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Abstract(s)
O processo de fresagem é um processo de maquinagem de corte por arranque de apara, muito utilizado nas indústrias metalomecânicas. As constantes evoluções das máquinas CNC fazem com que o processo de fresagem se torne bastante versátil. Assim sendo, e com vista ao acompanhamento desta evolução, surge a necessidade de evoluir as ferramentas de corte. Desta forma, os revestimentos em ferramentas tem-se tornado o fator-chave na maquinagem de novas ligas metálicas, que constituem alguns produtos da engenharia. Os estudos dos revestimentos permitem que as ferramentas de corte sejam cada vez mais desenvolvidas e acompanhem essencialmente as exigências que o mercado dos materiais oferece relativamente à sua maquinabilidade. Por outro lado, a constante evolução das ligas metálicas é um indicador que as empresas devem acompanhar com atenção, de forma a resolver os problemas que estes materiais podem desenvolver. Assim, a liga de cobre-berílio (AMPCOLOY® 83) é o material que estará no centro de toda esta investigação. Existem vários problemas no processamento desta liga, nomeadamente a deterioração da ferramenta de corte durante o processo de maquinagem, devido à adesão de material à superfície da ferramenta, causada pela natureza dúctil desta liga. Foram realizados ensaios de maquinagem de topo com parâmetros fornecidos pelo fabricante das ferramentas, fazendo-se variar apenas a velocidade de avanço e o comprimento de corte. Nos resultados, foi realizada uma avaliação ao desgaste da ferramenta após a maquinagem da liga de Cu-Be (AMPCOLOY® 83), utilizando ferramentas revestidas e não revestidas. Os resultados oferecem uma comparação do desempenho da maquinagem e do comportamento de desgaste das ferramentas tóricas não revestidas de metal duro e, ferramentas com a mesma geometria, revestidas com uma multicamada de CrN/DLC. Em cada ensaio, foi analisada a rugosidade superficial da superfície maquinada, o desgaste do flanco da ferramenta e os mecanismos de desgaste que essas ferramentas sofreram. As ferramentas revestidas apresentaram um melhor desempenho para comprimentos de corte mais curtos, produzindo uma rugosidade menor na superfície da peça maquinada. O desgaste para esta ferramenta foi menos intenso do que o da ferramenta não revestida, que sofreram danos adesivos. Contudo, observou-se que para comprimentos de corte mais elevados, as ferramentas não revestidas obtiveram um melhor desempenho em termos de rugosidade da superfície maquinada, assim como ao nível do desgaste da ferramenta.
The milling process is a cheap cutting machining process widely used in metalworking industries. The constant evolutions of CNC machines make the milling process very versatile. Therefore, and in order to follow this evolution, the need to evolve the cutting tools arises. In this way, coatings on tools become the key factor in the machining of new metal alloys usually used on engineering products. The studies on coatings allow cutting tools to be increasingly developed and to follow the demands that the materials market offers, in relation to their machinability. On the other hand, the constant evolution of metallic alloys is an indicator that companies must follow carefully, in order to solve the problems that these materials can develop. Thus, the copper-beryllium alloy (AMPCOLOY® 83) is the material that will be at the center of all this research. There are several problems in the processing of this alloy, namely the deterioration of the cutting tool during the machining process, due to the adhesion of material to the tool surface caused by the ductile nature of this alloy. Top machining tests were performed with parameters provided by the tool manufacturer, varying only the feed rate and length of cut. In the results, an evaluation was observed on the tool wear after machining the Cu-Be alloy (AMPCOLOY® 83) using coated and uncoated tools. The results provide a comparison of the machining performance and wear behaviour of uncoated toroidal carbide tools and tools with the same geometry, coated with a CrN/DLC multilayer. In each test, surface roughness of the machined surface, tool flank wear and the wear mechanisms affecting the tools were analysed. The coated tools performed better for lower cutting lengths, producing a lower surface roughness on the machined part. The wear for this tool was less intense than that of the uncoated tool, which suffered adhesive and abrasive damage. However, it was observed that for higher cutting lengths, the uncoated tool performed better in terms of surface roughness, as well as wear sustained.
The milling process is a cheap cutting machining process widely used in metalworking industries. The constant evolutions of CNC machines make the milling process very versatile. Therefore, and in order to follow this evolution, the need to evolve the cutting tools arises. In this way, coatings on tools become the key factor in the machining of new metal alloys usually used on engineering products. The studies on coatings allow cutting tools to be increasingly developed and to follow the demands that the materials market offers, in relation to their machinability. On the other hand, the constant evolution of metallic alloys is an indicator that companies must follow carefully, in order to solve the problems that these materials can develop. Thus, the copper-beryllium alloy (AMPCOLOY® 83) is the material that will be at the center of all this research. There are several problems in the processing of this alloy, namely the deterioration of the cutting tool during the machining process, due to the adhesion of material to the tool surface caused by the ductile nature of this alloy. Top machining tests were performed with parameters provided by the tool manufacturer, varying only the feed rate and length of cut. In the results, an evaluation was observed on the tool wear after machining the Cu-Be alloy (AMPCOLOY® 83) using coated and uncoated tools. The results provide a comparison of the machining performance and wear behaviour of uncoated toroidal carbide tools and tools with the same geometry, coated with a CrN/DLC multilayer. In each test, surface roughness of the machined surface, tool flank wear and the wear mechanisms affecting the tools were analysed. The coated tools performed better for lower cutting lengths, producing a lower surface roughness on the machined part. The wear for this tool was less intense than that of the uncoated tool, which suffered adhesive and abrasive damage. However, it was observed that for higher cutting lengths, the uncoated tool performed better in terms of surface roughness, as well as wear sustained.
Description
Keywords
Maquinagem Liga Cobre-Berílio (AMPCOLOY® 83) Ferramentas de corte Revestimentos Rugosidade superficial Mecanismos de desgaste Machining Cu-Be alloy (AMPCOLOY® 83) Cutting tools Coating Surface roughness Wear mechanisms