Non destructive testing of fabric weight in the weaving process

Y.-S. Gloy, T. Gries and G. Spies

13th International Symposium on Nondestructive Characterization ofMaterials

Content

Institut für Textiltechnik der RWTH Aachen University

Testing of fabric weight in the

weaving process

Introduction

Capacitive sensor

X-ray sensor

Closed-loop control

Validation

Summary and outlook

Content

Institut für Textiltechnik der RWTH Aachen University

Testing of fabric weight in the

weaving process

Introduction

Capacitive sensor

X-ray sensor

Closed-loop control

Validation

Summary and outlook

36.000 Students in 126 courses of study

340 Institutes with 480 professorships

6900 Employees (thereof 65% scientists)

750 Mio € Total budget, thereof:

320 Mio € Third party funding

RWTH Aachen University

4

Source: RWTH Aachen University,Photos Peter Winandy

New form of cooperation

between industry and

university:

15 relevant clusters

Exchange of research results,

employees,

further resources

Biggest european technology

campus

Ca. 2 Bill € investment

till 2020

Source: rha reicher haase + associierte

ITA

RWTH Aachen Campus

5

The unique position of ITA

6

ap

plic

ati

on

fie

lds

mobility

building & living

health

energy

Comprehensive textile process chains

technology and competence fields

raw

mat

eria

ls:

nat

ura

l fi

ber

s, p

oly

mer

s,..

.

sem

i-fi

nis

hed

tex

tile

s &

p

rod

uct

s

Budget: ca. 14,3 Mio. €

Staff:

85 Scientists

55 Service personnel

190 Graduate research assistants

50 Students majoring in textile

technology each year

Research and development

Publicity and third party

funded research

Academic and industrial education

Development and transfer

Direct industrial research

Further educationpartially public

publ

ic

Str

ictly

con

fiden

tialFundamental

Researchca. 30%

Industrial Fundingca. 31%

Industry-RelatedPublic Funding

ca. 35%

Subsidyca. 4%

Institut für Textiltechnik der RWTH Aachen University

7

Content

Institut für Textiltechnik of RWTH Aachen University

Testing of fabric weight in the

weaving process

Introduction

Capacitive sensor

X-ray sensor

Closed-loop control

Validation

Summary and outlook

Woven fabrics

Woven fabrics

Rectangular crossing of warp and weft

Applications

Clothing

Technical textiles e.g.

Airbags, Parachutes, Composites

Weaving machines

Standard machine speed up to 1000 rpm

Weft insertion efficiency of 2000 m/min

150.000 machines produced worldwide (2011)

Fabric weight important quality criteria

3D-Fabric; Source: ITA

Weaving Maschine; Source: Picanol nv, Ieper, Belgium

Airbag; Source: ITA

9

Principle of a weaving machine

Warp beam

Back restWarp stop motion

Shed

Reed

Fabric take-off

Fabric beam

Weft

Warp Fabric

Direction of production

Principle of a weaving machine; Source: ITA

10

Content

Institut für Textiltechnik of RWTH Aachen University

Testing of fabric weight in the

weaving process

Introduction

Capacitive sensor

X-ray sensor

Closed-loop control

Validation

Summary and outlook

U(C)

C=C(ε)ε

Capacitive sensor

Capacity of a parallel plate capacitor is

determined by

Where C = capacity; ε0 = 8.854 x 10-12,

εr = dielectric relative constant, S = area and d = distance

According to Carvalho et al. a relationship is established between the capacity and a

passing yarn mass

Measurement slot

Electrodes

Capacitive sensor ; Source: ITA

Principle of a capacitive sensor

12

Installation of capacitive sensor

Instalation of capacitive sensor on a weaving machine; Source: ITA

13

Validation of capacitive sensor

1,80

2,30

2,80

3,30

3,80

6 8 10 12 14 16 18

17 picks per cm

8 picks per cm

Picks per cm

Cap

aciti

vese

nsor

sign

al[V

]

14

Content

Institut für Textiltechnik of RWTH Aachen University

Testing of fabric weight in the

weaving process

Introduction

Capacitive sensor

X-ray sensor

Closed-loop control

Validation

Summary and outlook

X-ray sensor

Principle of an X-Ray sensor, Source: ITA

with

Radiometric absorption according to Beer-Lambert law

where I = Intensity of the beam, I0 = original intensity of the beam, L = length of beam into the substance, e =

