The Prediction of Machined Surface Hardness Using a New Physics-based Material Model

AbstractThis paper investigates the predictionof machined surface hardness, a key material property, as a direct consequence of machining induced microstructure evolution. To this end, a newphysics-based material model is implemented into the AdvantEdgeTM software via a user-defined material subroutine and used to simulate the orthogonal cutting of OFHC copper. This material model explicitly integrates the microstructure, represented by dislocation density and grain size, into the constitutive description of inelastic deformation. The associated microstructure evolution laws in conjunction with the constitutive law provide a unified microstructure-property framework in which the microstructure evolves during deformation via hardening, dynamic recovery, and dynamic recrystallization mechanisms and the evolved microstructure features are directly fed back to the flow stress model. The predicted hardness distribution in the spatial domain of deformation in orthogonal cutting is benchmarked against experimental data

Experimental study of micro- and nano-scale cutting of aluminum 7075-T6

10.1016/j.ijmachtools.2005.08.004International Journal of Machine Tools and Manufacture469929-936IMTM

Hybrid laser assisted machining: a new manufacturing technology for ceramic components

Abstract Silicon nitride is a high-performance ceramic used for high-temperature structural applications due to its elevated strength, fracture toughness and corrosion resistance. These properties make this material extremely difficult to machine, leading to component costs that can be prohibitive in many fields where its characteristics could provide improvements in performance. In order to overcome manufacturing limitations, a new technique is proposed in this paper: a hybrid solution that combines laser and conventional cutting tools where the laser source induces controlled cracking into the surface of the material. By properly selecting the laser parameters (laser power, scanning speed, etc.), the crack depth can be smaller than the machining depth of cut. Cracking can be performed in a preceding phase so that no thermal load is induced in the inserts, while maximum cutting load is reduced, thus increasing tool life

Dry generating gear grinding: Hierarchical two-step finite element model for process optimization

Recent developments in the automotive industry have led to more stringent requirements for transmission gear quality. This aspect, combined with a massive increase in the number of gears produced per year, has seen generating grinding become the finishing method of choice for mass production of gears. Due to the intrinsic nature of grinding, this process remains the only manufacturing phase that still requires the widespread use of lubricant. With the aim of improving the environmental sustainability of this process chain, recent attempts at performing dry grinding without lubricant have highlighted the critical aspect of thermal damage produced under these conditions. In the present work, a twostep finite element modeling approach is presented for predicting thermal damage during dry generating gear grinding. Grinding forces and thermal energy generated by the interaction of a single grain with the workpiece are first calculated based on real grain geometry acquired via computed tomography. Results of this single-grain model are then applied at a gear tooth level together with process kinematics to determine the temperature distribution during dry generating grinding. Single-grain and generating grinding tests are performed to verify the predicted onset of thermal damage and the ability to optimize process parameters using the proposed hierarchical modeling approach