Incremental sheet forming process is a relatively new method of forming which is increasingly being used in the industry. Complex shapes can be manufactured using this method and the forming operation doesn't require any dies. High strains of over 300 % can also be achieved. Incremental sheet forming method is used to manufacture many different components presently. Prototype examples include car headlights, tubs, train body panels and medical products. The work done in the thesis deals with the prediction of the steady state forces acting on the tool during forming. Prediction of forces generated would help to design the machine against excessive vibrations. It would help the user to protect the tool and the material blank from failure. An efficient design ensures that the tool would not get deflected out of its path while forming, improving the accuracy of the finished part. To study the forces, experiments were conducted by forming pyramid and cone shapes. An experimental arrangement was set up and experimental data was collected using a data acquisition system. The effect that the various process parameters, like the thickness of the sheet, wall angle of the part and tool diameter had on the steady state force were studied. A three dimensional model was developed using commercial finite element software ABAQUS using a new modeling technique to simulate the deformation of the sheet metal blank during incremental sheet forming. The steady state forces generated for any shape, with any set of parameters used, could be predicted using the numerical model. The advantage of having a numerical model is that the forces can be predicted without doing experiments. The model was used to predict the steady state forces developed during forming of pyramid and cone shapes. The results were compared and were seen to be reasonably close to the experimental results. Later, the numerical model was validated by forming arbitrary shapes and comparing the value obtained from simulations to the value of the measured steady state forces. The results obtained from the numerical model were seen to match very well with the experimental forces for the new shapes. The numerical model developed using the new technique was seen to predict forces to a reasonable extent with less computational time as compared to the models currently available.

Este trabalho descreve a adaptação de um equipamento CNC e ferramentas computacionais CAD/CAM (desenvolvidas originalmente para a área de usinagem) na conformação de chapas de alumínio comercialmente puro, através do processo de estampagem incremental. Através das simulações e dos testes reais foi possível obter resultados práticos, relativos às limitações geométricas e ao acabamento superficial. As peças conformadas têm o formato básico de um tronco de cone, onde foram alterados a profundidade e o ângulo do cone. A análise dimensional das peças, comparadas com seu respectivo modelo CAD revelou razoável conformidade geométrica. Por outro lado, ângulos de parede maiores que 65° causaram o rompimento da chapa. As estampagens foram realizadas em um centro de usinagem, e utilizaram-se como valores máximos a velocidade de avanço de 2.200 mm/min e o incremento vertical de 1mm, por questões de segurança e também pela constatação de problemas de acabamento superficial e de vibrações excessivas do equipamento. Como conclusão final, foi demonstrado que, para o tipo específico de peça (material, espessura e geometria), dispositivo prensa-chapas, ferramentas, equipamento CNC e softwares utilizados, o processo de estampagem incremental seria viável para lotes de até 600 peças. / This paper describes the adaptation of a CNC equipment and CAD/CAM computational tools (originally developed for the machining area) on the conformation of sheets of commercially pure aluminum, through the process of incremental forming. Through simulations and tests were unable to get practical results, for the geometric constraints and surface finishing. Forming parts have the basic format of a truncated cone, which have changed the depth and angle of the cone. A dimensional analysis of the parts, compared with their CAD model showed geometric reasonable compliance. Moreover, the wall angles greater than 65 ° caused the breaking of the plate. The sheets formings were performed in a machining center, with a maximum speed of advance of 2,200 mm/min and the vertical increase of 1mm, for reasons of safety and also for finding finishing surface problems and the excessive vibration equipment. As final conclusion, it was demonstrated that, for the specific type of piece (material, thickness and geometry), device-press plates, tools, CNC equipment and software used, the process of incremental sheet forming feasible for batches of up to 600 pieces.

