The technology of multi-axis machining has been applied extensively to the manufacturing of dies, molds, and various aerospace components. For machining mechanical parts with complex, sculptured surfaces, the use of multi-axis machine tools is probably the only one solution for avoiding tool-part collision during machining. Since cutting force will be changed by cutter attitudes, the machined surface characteristic can also be affected by cutter attitudes. In this thesis, the major concern is focused on investigating the effect of the cutter attitude on machined surface roughness. Based on the relationship between the cutter incline angle and the enveloped condition in cutting, the correlation of the mean chip thickness and the cutter incline angle is observed. To identify the relationship between the cutter attitude and the workpiece surface roughness, experimental verification is performed by milling aluminum alloy material. By fixing the cutting depths and the width of tool paths, different spindle rotational speeds and cutter incline angles are taken to machine the workpieces. And then, the machined surfaces are measured for their surface roughness. Form the experimental results, it shows that the surface roughness will reach a peak value at a special cutter incline angle. The tendency between the surface roughness and the incline angle agrees with that between the mean chip thickness and the cutter attitude approximately.

To further the research done in machining complex surfaces, Jensen [1993] developed an algorithm that matches the normal curvature at a point along the surface with the resultant radius formed by tilting a standard flat end mill. The algorithm called Curvature Matched Machining (CM2) is faster and more efficient than conventional three-axis machining [Jensen 1993, Simpson 1995 & Kitchen 1996]. Despite the successes of CM2 there are still many areas available for research. Consider the machining of a mold or die. The complex nature of a mold requires at least 20-30 weeks of lead time. Of those 20-30 weeks 50% is spent in machining. Of that time 50-65% is spent in rough machining. For a mold or die that amounts to 7 to 8 weeks of rough machining. If one could achieve as much as a 10-15% reduction in machining time that would amount to almost one week worth of time savings. As can be seen, small improvements in time and efficiency for rough machining can yield significant results [Fallbohmer 1996]. This research developed an algorithm that focused on reducing the overall machining time for parts and surfaces. Particularly, the focus of this research was within rough machining. The algorithm incorporated principles of three-axis rough cutting with five-axis CM2, hence Rough Curvature Matched Machining (RCM2). In doing so, the algorithm ‘morphed‘ planar machining slices to the semi-roughed surface allowing the finish pass to be complete in one pass. This roughing algorithm has significant time-savings over current roughing techniques.

Orientador: Anselmo Eduardo Diniz / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecanica / Made available in DSpace on 2018-08-07T18:44:10Z (GMT). No. of bitstreams: 1 Krabbe_DanielFernandoMoreira_M.pdf: 4840835 bytes, checksum: 3db5447d6c84ae0db244c137740e2a84 (MD5) Previous issue date: 2006 / Resumo: No processo de desbaste, a máxima taxa de material removido por unidade de tempo (cm3 x min), dentro do intervalo de máxima eficiência, é o foco principal para as mais diversas empresas de usinagem. Afirmando este conceito, procurou-se neste trabalho obter para dois diferentes diâmetros de fresas inteiriças de metal duro, a máxima vida de ferramenta por volume removido de material, na usinagem da liga de aço inoxidável endurecível por precipitação 15-5 PH. As variáveis deste estudo foram os diâmetros da ferramenta (16 e 20 mm), a profundidade de corte ¿ap¿ (5 a 16 mm), a profundidade radial de corte ¿ae¿ (33%D e 77%D) a velocidade de corte ¿vc¿ (80 e 100 m/min). Mantiveram-se constantes o número de dentes da fresa, a classe do metal duro e revestimento, a espessura média de cavaco, o fluido de corte e a taxa de remoção de material para cada profundidade radial de corte. Os parâmetros de avaliação foram o desgaste de flanco ¿vb¿ da aresta principal de corte, a potência consumida e o comprimento de corte fresado por vida da ferramenta. Os resultados demonstram que a fresa de menor diâmetro (16 mm) apresentou sempre uma maior vida de ferramenta para a mesma taxa de remoção de material quando comparada à fresa de maior diâmetro (20 mm). Demonstram também que para a menor condição de profundidade radial de corte estudada a uma profundidade axial de corte elevada (baixo ¿ae¿ alto ¿ap¿), a vida da ferramenta é superior quando comparada à mesma condição de taxa de remoção de material, porém com profundidade radial alta (alto ¿ae¿ e baixo ¿ap¿) / Abstract: In the roughing machining process, the maximum removal rate (cm3 x min-1) inside of the maximum efficiency interval, is the main target of the most different machining shops. Based in this concept, the target of these experiments was to find for two different end mill diameters in the milling process, the maximum removal rate per tool life in the 15-5 precipitation hardening stainless steel alloy. The input variables of these experiments were the end mill diameter (16 and 20 mm), the depth of the cut ¿ap¿ (from 5 to16 mm), the radial depth of cut ¿ae¿ (33%D and 77%D) the cutting speed ¿vc¿ (80 and 100 m/min). The end mill number of teeth, the solid carbide and surface coating characteristics, the average chip thickness, the cutting fluid and the removal rate for each radial depth of cut were kept constants. The evaluation parameters were the wear on the main cutting edge, the spindle power and the work piece machined length. The analysis of results showed that for a smaller end mill diameter (16 mm) always a longer tool life was reached for the same removal volume rate when compared with the end mill with larger diameter (20 mm). It also shows that for a smaller radial depth of cut and big depth of cut (small ¿ae¿ large ¿ap¿), the tool life is higher than when compared with the same removal rate condition, however with larger radial depth of cut and smaller depth of cut (big ¿ae¿ small ¿ap¿) / Mestrado / Engenharia de Fabricação / Mestre em Engenharia Mecânica

