Development of FEM-based digital twins for machining difficult-to-cut materials: A roadmap for sustainability

To achieve sustainable production in machining, it is necessary to develop strategies to effectively modify the way that components are produced industrially, with a particular concern regarding metalworking fluids. This review integrates many of the relevant aspects in the development of coolant assisted finite element method (FEM) simulations, including: (1) the description of the main cooling and lubrification systems applied in difficult-to-cut materials and their impact in the machining response; (2) the identification of the relevant simulation variables; (3) it also reports on the methodologies (such as computational fluid dynamics (CFD), empirical correlations, inverse FEM modelling, etc) for converting experimental variables in parameters for FEM simulation; (3) it presents an extensive database of coolant assisted FEM models for cryogenic, MQL, HPC and flooded machining, detailing the experimental parameters (type of coolant, delivery method (nozzle, internal cooling, etc), coolant pressure, flow rate, etc), the simulation variables (software, material and friction models, thermo-mechanical boundary conditions, etc), the studied machining responses, as well as details regarding the numerical model implementation, its validation through experimental tests and other relevant contributions. The main idea was to emphasize how machining simulations can be a practical tool for selecting cutting configurations, in particular those related to the use of coolants, but also raise awareness about the challenges when developing coolant assisted machining simulations. The review main conclusion was that the experimental efforts, in terms of sustainable cooling techniques are much more developed than the numerical models available, however, the available FEM models (flood, HPC, cryogenic, MQL) were able to predict with accuracy important variables for machining process optimization, such as cutting forces, temperature gradient and metal chip formation. In the case of cryogenic cooling, there are already validated FEM models for microstructural changes (grain size, hardness) and tool wear prediction.

Automated summary

This review discusses the application of coolant assisted finite element method (FEM) simulations in machining and provides an extensive database of models. The study concludes that the available FEM models can accurately predict important variables for machining optimization, but the experimental research is still more developed.