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© 05/2010 inspire AG 1
Static and dynamic testing of machine tools
Thomas Liebrich1, Michael Gebhardt2, Stefan Thoma1, Hop Nguyen2, SaschaWeikert2, Wolfgang Knapp1, Konrad Wegener1
1Institute for Machine Tools and Manufacturing (IWF), Swiss Federal Institute of Technology (ETH), Zurich, Switzerland
2inspire AG for Mechatronic Systems and Manufacturing Technology, Zurich, Switzerland
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1 Introduction2 Static measurements3 Dynamic measurements4 Preparation for test piece machining5 Future steps6 Conclusions
Overview
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IWF/inspire research on 5-axis machine tools- geometric testing- compensation- dynamic testing- thermal testing
since begin of 2010 new5-axis machining center- with swiveling rotary
table- vertical machining center
t-(C)-Z-X-Y-b-B-C-w
Introduction
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for testing X, Y, Z axes, ball plate on 0 / 80 / 160 / 240 / 320 mm height (Z direction)
Static measurements, 3D ball plate
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results, volumetric accuracyVXYZ,X = 11 µmVXYZ,Y = 17 µmVXYZ,Z = 12 µm
Static measurements , 3D ball plate
-100 0 100 200 300 400 500 0 200 400-200
-100
0
100
200
300
400
Y [mm]
Measuring results 3D- ball plate, magnification 3000x
X [mm]
Z [m
m]
-100 0 100 200 300 400 5000
200400-200
-100
0
100
200
300
400
Y [mm]X [mm]
Measuring results 3D- ball plate, magnification 3000x
Z [m
m]
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component errors, straightness error motions
EXY, EZY < 5 µm
straightness error motions of X, EYX, EZX < 2 µm EXZ, EYZ < 6 µm
Static measurements , 3D ball plate
0 50 100 150 200 250 300 350 400 450 500-1
-0.5
0
0.5
1
1.5Straightness deviation of X-axis
EY
X [ μm
]
0 50 100 150 200 250 300 350 400 450 500-2
-1
0
1
2
Position X-axis [mm]
EZX
[ μm
]
0 50 100 150 200 250 300 350 400 450 500-2
-1
0
1
2Straightness deviation of Y-axis
EX
Y [ μm
]
0 50 100 150 200 250 300 350 400 450 500-4
-2
0
2
4
Position Y-axis [mm]
EZY
[ μm
]
0 50 100 150 200 250 300 350-4
-2
0
2
4Straightness deviation of Z-axis
EX
Z [ μ
m]
0 50 100 150 200 250 300 350-4
-2
0
2
4
Position Z-axis [mm]
EY
Z [ μ
m]
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component errors, positioning error motions
EXX < 3 µm
positioning error motion of Y, EYYEYY = 6 µm, on the table, X = 0EYY = 4 µm, on the table, X = 500EYY = 13 µm, 320 above table, X = 0EYY = 16 µm, 320 above table, X = 500EYY = 3 µm, acceptance test EZZ < 18 µm
Static measurements , 3D ball plate
0 50 100 150 200 250 300 350 400 450 500-3
-2
-1
0
1
2
3Positional deviation of X-axis
Position X-axis [mm]
Pos
ition
al d
evia
tion
EX
X [ μ
m]
0 50 100 150 200 250 300 350-20
-15
-10
-5
0
5Positional deviation of Z-axis
Position Z-axis [mm]
Pos
ition
al d
evia
tion
EZZ
[ μm
]
0 100 200 300 400 500-20
-15
-10
-5
0
5
10
Position Y-axis [mm]
Positio
nal devia
tion E
YY
[µm
]
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squareness error C0Y (squareness between X and Y)
C0Y on table +10 to +19 µm/m C0Y 320 mm above table ±2 µm/m
Static measurements , 3D ball plate
-100 0 100 200 300 400 500 600-100
0
100
200
300
400
500
Reference X-axis [mm]
Y-a
xis
[m
m]
8.3µm
-100 0 100 200 300 400 500 600-100
0
100
200
300
400
500
Reference X-axis [mm]
Y-a
xis
[m
m]
8.3µm
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Static measurements , R-Test
R-Test set-upprecision sphere in spindle3D probe system on rotary table
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Static measurements , R-Test
C axis axial component
GXYC (axial) = 5 µm
-200 -100 0 100 200
-200
-100
0
100
200
X-Axis [mm]
Y-Ax
is [m
m]
10μm
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Static measurements , R-Test
C axis radial component
GXYC (radial) = 6 µmpeaks at reversal points < 2 µm
positions and orientations
X0C=+3.6 µm Y0C=-27 µm A0C=+14 µm/m B0C=+5.1 µm/mX0B=-1.7 µm Z0B=+12 µm A0B=-40 µm/m C0B=-37 µm/m
correction of machine tool model in numerical control
-200 -100 0 100 200
-200
-100
0
100
200
X-Axis [mm]
Y-Ax
is [m
m]
10μm
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Static measurements , R-Test
C axis tangential component
