Material Structural Aspects of Micro-Scale Chip Removal

Abstract

In these days one of the most important field of interest lies in the manufacturing of miniaturized parts. The economical and flexible alternative for production in small and medium lot sizes is machining with miniature, fine-grained carbide end mill. The experimental research and analytical observations of the authors in connection with material structural aspects of micro scaled chip removal and the effects of the very thin micro milling tool are described in this paper.

Micromilling of hardened tool steel for mould making applications

“…When the whole shear deformation occurs within a single grain, the stresses applied to the tool are dependent on individual grain orientation, causing high frequency fluctuations of cutting forces. Prediction of cutting forces in such situations would probably require models for single crystal machining [4], where plastic deformation takes place along crystal's slip planes, and able to take into account the statistical distribution of grains' orientation. A mechanistic model for force prediction in micromilling of multiphase materials has been developed by Vogler et al [5].…”

Mechanical Micro‐Machining

“…The features of a micro-machined surface are influenced by the crystallographic orientation of the grains, with three distinct cases: (i) machining of amorphous materials; (ii) machining of single crystals; and (iii) cutting of polycrystalline materials [43][44][45].…”

“…As a result, it is recommended that machining of steel be performed in the hardened state which has fine [43]. The structure of steel at the normalized state causes considerable difficulty in mechanical micro-machining because of a difference in hardness and ductility between the pearlitic and ferritic regions, which affects the constancy of the machining conditions.…”

“…It was demonstrated that the tool deflections create serious deficiencies in feature accuracy [43] as shown in Fig. However, the higher the ratio, the greater the tool deflections affecting the geometrical feature accuracy and tolerances.…”

“…10 Tool deflections on the geometrical accuracy: (a) cross-sectional view of a groove fabricated with micro-end-milling, and (b) FEA of buckling in micro-endmills[43].…”