New Developments on Gear Metrologymensor.cenam.mx/ammc/eventos/evento2009/S4_1-HAERTIG.pdf · 2009-10-01 · NACMA-3 Queretaro - 31 - Idea „On-site“- metrology based on 4 LaserTracer

NACMA-3 Queretaro - 1 -

New Developments on

Gear Metrology

Frank Härtig

Physikalisch-Technische Bundesanstat


Basis of involute measurements

Measurement of micro-gears

Measurement of macro-gears

Determination of periodic structures on flank surfaces

Certification of involute gear software

Estimation of measurement uncertainty by simulation

Outline


Fundamental Low of Gearing

Leonard Euler, 18th century

Form of teeth derived from

application -> involute

Fundamental Law of Gearing

Former 10 Franken bank note,

Switzerland

A pair of gears is free of errors if

a driving gear

gives at constant angular velocity

a driven gear

an also constant angular velocity.


Types of Involute Gears


profile lead pitch

outside diameter

50 - 400 mm

gearbox car

source ZF

Evaluation - Traditional Gear Artifacts

workiec-like

artifacts


Evaluation

involute gear flank

evaluation in cross-section

ball

evaluation in direction of

norm vectors


profile lead pitch

Evaluation

Evaluation surfaces:

profile: evaluation perpendicular to the gear axis

lead, pitch: co-axial to the gear axis

Advantages:

control of manufacturing process

knowledge about functionality


Flank surface of involute gears are often modified

root- and tip relief, crowning

Evaluation of cylindrical gears became of

increasing complexity 20 instead of 6 parameters

Evaluation


Common Gear Measuring Devices

coordinate measuring machine gear measuring instrument


Micro-Gears

0.001 mm ≤ module ≤ 1 mm


optical probe

colour focus

taktile-optical

probe

tactile

probe

source Werth source Zeiss

source Alicona source BIR

x-ray

CT

Micro-Gears; Potential Measuring Devices


Epicyclic gear

gearbox diam.: 1.9 mm

reduction: 47:1

torque: 150 µNm

micro gear module 0.05 mm

outside diameter 0.5 mm

number of teeth 8

Micro-Gears


paperclip

pin

gear

module 0.12 mm

gear

module 0.05 mm

Micro-Gears


d=0.5 mm

Micro-Gears


Micro-Gears; Tactile-Optical Probe






-100

-150

-50length of roll [mm]

0.22 foot

0.25 tip

Z [µm

]

opticalsensor

opto-tactilesensor

1µ

m

error

left flank



2D CT-scanner

Micro-Gears; CT Measurement Principle


Advantages

Measurement of small structures

Measurement of different materials

Huge amount of measurement points

Non-destructive probing

Evaluation of gear parameters

Today’s disadvantages

Relatively high measurement uncertainty (>20µm)

Complex evaluation tools

Measurement and evaluation time take several hours

Micro-Gears; CT Measurement


z=12, mn = 0.12mm, α=20°, da= 2mm

1 Mio. data points

2

2

selected bands

for profile evaluation

Micro-Gears; CT Evaluation Principle


Micro-Gears; CT Filter

point artifacts


unfiltered filtered

Micro-Gears; CT Filter


Big-Gears

0.5 mm ≤ module ≤ 4 mm


fossil fuels are finite

global worming

EU program 20-20-20

20% renewable energy in 2020

today 8,5%

Big-Gears

http://www.wind-energie.de/fileadmin/bilder/highres/Natur_und_Landschaft/Windparkdubener_platte.jpg

http://www.wind-energie.de/fileadmin/bilder/highres/Offshore/middelgrunden.jpg


Technical development ~last 30 years 3 blade rotors (6-15 rpm)

epicyclic gears (ratio 1:10)

pitch controlled blades

average capacity 1.5 MW

(trend re-powering existing WTG)

expected lifetime 20 years

7 MW (11MW)

Big-Gears - Wind Turbine Generators


source Kingelnberg

source Leitz

source Leitz

outside diameter

< 3 600 mm

outside diameter

< 1 000 mm

outside diameter

< 5 000 mm

Big-Gears


source Leitz7300

6000 x 4000

gear wheel

sections

Big-Gears - Selected Application


outside diameter

< 10 000 mm

source Leitz

two horizontal arm machines

one rotary table

synchronised software (master, slave)

Big-Gears - Selected Application


Shopfloor measurements (tolerances ~10µm)

mounting (reproducibility)

heavy weight of the gears

CMM errors

harsh environmental conditions

(temperature, dust)

missing reference surfaces

source Leitz

Big-Gears - Challenges


Idea

„On-site“- metrology based on

4 LaserTracer

Calibration of product-like artifacts

Principle

Coordinate Measuring Machine as mover

Retro-reflector mounted at the stylus

Determination of the

LaserTRACER positions

Simultaneous read out

of all length information

Evaluation of the x-y-z-coordinates

by PTB software

Evaluation of the gear parameter

by CMM software

Schedule

2009

prototype on CMM 1m^3 at PTB

2010

1st calibration on

commercial CMM in industry

Big-Gears - Mobile Measuring Device


Number of teeth: 38

Module: 25 mm

Pressure angle: 20°

Root diameter: 905 mm

Tip diameter: 1000 mm

Segment of gear of 1 m in diameter (segment angle of 50°)

3 teeth with different lead directions

Material: steel

500 kg

Reference bands in the gear centre (form tolerance approx. 1 µm)

Counter mass for weight compensation

Big-Gears - Mobile Measuring Device


mn = 1.5 mm

z = 30

...

