatòria) i classificació. Durant la investigació es van provar diferents mètodes per a la classificació d'alternatives i selecció final a partir de vectors d'ordre quantitatiu amb pesos ponderats. Per a aquesta finalitat es va adoptar la metodologia proposada per Lan et al. (2005) el qual es descriu en el capítol 5 d'aquest treball. · Xarxes Neuronals Artificials. Aquestes han estat aplicades per a la modelització i simulació d'alguns processos de Fabricació Ràpida prèviament seleccionats. Per exemple, el procés de Sinteritzat Selectiu Làser es va aconseguir modelar utilitzant Xarxes Neuronals amb un algorisme de "backpropagation", prenent com a informació base, les dades proporcionades pel software propietari de l'equip. Aquesta xarxa neuronal simula una màquina de sinteritzat làser model DTM Vanguard, disponible a la FundacioCIM-UPC a Barcelona. D'altra banda el procés de Fusió selectiva per làser ha estat modelat també mitjançant Xarxes Neuronals a partir de l'equip Concep Laser M2, disponible al laboratori d'Enginyeria mecànica de la Universitat Catòlica de Lovaina, Bèlgica. Els models extrets d'aquestes simulacions mostren una estimació del temps total de fabricació menor al 10% la qual cosa representa una millora substancial respecte a mètodes d'estimació paramètrics. · Finalment s'ha utilitzat la tècnica de bases de dades relacionals per a la gestió i emmagatzematge d'informació sobre materials. Aquestes bases de dades han estat creades en Ms Access, que proporciona la facilitat d'accés, filtrat, graficació i presentació de la informació requerida. Aquesta informació pot ser extreta automàticament mitjançant trucades ODBC, executades des de l'entorn Matlab.Per a il·lustrar el funcionament de les eines descrites en una forma integrada, s'ha optat per desenvolupar una aplicació pilot en Matlab, utilitzant alguns "Tool boxes" especialitzats com: Lògica difusa, Xarxes neuronals, Estadística, Utilitats de graficació, Creació d'interfície d'usuari (GUI), Bases de dades. El resultat d'aquesta integració és una aplicació pilot anomenada RMADS (Rapid Manufacturing Advice System), el qual compta amb una interfície gràfica d'usuari que es divideix en tres mòduls: · Requeriments generals de disseny. Aquest mòdul analitza els paràmetres usualment definits en les especificacions inicials de Producte, per exemple: tipus de material, toleràncies, acabat superficial, complexitat geomètrica, etc. · Mòdul de costos. Aquest mòdul utilitza paràmetres d'entrada prèviament introduïts com: volum de peça, mida de lot i dimensions totals, per a realitzar càlculs mitjançant mètodes paramètrics i models basats en xarxes neuronals. El resultat és una estimació del cost per peça i també el cost estès per volums grans. · Selecció de materials. Aquest mòdul mostra la natura iterativa del procés de selecció de materials, a través de criteris de "filtratge" o selecció, de manera que a cada iteració el nombre d'opcions sigui limitat a un nombre raonable d'alternatives. / The intention of this research is to go beyond currently available systems for the assessment and selection of Rapid Prototyping processes, hence introducing a new methodology devoted to 'Manufacturing' applications. Specifically the system would include a number of state of the art artificial Intelligence techniques to comprise a fully concurrent methodology, namely:· Expert systems are included to aid in the decision making process with multiple alternatives. Expert systems typically use If-Then-Else or CASE structures so that the available options can be screened specially during the first selection stages.· Fuzzy logic for decision making. Usually in manufacturing, linguistic terms or qualitative parameters are used to define states of properties. For instance it is common to find terms such as 'Good mechanical properties' or 'High absortivity rates' therefore it is necessary to have a method to translate and manage such information. Fuzzy logic has been adopted as a means to translate qualitative terms to quantitative information.· Multi-criteria decision making, aggregation and ranking. Different methods for selecting and ranking alternatives were tested which allows the integration of quantitative vectors with weighting factors that reflect the user preferences. For this purpose the method proposed by Lan et al. (2005) has been adopted as discussed in Chapter 5.· Artificial Neural Networks (ANNs) are being applied for the modelling and simulation of a number of Rapid Manufacturing Methods. Selective Laser Sintering has been modelled using a back propagation algorithm ANN taking as a basis the information provided by the machine software. The ANN simulates a DTM Vanguard SLS machine available at Fundacio CIM-UPC, Barcelona, while the Selective Laser Melting has been modelled with the parameters and settings used by the Concept Laser M2 machine available at the Mechanical Engineering Lab of the Catholic University of Leuven, Belgium. The extracted models exhibit a build-time prediction error rate lower than 10%, which is a significant improvement compared to conventional parametric methods.· Finally, relational databases have been applied for storing and handling materials information. These databases have been stored as Ms Access data which provides the ease to access, filter, screen and plot the required information. This data can be automatically called and extracted by means of an ODBC call deployed within the Matlab environment.In order to illustrate the functionality of the previous tools put together, a pilot application was designed in Matlab, making use of a number of specialized toolboxes namely: Fuzzy logic, Neural Network, Statistics, Plotting utilities, GUI builder, Database.The result is a prototype system with a graphic user interface divided in three modules: · General design requirements: which deals with those parameters usually defined in the product PDS, for instance: material type, tolerances, surface roughness, geometrical complexity, etc.· Costing module: which makes use of parametric cost estimation and ANN-based models to perform the calculation of cost per part, and for low volumes· Materials selection: Shows the iterative nature of materials selection through screening steps so that the range of suitable options is limited.

