Biomedical Engineering Reference
In-Depth Information
altering the shape of the chip. Also, high strain rates appear to provide less
dependence on material properties in determining chip formation and shape.
A model of chip curl at the microscale has been developed and agrees well
with experimental data. It appears that the bending of the cutting tool
contributes significantly to the primary chip prior to significant frictional
interactions on the rake face of the cutting tool. It is shown that primary chip
curl is initiated by the amount of material deposited onto the cutting tool that
manifests itself as a wedge angle that controls the amount of material pushed
into the base of the segment of the chip between oscillations of the primary
shear plane. The future development of this technique lies in the ability to
rotate cutting tools at extremely high spindle speeds.
The experimental results also suggest that a number of primary shear
planes are created during the initial stages of chip formation that contradicts
the assumptions made by Ernst and Merchant. Although their experiments
were characterized by machining soft, ductile metals at low speeds, it seems
appropriate to suggest that their model cannot be initially applied to the
machining of laminate structures such as bone. However, a series of single
shear planes dominated by dynamic shearing events may describe the
machining of a laminate structure. Further investigations on the primary
causes of shearing in bone and how they are modeled are required.
A
CKNOWLEDGMENTS
The authors are grateful to Inderscience for allowing the authors to
reproduce material published in the International Journal of Nano and
Biomaterials, 2009, volume 2, number 6, p. 505. Inderscience retains
copyright of the material used in this chapter.
B
IOGRAPHICAL
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ETAILS
Prof. Mark J. Jackson
(jacksomj@purdue.edu)
is Associate Professor of
Mechanical Engineering in the College of Technology at Purdue University.
He was educated at Liverpool in Mechanical Engineering and conducted
research at the Cavendish Laboratory, University of Cambridge. His areas of
research include machine and grinding technologies.
