1. D. Grandy, P. Koshy McMaster University, Canada F. Klocke RWTH Aachen, Germany Pneumatic Non-Contact Roughness Assessment of Moving Surfaces

2. 2/23 Pneumatic Non-contact Roughness Assessment of Moving Surfaces D. Grandy, P. Koshy, F. Klocke 59 th CIRP General Assembly Boston, August 26, 2009 Development towards in-process roughness estimation Issues with machining debris and cutting fluid Development of a pneumatic sensor www.taylor-hobson.com

3. 3/23 Pneumatic Non-contact Roughness Assessment of Moving Surfaces D. Grandy, P. Koshy, F. Klocke 59 th CIRP General Assembly Boston, August 26, 2009 Principle of pneumatic gauging work pbpb xixi air P control orifice pressure transducer psps Back pressure p b depends on x i pbpb xixi psps Primarily quasi-static applications

4. work air piezoelectric pressure transducer 4/23 Pneumatic Non-contact Roughness Assessment of Moving Surfaces D. Grandy, P. Koshy, F. Klocke 59 th CIRP General Assembly Boston, August 26, 2009 5 mm Surface porosity detection in machined castings Sensor integrated into the cutting tool holder for in-process application, in the presence of a flood coolant Menzies & Koshy (2009)

5. 5/23 Pneumatic Non-contact Roughness Assessment of Moving Surfaces D. Grandy, P. Koshy, F. Klocke 59 th CIRP General Assembly Boston, August 26, 2009 US patent 2,417,988 (1947) US patent 7,325,445 (2004) Reliability of pneumatic gauging deteriorates as the peak-to-valley height of the surface exceeds about 3 µm Related previous work Nicolau (1937) Hamouda (1979) Tanner (1982) Wang & Hsu (1987) Woolley (1992) Nozzle is in contact with workpiece, and is hence not suitable for in-process application

6. 6/23 Pneumatic Non-contact Roughness Assessment of Moving Surfaces D. Grandy, P. Koshy, F. Klocke 59 th CIRP General Assembly Boston, August 26, 2009 work pbpb xixi air P frequency decomposition The present work pertains to non-contact roughness assessment of moving surfaces Roughness is related to the frequency content of the back pressure signal

7. 7/23 Pneumatic Non-contact Roughness Assessment of Moving Surfaces D. Grandy, P. Koshy, F. Klocke 59 th CIRP General Assembly Boston, August 26, 2009 Working principle nozzle nozzle traverse

8. 8/23 Pneumatic Non-contact Roughness Assessment of Moving Surfaces D. Grandy, P. Koshy, F. Klocke 59 th CIRP General Assembly Boston, August 26, 2009 Experiments on plane surfaces nozzle diameter (d n ) 1.5 mm control orifice diameter (d c ) 0.84 mm supply pressure (p s ) 138 kPa stand-off distance (x i ) 50 µm nozzle feed rate 0.4 m/min piezo pressure transducer nozzle

9. 9/23 Pneumatic Non-contact Roughness Assessment of Moving Surfaces D. Grandy, P. Koshy, F. Klocke 59 th CIRP General Assembly Boston, August 26, 2009 Comparison of stylus and pneumatic signals from milled and turned surfaces of roughness 3.2 µm Ra Distance (mm) Height (µm) Voltage (V) milled surfaceturned surface stylus pneumatic

10. 10/23 Pneumatic Non-contact Roughness Assessment of Moving Surfaces D. Grandy, P. Koshy, F. Klocke 59 th CIRP General Assembly Boston, August 26, 2009 Frequency domain comparison of stylus and pneumatic signals Frequency (mm -1 ) Amplitude (V) Amplitude (µm) turned surfacemilled surface stylus pneumatic

11. 11/23 Pneumatic Non-contact Roughness Assessment of Moving Surfaces D. Grandy, P. Koshy, F. Klocke 59 th CIRP General Assembly Boston, August 26, 2009 Frequency spectra corresponding to milled surfaces of various roughness values 5 plots shown for each roughness ??

