Static and dynamic testing of machine tools · Static and dynamic testing of machine tools Thomas Liebrich1, Michael Gebhardt2, Stefan Thoma1, Hop Nguyen2, Sascha Weikert2, Wolfgang

1

© 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


1 Introduction2 Static measurements3 Dynamic measurements4 Preparation for test piece machining5 Future steps6 Conclusions

Overview

2


IWF/inspire research on 5-axis machine toolsgeometric testing- compensation- dynamic testingthermal 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


for testing X, Y, Z axes, ball plate on 0 / 80 / 160 / 240 / 320 mm height (Z direction)

Static measurements, 3D ball plate

3


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]


component errors, straightness error motions

EXY, EZY < 5 µm

straightness error motions of X, EYX, EZX < 2 µm EXZ, EYZ < 6 µm


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]

4


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


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

]


squareness error C0Y (squareness between X and Y)

C0Y on table +10 to +19 µm/m C0Y 320 mm above table ±2 µm/m


-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

5


Static measurements , R-Test

R-Test set-upprecision sphere in spindle3D probe system on rotary table

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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

6

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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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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

7

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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

]

8

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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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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

]

9

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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


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 [°]�

10

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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


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

© 05/2010 inspire AG 24

IWF/inspire thanks MTTRF for supporting our research for 5-axis machining centers.

Acknowledgement

Documents

Static and dynamic testing of machine tools · Static and dynamic testing of machine tools Thomas Liebrich1, Michael Gebhardt2, Stefan Thoma1, Hop Nguyen2, Sascha Weikert2, Wolfgang