Some aspects of traceability of camshafts and large gears

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Esmond Walters
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1 Some aspects of traceability of camshafts and large gears Otto Jusko, Folke Santel, Frank Härtig, Waheed Adeyemi, Kerstin Rost, PTB Braunschweig, Germany Raimund Volk / Hommel-Etamic GmbH, Schwenningen, Germany

2 Contents Part 1 camshaft meas. topics development and manufacturing of a camshaft standard strategies for evaluating of cam profiles estimation of measurement uncertainty standardization

3 motivation cylinder coordinate shaft measuring instruments 1st meeting PTB / industry June 2005 profile shapes at steep surfaces high-precison rotation axis objectives comparability of measurement results traceability to national standards and SI system acceptance tests

4 camshaft standard components 1 reference surface dealing as rotational datum 3 bearing surfaces L1, L2, and L3 2 excentric circular discs Ex1 und Ex2 2 cams N1, and N2

5 camshaft standard measures length = 300 mm mass = 1,4 kg hardness = 61 HRC measurement parameters Probing force = 2 N

6 camshaft standard parameters ϕ N : cam rotational angle h N : cam stroke probing geometry radius probe (disc) flat probe (rod)

7 cam stroke H camshaft standard function oriented evaluation Starting with inlet proceeding with outlet main cam cam zenith alignment coordinate system of drive dir. of rotation cam rot. angle h: cam stroke at ( rel. measure ) H: cam stroke (abs. measure)

8 camshaft standard application in machines / combustion engines roller follower (circular) flat follower roller follower (rolling tap) flat follower (sliding tap) morphological filtering moving point of contact conversion cam profiles

9 camshaft standard - measurements measurement instruments camshaft measuring instrument form measuring instrument hardness dimensional parameters diameter profile form straightness / parallelism roundness

10 camshaft standard - measurements camshaft datums manufacturing: live centers engine: bearing surfaces measurement camshaft measuring instrument: live centers form measuring instruments: centered

11 basic parameters form measuring instrument centering to excenter application of reversal procedure parameters roundness = 1,4 µm straightness = 2,3 µm prototype values!

software validation synthetic profiles simple rule geometries analytical computation possible Reference result Test data comparison procedure

12 software validation synthetic profiles simple rule geometries analytical computation possible Reference result Test data comparison procedure evaluation as pseudo measurement diff. pseudo measurement - theory Test software Test result Comparison test result vs. reference PTB certificate

13 Software test test data profile synthesis circle segments and tangents radius and angle offsets sampling Probing of the synthetic profile numerical profile as reference

14 Software test reference software fitting procedure angular position of cam definitions required Cam profile speed profile Slope 100% Fitting angle actual curve ref. curve alignment area opening Slope 60 % Slope 60 % Slope 100% alignment area closing cam form deviation area equality after alignment

15 Software test result example data set Base- Radius [mm] error free parameters Cam stroke [mm] Angle to datum [mm] Reference Data intended error Base Radius [mm] Cam stroke [mm] datum angle [mm] differences Base circ- [mm] Base circ+ [mm] HN- [mm] HN+ [mm] N2.1R 20,0000 5,0000 0,0000 none 0,0001 0,0000 0,0000 0,0000 0,0000-0,0001 0,0001 N2.2R 20,0000 5, ,0000 angle deviation 14 0,0001 0,0000 0,0000 0,0000 0,0000-0,0001 0,0001 N3.1R 18,0000 7,0000 0,0000 shrinked by 0.7 mm 0,0001-0,0004 0,0000-0,0004-0,0003-0,0004-0,0003 N3.2R 18,0000 7,0000 0,0000 Inflated by 0.4 mm 0,0001 0,0001 0,0000 0,0001 0,0001 0,0000 0,0001 N4.1R 16,0000 7,0000 0,0000 alternating positive and negative deviations of ±0.3 mm -0,0001 0,0001 0,0000 0,0001 0,0001 0,0001 0,0002 N5.1R 23,0000 5,0000 0,0000 cam stroke increased by 1,3 mm 0,0001-0,0002 0,0000-0,0001-0,0001-0,0001-0,0001 N5.2R 23,0000 5,0000 0,0000 cam stroke decreased by 0,8 mm 0,0001 0,0000 0,0000 0,0000 0,0000 0,0000 0,0000 N6.1R 15,0000 6,0000 0,0000 flank circles shrinked by 0.9 mm 0,0001 0,0000 0,0000 0,0000 0,0000 0,0000 0,0001