12. 12/23 Pneumatic Non-contact Roughness Assessment of Moving Surfaces D. Grandy, P. Koshy, F. Klocke 59 th CIRP General Assembly Boston, August 26, 2009 Roughness Ra (µm) Amplitude (V) Area (V/mm) Roughness Ra (µm) 03691215 0.00 0.15 0.30 0.45 03691215 0.0 0.5 1.0 1.5 Correlation of pneumatic indices to roughness measured using a stylus instrument Area under the frequency plot Amplitude of dominant frequency

13. 13/23 Pneumatic Non-contact Roughness Assessment of Moving Surfaces D. Grandy, P. Koshy, F. Klocke 59 th CIRP General Assembly Boston, August 26, 2009 Supply pressure (kPa) Normalized amplitude 0100200300400 0 3 6 9 Effect of supply pressure work pbpb xixi air P dcdc psps dndn

14. 14/23 Pneumatic Non-contact Roughness Assessment of Moving Surfaces D. Grandy, P. Koshy, F. Klocke 59 th CIRP General Assembly Boston, August 26, 2009 Effect of control orifice diameter  d c work pbpb xixi air dcdc psps dndn Stand-off distance (µm) Normalized amplitude d c = 0.84 mm d c = 0.50 mm d c = 0.84 mm 0 1 2 3 050100150200250300 0 1 2 3 experimental analytical

15. 15/23 Pneumatic Non-contact Roughness Assessment of Moving Surfaces D. Grandy, P. Koshy, F. Klocke 59 th CIRP General Assembly Boston, August 26, 2009 Experiments on rotating cylindrical surfaces quenchant hardness nozzle turned surface nozzle workpiece diameter ~25 mm surface speed 30 m/min nozzle feed rate 0.2 mm/rev stand-off distance (x i ) 50 µm supply pressure (p s ) 138 kPa nozzle diameter (d n ) 1.5 mm control orifice diameter (d c ) 0.84 mm nozzle workpiece

16. 16/23 Pneumatic Non-contact Roughness Assessment of Moving Surfaces D. Grandy, P. Koshy, F. Klocke 59 th CIRP General Assembly Boston, August 26, 2009 Effect of increasing roughness Frequency (Hz) Amplitude (V) Frequency (Hz) quenched end of Jominy specimen 1 mm increasing roughness 1.2 µm Ra3.8 µm Ra

17. 17/23 Pneumatic Non-contact Roughness Assessment of Moving Surfaces D. Grandy, P. Koshy, F. Klocke 59 th CIRP General Assembly Boston, August 26, 2009 Effect of relative speed between nozzle and work Sensor response can be improved by minimizing the volume of the variable pressure chamber

18. 18/23 Pneumatic Non-contact Roughness Assessment of Moving Surfaces D. Grandy, P. Koshy, F. Klocke 59 th CIRP General Assembly Boston, August 26, 2009 Effect of application of cutting fluid Flood coolant application has minimal influence on sensor performance

19. 19/23 Pneumatic Non-contact Roughness Assessment of Moving Surfaces D. Grandy, P. Koshy, F. Klocke 59 th CIRP General Assembly Boston, August 26, 2009 Recent work on extension to fine surfaces 0.1 µm Ra ground0.1 µm Ra lapped Back pressure signals are noisy, and are affected by vibration 

20. X1X1 X2X2 X3X3 P S t1t1 t2t2 X1X2X3 … … G1 G2 L1 L2 Variables Observations … 20/23 Pneumatic Non-contact Roughness Assessment of Moving Surfaces D. Grandy, P. Koshy, F. Klocke 59 th CIRP General Assembly Boston, August 26, 2009 Principal Components Analysis

21. 21/23 Pneumatic Non-contact Roughness Assessment of Moving Surfaces D. Grandy, P. Koshy, F. Klocke 59 th CIRP General Assembly Boston, August 26, 2009 Application of principal components analysis Filled symbols refer to test data not considered when building the model

22. 22/23 Pneumatic Non-contact Roughness Assessment of Moving Surfaces D. Grandy, P. Koshy, F. Klocke 59 th CIRP General Assembly Boston, August 26, 2009 Proof-of-concept of pneumatic non-contact roughness assessment of moving surfaces has been established In its present state of development, the system is best suited for in-situ process monitoring based on appropriate calibration The system exhibits potential for in-process application in the presence of machining debris and cutting fluid that generally obscure the measurement process when using optical instruments Future work will focus on the physics of jets impinging on laterally moving surfaces, taking roughness into consideration Conclusions

23. 23/23 Thank you for your attention! Pneumatic Non-contact Roughness Assessment of Moving Surfaces D. Grandy, P. Koshy, F. Klocke 59 th CIRP General Assembly Boston, August 26, 2009 Natural Sciences & Engineering Research Council of Canada For more details please see: D. Grandy, P. Koshy, F. Klocke, Pneumatic non-contact roughness assessment of moving surfaces, CIRP Annals 58 (2009) 515-518.