Nos processos usuais de prototipagem rapida, a transformacao do material para a construcao do prototipo, de maneira geral, e realizada por fusao ou polimerizacao oriunda do aquecimento via laser ou resistencia eletrica. Isso, necessariamente, envolve equipamento especial para o processo de fusao e deposicao do material para a construcao das superficies camada por camada, o controle de temperatura para assegurar a qualidade e o tratamento de gases exalados pela transformacao entre outros. Essa forma de transformacao nos processos de prototipagem rapida tem assim custos relativamente altos do prototipo e do equipamento. Uma alternativa para o processo de transformacao inclui evidentemente outros materiais para construcao do prototipo. Entretanto, no levantamento bibliografico realizado observou-se que nao existem trabalhos que explorem materiais e processos alternativos. Assim varios materiais foram analisados com base nas seguintes propriedades: processamento sob temperatura ambiente, capacidade de aderencia entre as camadas, tempo de consistencia e de cura do material, custo e disponibilidade no mercado nacional. Com base nesse estudo foi selecionado o seguinte material: composito a base de complexo de carboidrato, o qual transforma-se, de estado fisico, sob temperatura ambiente. Inicialmente analisaram-se os aspectos de aderencia e tempo de cura. Posteriormente estudaram-se as caracteristicas dos dispositivos e dos processos Fused Layer Modeling (FLM). Baseado nesse estudo foi fabricado um dispositivo para se extrudar material em forma de filamentos. Em seguida modelou-se o cinematismo da velocidade de deposicao do dispositivo extrusor e assim delinear o projeto de experimentos para se obter, do processo proposto, os aspectos qualitativo (operacao, preparacao, custos, utilizacao dos prototipos, entre outros) e quantitativo (velocidade de deslocamento dos eixos X e Y, alturas entre camadas, rugosidade e forma geometrica). Desse estudo resulta que a proposta demonstra potencial para aplicacao na fabricacao de mostruarios, pecas de brinquedos, utilizacao em cursos de formacao profissional, prototipos para moldagem a temperatura ambiente, moldes para fundicao em areia. / In usual processes of rapid prototyping the transformation of the material into the prototype construction is usually made by fusion or polymerization by means of heating by laser or electrical resistance. It necessarily requires special equipment for the fusion process and deposition of material for the surface construction, layer on top of layer, the temperature control to certify quality, the treatment of exhalation during the transformation process, among others. This kind of transformation in the rapid prototyping process is relatively expensive compared with the conventional process of prototyping. An alternative for the transformation process includes, obviously, other kinds of material for the prototype construction. However, bibliographic research has show, that there are no such works which explore alternative materials and processes especially in the national context. Therefore, several kinds of material have been analyzed based on the following properties: required temperature for the work, adherence capacity between the layers, consistence time or cure time of the prototype, cost and availability on the national market. The following material was chosen, based on this study: a compound, based on a carbohydrate complex, because it transforms itself from the physical form at room temperature. First of all, adherence aspects and curing time were analyzed,. Then characteristics of the apparatuses and devices of the Fused Layer Modeling process (FLM). Based on these characteristics the project of the extrusion device was developed, to extrude the carbohydrate composite in form of filaments and its kinematics was modeled to determine the depositing speed and design of experiments to obtain, out of the proposed process, the qualitative aspects (operation, preparation, costs, utilization of the prototype, among others) and quantitative (speed of the dislocation of the table at x-y axis, height between the layers, roughness and geometric form, among others). At that rate the developed proposal shows potentiality to be used in production of showcases, toy pieces, utilization in course for professional training, prototypes for molding at room temperature, forms for sand castings.