No description available.

<p>This thesis was done at Siemens Industrial Turbomachinery AB in Finspång.</p><p>Placed in the inlet to a steam turbine is a filter, a steam strainer, which separates particles and larger objects from the steam. These particles and objects will cause solid particle erosion in the actual turbine if they pass by. The strainer is exposed to large pressure drops when clogged, i.e., static loads which require a good creep resistance in the material. The temperature of the steam in the turbines is increased in order to deliver more energy; today’s turbines are dimensioned for almost 600°C. The material in parameters, such as the strainer, should also be adjusted to the higher temperatures. Today’s temperature is suspected to be the cause of damage in the strainer because the present material might get brittle at higher temperatures.</p><p>The purpose of the thesis is to find a new material for the strainers and also to find a new concept for how to manufacture them. There are nine sizes of steam strainers but only five of them are exposed to the highest temperatures and pressure drops, which make only these five interesting to examine in this thesis.</p><p>The concepts were chosen according to the method of Ulf Liedholm (1999), Systematic Concept Development. The thesis did not end up with only one concept because not all possible methods were tested but the suggestions are all based on a strainer built out of membranes as before. The discussed methods to join the membranes are EB-welding, laser welding and brazing.</p><p>An investigation to find if it was possible to improve the strength of the strainer by simple design changes and a calculation of what percentage of clogging the strainer would hold for was also done.</p><p>The chosen material was a creep resistant, alloy special steel. Three suggestions on concepts were presented. The improvements in strength from simple changes in design were too small and too costly but are enclosed as an appendix in this report. Calculations on the strength were done without regard taken to fatigue caused by possible vibrations, so-called high cycle fatigue.</p><p>What would be interesting to do as a future work based on this thesis is, of course, to test the three manufacturing methods and evaluate them thoroughly but also to discuss other ways of improving the strength through design changes. These should be done regarding the flow. Also high cycle fatigue should be considered.</p> / <p>Examensarbetet utfördes i Finspång på Siemens Industrial Turbomachinery AB.</p><p>I inloppet till en ångturbin sitter ett filter, en ångsil, som silar bort partiklar och större föremål från ångan. Dessa partiklar och föremål skadar turbinen genom erosion om de tillåts passera. Ångsilen i sig utsätts för stora tryckfall när den blir igensatt, vilket kräver god krypresistans i materialet. För att kunna leverera allt mer energi utvecklas ångturbiner som kan arbeta vid allt högre ångtemperaturer. De som konstrueras idag dimensioneras för närmare 600 °C. Då måste även materialet i detaljer, som silen, anpassas. De temperaturer som används idag misstänks vara en orsak till skador på silarna eftersom nuvarande material kan bli sprött då temperaturen stiger.</p><p>Syftet med arbetet är att välja ett nytt material till ångsilarna samt att finna nya koncept för hur ångsilen kan tillverkas. Nio storlekar på ångsilar finns men bara fem av dessa används vid högsta temperatur och tryck och därför har enbart dessa fem använts vid beräkningar i detta examensarbete.</p><p>Koncept valdes enligt Liedholms (1999) metod, Systematisk Konceptutveckling. Istället för ett slutligt koncept lämnas istället tre förslag. Detta görs då de olika förslagen inte har testats ordentligt. Samtliga tre förslag är baserade på den typen av sil uppbyggd av membran som används idag men med nya metoder att sammanfoga membranen med. Metoderna är EB-svetsning, lasersvetsning och vakuumlödning.</p><p>En undersökning om det var ekonomiskt rimligt att förbättra hållfastheten genom enkla designändringar samt en beräkning över hur stor igensättning silen klarar gjordes.</p><p>Materialet som valdes var ett krypresistant, legerat specialstål. De tre förslagen på koncept lades fram. Designändringarna gav inte det resultat som det hade hoppats på och var framförallt för dyra att genomföra. Hållfasthetsberäkningar gjordes utan hänsyn till utmattning på grund av eventuella vibrationer, så kallad högcykelutmattning.</p><p>Som framtida arbete med detta examensarbete som språngbräda rekommenderas i första hand att testa de föreslagna metoderna för sammanfogning av membranen men även djupare diskussioner kring hur hållfastheten skulle kunna förbättras genom designförändringar borde tas. Dessa skulle kunna genomföras med avseende på flödet. Även högcykelutmattning, HCF, borde undersökas.</p>

