INTERNATIONAL JOURNAL OF PRECISION ENGINEERING AND MANUFACTURING Vol. 15, No. 6, pp. 1165-1171 JUNE 2014 / 1165
© KSPE and Springer 2014
A New Tool Holder Design with Two-Dimensional Motion
for Fabricating Micro-Dimple and Groove Patterns
Rendi Kurniawan
1
and Tae Jo Ko
1,#
1 School of Mechanical Engineering, Yeungnam University, 214-1, Dae-dong, Gyeongsan-si, Gyeongsanbuk-do, South Korea, 712-749
# Corresponding Author / E-mail: tjko@yu.ac.kr, TEL: +82-53-810-3836, FAX: +82-53-810-4627
KEYWORDS: Micro-dimple and groove pattern, Developed tool holder, Elliptical vibration texturing
This paper presents an elliptical vibration machining (EVM) method, which is utilized to establish a micro-dimple or groove pattern
for surface texturing. The EVM has been explored extensively by the precision community to significantly improve machining
performance through lower cutting force, reducing tool wear, burr suppression, extended tool life and lower surface roughness. A new
design of a tool holder has been developed, yielding two-directional motions of the tool tip of about 10 μm and 30 μm in the axial
and transverse directions, respectively. The tool holder design uses a four-bar flexure hinge, of which the flexure body has a first
natural frequency of about 4.6 kHz according to an impact test. In this research, two piezo actuators have been driven in open-loop
conditions by energizing two sinusoidal voltages from a function generator with the developed tool holder attached to a conventional
computer numerical controlled (CNC) 3-axis milling machine. The micro-dimples and grooves have been successfully built using a
vibration frequency of 100 Hz with various phases between 15
o
and 60
o
to verify the cutting performance of the developed tool holder.
Manuscript received: April 15, 2013 / Revised: May 1, 2014 / Accepted: May 7, 2014
1. Introduction
The performance of micro-dimple or groove patterns has been an
area of prime interest for many researchers for reducing the friction
coefficient of the planar surface of various mechanical parts.
1,2
The
micro-dimples act as lubricant reservoirs to enhance lubricant retention,
and by capturing wear debris,
3
they provide advantages in either
tribology or industrial uses. Dimple size at the micro/nano scale can be
easily achieved by recent manufacturing technologies for self-cleaning
by creating a super-hydrophobic or engineered surface.
4
Various texturing processes can be used, such as machining,
lithography, deposition, abrasive-jet machining (AJM), electrochemical
machining (ECM),
5
laser beam machining (LBM) and common laser
surface texturing (LST). For example, with machining technology,
NOMENCLATURE
K
R
= Overall stiffness of the flexure body
K
B
= Bending stiffness of single circular flexure hinge
K
S
= Linear stiffness of single circular flexure hinge
F = Generated force from piezo actuator
x, z = Cartesian coordinate axis
D
1
, D
2
= Output displacement of 1
st
and 2
nd
piezo actuators
L
1
, L
2
= Length of the center rotation perpendicular to force
direction in the z and x directions
A
1
, A
2
= Amplitude of sinusoidal waves
f
m
= Frequency vibration
t = Time
φ = Phase shift
ψ = Half of angle between first and second piezo
θ = Half of angle between link B1 and B2
C
L
(X
T
, Z
T
) = Cutter location point
F
T
= Texturing feed
F
G
= Grooving feed
Δd = Distance between tip tool and a surface
DOC = Depth of cut
α = Rake angle
β = Clearance angle
R = Radius of cutting tool insert
DOI: 10.1007/s12541-014-0452-4