Case Study: Window Regulator Assembly Line

Hankinson Inc.

Julian Hankinson

www.hankinsoninc.com

Performance & NVH Test Station

Accelerometer Actuators

Rail Bracket Motor

Example Data & Test Criteria

Rail Vibration Data for Cable Grinding Issue

1.4 1.45 1.5 1.55 1.61

0

1

0

1

0

1

Time [sec]

Acce

l [G

]

Cable Pass Period

Cable Pass Period

Good Unit

Moderate Cable Grinding

Severe Cable Grinding

Rail Vibration Spectrums

0 200 400 600 800 10000

0.01

0.02

0.03

0.04

0.05

Frequency [Hz]

G r

ms

Cable GrindingNo Cable Grinding

Band of ConsistentDifference

Filtered & Enveloped Rail Vibration Data

1.4 1.45 1.5 1.55 1.61

0

1

0

1

0

1

Time [sec]

Acce

l [G

]

Cable Pass Period

Cable Pass Period

Good Unit

Moderate Cable Grinding

Severe Cable Grinding

Spectrums of Enveloped Data

0 50 100 150 2000

0.005

0.01

0.015

0.02

0.025

0.03

0.035

0.04

Frequency [Hz]

G r

ms

Good UnitModerate Cable GrindingSevere Cable Grinding

Cable Coil Pass Frequency

Statistical Analysis of Envelope Criteria

for Cable Grinding Issue

0 0.02 0.04 0.060

10

20

30

40

50

Envelope Magnitude @ Cable Pass Frequency

Nu

mb

er

of U

nits

"Good" Units ( 3 )"Bad" Units

Moderate Cable Grinding

Severe CableGrinding

Statistical Analysis of Kurtosis Criteria

for Cable Grinding Issue

2 3 4 5 60

20

40

60

80

100

120

140

Kurtosis

Nu

mb

er

of U

nits

"Good" Units ( 3 )"Bad" Units

Acoustic Spectrum Comparison

for Motor Noise Issue

0 1000 2000 3000 4000 50000

0.5

1

Vo

lts p

ea

k

0 1000 2000 3000 4000 50000

0.5

1

Frequency [Hz]

Vo

lts p

ea

k

Quiet Motor

Loud Motor High FrequencyContent

Statistical Analysis of High Frequency

Energy Band Criteria for Motor Noise Issue

0 0.1 0.2 0.3 0.4 0.5 0.60

20

40

60

80

100

Frequency Band Energy, Motor Microphone

Nu

mb

er

of U

nits

"Good" Units ( 3 )"Bad" Units