Browsing by Author "Matos, Marina A."
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- Build orientation optimization of car hoodvent with additive manufacturingPublication . Matos, Marina A.; Rocha, Ana Maria A.C.; Costa, Lino; Pereira, Ana I.Additive manufacturing is a widely used process consisting in the building of a three-dimensional (3D) object from a model projected on a computer, adding the material layer-by-layer. This technology allows the printing of complex shape objects and is being increasingly adopted by the aircraft industry, medical implants, jewelry, footwear, automotive, fashion products, among others. The build orientation optimization of 3D models has a great influence on costs and surface quality when printing three-dimensional objects. In this work, three build orientation optimization problems are studied: single objective problem, bi-objective problem and many-objective problem. To this end, three quality measures are applied: the support area, the build time and the surface roughness, for the Car Hoodvent model. First, a single-objective optimization problem is presented and solved by the genetic algorithm, obtaining optimal solutions for each objective function. Then, the study of the bi-objective optimization problem is carried out for each pair of two objectives and some representative trade-off solutions are identified. Finally, the study of the many objective optimization problem, considering the three measures optimized simultaneously, is presented with some more optimal solutions found. The bi-objective and many-objective problems are solved by a multi-objective genetic algorithm. For a better analysis and comparison of the solutions found, the Pareto fronts are used, enabling a better visualization of the solutions between the objectives. This study aims to assist the decision-maker in choosing the best part print orientation angles according to his/her preferences. The optimal solutions found confirmed the effectiveness of the proposed approach.
- Escalonamento de veículos para realizar visitas ao domicílio em Unidades de SaúdePublication . Matos, Marina A.; Pereira, Ana I.; Fernandes, AdíliaAtualmente, em Portugal, a população está cada vez mais envelhecida. Assim sendo, os serviços de prestação de cuidados de saúde ao domicílio estão a tornar-se numa importante área de investigação. As visitas ao domicílio têm vindo a crescer, de modo a proporcionar às pessoas incapazes de se mover até aos Centros de Saúde, um grande auxílio em tratar, cuidar e apoiar, procurando promover uma melhor qualidade de vida para estas pessoas. Este serviço de saúde é realizado por profissionais de saúde, normalmente, enfermeiros. Habitualmente, as visitas são planeadas manualmente e sem apoio computacional. Neste projeto pretende-se realizar o planeamento automático das visitas ao domicílio, da Unidade de Saúde de Bragança, uma vez que, nesta região o número de pessoas idosas está a aumentar. O objetivo deste trabalho consiste em minimizar o tempo máximo gasto pelos veículos que transportam os profissionais de saúde até às habitações dos pacientes com necessidade de tratamentos, de modo a reduzir-se custos destas operações. Para isso, foi desenvolvida e testada uma modelação matemática, em que foi aplicada a dois algoritmos, o Algoritmo Genético e o Algoritmo de Enxame de Partículas. Esta foi desenvolvida no software MatLab, permitindo resolver o problema eficazmente, onde se obteve soluções para cada dia da semana em estudo, 18 a 22 de abril de 2016. Em todos os escalonamentos obtidos pelos dois algoritmos, verificou-se uma grande melhoria, ou seja, uma redução do tempo total despendido pelos veículos, em relação aos escalonamentos desenvolvidos manualmente, pelo Centro de Saúde de Bragança.
- Implementation of robust multi-objective optimization in the build orientation problemPublication . Matos, Marina A.; Rocha, Ana Maria A.C.; Costa, Lino; Pereira, Ana I.Additive manufacturing (AM) is an emerging technology to create 3D objects layer-by-layer directly from a 3D CAD model. The build orientation is a critical issue in AM and its optimization will significantly reduce the building costs and improve object accuracy. This paper aims to optimize the build orientation problem of a 3D CAD model using a robust multi-objective approach, taking into account the staircase effect and the support area characteristics. Thus, themain objective is to obtain a robust Pareto optimal front, composed of solutions that are not quite sensitive to perturbations in the variables. In this manner, a set of robust solutions is presented as alternatives and the decision-maker can identify the compromise solutions and choose according to his/her preferences.
- Improving additive manufacturing performance by build orientation optimizationPublication . Matos, Marina A.; Rocha, Ana Maria A.C.; Pereira, Ana I.Additive manufacturing (AM) is an emerging type of production technology to create three-dimensional objects layer-by-layer directly from a 3D CAD model. AM is being extensively used in several areas by engineers and designers. Build orientation is a critical issue in AM since it is associated with the part accuracy, the number of supports required and the processing time to produce the object. This paper presents an optimization approach to solve the part build orientation problem taking into account some characteristics or measures that can affect the accuracy of the part, namely the volumetric error, the support area, the staircase effect, the build time, the surface roughness and the surface quality. A global optimization method, the Electromagnetism-like algorithm, is used to solve the part build orientation problem.