Este trabalho descreve a adaptação de um equipamento CNC e ferramentas computacionais CAD/CAM (desenvolvidas originalmente para a área de usinagem) na conformação de chapas de alumínio comercialmente puro, através do processo de estampagem incremental. Através das simulações e dos testes reais foi possível obter resultados práticos, relativos às limitações geométricas e ao acabamento superficial. As peças conformadas têm o formato básico de um tronco de cone, onde foram alterados a profundidade e o ângulo do cone. A análise dimensional das peças, comparadas com seu respectivo modelo CAD revelou razoável conformidade geométrica. Por outro lado, ângulos de parede maiores que 65° causaram o rompimento da chapa. As estampagens foram realizadas em um centro de usinagem, e utilizaram-se como valores máximos a velocidade de avanço de 2.200 mm/min e o incremento vertical de 1mm, por questões de segurança e também pela constatação de problemas de acabamento superficial e de vibrações excessivas do equipamento. Como conclusão final, foi demonstrado que, para o tipo específico de peça (material, espessura e geometria), dispositivo prensa-chapas, ferramentas, equipamento CNC e softwares utilizados, o processo de estampagem incremental seria viável para lotes de até 600 peças. / This paper describes the adaptation of a CNC equipment and CAD/CAM computational tools (originally developed for the machining area) on the conformation of sheets of commercially pure aluminum, through the process of incremental forming. Through simulations and tests were unable to get practical results, for the geometric constraints and surface finishing. Forming parts have the basic format of a truncated cone, which have changed the depth and angle of the cone. A dimensional analysis of the parts, compared with their CAD model showed geometric reasonable compliance. Moreover, the wall angles greater than 65 ° caused the breaking of the plate. The sheets formings were performed in a machining center, with a maximum speed of advance of 2,200 mm/min and the vertical increase of 1mm, for reasons of safety and also for finding finishing surface problems and the excessive vibration equipment. As final conclusion, it was demonstrated that, for the specific type of piece (material, thickness and geometry), device-press plates, tools, CNC equipment and software used, the process of incremental sheet forming feasible for batches of up to 600 pieces.

Este trabalho descreve a adaptação de um equipamento CNC e ferramentas computacionais CAD/CAM (desenvolvidas originalmente para a área de usinagem) na conformação de chapas de alumínio comercialmente puro, através do processo de estampagem incremental. Através das simulações e dos testes reais foi possível obter resultados práticos, relativos às limitações geométricas e ao acabamento superficial. As peças conformadas têm o formato básico de um tronco de cone, onde foram alterados a profundidade e o ângulo do cone. A análise dimensional das peças, comparadas com seu respectivo modelo CAD revelou razoável conformidade geométrica. Por outro lado, ângulos de parede maiores que 65° causaram o rompimento da chapa. As estampagens foram realizadas em um centro de usinagem, e utilizaram-se como valores máximos a velocidade de avanço de 2.200 mm/min e o incremento vertical de 1mm, por questões de segurança e também pela constatação de problemas de acabamento superficial e de vibrações excessivas do equipamento. Como conclusão final, foi demonstrado que, para o tipo específico de peça (material, espessura e geometria), dispositivo prensa-chapas, ferramentas, equipamento CNC e softwares utilizados, o processo de estampagem incremental seria viável para lotes de até 600 peças. / This paper describes the adaptation of a CNC equipment and CAD/CAM computational tools (originally developed for the machining area) on the conformation of sheets of commercially pure aluminum, through the process of incremental forming. Through simulations and tests were unable to get practical results, for the geometric constraints and surface finishing. Forming parts have the basic format of a truncated cone, which have changed the depth and angle of the cone. A dimensional analysis of the parts, compared with their CAD model showed geometric reasonable compliance. Moreover, the wall angles greater than 65 ° caused the breaking of the plate. The sheets formings were performed in a machining center, with a maximum speed of advance of 2,200 mm/min and the vertical increase of 1mm, for reasons of safety and also for finding finishing surface problems and the excessive vibration equipment. As final conclusion, it was demonstrated that, for the specific type of piece (material, thickness and geometry), device-press plates, tools, CNC equipment and software used, the process of incremental sheet forming feasible for batches of up to 600 pieces.

