url: 12-1, hisakata 2-chome, tempaku-ku, nagoya 468-8511 japan (c)2001 manufacturing engineering...
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(C)2001 Manufacturing Engineering Laboratory, Toyota Technological Institute
UR
L: h
ttp://
ww
w.to
yota
-ti.a
c.jp
/Lab
/Kik
ai/5
k60/
12-1
, His
akat
a 2-
chom
e, T
empa
ku-k
u, N
agoy
a 46
8-85
11 JA
PAN
In-process Measurement of Wear of Grinding Wheel
by Using Hydrodynamic PressureBackground and problem• Monitoring of grinding wheel wear for precision grinding
• Disturbance of light by working fluid
Solution• Gap sensing by using hydrodynamic pressure with pressure sensor arranged with small gap
Advantages• Simple sensing device• In-process measurement of radius and topography of grinding wheel
• Dependence of only geometry of grinding wheel
Results• Relationship among pressure, gap and speed• Enable to run-out by arranging several sensors• Standard deviation of 1 m in measured radii• Enable to detect loading, shedding and dulling
Applicable field• Plunge grinding• Creep-feed grinding• High precision grinding such as ELID• Grinding expensive material• Small-amount products
W o r k in gf lu id
P re s s u res e n s o r
R o ta t io n
G rin d in gw h e e l
In it ia l g a p
W e a r
W o rk p ie c e
渦 電 流 式 変 位 セ ン サ
軸
カ ッ プ リ ン グ
モ ー タ タ コ ジ ェ ネ レ ー タ
円 盤
圧 力 セ ン サ
DiskEddy current sensorShaftCoupling
TachometerPressure sensors DC motor
Principle of measurement by using hydrodynamic pressure
Experimental apparatus
0 20 40 60 80
Time ms
Hyd
rody
nam
ic p
ress
ure
50
kPa/
div
Gap
50
m/d
iv
Pressure
Gap
1 10 100 1000
Frequency Hz
Pres
sure
kPa
Gap
m
Pressure
Gap
102
100
10-2
10-4
103
101
10-1
Examples of outputs of sensors
0
5
10
15
0 50 100 150 200 250
Minmum gap m
Pres
sure
kPa
3rd cut
2nd cut
1st cut
Initial
0 50 200 250Gap m
Pres
sure
kPa
0
15
Initial
1st cut
2nd cut
3rd cut
10
5
150100
Trajectory of pressure to gap
5
6
7
100 110 120 130 140Gap m
Pres
sure
kPa
Initial1st cut 2nd cut
3rd cut
Average pressure vs. gap
0
10
20
30
40
0 20 40 60 80 100Minimum gap m
Pres
sure
kPa
D#400
WA#800
WA#46
x=+1.5 mmPeripheral speed 28.7 m/s
Influence of grain size
0
20
40
60
0 20 40 60 80 100
Minimum gap m
Pres
sure
kPa
0
0.5
1
1.5
P max
-Pm
in k
Pa
Measured pressure
Pmax-Pmin
Dispersion of measured pressureDetection of loading of grinding wheel
1 10 100 1000 10000Frequency Hz
Pres
sure ×
10 k
Pa/d
iv
Just after dressing
After initial wear with SUJ2
Grinding 5 m
Grinding 10 m
Grinding 15 m
Grinding 20 mGap: 10 mFluid: 5.0 l/minWorkpiece: Aluminium
Prog
ress
of
load
ing
(C)2001 Manufacturing Engineering Laboratory, Toyota Technological Institute
UR
L: h
ttp://
ww
w.to
yota
-ti.a
c.jp
/Lab
/Kik
ai/5
k60/
12-1
, His
akat
a 2-
chom
e, T
empa
ku-k
u, N
agoy
a 46
8-85
11 JA
PAN
Three-dimensional Form Generationby Dot-matrix Electrical Discharge Machining
Background and problem• Needs for rapid production system for metals• Difficulty in production of tool electrode to mach
ine small shape
Solution• Shaping profile of bundled electrodes by controll
ing their length and scanning them as one electrode
Advantages• Enable to skip making process of electrode• Mechanical strength of electrode• Enable to compensate electrodes for heavy wear
by feeding them• Use of thin wire for electrodes
Results• Machining 3D shape with 6 thin electrodes• Less cracks by divided power because of dischar
ge dispersion
Applicable fields• Micromachining• Micromold fabrication• Rapid prototyping for metals
Main axis of electrical discharge machine