standardization challenges global production has to

instruments may be applied missing definitions

for mandatory evaluation methods draft as

16 standardization challenges global production has to deliver the same results various measurement instruments may be applied missing definitions coordination of users and manufacturers agreement for mandatory evaluation methods draft as (inter)national standard comparison measurements with camshaft standards

17 Part II Large gear standard Background Economic Importance of Large Gears Assuring the Quality of Large Gears Measuring Instruments Importance of Measurement Uncertainty Concepts of Traceability Motivation Establishing a reliable and economically efficient quality control Realization Large Gear Measurement Standard First measurement results Concepts of evaluating the measurement uncertainty in industry Experimental uncertainty budget VCMM-Gear: Monte-Carlo Simulation Conclusion & Outlook

18 Source: Headhuey, WikimediaCommons, Licence: GNU fdl Economic Impact of Large Gears 2008: Worldwide total wind energy capacity: MW Min. 36,000 Wind Turbine Generators (WTG) worldwide (Germany alone: ) Approx. 75 % equipped with gearboxes 2012: Worldwide total wind energy capacity: MW (DEWI scenario) Growing market for new WTG and therefore gearboxes Increasing demand for large gears Gear diameters up to 3000 mm

Source: Headhuey, WikimediaCommons, Licence: GNU fdl Economic impact of large gears Wind Turbine Generators Designed life expectancy 20 years Operating time 13 years Highly reliable, low-maintenance

19 Source: Headhuey, WikimediaCommons, Licence: GNU fdl Economic impact of large gears Wind Turbine Generators Designed life expectancy 20 years Operating time 13 years Highly reliable, low-maintenance gear box Smooth, quiet running, low noise emission High-quality gears, especially for offshore-turbines Required tolerances: Some 10 µm for major gear specifications ISO :1995 d = 1000 mm, b = 400 mm, m n = 20 mm, accuracy grade 5: F = 21 µm, F β = 18 µm Even stricter requirements for inspection processes

Quality assurance of large gears Measuring Instruments Coordinate Measuring Machines Gear Measuring Instruments Gears: Standard measuring task Modern instruments: Gear maximum

20 Quality assurance of large gears Measuring Instruments Coordinate Measuring Machines Gear Measuring Instruments Gears: Standard measuring task Modern instruments: Gear maximum dimensions: diameter: mm height: mm weight: kg Larger gears: special applications Challenges for large gears Alignment, deformation Reliable Measurements needed

21 Designing a large gear standard Design parameters Industrial requirements Limited measuring facilities at PTB Expanded measurement uncertainty less than U(k=2)=5 µm for involute profile and helix slope deviations Segmentation allows easy handling and shipping Dismountable countermass for symmetric weight distribution

/ hand Outside diameter d a Weight Reference bands diameter (form

22 Quality assurance of large gears Parameter Value Number of teeth z 38 Normal module m n 20 mm Pressure angle n 20 Face width b Helix angle β / hand Outside diameter d a Weight Reference bands diameter (form deviation) 400 mm 0 /spur; 10 /R; 20 /L 1000 mm 450 kg (700 kg) 200 mm (1 µm)

23 Large gear standard during meas.

24 Commercial gear standard

25 Flankenlinienabweichung in µm Helix deviation in µm First measurements Good profile and helix form Reproducibility of measurements Profile slope deviation f H <= 1.1 µm Helix slope deviation f Hb <= 2.2 µm Flankenlinie 0 Rechtsflanke Helix 0 right flank Zahnbreite in mm Facewidth in mm -10

26 Muchas gracias!

HPN E The solution to determine the measurement uncertainty

HPN E The solution to determine the measurement uncertainty HPN E 04 2013 The solution to determine the measurement uncertainty General Information Artefacts should be geometrically similar to the test pieces. (= identity condition) IC Artefacts A new approach