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This thesis develops an algorithm to decrease high-curvature sections in tool paths for complex parts to achieve shorter machining times resulting in higher production rates. In the research sample cases, the algorithm decreased machining times by 1% to 9% for design-induced sections of high curvature and by 16% to 75% for CAM induced ripples using high path tolerances. High-curvature sections in tool paths are caused by complex part geometry, noise, and discontinuities in the model. The curvature is decreased by deviating the tool path within an allowable path tolerance. The feedrate along the tool path is directly related to the curvature of the tool path. High-curvature sections cause the NC machine to reduce the feedrate along the tool path due to acceleration and jerk limits. These lower feedrates increase machining time and slow production rates. This new algorithm decreases curvature, which increases feedrates and decreases machining times, thereby increasing production rates for manufacturing companies. The tool paths are represented by cubic B-splines. The algorithm is based on the basic principle that the curvature of a B-spline directly relates to the geometry of its control polygon. If the control polygon's geometry has many tight corners then the B-spline will have high curvature. If the control polygon's geometry is a straight line then the B-spline will be a straight line with zero curvature. The algorithm deviates the control polygon's points so that they move towards forming a straight line. The control polygon will rarely form a straight line because the spline is limited by the path tolerance. However, as the control polygon moves towards forming a straight line, the curvature decreases, which allows the feedrate to increase. Six sample cases are explored in which the machining time is decreased. Three of the cases are tool paths that contain curvature sections with a range of unnecessary curvature from low to high. One sample is the tool path for the complex geometry in a snow tire mold. Another sample tool path contains ripples caused by noise in the CAD model. The last tool path contains ripples caused by tangency discontinuities in the CAD model. The percent of time saved directly relates to the severity of the curvature in the part. This thesis provides a quick and efficient means to reduce curvature in complex parts, resulting in decreased machining times and increased production rates.

Impellers are important components in the field of aerospace, energy technology, and precision machine industries. Considering the high accuracy and structural integrity, impellers might be manufactured by cutting. Due to their complex geometries and high degrees of interference in machining, multi-axis machines are requested to produce impellers. The object of this thesis is to improve 5-axis tool paths for surface quality of impellers by smoothing point cutting tool paths in terms of linear segments and B-Splines and by using flank milling technologies with linear segment and B-Splines tool paths. Experimental results show that the surface quality of impeller blades can be improved by point cutting with smoothed tool paths and by flank milling. Moreover, the required milling time can be reduced by 18 percent and 13percent based on smoothed linear tool paths and smoothed B-Splines tool paths, respectively.

This thesis is focused on techology of manufacturing a "cage" component at CCI Brno company. It solves drilling holes to the outside diameter of it. In the first part the company CCI is introduced, and in the second part is focused on component and material analysis. Next step is analyzing present manufacturing procedures and proposing its change. At the end of this thesis is techno-economic comparison of the present and proposed technological change.