This thesis was done at Siemens Industrial Turbomachinery AB in Finspång. Placed in the inlet to a steam turbine is a filter, a steam strainer, which separates particles and larger objects from the steam. These particles and objects will cause solid particle erosion in the actual turbine if they pass by. The strainer is exposed to large pressure drops when clogged, i.e., static loads which require a good creep resistance in the material. The temperature of the steam in the turbines is increased in order to deliver more energy; today’s turbines are dimensioned for almost 600°C. The material in parameters, such as the strainer, should also be adjusted to the higher temperatures. Today’s temperature is suspected to be the cause of damage in the strainer because the present material might get brittle at higher temperatures. The purpose of the thesis is to find a new material for the strainers and also to find a new concept for how to manufacture them. There are nine sizes of steam strainers but only five of them are exposed to the highest temperatures and pressure drops, which make only these five interesting to examine in this thesis. The concepts were chosen according to the method of Ulf Liedholm (1999), Systematic Concept Development. The thesis did not end up with only one concept because not all possible methods were tested but the suggestions are all based on a strainer built out of membranes as before. The discussed methods to join the membranes are EB-welding, laser welding and brazing. An investigation to find if it was possible to improve the strength of the strainer by simple design changes and a calculation of what percentage of clogging the strainer would hold for was also done. The chosen material was a creep resistant, alloy special steel. Three suggestions on concepts were presented. The improvements in strength from simple changes in design were too small and too costly but are enclosed as an appendix in this report. Calculations on the strength were done without regard taken to fatigue caused by possible vibrations, so-called high cycle fatigue. What would be interesting to do as a future work based on this thesis is, of course, to test the three manufacturing methods and evaluate them thoroughly but also to discuss other ways of improving the strength through design changes. These should be done regarding the flow. Also high cycle fatigue should be considered. / Examensarbetet utfördes i Finspång på Siemens Industrial Turbomachinery AB. I inloppet till en ångturbin sitter ett filter, en ångsil, som silar bort partiklar och större föremål från ångan. Dessa partiklar och föremål skadar turbinen genom erosion om de tillåts passera. Ångsilen i sig utsätts för stora tryckfall när den blir igensatt, vilket kräver god krypresistans i materialet. För att kunna leverera allt mer energi utvecklas ångturbiner som kan arbeta vid allt högre ångtemperaturer. De som konstrueras idag dimensioneras för närmare 600 °C. Då måste även materialet i detaljer, som silen, anpassas. De temperaturer som används idag misstänks vara en orsak till skador på silarna eftersom nuvarande material kan bli sprött då temperaturen stiger. Syftet med arbetet är att välja ett nytt material till ångsilarna samt att finna nya koncept för hur ångsilen kan tillverkas. Nio storlekar på ångsilar finns men bara fem av dessa används vid högsta temperatur och tryck och därför har enbart dessa fem använts vid beräkningar i detta examensarbete. Koncept valdes enligt Liedholms (1999) metod, Systematisk Konceptutveckling. Istället för ett slutligt koncept lämnas istället tre förslag. Detta görs då de olika förslagen inte har testats ordentligt. Samtliga tre förslag är baserade på den typen av sil uppbyggd av membran som används idag men med nya metoder att sammanfoga membranen med. Metoderna är EB-svetsning, lasersvetsning och vakuumlödning. En undersökning om det var ekonomiskt rimligt att förbättra hållfastheten genom enkla designändringar samt en beräkning över hur stor igensättning silen klarar gjordes. Materialet som valdes var ett krypresistant, legerat specialstål. De tre förslagen på koncept lades fram. Designändringarna gav inte det resultat som det hade hoppats på och var framförallt för dyra att genomföra. Hållfasthetsberäkningar gjordes utan hänsyn till utmattning på grund av eventuella vibrationer, så kallad högcykelutmattning. Som framtida arbete med detta examensarbete som språngbräda rekommenderas i första hand att testa de föreslagna metoderna för sammanfogning av membranen men även djupare diskussioner kring hur hållfastheten skulle kunna förbättras genom designförändringar borde tas. Dessa skulle kunna genomföras med avseende på flödet. Även högcykelutmattning, HCF, borde undersökas.

