An acoustic emission-based touch-off detection system has been developed to determine contact between a rotating microtool and a workpiece surface with micron-level accuracy. The system has been implemented on an existing three-axis microscale machine tool. The system has been tested with microendmills as small as 50μm in diameter and microdrills as small as 254μm in diameter. The accuracy of the system has been found to depend on tool geometry and workpiece surface characteristics and is generally on the order of 1μm. An analytical model has been constructed to predict touch-off detection error. The calibrated model has been shown to predict surface overshoot and undershoot trends quite well. Simulations have shown that touch-off error is dominated by part surface roughness.

1.
Langstaff
,
G.
, 2005, “
Development of Automation Technologies for Microfactory Automation
,” Master’s thesis, University of Illinois, Urbana, IL.
2.
Dornfeld
,
D.
, and
Handy
,
C.
, 1987, “
Slip Detection Using Acoustic Emission Signal Analysis
,”
Proceedings IEEE International Conference on Robotic and Automation
, pp.
1868
1875
.
3.
Shinoda
,
H.
, and
Ando
,
S.
, 1994, “
Ultrasonic Emission Tactile Sensor for Contact Localization and Characterization
,”
Proceedings IEEE International Conference on Robotics and Automation
, pp.
2536
2543
.
4.
Dunegan
,
H. L.
, 1998, “
An Acoustic Emission Technique for Measuring Surface Roughness
,” DECI Technical Report No. 9810, http://w/w.deci.com/publications.htmlhttp://w/w.deci.com/publications.html
5.
Mba
,
D.
,
Cooke
,
A.
,
Roby
,
D.
, and
Hewitt
,
G.
, 2004, “
Detection of Shaft-Seal Rubbing in Large-Scale Power Generation Turbines With Acoustic Emissions. Case Study
,”
Proc. Inst. Mech. Eng., Part A
0957-6509,
218
(
2
),
71
81
.
6.
Youmin
,
L.
,
Chi
,
L.
, and
Atef
,
E.
, 1997, “
Acoustic Emission Study of Lubricant Effect on Proximity Contact Recording
,”
IEEE Trans. Magn.
0018-9464,
33
(
5
), pp.
3160
3162
.
7.
Dornfeld
,
D.
, and
Cai
,
H. G.
, 1984, “
An Investigation of Grinding and Wheel Loading Using Acoustic Emission
,”
ASME J. Eng. Ind.
0022-0817,
106
, pp.
28
33
.
8.
Honegger
,
A.
, 2005, “
Micro∕Meso-Scale Machine Tool Development and Calibration
,” Master’s thesis, University of Illinois, Urbana, IL.
9.
Liu
,
J. J.
, and
Dornfeld
,
D. A.
, 1992, “
Modeling and Analysis of Acoustic Emission in Diamond Turning
,” Winter Annual Meeting of the American Society of Mechanical Engineers, Anaheim, CA, Nov. 8–13, ASME, Production Engineering Division (publication), PED, Vol.
58
, Precision Machining: Technology and Machine Development and Improvement, pp.
43
58
.
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