GXYC (tangential) = 12 µmtangential vibration of 5 µm
-200 -100 0 100 200
-200
-100
0
100
200
X-Axis [mm]
Y-Ax
is [m
m]
20μm
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principle
Cross Talk
driving force
center of gravity
rolling elements of guideway
cross talk
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Dynamic measurements, cross talk of Y
step Y 4mm, F=100 mm/min (programmed)
-3 -2 -1 0 1 2 3-0.6
-0.4
-0.2
0
0.2
0.4
0.6
Y travel [mm]
X d
evia
tion
[ μm
]
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Dynamic measurements, cross talk of Y
step Y 4mm, F=6000 mm/min (programmed), amax = 0.4 m/s2
-3 -2 -1 0 1 2 3-0.6
-0.4
-0.2
0
0.2
0.4
Y travel [mm]
X d
evia
tion
[μm
]
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Dynamic measurements, cross talk of Y
step Y 4mm, F=6000 mm/min (programmed), amax = 0.4 m/s2
-3 -2 -1 0 1 2 3-0.5
0
0.5
1
Y travel [mm]
Z de
viat
ion
[μm
]
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inclined cone frustrum test piece
test piece design movements of linear axes
Test piece for 5-axis machining
-200
0
200-200
0
200
0
100
200
300
y
frame 4: machine coordinate systemphi = 0, C = 0°, B = -15°
α = 45°, β =30°, rA = 129.8
Min2 = [-149.8, 0, 296.034]Ain2 = [-129.8, 0, 330.675]
XM: [-39.79:353], YM: [-129.8:129.8], ZM: [-96.36:296.4]X180 = 353.0017, 2r = 80, Δ X = 392.8, Δ Y = 259.6, Δ Z = 392.8
x
z
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inclined conical test piece, movements of axesdistance to C 150 mmdistance to B 300 mm
Test piece for 5-axis machining
395.8Z – direction260.0Y – direction395.8X – direction
Total movement [mm]
400
200
0
-200
X [
mm
]
200100
0
400
200
0
-200
Z [
mm
]
400
200100
0
C [
°]
300
-50
-100
B [
°]
0
Y[m
m]
� �= 45°, = 30°, r = 130A
0 90 180 270 360
0 90 180 270 360
0 90 180 270 360
0 90 180 270 360
0 90 180 270 360
-100-200
Radial cone angle [°]�
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inclined conical test piece, movements of axesdistance to C 250 mmdistance to B 280 mmlarger movements of linear axes X, Y, Z
Test piece for 5-axis machining
504.2Z – direction460.0Y – direction505.7X – direction
Total movement [mm]
0 90 180 270 360
0 90 180 270 360
0 90 180 270 360
0 90 180 270 360
0 90 180 270 360
400200
0
-200
400
200
0
-200
Z [m
m]
400
200100
0
C [°]
300
-50
-100
B [°]
0
Y[m
m]
-400
� �= 45°, = 30°, r = 230A
Radial cone angle [°]�
400
200
0
-200
X [m
m]
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- simulation of machining with tolerances and measurement results of error motions
- manufacturing of test piece- comparison of simulation with machined part- bending of fixture for test piece machining, 1.2 µm for horizontal orientation
Future activities, test piece machining
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thermal influences, including rotary axes- drift tests- infrared camera, movement of rotary table axis C
Future activities
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machine tool used for demonstrations and practical exercises in the following lectures:
manufacturing processes 1 and 2NC programming, milling
production machines 1 and 2design of machine tools, components of machine tools, machine tool performance, modeling of machine tools
quality of machine toolsgeometric and dynamic testing of machine tools, machine tool calibration
engineering tools course in CAMCAD-CAM coupling, machine tool as application example
master and bachelor projectsgeometric, dynamic, thermal measurements; calibration; simulation
Use of machine tool for education
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geometry very gooderror motions, errors in position and orientation are well within tight tolerances
dynamic behavior very goodsmall cross talkconcept ‘Driven at the Center of Gravity’, DCG
inclined cone frustrum test pieceoptimized position for large movements of linear axesdia. of circular path 80 mm, distance to C of 150 mm, distance to B of 300 mm
future activitiessimulation and machining of 5-axis test piecedynamic testingthermal testing including rotary axesenhancement of machine tools
Summary
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IWF/inspire thanks MTTRF for supporting our research for 5-axis machining centers.
Acknowledgement