O objetivo principal da tese foi desenvolver um método multicriterial de seleção de processos de fundição de metais (MMSPF) para fabricação de componentes, considerando-se critérios técnicos, ambientais e econômicos para ser aplicado nas fases iniciais do desenvolvimento do componente. O MMSPF é constituído pelos módulos de seleção técnica e econômica. O módulo de seleção técnica é destinado a antecipar as atividades de seleção de processos, a serem desenvolvidas na fase de projeto preliminar, enquanto o módulo de seleção econômica é destinado a antecipar as atividades de seleção de processos, necessárias à fase de projeto detalhado. O MMSPF realiza a seleção de processos de forma sequencial. Inicialmente, avaliando aspectos técnicos e, posteriormente, considerando aspectos econômicos. O MMSPF contempla as seis classes de ligas metálicas mais utilizadas na produção de componentes fundidos: aços, ferros fundidos, ligas de alumínio, ligas de cobre, ligas de magnésio e ligas de zinco, apropriadas aos processos de fundição de metais destinados à produção de peças. O MMSPF contempla os quinze principais processos de fundição de metais destinados a produção de peças: areia verde – manual (P1), areia verde – mecanizada (P2), areia verde – automatizada (P3), areia silicato - CO2 (P4), areia com resina – cura frio (P5), areia com resina – shell molding (P6), processo molde de gesso – plaster molding (P7), processo molde cerâmico (P8), investment casting (P9), molde cheio - lost foam (P10), fundição centrífuga - molde metálico (P11), molde permanente – gravidade (P12), molde permanente - baixa pressão (P13), fundição sob pressão - die casting (P14) e squeeze casting (P15) como conjunto solução da seleção. As inovações propostas pelo MMSPF foram: (i) consolidação das diferentes fontes de informação dos processos a serem utilizadas no MMSPF, por meio de uma função de agregação; (ii) utilização de aspectos ambientais como critérios para seleção de processos de fundição de metais; (iii) consideração da estimação de custos de fabricação para realizar a seleção de processos de fundição de metais a partir de um índice de custo de fabricação, relativo ao desempenho técnico. Também foi desenvolvido um aplicativo computacional para implementar o MMSPF composto por três elementos principais: um software de planilha eletrônica (Microsoft Excel), no qual são realizadas todas as operações matemáticas necessárias ao desenvolvimento das etapas operacionais do MMSPF; um banco de dados, o software livre SQLite, responsável por armazenar as informações utilizadas no aplicativo computacional do MMSPF; e a interface gráfica do usuário, que atua como elemento de conexão entre o banco de dados, o software de planilha eletrônica e o usuário. / The main objective of this thesis was to develop a Multi-criteria Method for metal Casting Process Selection (MMCPS) to manufacturing components, considering technical criteria, environmental and economic to be applied in the early stages of design of the component. The MMCPS consists modules for the technical and economic selection. The technique selection module is designed to anticipate the activities of processes selection to be developed in the embodiment design, while the economic selection module is designed to anticipate selection process activities, necessary the detailed design phase. The MMCPS conducts the selection process sequentially. Initially, evaluating technical aspects and, subsequently, considering economic aspects. The MMCPS includes the six classes of metal alloys more used in the production of cast components: steel, cast iron, aluminum alloys, copper alloys, magnesium alloys and zinc alloys, suitable for metal shape casting processes. The MMCPS covers the fifteen main metal shape casting processes: green sand – hand molding (P1), green sand – mechanized molding (P2), green sand - automatic molding (P3), silicate-CO2 (P4), air-set/nobake (P5), shell molding (P6), plaster molding (P7), ceramic mold (P8), investment casting (P9), lost foam (P10), centrifugal casting – metallic mold (P11), permanent mold-gravity (P12), permanent mold-low pressure (P13), die casting (P14) and squeeze casting (P15) as the set solution for the selection process. The innovations proposed by MMCPS were: (i) consolidation of different sources of information processes to be used in MMCPS through an aggregation function; (ii) use of environmental aspects as criteria for selection of metal casting processes; (iii) consideration of the cost estimation of manufacturing to make the metal casting process selection from an index of manufacturing cost on the technical performance. Also developed a computational tool to implement the MMCPS composed of three main elements: a spreadsheet software (Microsoft Excel), which are held every mathematical operations necessary for the development of operational steps MMCPS; a database, freeware SQLite, responsible for storing information used in the application of computational MMCPS, and the graphical user interface, which acts as a link between the database, the spreadsheet software and the user.