Metal matrix composites have seen a rise in demand within the last decade. Aluminum alloy reinforced with silicon carbide particles is a type of particle metal matrix composite that has seen applications in the aerospace, ground transportation, and electronics industry. However, the abrasive SiC particles have made this material difficult to machine through conventional machining strategies. This research will focus on using computer aided manufacturing with trochoidal tool paths to maximize machining productivity and extend the tool life of CVD diamond coated end mills. The focus of this research will be on AlSiCp with a high volume fraction of reinforcement (30%) to expand the potential applications of this pMMC. The cutting experiments are divided into three parts: cutting test, confirmation test, and endurance test. Taguchi method will be used to perform an analysis of variance and signal-to-noise ratio to optimize a combination of material removal rate, average cutting forces, and surface roughness. The optimal cutting conditions were found to be 254 mm/min, 30°, and 9500 r/min for MRR+AvgFxy+Ra, 1524 mm/min, 30°, and 9500 r/min for MRR+AvgFxy, and 1524 mm/min, 90°, and 9500 r/min. The cutting conditions for MRR+AvgFx+Ra was not considered for the endurance tests as the machining productivity was too low to be considered a feasible option in the industry. It was concluded that trochoidal milling under wet cutting conditions produced nearly half the tool wear as previous research with conventional milling strategies. However, the longer the CVD diamond coated end mills were engaged in the AlSiCp workpiece, the more dominant the abrasive wear mechanisms appear and cause tool damage. It was concluded that square end mills may not be suitable for machining AlSiCp and that future research should focus on varying the tool geometry or utilizing ball end mills.

Vid skärande bearbetning av material för att framställa olika produkter med önskade egenskaper orsakas förslitningar av verktygen som är viktiga att fotografera och analysera för att uppskatta livslängden. Detta kräver erfaren personal med precision som är svår att upprepa där automation kan vara en lösning för att avlasta personal från ett monotont arbete.  Syftet med studien är att bidra med kunskap om hur man kan fotografera förslitningen av verktyg med hjälp av automation och ge förslag på en lösning. För att komma med ett lösningsförslag har en nulägesanalys genomförts med hjälp av observationer och intervjuerhos Sandvik Coromant, litteratursökning för att undersöka vad som gjorts inom området redan och simuleringar.  Resultatet blev ett konstruktionsförslag för en kamerafixtur och cykeltider för att fotografera samtliga förslitningsområden för de testade verktygen i ett simuleringsprogram. Om lösningsförslaget ska implementeras i verkligheten kommer den behöva testas för att med säkerhet kunna fotografera med tillräckligt bra fokus och ljussättning samt att kamerafixturen inte blir för skakig vid rörelse med roboten. / The use of cutting tools in cutting processing cause tool wear which need be analysed and photographed to predict tool life. To analyse the tool wear you need technicians with experience with precision that is hard to repeat in which automation could be a solution.  The purpose of this study is to contribute with knowledge on how you could photograph tool wear using automation and suggest a solution. This was done with a current situation analysis with the use of observation and interview of the technicians at Sandvik Coromant. A literature study was conducted to gather information about what has been done earlier in this field. Later a suggestion on the design of the camera fixture was made and simulated in a simulation program with the robotic cell to ensure it is possible to implement in real life.  The result from the study suggests that the camera fixture with the current robotic cell is capable of automatically photograph the tool wear of the tested tools. If the suggested camera fixture should be implemented in real life it needs to be tested with the camera to confirm it gets good enough focus and lightning inside the CNC-machine. It also needs to be tested so it does not wobble to much with the usage of the robot.

The diploma thesis is focused on machining using the ball-end shank mill. Content of the preliminary part of the work is a shank mill characteristic and a consequent part shows a splitting of ball-end milling cutters, its application, the cutting tool geometry and a characteristic signs of machining. The cutting force model of the ball-end mill is presented as well. A part of proposed model is the conversion of the resultant force too. Practical part is aimed at cutting force analysis of the ball-end mill and the main purpose of this part is a quantification of the cutting force for different work piece tilt angles while milling is performed.

Since aircrafts manufacturers intend to produce low consumption and efficient aircrafts, parts become more and more difficult to machine. Some processes like „air machining“ enables a one-step production for complex aluminium alloy shaped parts. Although the assembly offers a large access to cutting tool, the lack of stiffness for large parts, and especially for thin-walled aeronautics parts implies strong vibrations during machining. The aim of the study is to solve these difficulties in order to keep productivity and improve surface quality. Further innovative solutions are considered like modal analysis, in-phase machining, spindle speed variation, 3 flutes end mill and variable helix angle mill. All propositions are tested on DMG 65 machine tool with Siemens 840D controller. Although vibrations are intrinsic to flexible parts, surface quality has been improved with higher cutting continuity and variable helix angle cutting tool.