Static and dynamic testing of machine tools

Transcription

1 Static and dynamic testing of machine tools Thomas Liebrich, Michael Gebhardt, Stefan Thoma, Hop Nguyen, Sascha Weikert, Wolfgang Knapp, Konrad Wegener Institute for Machine Tools and Manufacturing (IWF), Swiss Federal Institute of Technology (ETH), Zurich, Switzerland inspire AG for Mechatronic Systems and Manufacturing Technology, Zurich, Switzerland 5/ inspire AG Overview Introduction Static measurements 3 Dynamic measurements 4 Preparation for test piece machining 5 Future steps 6 Conclusions 5/ inspire AG

2 Introduction IWF/inspire research on 5-axis machine tools - geometric testing - compensation - dynamic testing - thermal testing since begin of new 5-axis machining center - with swiveling rotary table - vertical machining center t-(c)-z-x-y-b-b-c-w 5/ inspire AG 3 Static measurements, 3D ball plate for testing X, Y, Z axes, ball plate on / 8 / 6 / 4 / 3 mm height (Z direction) 5/ inspire AG 4

3 Static measurements, 3D ball plate results, volumetric accuracy V XYZ,X = µm V XYZ,Y = 7 µm V XYZ,Z = µm Measuring results 3D- ball plate, magnification 3x Z [mm] 4 3 Measuring results 3D- ball plate, magnification 3x X [mm] 4 Y [mm] Z [mm] X [mm] Y [mm] 4 5/ inspire AG 5 Static measurements, 3D ball plate EYX [ μm] component errors, straightness error motions Straightness deviation of X-axis EXY [ μm] EZY [ μm] Straightness deviation of Y-axis Position Y-axis [mm] EXY, EZY < 5 µm EZX [ μm] Position X-axis [mm] straightness error motions of X, EYX, EZX < µm EXZ, EYZ < 6 µm EXZ [ μm] EYZ [ μm] 4 - Straightness deviation of Z-axis Position Z-axis [mm] 5/ inspire AG 6 3

4 Static measurements, 3D ball plate component errors, positioning error motions Positional deviation EYY [µm] Positional deviation EXX [ μm] Position X-axis [mm] EXX < 3 µm 5 Positional deviation of X-axis Positional deviation of Z-axis Position Y-axis [mm] positioning error motion of Y, EYY - EYY = 6 µm, on the table, X = EYY = 4 µm, on the table, X = 5-5 EYY = 3 µm, 3 above table, X = EYY = 6 µm, 3 above table, X = 5 EYY = 3 µm, acceptance test EZZ < 8 µm Positional deviation EZZ [ μm] Position Z-axis [mm] 5/ inspire AG 7 Static measurements, 3D ball plate squareness error CY (squareness between X and Y) Y-axis [mm] 3 Y-axis [mm] 3 8.3µm Reference X-axis [mm] CY on table + to +9 µm/m 8.3µm Reference X-axis [mm] CY 3 mm above table ± µm/m 5/ inspire AG 8 4

5 Static measurements, R-Test R-Test set-up precision sphere in spindle 3D probe system on rotary table 5/ inspire AG 9 Static measurements, R-Test C axis axial component G XYC (axial) = 5 µm Y-Axis [mm] - μm X-Axis [mm] 5/ inspire AG 5

6 Static measurements, R-Test C axis radial component G XYC (radial) = 6 µm peaks at reversal points < µm Y-Axis [mm] - μm - positions and orientations XC=+3.6 µm YC=-7 µm AC=+4 µm/m BC=+5. µm/m XB=-.7 µm ZB=+ µm AB=-4 µm/m CB=-37 µm/m correction of machine tool model in numerical control - - X-Axis [mm] 5/ inspire AG Static measurements, R-Test C axis tangential component G XYC (tangential) = µm tangential vibration of 5 µm Y-Axis [mm] - μm X-Axis [mm] 5/ inspire AG 6

7 Cross Talk principle driving force center of gravity rolling elements of guideway cross talk 5/ inspire AG 3 Dynamic measurements, cross talk of Y step Y 4mm, F= mm/min (programmed).6.4 X deviation [ μm] Y travel [mm] 5/ inspire AG 4 7

8 Dynamic measurements, cross talk of Y step Y 4mm, F=6 mm/min (programmed), a max =.4 m/s.4 X deviation [μm] Y travel [mm] 5/ inspire AG 5 Dynamic measurements, cross talk of Y step Y 4mm, F=6 mm/min (programmed), a max =.4 m/s Z deviation [μm] Y travel [mm] 5/ inspire AG 6 8

9 Test piece for 5-axis machining inclined cone frustrum test piece test piece design movements of linear axes frame 4: machine coordinate system phi =, C =, B = -5 α = 45, β =3, r A = 9.8 Min = [-49.8,, 96.34] Ain = [-9.8,, ] X M : [-39.79:353], Y M : [-9.8:9.8], Z M : [-96.36:96.4] X 8 = 353.7, r = 8, Δ X = 39.8, Δ Y = 59.6, Δ Z = 39.8 z 3 - x - y 5/ inspire AG 7 Test piece for 5-axis machining inclined conical test piece, movements of axes distance to C 5 mm distance to B 3 mm X direction Y direction Z direction Total movement [mm] X [mm] Y [mm] Z [mm] B [ ] -5 C [ ] Radial cone angle [ ] = 45, = 3, r = 3 A 5/ inspire AG 8 9

10 Test piece for 5-axis machining inclined conical test piece, movements of axes distance to C 5 mm distance to B 8 mm larger movements of linear axes X, Y, Z X direction Y direction Z direction Total movement [mm] X [mm] Y [mm] Z [mm] B [ ] -5 C [ ] Radial cone angle [ ] = 45, = 3, r = 3 A 5/ inspire AG 9 Future activities, test piece machining - 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,. µm for horizontal orientation 5/ inspire AG

11 Future activities thermal influences, including rotary axes - drift tests - infrared camera, movement of rotary table axis C 5/ inspire AG Use of machine tool for education machine tool used for demonstrations and practical exercises in the following lectures: manufacturing processes and NC programming, milling production machines and design of machine tools, components of machine tools, machine tool performance, modeling of machine tools quality of machine tools geometric and dynamic testing of machine tools, machine tool calibration engineering tools course in CAM CAD-CAM coupling, machine tool as application example master and bachelor projects geometric, dynamic, thermal measurements; calibration; simulation 5/ inspire AG

12 Summary geometry very good error motions, errors in position and orientation are well within tight tolerances dynamic behavior very good small cross talk concept Driven at the Center of Gravity, DCG inclined cone frustrum test piece optimized position for large movements of linear axes dia. of circular path 8 mm, distance to C of 5 mm, distance to B of 3 mm future activities simulation and machining of 5-axis test piece dynamic testing thermal testing including rotary axes enhancement of machine tools 5/ inspire AG 3 Acknowledgement IWF/inspire thanks MTTRF for supporting our research for 5-axis machining centers. 5/ inspire AG 4