O objetivo principal da tese foi desenvolver um método multicriterial de seleção de processos de fundição de metais (MMSPF) para fabricação de componentes, considerando-se critérios técnicos, ambientais e econômicos para ser aplicado nas fases iniciais do desenvolvimento do componente. O MMSPF é constituído pelos módulos de seleção técnica e econômica. O módulo de seleção técnica é destinado a antecipar as atividades de seleção de processos, a serem desenvolvidas na fase de projeto preliminar, enquanto o módulo de seleção econômica é destinado a antecipar as atividades de seleção de processos, necessárias à fase de projeto detalhado. O MMSPF realiza a seleção de processos de forma sequencial. Inicialmente, avaliando aspectos técnicos e, posteriormente, considerando aspectos econômicos. O MMSPF contempla as seis classes de ligas metálicas mais utilizadas na produção de componentes fundidos: aços, ferros fundidos, ligas de alumínio, ligas de cobre, ligas de magnésio e ligas de zinco, apropriadas aos processos de fundição de metais destinados à produção de peças. O MMSPF contempla os quinze principais processos de fundição de metais destinados a produção de peças: areia verde – manual (P1), areia verde – mecanizada (P2), areia verde – automatizada (P3), areia silicato - CO2 (P4), areia com resina – cura frio (P5), areia com resina – shell molding (P6), processo molde de gesso – plaster molding (P7), processo molde cerâmico (P8), investment casting (P9), molde cheio - lost foam (P10), fundição centrífuga - molde metálico (P11), molde permanente – gravidade (P12), molde permanente - baixa pressão (P13), fundição sob pressão - die casting (P14) e squeeze casting (P15) como conjunto solução da seleção. As inovações propostas pelo MMSPF foram: (i) consolidação das diferentes fontes de informação dos processos a serem utilizadas no MMSPF, por meio de uma função de agregação; (ii) utilização de aspectos ambientais como critérios para seleção de processos de fundição de metais; (iii) consideração da estimação de custos de fabricação para realizar a seleção de processos de fundição de metais a partir de um índice de custo de fabricação, relativo ao desempenho técnico. Também foi desenvolvido um aplicativo computacional para implementar o MMSPF composto por três elementos principais: um software de planilha eletrônica (Microsoft Excel), no qual são realizadas todas as operações matemáticas necessárias ao desenvolvimento das etapas operacionais do MMSPF; um banco de dados, o software livre SQLite, responsável por armazenar as informações utilizadas no aplicativo computacional do MMSPF; e a interface gráfica do usuário, que atua como elemento de conexão entre o banco de dados, o software de planilha eletrônica e o usuário. / The main objective of this thesis was to develop a Multi-criteria Method for metal Casting Process Selection (MMCPS) to manufacturing components, considering technical criteria, environmental and economic to be applied in the early stages of design of the component. The MMCPS consists modules for the technical and economic selection. The technique selection module is designed to anticipate the activities of processes selection to be developed in the embodiment design, while the economic selection module is designed to anticipate selection process activities, necessary the detailed design phase. The MMCPS conducts the selection process sequentially. Initially, evaluating technical aspects and, subsequently, considering economic aspects. The MMCPS includes the six classes of metal alloys more used in the production of cast components: steel, cast iron, aluminum alloys, copper alloys, magnesium alloys and zinc alloys, suitable for metal shape casting processes. The MMCPS covers the fifteen main metal shape casting processes: green sand – hand molding (P1), green sand – mechanized molding (P2), green sand - automatic molding (P3), silicate-CO2 (P4), air-set/nobake (P5), shell molding (P6), plaster molding (P7), ceramic mold (P8), investment casting (P9), lost foam (P10), centrifugal casting – metallic mold (P11), permanent mold-gravity (P12), permanent mold-low pressure (P13), die casting (P14) and squeeze casting (P15) as the set solution for the selection process. The innovations proposed by MMCPS were: (i) consolidation of different sources of information processes to be used in MMCPS through an aggregation function; (ii) use of environmental aspects as criteria for selection of metal casting processes; (iii) consideration of the cost estimation of manufacturing to make the metal casting process selection from an index of manufacturing cost on the technical performance. Also developed a computational tool to implement the MMCPS composed of three main elements: a spreadsheet software (Microsoft Excel), which are held every mathematical operations necessary for the development of operational steps MMCPS; a database, freeware SQLite, responsible for storing information used in the application of computational MMCPS, and the graphical user interface, which acts as a link between the database, the spreadsheet software and the user.