Euler's number, about 2.718, µ = the attenuation coefficient ρ = the density, µ/ρ = the mass attenuation

coefficient and ρ•L = the area density, m = total mass of the object and A = total area

Sensor from BST ProControl Rengsdorf GmbH,

Rengsdorf, Germany

Radiometric absorption system

Accelerating voltage < 5kV, can be used

in Germany without approval

Measurements between 50 and 1000 g/m²

Resolution of 0,1 g/m²

16

Installation of X-ray sensor

Installation of x-ray sensor on a weaving machine; Source: ITA

17

Comparison – X-Ray sensor vs. fabric weight (DIN EN 12127) Weaving machine running at 400 rpm

-2,75

-2,7

-2,65

-2,6

-2,55

-2,5

-2,45

-2,4

-2,35

300

310

320

330

340

350

360

370

380

390

400

10 12 14 16 18 20

DIN EN 12127

X-ray sensor

Picks per cm

Fa

bri

cw

eig

ht [

g/m

2]

X-ra

y se

ns

or s

ign

al [V

]

18

Content

Institut für Textiltechnik of RWTH Aachen University

Testing of fabric weight in the

weaving process

Introduction

Capacitive sensor

X-ray sensor

Closed-loop control

Validation

Summary and outlook

Closed-loop control

Due to dead time (depending on rpm and weft density) use of Smith Predictor

PI Controller and prediction of plant without dead time

Integration into loom via components form iba AG, Fürth, Germany components

Smith Predictor control of fabric weight; Source: ITA

FW = Fabric weightGF = transfer element of signal to fabric weightGR = transfer element of PI ControllerGS = transfer element of sensorGW = transfer element of weaving machineGT = transfer element of dead time = transfer element of model of the plantiG

~

20

Step response

Step in weft density

21

Sen

sor

volt

age

US [

V]

Content

Institut für Textiltechnik of RWTH Aachen University

Testing of fabric weight in the

weaving process

Introduction

Capacitive sensor

X-ray sensor

Closed-loop control

Validation

Summary and outlook

Field trial within WeyermannTechnical Textiles GmbH & Co. KG, Wegberg, Germany

Accuracy of fabric control less 3 %

System accepted by weaving mill workers

Validation of Smith Predictor

0 50 100 150 200 250 30010

12

14

16

18

20

22

0 50 100 150 200 250 3002.54

2.56

2.58

2.6

2.62

2.64

2.66

2.68

2.7

Time t [s]

Sen

sor v

olta

geU

s[V

]W

eftd

ensi

tyD

Wef

t[1

/cm

]

Sensor signal

actuating variable

Simulation Measurement

0 50 100 150 200 250 30010

12

14

16

18

20

22

0 50 100 150 200 250 3002.54

2.56

2.58

2.6

2.62

2.64

2.66

2.68

2.7

Time t [s]

Sen

sor v

olta

geU

s[V

]W

eftd

ensi

tyD

Wef

t[1

/cm

]

Sensor signal

actuating variable

Conventional controller

Actuating variable

Smith Predictor

ΔF

W /

ΔF

W d

esi

red

23

Content

Institut für Textiltechnik of RWTH Aachen University

Testing of fabric weight in the

weaving process

Introduction

Capacitive sensor

X-ray sensor

Closed-loop control

Validation

Summary and outlook

Summary and outlook

Summary

Capacitive sensor not suitable

X-Ray sensor can be used to monitor fabric weight

Smith predictor as control loop for field test

Outlook

Integration of further sensor

Camera system to detect weft errors and

weft density developed at ITA

Transfer to further textile processes

x

y

z54 x 45 mm²

vx

vy

25

Thank you for your attention

The authors would like to thank the German Research Foundation DFG for their

support of the depicted research within the Cluster of Excellence "Integrative

Production Technology for High-Wage Countries“

Backup

Backup

Backup

Backup

Gehäuse

Sensorfenster

Montagering

Backup

Empfängerfenster

Senderfenster

Sensoreinflussbereich

80

34

,37

20