Nos processos usuais de prototipagem rapida, a transformacao do material para a construcao do prototipo, de maneira geral, e realizada por fusao ou polimerizacao oriunda do aquecimento via laser ou resistencia eletrica. Isso, necessariamente, envolve equipamento especial para o processo de fusao e deposicao do material para a construcao das superficies camada por camada, o controle de temperatura para assegurar a qualidade e o tratamento de gases exalados pela transformacao entre outros. Essa forma de transformacao nos processos de prototipagem rapida tem assim custos relativamente altos do prototipo e do equipamento. Uma alternativa para o processo de transformacao inclui evidentemente outros materiais para construcao do prototipo. Entretanto, no levantamento bibliografico realizado observou-se que nao existem trabalhos que explorem materiais e processos alternativos. Assim varios materiais foram analisados com base nas seguintes propriedades: processamento sob temperatura ambiente, capacidade de aderencia entre as camadas, tempo de consistencia e de cura do material, custo e disponibilidade no mercado nacional. Com base nesse estudo foi selecionado o seguinte material: composito a base de complexo de carboidrato, o qual transforma-se, de estado fisico, sob temperatura ambiente. Inicialmente analisaram-se os aspectos de aderencia e tempo de cura. Posteriormente estudaram-se as caracteristicas dos dispositivos e dos processos Fused Layer Modeling (FLM). Baseado nesse estudo foi fabricado um dispositivo para se extrudar material em forma de filamentos. Em seguida modelou-se o cinematismo da velocidade de deposicao do dispositivo extrusor e assim delinear o projeto de experimentos para se obter, do processo proposto, os aspectos qualitativo (operacao, preparacao, custos, utilizacao dos prototipos, entre outros) e quantitativo (velocidade de deslocamento dos eixos X e Y, alturas entre camadas, rugosidade e forma geometrica). Desse estudo resulta que a proposta demonstra potencial para aplicacao na fabricacao de mostruarios, pecas de brinquedos, utilizacao em cursos de formacao profissional, prototipos para moldagem a temperatura ambiente, moldes para fundicao em areia. / In usual processes of rapid prototyping the transformation of the material into the prototype construction is usually made by fusion or polymerization by means of heating by laser or electrical resistance. It necessarily requires special equipment for the fusion process and deposition of material for the surface construction, layer on top of layer, the temperature control to certify quality, the treatment of exhalation during the transformation process, among others. This kind of transformation in the rapid prototyping process is relatively expensive compared with the conventional process of prototyping. An alternative for the transformation process includes, obviously, other kinds of material for the prototype construction. However, bibliographic research has show, that there are no such works which explore alternative materials and processes especially in the national context. Therefore, several kinds of material have been analyzed based on the following properties: required temperature for the work, adherence capacity between the layers, consistence time or cure time of the prototype, cost and availability on the national market. The following material was chosen, based on this study: a compound, based on a carbohydrate complex, because it transforms itself from the physical form at room temperature. First of all, adherence aspects and curing time were analyzed,. Then characteristics of the apparatuses and devices of the Fused Layer Modeling process (FLM). Based on these characteristics the project of the extrusion device was developed, to extrude the carbohydrate composite in form of filaments and its kinematics was modeled to determine the depositing speed and design of experiments to obtain, out of the proposed process, the qualitative aspects (operation, preparation, costs, utilization of the prototype, among others) and quantitative (speed of the dislocation of the table at x-y axis, height between the layers, roughness and geometric form, among others). At that rate the developed proposal shows potentiality to be used in production of showcases, toy pieces, utilization in course for professional training, prototypes for molding at room temperature, forms for sand castings.

Today's commercial rapid prototyping systems (i.e., solid freeform fabrication, layered manufacturing) rely on human intervention to load and unload build jobs. Hence, jobs are processed subject to both the machine's and the operator's schedules. In particular, first-in-first-out (FIFO) queuing of such systems will result in machine idle time whenever a build job has been completed and an operator is not available to unload that build job and start up the next one. These machine idle times can significantly affect the system throughput, and, hence, the effective cost rate. This thesis addresses this problem by rearranging the job queue to minimizing the machine idle time, subject to the machine's and operator's schedules. This is achieved by employing a general branch-and-bound search method, that, for efficiency, reduces the search space by identifying contiguous sequences and avoiding reshuffling of those sequences during the branching procedure. The effectiveness of this job scheduling optimization has been demonstrated using a sequence of 30 jobs extracted from the usage log for the FDM 1600 rapid prototyping system in the Department of Mechanical Engineering at Virginia Tech. / Master of Science