The Caribbean steelpan is a pitched percussion instrument that originated in Trinidad and Tobago during the Second World War. Despite several research initiatives to improve the making of this relatively new instrument, several areas remain unaddressed. This thesis presents new approaches to help improve the making of the instrument. These approaches are situated in the production, vibration and material aspect of the steelpan. A novel sheet forming technology termed Incremental Sheet Forming (ISF) is applied to the production of miniature steelpan dishes. The thickness distribution in the wall of the ISF dishes is compared to the wall thickness distribution in a traditionally formed steelpan dish and a wheeled dish. Unlike traditional forming and wheeling, ISF produces stretching in only a portion of the walls of the formed dishes. Multi-pass ISF is used to extend the stretched zone but this extension is minimal. A break even analysis is also applied to investigate the fiscal viability of ISF application to the production of miniature and full size steelpan dishes. The application of ISF to steelpan making is found to be commercially profitable but could be jeopardised by the tuning stage of the steelpan making process. A preliminary study on the effect of impact on tone stability is conducted on a pair of notes on a fullsize steelpan and detuning is found more likely to occur by repeated impact of the note at its centre. Mode confinement in test-pans is also investigated. ISF is used to produce miniature test-pans with test-notes that are geometrically identical to notes on full size pans. It is possible to confine modes by varying the curvature of the bowl surrounding the test-note. The number of localised modes in the test-note increases as the radius of curvature of the surrounding bowl increases. The natural frequency of the first confined mode in the test-notes is sensitive to material springback in ISF and the mechanism of confinement appears to be due to the change in geometry that occurs between the flat test-note region and the bowl wall. This control of mode confinement may find use in future efforts to completely or partially automate the steelpan making process. Material damping and mechanical properties in low-carbon steel used to produce steelpans are researched. Damping and mechanical properties are extracted from low-carbon steel that is subjected to identical stages to the steelpan production process. Material damping trends suggest that an annealing temperature between 300°C and 400°C would be appropriate for the heat treatment of steelpans. Air-cooled and water-quenched low-carbon specimens exhibit comparable damping trends. Hardness increases in cold formed low-carbon specimens is attributed to strain hardening and not strain ageing. Investigation of damping trends and mechanical properties in ultra low bake-hardenable and interstitial-free steels reveals that a wider range of low-carbon steels may be suitable for steelpan making.

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O presente trabalho possui o objetivo de avaliar a aplicabilidade da metrologia em uma ferramenta de estampagem incremental de chapas. Para o estudo foi confeccionada uma ferramenta de estampagem com rebaixos em seu corpo cilíndrico para a fixação dos sensores que mediram a deformação relativa. As análises apresentadas nesta pesquisa representam os cuidados e processos necessários ao uso de extensômetros aliado a um processo de fabricação mecânica. No presente estudo define-se a calibração de um sistema de medição da deformação superficial da ferramenta de estampagem com auxílio da Extensometria. Para validar os resultados obtidos pelos métodos da instrumentação das medidas das deformações e forças no processo de estampagem incremental foram utilizados os métodos de Cálculos Analíticos e Simulação Numérica por meio de softwares de Elementos Finitos. No método de medida se considerou parâmetros que podem comprometer os valores medidos tais como a medida da temperatura utilizando equipamentos termovisor. Além disso, foram realizados 04 (quatro) ensaios preliminares com o intuito de avaliar a medição de forma satisfatória nos eixos X e Y do processo de estampagem incremental, efetuando análises das forças nesses eixos em tração e compressão. A estampagem incremental ocorreu por meio de um total de 09 (nove) Ensaios variando-se ângulo de parede (ψ) e espessura das chapas (s0). Os experimentos baseiam-se na variante de estampagem incremental denominada Estampagem Incremental de Ponto Simples (SPIF – Single Point Incremental Forming). Para a execução dos testes práticos foram utilizados recursos de hardware como Ponte Wheatstone, extensômetros, Termovisor, Centro de Usinagem CNC, matriz incremental, ferramenta de estampagem incremental e um dispositivo prensa chapas. Além de recursos de software CAD/CAM, DAQ (Data Acquisition System), Análise de Elementos Finitos. E recursos de cálculos analíticos como forma comprobatória de resultados. A partir dos procedimentos executados junto com aparato tecnológico foi possível efetuar as análises e medições das forças na ferramenta de estampagem incrementa com referência aos eixos X e Y. Demonstrando neste a aplicabilidade de extensometria para leitura e análise de forças no processo de ISF. / This present work has the objective of assessing the applicability of instrumentation science in an incremental forming tool. For this study was made a tool with recesses on its cylindrical body as a means of fixing the strain sensors. The study presented demonstrate some of the warning and processes required the use of Strain Gages combined with a mechanical manufacturing process. In the present study is defined as an acceptable calibration measuring system with the aid of Extensometry. To validate the results obtained by the methods of instrumentation measurements of the deformations and forces in incremental sheet forming process were used Analytical Calculations and Numerical Simulation using Finite Elements. The measurement method was considered parameters that can compromise the measured values such as temperature measurement devices using thermometer. In addition, we conducted four (04) preliminary tests in order to evaluate the measurement system in satisfactory form with measured variables such as X and Y axes. We analyses the traction and compression forces in both axes. After the preliminary step, was performed a total of nine (09) tests with incremental sheet forming process, varying wall angle (ψ) and the thickness (s0). The experiments are based on the Single Point Incremental Forming - SPIF. For the implementation of the practical tests were used hardware resources such as CNC Machining Center, Wheatstone Bridge, Strain Gauges, Thermal Imager, incremental matrix and incremental forming tool. Besides, we used softwares such as CAD/CAM, DAQ (Data Acquisition System) and Finite Element Analysis. From the technological procedures perform with apparatus was possible do carry out the analyzes and measurement of forces in incremental sheet forming tool increases about to the axes X and Y. Demonstrating the applicability of the extensometry for reading and analyzing forces in the ISF process.