Wire electrode
Electrode feeding device
Electrode guide
NC table
Workpiece
Machining unit
Concept of dot-matrix electrical discharge machining
System configuration
Equi-potential power Divided power
Types of power supply for dot-matrix EDM
Machining sequence
Positioning sequence of electrodes
-5.1mm0
0-0
.5m
m
0
-0 5.1mm
0-0
.5m
m
-300
-250
-200
-150
0 2000 4000 6000
x m
Dep
th
m
-300
-250
-200
-150
0 2000 4000 6000x m
Dep
th
m
Example of machiningImprovement of wavinessEquii-potential power Divided power
0 10 20 30Time ms
Dis
char
ge c
urre
nt
EL5
EL2
EL6
EL4
EL3
EL1 0.5
A
0 10 20 30Time ms
Dis
char
ge c
urre
nt
EL6
EL5
EL4
EL3
EL2
EL1
0.5
A
Discharge dispersion
Designed shape
Result of machining
Appearance of machining unit
Quill of electrical discharge machine
(C)2001 Manufacturing Engineering Laboratory, Toyota Technological Institute
UR
L: h
ttp://
ww
w.to
yota
-ti.a
c.jp
/Lab
/Kik
ai/5
k60/
12-1
, His
akat
a 2-
chom
e, T
empa
ku-k
u, N
agoy
a 46
8-85
11 JA
PAN
Precision Positioning Table Employing Parallel Mechanism
for Scanning Probe Microscope
C a n tile v e r
S e m ic o n d u c to r la se r(5 m W ,6 3 5 n m )Q u a d ra n t
p h o to d e te c to r
S p e c im e n
T a b le
B a s e p la tfo rm
L in kP a ra l le llin k
V ib ra t io n is o la t in g ta b le
P ro b e
75
I n v e rs ek in e m a tic s
P ie z oL P F
S e n s o r
K PG iv e np o s tu r eo f t a b le
L in kle n g thfo r g iv e np o s tu r e ,
R i
L 1R 1
P ie z oL P F
S e n s o r
K P
P ie z oL P F
S e n s o r
K P
L 2
R 2
L 6
R 6
B a se p late T ab le
E d d y cu rre n td isp lac em en tse n so rs
L ev er m ec h an ismw ith fle xu re h in g es
F le xu re jo in ts
E lectro d efo r d e tec tio n
S tac ke d p iez o
X
YZ
E le c tr o d e s f o rd e te c tio n
T a b le
F le x u rejo in ts
E d d y c u rr e n ts e n so r
S ta c k e dp ie z o
L e v e r m a c h a n ismw ith fle x u r e h in g e s
B a sep la te
1 6 0
6 °
(a) Open loop control
-0.1
0.0
0.1
0.2
-1.0 -0.5 0.0 0.5Displacement of table m
Out
put o
f P.D
. V
① ②③
④⑤⑥⑦
(b) Displacement feedback control
-0.1
0.0
0.1
0.2
-1.0 -0.5 0.0 0.5Displacement of table m
Out
put o
f P.D
. V
① ②③
④⑤⑥⑦
(c) Induced charge feedback control
-0.1
0.0
0.1
0.2
-1.0 -0.5 0.0 0.5Displacement of table m
Out
put o
f P.D
. V
① ②③ ④
⑤⑦ ⑥
Background and Problem• Cutting machine for nanometer depth of cut• unavoidable tilt of tube type piezoelectric actuato
r in general scanning probe microscope (SPM)
Solution• Stewart platform type parallel mechanism control
led by induced charge feedback method
Advantages• 6 degrees of freedom• High resolution in z because of small elevation an
gle• Flexible tool path• Enable to use in vacuum because of no slipping el
ement
Results• Smaller tilt (1/10 to tube type)• High positioning accuracy (16 nm in z)• Linearity within 20×20 m by semi-closed loop c
ontrol
Applicable fields• Ductile mode cutting of brittle materials• Micromachininig• Fine motion stage for SPM
Appearance of device
Sectional view
Setup for atomic force microscope
AFM image of diffraction gratings Force curve on Silicon
SpecificationsSize: 16016085 mmMass of table: 24 gMovable range:
100 m in xy, 20 m in zResonance frequency:
100 Hz in xy, 75 Hz in zDegrees of freedom: 6Actuators: Piezoelectric actuatorsMagnification: 12.5
Block diagram of control system
Cross talk ratio %Feedback x/y z/yPitching error
radNone 19.6 8.2 12
Displacement 11.7 3.9 17Induced charge 3.5 4.7 17
Cross-talk ratio
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