O objetivo principal da tese foi desenvolver um método multicriterial de seleção de processos de fundição de metais (MMSPF) para fabricação de componentes, considerando-se critérios técnicos, ambientais e econômicos para ser aplicado nas fases iniciais do desenvolvimento do componente. O MMSPF é constituído pelos módulos de seleção técnica e econômica. O módulo de seleção técnica é destinado a antecipar as atividades de seleção de processos, a serem desenvolvidas na fase de projeto preliminar, enquanto o módulo de seleção econômica é destinado a antecipar as atividades de seleção de processos, necessárias à fase de projeto detalhado. O MMSPF realiza a seleção de processos de forma sequencial. Inicialmente, avaliando aspectos técnicos e, posteriormente, considerando aspectos econômicos. O MMSPF contempla as seis classes de ligas metálicas mais utilizadas na produção de componentes fundidos: aços, ferros fundidos, ligas de alumínio, ligas de cobre, ligas de magnésio e ligas de zinco, apropriadas aos processos de fundição de metais destinados à produção de peças. O MMSPF contempla os quinze principais processos de fundição de metais destinados a produção de peças: areia verde – manual (P1), areia verde – mecanizada (P2), areia verde – automatizada (P3), areia silicato - CO2 (P4), areia com resina – cura frio (P5), areia com resina – shell molding (P6), processo molde de gesso – plaster molding (P7), processo molde cerâmico (P8), investment casting (P9), molde cheio - lost foam (P10), fundição centrífuga - molde metálico (P11), molde permanente – gravidade (P12), molde permanente - baixa pressão (P13), fundição sob pressão - die casting (P14) e squeeze casting (P15) como conjunto solução da seleção. As inovações propostas pelo MMSPF foram: (i) consolidação das diferentes fontes de informação dos processos a serem utilizadas no MMSPF, por meio de uma função de agregação; (ii) utilização de aspectos ambientais como critérios para seleção de processos de fundição de metais; (iii) consideração da estimação de custos de fabricação para realizar a seleção de processos de fundição de metais a partir de um índice de custo de fabricação, relativo ao desempenho técnico. Também foi desenvolvido um aplicativo computacional para implementar o MMSPF composto por três elementos principais: um software de planilha eletrônica (Microsoft Excel), no qual são realizadas todas as operações matemáticas necessárias ao desenvolvimento das etapas operacionais do MMSPF; um banco de dados, o software livre SQLite, responsável por armazenar as informações utilizadas no aplicativo computacional do MMSPF; e a interface gráfica do usuário, que atua como elemento de conexão entre o banco de dados, o software de planilha eletrônica e o usuário. / The main objective of this thesis was to develop a Multi-criteria Method for metal Casting Process Selection (MMCPS) to manufacturing components, considering technical criteria, environmental and economic to be applied in the early stages of design of the component. The MMCPS consists modules for the technical and economic selection. The technique selection module is designed to anticipate the activities of processes selection to be developed in the embodiment design, while the economic selection module is designed to anticipate selection process activities, necessary the detailed design phase. The MMCPS conducts the selection process sequentially. Initially, evaluating technical aspects and, subsequently, considering economic aspects. The MMCPS includes the six classes of metal alloys more used in the production of cast components: steel, cast iron, aluminum alloys, copper alloys, magnesium alloys and zinc alloys, suitable for metal shape casting processes. The MMCPS covers the fifteen main metal shape casting processes: green sand – hand molding (P1), green sand – mechanized molding (P2), green sand - automatic molding (P3), silicate-CO2 (P4), air-set/nobake (P5), shell molding (P6), plaster molding (P7), ceramic mold (P8), investment casting (P9), lost foam (P10), centrifugal casting – metallic mold (P11), permanent mold-gravity (P12), permanent mold-low pressure (P13), die casting (P14) and squeeze casting (P15) as the set solution for the selection process. The innovations proposed by MMCPS were: (i) consolidation of different sources of information processes to be used in MMCPS through an aggregation function; (ii) use of environmental aspects as criteria for selection of metal casting processes; (iii) consideration of the cost estimation of manufacturing to make the metal casting process selection from an index of manufacturing cost on the technical performance. Also developed a computational tool to implement the MMCPS composed of three main elements: a spreadsheet software (Microsoft Excel), which are held every mathematical operations necessary for the development of operational steps MMCPS; a database, freeware SQLite, responsible for storing information used in the application of computational MMCPS, and the graphical user interface, which acts as a link between the database, the spreadsheet software and the user.

