Modeling methodes for analysis the cutting fluid and transient chip formation when drilling

What is it about?

In this paper, two approaches for the modeling and simulation of drilling processes are presented. On the one hand, the Finite Volume Method is used for the stationary simulation of the flow field. Assuming the entire bore to be filled with coolant, the focus is laid on a precise description of important fluid mechanical quantities along the cutting edges. The results show that the mass exchange of the cooling lubricant close to the cutting edge is far too low in order to guarantee the required cooling effect. On the other hand, a coupled meshless approach for the transient simulation is presented. The cooling lubricant is there modeled by the Smoothed Particle Hydrodynamics method and the Discrete Element Method is used for the description of chips. In contrast to the Finite Volume simulation, the main focus is laid on the evolution of the free surfaces and the transport of particles.

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Photo by Vincent Botta on Unsplash

Photo by Vincent Botta on Unsplash

Why is it important?

In future studies, specific tool modifications aiming for a better coolant lubrication will be performed based on the methods presented in this work. For that purpose, the results obtained from an FEM or DEM simulation of chip formation will be used for the initialization of the FVM as well as the SPH–DEM simulations. Furthermore, models for the simulation of heat transfer and lubrication will be included in both models. In order to respect the physical topology of the cooling lubricant as it appears within real drilling processes, the fluid distribution from the transient SPH simulations can be used for the initialization of the FVM fluid domain. This way, the FVM assumption of an entirely filled V-channel is no more necessary allowing for more accurate descriptions that are even closer to the real system than the one presented in this paper. Besides the implementation of models for lubrication and heat transfer, an adaptive model for the SPH formulation will be included allowing for dynamic particle refinement and coarsening where needed. This way, the discretization level can be locally customized to the simulation needs, as it is common practice for meshbased CFD methods, without the introduction of unnecessary computational overhead.

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