Atualmente, nota-se um crescimento na fabricação de produtos utilizando moldes e matrizes contendo formas geométricas complexas. No entanto, a fabricação destes ferramentais onde se emprega, principalmente, operações de fresamento, não tem acompanhado esta evolução com a mesma velocidade. O advento dos sistemas CAD/CAM, máquinas CNC e da tecnologia de usinagem em altas velocidades (HSC) influenciaram positivamente a fabricação de superfícies complexas. Contudo, nota-se ainda ineficiências neste processo produtivo. A qualidade superficial após as operações de usinagem ainda não é suficiente para que estes ferramentais entrem diretamente na linha de produção. Assim, operações manuais de acabamento são exigidas, elevando o tempo e custo de produção, comprometendo a qualidade dimensional. Com a finalidade de aprimorar a fabricação de moldes e matrizes, este trabalho apresenta uma revisão bibliográfica sobre a usinagem HSC; um estudo sobre a força de usinagem para o fresamento de formas complexas e uma análise sobre a metodologia utilizada por sistemas CAD/CAM e CNC para gerar e interpretar programas NC que contenham movimentações complexas de ferramenta. Análises práticas foram realizadas em um centro de usinagem HSC, e os resultados indicam que as limitações tecnológicas atuais na cadeia CAD/CAM/CNC limitam a usinagem de formas complexas com altas velocidades, reduzindo a velocidade de avanço programada e que as características intrínsecas deste processo de remoção de material demonstrou ser bastante complexo, acarretando em constantes alterações na força de usinagem / In recent years the number of products containing free-form shapes produced by dies and molds have been growing noticeably. However, the milling process used to manufacture those dies and molds does not meet their requirements. The arrival of the CAD/CAM systems and the High Speed Cutting Technology (HSC) helps to improve this manufacturing process. Although to obtain the surface quality needed to meet the dies and molds requirements, a hand finishing still requires. It involves time, money and decrease the product quality. Technological limitations in the CAD/CAM/CNC chain limit the feed rate when milling free-form shape. It also has a negative effect on the surface roughness. Besides, this kind of milling still lacks scientific knowledge of the cutting process. With the aim to support the dies and moulds fabrication, this work presents an overview about HSC Technology; the cutting forces in a non-planar milling; the cutting tool deflection; a detailed description of the process chain involving the CAD/CAM/CNC systems and the methodologies used by those systems to generate and accomplish free-free tool-paths. Free-form milling experiments applying the HSC Technology were made to study the behavior of this process, and the outcomes are presented

Atualmente, nota-se um crescimento na fabricação de produtos utilizando moldes e matrizes contendo formas geométricas complexas. No entanto, a fabricação destes ferramentais onde se emprega, principalmente, operações de fresamento, não tem acompanhado esta evolução com a mesma velocidade. O advento dos sistemas CAD/CAM, máquinas CNC e da tecnologia de usinagem em altas velocidades (HSC) influenciaram positivamente a fabricação de superfícies complexas. Contudo, nota-se ainda ineficiências neste processo produtivo. A qualidade superficial após as operações de usinagem ainda não é suficiente para que estes ferramentais entrem diretamente na linha de produção. Assim, operações manuais de acabamento são exigidas, elevando o tempo e custo de produção, comprometendo a qualidade dimensional. Com a finalidade de aprimorar a fabricação de moldes e matrizes, este trabalho apresenta uma revisão bibliográfica sobre a usinagem HSC; um estudo sobre a força de usinagem para o fresamento de formas complexas e uma análise sobre a metodologia utilizada por sistemas CAD/CAM e CNC para gerar e interpretar programas NC que contenham movimentações complexas de ferramenta. Análises práticas foram realizadas em um centro de usinagem HSC, e os resultados indicam que as limitações tecnológicas atuais na cadeia CAD/CAM/CNC limitam a usinagem de formas complexas com altas velocidades, reduzindo a velocidade de avanço programada e que as características intrínsecas deste processo de remoção de material demonstrou ser bastante complexo, acarretando em constantes alterações na força de usinagem / In recent years the number of products containing free-form shapes produced by dies and molds have been growing noticeably. However, the milling process used to manufacture those dies and molds does not meet their requirements. The arrival of the CAD/CAM systems and the High Speed Cutting Technology (HSC) helps to improve this manufacturing process. Although to obtain the surface quality needed to meet the dies and molds requirements, a hand finishing still requires. It involves time, money and decrease the product quality. Technological limitations in the CAD/CAM/CNC chain limit the feed rate when milling free-form shape. It also has a negative effect on the surface roughness. Besides, this kind of milling still lacks scientific knowledge of the cutting process. With the aim to support the dies and moulds fabrication, this work presents an overview about HSC Technology; the cutting forces in a non-planar milling; the cutting tool deflection; a detailed description of the process chain involving the CAD/CAM/CNC systems and the methodologies used by those systems to generate and accomplish free-free tool-paths. Free-form milling experiments applying the HSC Technology were made to study the behavior of this process, and the outcomes are presented