Porous metals, typically produced through powder metallurgy, represent a class of relatively new materials with wide industrial applications, lately extending into the microscale domain. Although produced in near-net shapes, most components fabricated from these materials still require some form of secondary machining. Despite the progress made in the field, relatively little is known either on the inherent cutting mechanism or on the behaviour of these materials under micromachining conditions. The present study reviews the main cutting theories proposed in macroscale machining, along with one of the primary parameters used to describe its machinability performances, namely cutting forces. Then, the feasibility of macroscale concepts is discussed in the context of micromachining technology that is characterized by comparable tool and pore sizes. The microslot cutting experiment performed in a porous titanium sample outlined the relative interplay between the magnitude of the cutting force and porosity of the material. Based on this, it was concluded that the impact of structural porosity on cutting forces experienced during micromachining is significant and therefore further in-depth investigations will be required.

A three-dimensional CFD model has been developed to predict track width during laser polishing (LP) of H13 tool steel. The developed model incorporates several different mechanisms for heat transfer such as conduction, convection, and radiation as well as temperature dependencies for relevant material properties. Experimental calibration was carried out to obtain adequate absorptivity value. After performing the mesh-sensitivity assessment, simulation results have been validated against experimental data. The relatively low errors obtained suggest that the developed model is capable to accurately describe the effect of process parameters on molten pool dimensions and/or geometry.Peer reviewed: YesNRC publication: Ye