Micro-/Nano-machining through Mechanical Cutting

Universidades tecnológicas: o que induziu esse modelo universitário no Brasil

“…Entre estas tecnologias estão o microprocessador inventado em 1971, a primeira calculadora eletrônica portátil a incorporar funções científicas em 1972 (MEHL, 2013), o primeiro computador eletrônico industrial criado em 1969, a fibra ótica e a produção de videocassetes (Sony) desenvolvidos em escala industrial, em meados da década de 1970de (CASTELLS, 1999PARKYN, 2005;SUN, CHENG, 2010). Em 1969, o Departamento de Defesa norte-americano inicia o uso de uma rede eletrônica de comunicação, que mais tarde se tornou a Internet (CASTELLS, 1999;TAIT, 2007).…”

A Review on Nanocomposites. Part 2: Micromachining

“…Size effects make the relationship between inputs (micromachining parameters) and outputs (surface quality, chip formation, cutting forces, tool wear) distinct to the conventional machining. Therefore, it could be seen that size effects are the key issues as well as the basis to explain the unusual aspects that micromachining processes have achieved [6,[8][9][10][11][12]. Size effects are the results of extrapolated-value aberration from macro to micromachining.…”

“…On the other hand, when micromachining using micro-tools, the tool edge radius approaches the grain size, homogenous and isotropic assumptions are no longer valid. Work-piece material structure is now considered as an assemblage of distinct grains with random distribution within the material system or anisotropic characteristic [9,10,18,19]. Therefore, in this case, the cutting mechanism takes place by breaking each individual grain [9,12,16] that requires more specific cutting energies or forces and mean flow stress due to atom bonds (Figure 4Figure 4).…”

“…A decrease of UCT into below the magnitude of edge radius (10-60 nm) leads to a significant increase of surface roughness for various levels of cutting speeds (10 and 150 m/min) [34]. In micromachining, shear stress increases around the cutting edge instead of along the shear plane [6,9], and the work-piece is ploughed or elastically deformed rather than being sheared/cut [35,36] when cutting depth and feed-rate below a threshold so-called 'minimum uncut chip thickness'. It was defined as a lower limit of minimum under form chip thickness that can be feasible to be removed [37] ( Figure 8Figure 8).…”

Convective heat transfer in microchannels with varying flow cross-section

“…Micromechanical cutting includes micro-milling, micro-turning, micro-drilling and micro-grinding [97]. The former two are the most commonly applied methods [98].…”