Skip to main content

Machining Research

The metal cutting or machining is a process of geometrically defined removal of material. Localized shear of a metal being cut leads to strain, strain rate and temperature far beyond the majority of other manufacturing processes. We work to explore, solve and innovate in all aspects of machining research.

Photos of drilling and milling operations. photo.

Machining performance 

Machining, as a manufacturing process, is at the intersection of mechanics, thermodynamics, materials science and tribology. Such complexity makes the machining performance highly unpredictable. Our research covers questions of process mechanics (e.g. chip formation, forces, vibrations), thermal phenomena, tribology and tribo-chemistry. We study machining performance for metallic materials, fiber reinforced polymers and metal matrix composites.

scanning electron microscopy of the tool flank wear. photo.

Tool wear and degradation

In machining, the tool experiences extreme temperature, sliding speed and pressure while staying in intimate contact with the being cut material. We work with analysis of individual wear mechanisms (abrasive, adhesive, oxidation, diffusional and chemical) and their interplay under multi-mechanism interaction. In-depth analysis relies on advanced material characterization and computational predictive modelling.

Worn tool cross-sections. photo.

In recent years we have discovered that tool-workpiece-environment interaction may not lead to the tool wear. On the contrary some of the reaction products are refractory metal nitrides (e.g. (Ti,Cr,Nb)N [Bushlya, 2021]), borides (e.g. (Ti,V)B2 [Lindvall, 2020]), carbides (e.g. NbC [Olsson, 2020]), oxides (e.g. FeAl2O4, MgAl2O4 [Bjerke, 2021])). These products act as a Tool Protection Layer (TPL).


    Microscopy image of in-process reaction layer. photo.

    Machinability of materials

    Machinability of materials is another topic of our research. It covers the influence of composition, heat treatment, inclusions, trace elements and micro-alloying of metallic materials on their machinability.

    Microstructure of cemented carbide and tool flank wear

    Based on the findings related to Tool Protection Layer, we have developed a concept of increased machinability of metallic materials via controlled micro-alloying which relies on controlled and continuous in-situ formation of a protective layer on the tool surfaces that is built-up of refractory reaction phases.

    Interaction of inclusion from a steel with the tool coating. photo.

    Tooling and tool materials

    We work with the design and sintering of superhard polycrystalline cubic boron nitride (PcBN) and polycrystalline diamond (PCD) advanced materials for tooling applications. Our latest developments are developed for high performance machining of Ni and Ti superalloys

    microsctrucutes of the cemented carbide

    Another area is coating research, in particular design of physical vapor deposition (PVD) coatings based on their response to wear mechanisms.

    SEM of Al2O3 coating. photo.

    Modelling and Simulation of Machining

    Drive for machining efficiency relies on predictability of process behavior. We work with modelling and simulation of mechanical and thermal phenomena in machining. The questions of chip formation, cutting forces, tool stresses, and surface integrity (sub-surface deformation and residual stresses) are routinely investigated in order to optimize the machining process, improve cutting tool design, match tool and workpiece materials, etc.

    finite element modelling of the turning process

    We have also developed a modelling framework to describe the chemical and diffusional interaction of the cutting process. These models have been used to characterize the wear of cutting tools, and to find materials and condition when the interaction products reduce the wear rate and protect the cutting tools.

    Thermodynamic modelling of tool coating interaction with the workpiece material. photo.

    Surface integrity

    Characterization of surface integrity may entail inspection for surface defects (cracks, porosity, build-up edges), measurement of sub-surface deformation and stresses, or analysis of phase transformations, whichever dictates performance or failure via fatigue, corrosion or other mechanisms.

    Surface integrity refers to the state of machined surface and sub-surface layer in terms of composition, microstructural and mechanical properties which jointly define product performance.

    Electron backscatter of the work tool and stress corosion cracking of  brass and nano-indentetion. photo.


    Volodymyr Bushlya,, 2023

    Page Manager: | 2023-02-10