O presente trabalho tem como objetivo avaliar o comportamento da chapa de latão 70/30 para o processo de Estampagem Incremental de Chapas (ISF - Incremental Sheet Forming), baseado nos parâmetros: ângulo de parede (ψ), passo vertical ( Z) e estratégia do caminho da ferramenta. Os experimentos baseiam-se na variante da Estampagem Incremental denominada Estampagem Incremental com Ponto Simples (SPIF - Single Point Incremental Forming). Foram realizados 18 ensaios usando uma ferramenta de estampar com raio (RT) de 5 mm. Para execução dos testes práticos, foram utilizados os recursos: softwares CAD/CAM, centro de usinagem CNC com três eixos, matriz incremental, ferramenta de estampagem incremental e um dispositivo prensa chapas. Além disso, o acabamento da superfície conformada foi medido através do parâmetro de rugosidade RZ nos principais ensaios, bem como a medição das deformações verdadeiras (j) e da espessura (s1). Os testes práticos demonstraram que a estratégia de usinagem espiral proporcionou um maior ângulo de parede, comparado à estratégia paralela de contorno. / This study aims to evaluate the behavior of 70/30 brass plate to the process of Incremental Sheet Forming - ISF, based on the parameters: wall angle (ψ), vertical step ( Z) and tool path strategy. The experiments were based on a variation of the ISF process, called SPIF (Single Point Incremental Forming). Eighteen tests were conducted using a punching tool with a radius (RT) of 5 mm. For the execution of practical tests, the resources were used: CAD / CAM software, CNC machining center with three axis. It was also used an incremental matrix, a tool for incremental forming and a sheet-press device. In addition, the surface finish was measured by RZ roughness parameter in the main tests, the same way the measurement of true strains (φ) and thickness (s1). The practice tests showed that the spiral machining strategy has provided a greater wall angle, compared to the parallel strategy contour.

O presente trabalho estuda o processo de estampagem incremental em chapas de alumínio puro, descrevendo as ferramentas e um suporte prensa chapas. Estuda e pesquisa bibliograficamente e experimentalmente o processo de estampagem incremental. O trabalho apresenta os procedimentos de caracterização utilizados para determinar os limites do processo, aplicáveis para chapas de 0,5 mm de espessura em alumínio puro. A caracterização da chapa, juntamente com o ensaio mecânico de tração e os testes práticos de estampagem fornecerão um panorama da estampagem incremental, para algumas situações diversas sobre o tema. Para a execução dos testes práticos foi fabricado um dispositivo prensa chapas e um punção, matriz incremental e ferramenta de estampagem incremental, também foram feitas adaptações na máquina CNC, centro de usinagem CNC com três eixos. / This paper studies the process of incremental sheet forming, in plates the aluminum pure, describing the tools and support a press plates. Studies and literature search and experimentally the process of stamping incremental. The work presents the characterization of procedures used to determine the limits of the process, applicable to plates of 0.5 mm thick pure aluminum. The characterization of the plate, along with mechanical traction test and practical tests of printing provide an overview of incremental printing, for some different situations on the subject. For the practical implementation of the tests was a device manufactured press plates and a puncture, matrix and incremental tool for stamping incremental, were also made adjustments in the CNC machine, CNC machining center with three axles.