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Most aircraft component are currently being manufactured by machining, forging, welding and also assembling such parts. However, the possibilities of cutting cost from a single component has brought about a growing trend towards looking into casting as a possible option for manufacturing aircraft parts. This thesis was done at the request of Saab Avitronics. It evaluates the possibilities of one aircraft part, a chassis for an electronic unit that was first designed to be machined from a blank, to be cast. The thesis goes through the multifaceted tasks of product development. Casting process selection, cast alloy selection as well as geometry modification were some of these tasks that were performed in this thesis. It also evaluates the performances of chosen casting processes, the design of gating systems as well as various process parameters set, by simulating the casting processes. The alloy chosen was A356.0 with a T6 temper and the casting processes chosen were plaster mold casting and rheocasting. The geometry of the original chassis, which had very thin sections and undercuts which were complex to cast, was modified and made easier to cast with an acceptable slight increase of mass and size. The modification done on the geometry as well as the gating systems used had proven to be worthwhile, as the simulation of both process showed that such a part can be casted with no crucial defects foreseen. However, probable cavities might occur at the very tip of the chassis’s thin-fins – that it has for carrying away heat. Minor subsurface porosities might also be formed, which would not impair the function of the chassis. The modified chassis was made as close to as finished piece as possible, for the purpose of reducing machining costs. The cost of producing such a part by casting was also seen to be much less than machining it from blank. This could be taken as rationale for casting the chassis with thicker sections, to avoid problems that may arise in casting, and to subsequently machine these faces later, as it would still be cheaper than machining the chassis from a blank.

<p>Most aircraft component are currently being manufactured by machining, forging, welding and also assembling such parts. However, the possibilities of cutting cost from a single component has brought about a growing trend towards looking into casting as a possible option for manufacturing aircraft parts.</p><p>This thesis was done at the request of Saab Avitronics. It evaluates the possibilities of one aircraft part, a chassis for an electronic unit that was first designed to be machined from a blank, to be cast. The thesis goes through the multifaceted tasks of product development. Casting process selection, cast alloy selection as well as geometry modification were some of these tasks that were performed in this thesis. It also evaluates the performances of chosen casting processes, the design of gating systems as well as various process parameters set, by simulating the casting processes.</p><p>The alloy chosen was A356.0 with a T6 temper and the casting processes chosen were plaster mold casting and rheocasting. The geometry of the original chassis, which had very thin sections and undercuts which were complex to cast, was modified and made easier to cast with an acceptable slight increase of mass and size. The modification done on the geometry as well as the gating systems used had proven to be worthwhile, as the simulation of both process showed that such a part can be casted with no crucial defects foreseen. However, probable cavities might occur at the very tip of the chassis’s thin-fins – that it has for carrying away heat. Minor subsurface porosities might also be formed, which would not impair the function of the chassis. The modified chassis was made as close to as finished piece as possible, for the purpose of reducing machining costs. The cost of producing such a part by casting was also seen to be much less than machining it from blank. This could be taken as rationale for casting the chassis with thicker sections, to avoid problems that may arise in casting, and to subsequently machine these faces later, as it would still be cheaper than machining the chassis from a blank.</p>