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Optimization of wet or dry microblasting on PVD films by various Al2O3 grain sizes for improving the coated tools' cutting performance.

Micro-blasting on PVD coated tools is an effective technology for improving their cutting
performance. Through micro-blasting, compressive stresses are induced into the film, thus
increasing the coating hardness, but its brittleness too. Simultaneously, abrasion phenomena
are activated, which may lead to roughness augmentation, film thickness decrease and substrate
revelation. In this way, for a successful process conduct, it is pivotal to adapt, among others, the
applied micro-blasting pressure to the employed medium, air or water. The paper deals with the
optimization of wet or dry micro-blasting pressure by various Al2O3 grain sizes for improving
the coated tool’s wear resistance. The wear behaviour of coated and variously dry or wet
micro-blasted tools was investigated in milling. Considering the grains’ penetration kinematics
into the coated tool surface and the film deformation mechanisms during dry or wet microblasting
by fine or coarse sharp–edged Al2O3 grains, optimum process pressures can be
determined.