X Y Z

105.0184 -0.6320 15.0000

105.0388 -0.6361 15.0000

105.0592 -0.6402 15.0000

105.0796 -0.6444 15.0000

...

Traceable Gear Measurements

Material standards

Workpieces

Numerical standard

Testdata

Software Certification


companies

1

2

0

-1

-2

fHb in µm

UPTB(k=2)

covering all error influences:

• software

• measurement process

• environment

• …

results of industryonly software

a b ec d

Helix test d0 = 100 mm

Software Certification - Test


testdata

reference software

evaluation results

test software (product)

evaluation results

Comparison (< 0.1 µm)

INDUSTRYPTB

Software Certification - Test-Principle


companies

1

2

0

-1

-2

fHb in µm

a b d ec

tolerance of the

certified software

UPTB(k=2)

covering all error influences:

• software

• measurement process

• environment

• …Helix test d0 = 100 mm

Software Certification - Test


Internet aided software validation

Software Certification via Internet


Waviness artifact


z

invflankzchandr

invflankzchandr

z

y

x

eibe

eibe

,

,

sin

cos

X

22

yebe lrr

n

i

biiyii rzcplae1

22cos

e

bbe

r

r

r

rinv arccosarccostan

ell yye

Waviness artifact


Waviness artifact


-0,030

-0,025

-0,020

-0,015

-0,010

-0,005

0,000

0,005

0,010

0,015

0,020

0,025

0,030

0 10 20 30 40 50 60 70

Length of roll in mm

Pro

file

for

m d

evia

tion

in m

m

Measured data

Calculated data

Difference

Waviness artifact


Superimposed wavelengths and

amplitudesWavelengths: 2.5 mm, 8 mm und 25 mm

Amplitudes: 5 µm, 7 µm und 10 µm

Evaluation with the new algorithm

Waviness artifact


Case a:

Measurement value / result within tolerance, clearly good part

delivery, sale

- 6 -

Gear:

d0 = 100 mm

mn = 2 mm

b = 80 mm

Quality 2

-4,2

-2,1

0

2,1

4,2

6,3

case a case b case c case d case e

tota

l p

rofi

le d

ev

iati

on

in

µm

nominal value

upper tolerance

lower tolerance

Measurement Uncertainty - Simulation


Case b:

Measurement value / result outside tolerance, clearly rejected part

Correction of the production machines according to systematic deviation

- 6 -

Gear:

d0 = 100 mm

mn = 2 mm

b = 80 mm

Quality 2

-4,2

-2,1

0

2,1

4,2

6,3


tota

l p

rofi

le d

ev

iati

on

in

µm

nominal value

upper tolerance

lower tolerance



Case c:

Measured value within tolerance, assumed good part,

approx. 40 % probability to be rejected part

Reduction of measurement uncertainty

(e.g. improvement of measurement conditions,

transfer to precision-measurement room)

- 6 -

Gear:

d0 = 100 mm

mn = 2 mm

b = 80 mm

Quality 2

-4,2

-2,1

0

2,1

4,2

6,3


tota

l p

rofi

le d

ev

iati

on

in

µm

nominal value

upper tolerance

lower tolerance



Case d:

Measured value outside tolerance, assumed rejected part

approx. 40 % probability to lie within tolerance

Reduction of measurement uncertainty

(e.g. improvement of measurement conditions,

transfer to precision-measurement room)

- 6 -

Gear:

d0 = 100 mm

mn = 2 mm

b = 80 mm

Quality 2

-4,2

-2,1

0

2,1

4,2

6,3


tota

l p

rofi

le d

ev

iati

on

in

µm

nominal value

upper tolerance

lower tolerance



Case e:

Measurement value within tolerance, assumed good part

Measurement uncertainty exceeds tolerance

Measurement conditions completely insufficient

drastic reduction of measurement uncertainty (new measuring instrument)

Production of poorer quality (larger tolerances)

Gear:

d0 = 100 mm

mn = 2 mm

b = 80 mm

Quality 2

- 6 -

-4,2

-2,1

0

2,1

4,2

6,3


tota

l p

rofi

le d

ev

iati

on

in

µm

nominal value

upper tolerance

lower tolerance


NACMA-3 Queretaro - 48 - - 8 -



New Developments on

Gear Metrology

Frank Härtig

Physikalisch-Technische Bundesanstat

Documents

New Developments on Gear Metrologymensor.cenam.mx/ammc/eventos/evento2009/S4_1-HAERTIG.pdf · 2009-10-01 · NACMA-3 Queretaro - 31 - Idea „On-site“- metrology based on 4 LaserTracer