- A multi-objective approach to solve the build orientation problem in additive manufacturingPublication . Matos, Marina A.; Rocha, Ana Maria A.C.; Costa, Lino; Pereira, Ana I.Additive manufacturing (AM) has been increasingly used in the creation of three-dimensional objects, layer-by-layer, from three-dimensional (3D) computer-aided design (CAD) models. The problem of determining the 3D model printing orientation can lead to reduced amount of supporting material, build time, costs associated with the deposited material, labor costs, and other factors. This problem has been formulated and studied as a single-objective optimization problem. More recently, due to the existence and relevance of considering multiple criteria, multi-objective approaches have been developed. In this paper, a multi-objective optimization approach is proposed to solve the part build orientation problem taking into account the support area characteristics and the build time. Therefore, the weighted Tchebycheff scalarization method embedded in the Electromagnetism-like Algorithm will be used to solve the part build orientation bi-objective problem of four 3D CAD models. The preliminary results seem promising when analyzing the Pareto fronts obtained for the 3D CAD models considered. Concluding, the multi-objective approach effectively solved the build orientation problem in AM, finding several compromise solutions.
- Multi-objective optimization in the build orientation of a 3D CAD modelPublication . Matos, Marina A.; Rocha, Ana Maria A.C.; Costa, Lino; Pereira, Ana I.Over the years, rapid prototyping technologies have grown and have been implemented in many 3D model production companies. A variety of different additive manufacturing (AM) techniques are used in rapid prototyping. AM refers to a process by which digital 3D design data is used to build up a component in layers by depositing material. Several high-quality parts are being created in various engineering materials, including metal, ceramics, polymers and their combinations in the form of composites, hybrids, or functionally classified materials. The orientation of 3D models is very important since it can have a great influence on the surface quality characteristics, such as process planning, post-processing, processing time and cost. Thus, the identification of the optimal build orientation for a part is one of the main issues in AM. The quality measures to optimize the build orientation problem may include the minimization of the surface roughness, build time, need of supports, maximize of the part stability in building process or part accuracy, among others. In this paper, a multi-objective approach was applied to a computer-aided design model using MATLAB® multi-objective genetic algorithm, aiming to optimize the support area, the staircase effect and the build time. Preliminary results show the effectiveness of the proposed approach. © 2021, The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Switzerland AG.
- On optimizing the build orientation problem using genetic algorithmPublication . Matos, Marina A.; Rocha, Ana Maria A.C.; Pereira, Ana I.Build orientation is a critical issue in Additive manufacturing (AM), where three-dimensional objects are created layer-by-layer directly from a 3D CAD model, since it is associated with the object accuracy, the number of supports required and the processing time to produce the object. Finding the best build orientation in the AM will reduce, significantly, the building costs and will improve the object accuracy. This work presents the solutions obtained by the Genetic Algorithm (GA) in solving the part build orientation optimization problem, considering the staircase effect, support area characteristics and the building time of four models. Preliminary experiments show that GA gives competitive results in solving the build orientation problem when compared with other metaheuristics.
- Path generation, control, and monitoringPublication . Faria, Carlos; Martins, Daniela A.L.; Matos, Marina A.; Pinho, Diana; Ramos, Bruna; Bicho, Estela; Costa, Lino; Espirito Santo, Isabel; Fonseca, Jaime; Monteiro, M. Teresa T.; Pereira, Ana I.; Rocha, Ana Maria A.C.; Vaz, A. Ismael F.A critical issue in additive manufacturing (AM) is the control of the printer actuators such that the deposition of material (or a few different materials) takes place in an organized way. Typically, the actuators are connected with a low-level controller that can receive computer numerical control (CNC) instruction. A 3D printer controller is, usually, expected to receive a set of CNC instructions in a format called G-Code, where a set of control instructions is provided. These instructions include the necessary settings for the printer to work (e.g., a temperature setup) and printer head movement instructions (e.g., the x-, y-, and z- positions in reference axes). The set of the printer actuators positions, where some operations take place, is called the printer path. Path planning or generation corresponds to the computation of the printer head trajectory during a period of time where the object is to be built. A five-degree of freedom/5-axis 3D printer that considers a hybrid process based on additive manufacturing of composites with long or short fibers reinforced thermoplastic matrix is being addressed in this book.