Simulation and optimization of the in-service behavior of coated inserts for turning and milling

Ivan Krajinovic

Research output: ThesisDoctoral Thesis

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Abstract

Within this work, a state-of-the-art finite element approach to the problem of the tool loading during milling processes is presented. The studied tool is based on an industrial hard coated fine-grained hard metal tool with 8 wt.% Co. The Arbitrary Lagrangian-Eulerian formulation of the continuum is used to create 2D orthogonal cutting and 2D milling models. The whole milling process over several cycles of cutting and cooling is studied using a 3D tool milling process model. Measured and literature based thermal and mechanical material parameters are used to describe the material behavior of the coatings and the substrate. The 2D orthogonal cutting model is validated by comparing to the orthogonal cutting experiments at different cutting speeds and cutting depths. The results show that the 2D ALE cutting model can be used for modeling of the tool loading. The 2D milling model is created as a tool box for parametric studies which provide guidelines for design of the tool design. It shows the importance of coatings as a thermal shield which decreases the plastic deformation of the hard metal substrate. Also, the model enables to study the influence of the tool loading on the hard metal substrates with different thermo-mechanical properties. The role of friction as a source of heat and damage is studied, too. The 3D tool milling process model allows investigating the behavior of stress-strain-temperature fields during multiple milling cycles. It shows the build-up of tensile out-of-plane stresses during cooling parts of the cycles. These stresses are responsible for the creation of combcracks which limit the tool service life. The build-up of tensile out-of-plane stresses occurs in the same region as experimentally discovered. The model also gives an insight in the plastic deformation of the substrate during the first milling cycles under conditions of high von Mises stresses and relatively low temperatures.
Translated title of the contributionSimulation und Optimierung des Betriebsverhaltens von beschichteten Schneidplatten beim Drehen und Fräsen
Original languageEnglish
QualificationDr.mont.
Supervisors/Advisors
  • Daves, Werner, Supervisor (internal)
  • Antretter, Thomas, Assessor A (internal)
  • Mitterer, Christian, Assessor B (internal)
Publication statusPublished - 2016

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