Energia específica de corte e integridade superficial no microfresamento do ABNT 1045
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Data
2012-06-22
Autores
Moreira, Suzana Regina da Silva [UNESP]
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
A microusinagem produz microcomponentes especialmente para as áreas microeletrônica, médica e aeroespacial, e encontra-se em contínua evolução com o surgimento de materiais com propriedades melhoradas, ferramentas de dimensões reduzidas e máquinas mais rígidas e precisas, porém o estudo da integridade superficial das peças, visando aprimorar o desempenho dos componentes miniaturizados, ainda é um campo de pesquisa incipiente. Este trabalho objetivou correlacionar os principais indicadores de integridade superficial à energia específica de corte no micro e macrofresamento de canais usinados no aço ABNT 1045. Foi determinada a influência do avanço por dente (f z) e da profundidade de usinagem (ap) na energia específica de corte, microdureza, microestrutura, temperatura de corte, formação de rebarbas e rugosidade da peça. Os ensaios foram conduzidos sem aplicação de fluido lubrirrefrigerante em um centro de usinagem CNC Hermle C800U, adotando simultaneamente corte concordante e discordante. Utilizou-se fresas de carbeto de tungstênio revestidas de TiNAl, 0,8 e 2,0 mm com duas arestas, aplicadas em micro e macrofresamento, respectivamente. Análise de Variância (ANOVA) foi empregada para a determinação de significâncias dos fatores de controle nas variáveis de resposta. Os resultados revelaram que a integridade superficial decorrente do microfresamento, mesmo com parâmetros de corte brandos, é mais afetada se comparada à do macrofresamento, pois, em média, a energia específica de corte foi superior 75%, a microdureza superficial 75%, a camada encruada 5x, a deformação microestrutural 60%, a temperatura de corte 3x e o tamanho da rebarda alcançou a largura do microcanal para avanços por dente inferiores a 1/3 do raio de aresta da ferramenta. Apenas a rugosidade diminuiu em média 16%, porém qualitativamente apresentou...
Micromachining produces microcomponents mainly for areas such as microelectronics, medical and aerospace, and it is continually evolving due to the release of new materials with improved properties, tools with reduced dimensions and machines more rigid and accurate, wherefore studies relating surface integrity of workpieces aiming at improving the performance of miniaturized components are still an incipient field of research. This research correlated the main surface integrity indicators to the specific cutting energy in the micro and macromilling of channels machined in ABNT 1045 steel. The effects of feed per tooth (f z) and depth of cut (ap) upon the specific cutting energy, microhardness, microstructure, cutting temperature, burr formation and workpiece roughness were determined. The experiments were carried out without coolant in a CNC machining center Hermle C800U by adopting simultaneously up and downmilling. 0.8 and 2.0 mm diameter endmills with two flutes, coated with TiNAl were used in tests for micro and macromilling, respectively. Analysis of Variance (ANOVA) allowed determining statistical significances of control factors on the response variables. The results revealed that surface integrity from micromilling, even with gentle cutting parameters, is more affected when comparing to that from macromilling, since specific cutting energy was superior on average 75%, surface microhardness 75%, work hardened layer 5 times, microstructure deformation 60%, cutting temperature 3 times and burr size reached the microchannel width for feeds per tooth lower than a third of tool edge radius. Only roughness reduced around 16%, but qualitatively caused microcracks, cavities and delamination. It is concluded that the choose appropriate of machining parameters concerning tool edge radius in micromachining is... (Complete abstract click electronic access below)
Micromachining produces microcomponents mainly for areas such as microelectronics, medical and aerospace, and it is continually evolving due to the release of new materials with improved properties, tools with reduced dimensions and machines more rigid and accurate, wherefore studies relating surface integrity of workpieces aiming at improving the performance of miniaturized components are still an incipient field of research. This research correlated the main surface integrity indicators to the specific cutting energy in the micro and macromilling of channels machined in ABNT 1045 steel. The effects of feed per tooth (f z) and depth of cut (ap) upon the specific cutting energy, microhardness, microstructure, cutting temperature, burr formation and workpiece roughness were determined. The experiments were carried out without coolant in a CNC machining center Hermle C800U by adopting simultaneously up and downmilling. 0.8 and 2.0 mm diameter endmills with two flutes, coated with TiNAl were used in tests for micro and macromilling, respectively. Analysis of Variance (ANOVA) allowed determining statistical significances of control factors on the response variables. The results revealed that surface integrity from micromilling, even with gentle cutting parameters, is more affected when comparing to that from macromilling, since specific cutting energy was superior on average 75%, surface microhardness 75%, work hardened layer 5 times, microstructure deformation 60%, cutting temperature 3 times and burr size reached the microchannel width for feeds per tooth lower than a third of tool edge radius. Only roughness reduced around 16%, but qualitatively caused microcracks, cavities and delamination. It is concluded that the choose appropriate of machining parameters concerning tool edge radius in micromachining is... (Complete abstract click electronic access below)
Descrição
Palavras-chave
Fresagem (Trabalhos em metal), Usinagem, Micromachining
Como citar
MOREIRA, Suzana Regina da Silva. Energia específica de corte e integridade superficial no microfresamento do ABNT 1045. 2012. 90 f. Dissertação (mestrado) - Universidade Estadual Paulista Júlio de Mesquita Filho, Faculdade de Engenharia de Ilha Solteira, 2012.