Facial Exercise Toning And Massage Workouts To Firm Baggy Hog Jowls At Home
Measurement and correction of baggy edges on paper … pptx.pdf · Measurement and correction of...
-
Upload
trannguyet -
Category
Documents
-
view
220 -
download
0
Transcript of Measurement and correction of baggy edges on paper … pptx.pdf · Measurement and correction of...
Measurement and correction of baggy edges on paper machinespaper machines
Frédéric Parent & Jean HamelFPInnovations
PaperCon 2011 Page 2454
Outlines
• A few words on baggy edges• Available tools to evaluate baggy edge• Case studies: correction of baggy edges• Conclusions• Conclusions
PaperCon 2011 Page 2455
A few words on baggy edges
PaperCon 2011 Page 2456
What is web tension non-uniformity in CD?
Baggy edge= lack of tension= tension drop
l b= longer web= slack edgeEtc.
PaperCon 2011 Page 2457
Issues related to baggy edges
• Print quality problems• MisregistrationMisregistration• Wrinkles/crepe wrinkles• Web breaks• Poor splicing• Poor winding• Web defects such as calender cuts,
crepe wrinkles, etc.
PaperCon 2011 Page 2458
Baggy edge rolls cause web weaving
Lateral oscillations vs CD position0.25
) Baggy edge rolls
0.15
0.2
an p
ositi
on (m
m) Baggy edge rolls
0
0.05
0.1
Stde
v of
med
ia
0A B Y Z
PaperCon 2011 Page 2459
Baggy edge rolls also cause misregistrationRoll median position stability on T12
0.25
0.3
0.35
sitio
n (m
m) Before printing
After printing
0 05
0.1
0.15
0.2
dev
of m
edia
n po
s
0
0.05
X12A202J V06A274C X13A203J Competitor X12A201J X13A195J X13A193J X13A192J
Std
Roll 1 Roll 2 Roll 3 Baggy roll Roll 5 Roll 6 Roll 7 Roll 8
Magenta
Cyan
PaperCon 2011 Page 2460
Baggy edge rolls even cause web breaks!
High tension = Risk of break
2 0
2.5
pli)
Bagginess zone
High tension Risk of break
1.0
1.5
2.0
ensi
on (p
Increasing the average tension
0
0.5
0 5 10 15 20 25 30 35 40 45
CD
Te Increasing the average tension
to reduce the bagginess on press
CD Position (inches)
PaperCon 2011 Page 2461
Origin of bagginess
Force
Longer Spring?L l St t h
Force
= Local Stretch = Bagginess
Bigger or smaller Spring?gg p gNo Bagginess
PaperCon 2011 Page 2462
MD/CD ratio profile
MD/CD ratio
Edge shrinkage effect
F t B k
Edge shrinkage effect
Front Back
Edge rolls usually have more expansion or shrinkage, dge o s usua y a e o e e pa s o o s age,leading to web elongation and bagginess at the edges
PaperCon 2011 Page 2463
Existing tools to evaluate baggy edge
PaperCon 2011 Page 2464
Some mills try to relate baggy edge to roll hardness
PaperCon 2011 Page 2465
Other mills try to relate baggy edge to TSI MD/g
)TSI MD kNm
Mean V.Std Dev.Min
7.5810.1798
7.001 (sho ld be less than 10%)
dex
(kN
m/
8.25
8.50MaxNo Val
7.0017.875
166
(should be less than 10%)
fnes
s In
d
7 50
7.75
8.00
nsile
Stif
f
7.00
7.25
7.50
MD
Te
0 9 19 28 38 47 56 66 756.50
6.75 Edge Edge
CD Position
PaperCon 2011 Page 2466
Existing tools to quantified baggy edge on machine
Beam with air pressure sensors that measure Beam with air pressure sensors that measure air pressure between paper and beam air pressure between paper and beam
Roll with a film force sensors mounted on it Roll with a film force sensors mounted on it in a helical arrangementin a helical arrangementgg
Both pictures have been taken from Metso publications and internet site
PaperCon 2011 Page 2467
Off-line tension beam to quantify baggy edges
• High accuracy (5% error)• Hi h l ti i CD ( 1”)• High resolution in CD (every 1”)• Width 50”
PaperCon 2011 Page 2468
Beam installation on roll tester equipment
Wound out tension
Paper rolls
Wound-out-tension
Lateral
ill ti
CD Tension
oscillations
Measurex
scannerDiameter, roundness scanner,
and length
PaperCon 2011 Page 2469
High resolution measurements in CDTension profiles of paper with baggy streaks - SCA paper
0.4
0.5
n (k
N/m
) cw ccw
0.1
0.2
0.3No
rmal
ized
tens
ion
Tension profiles of dried edges paper - newsprint
00 10 20 30 40 50 60 70 80 90 100 110 120 130
CD position (cm)
p g p p p
0.3
0.4
0.5
sion
(kN/
m)
cw ccw
0.1
0.2
Nor
mal
ized
tens
00 10 20 30 40 50 60 70 80 90 100 110 120 130
CD position (cm)
PaperCon 2011 Page 2470
Roll comparison from different CD positions
Rolls tension profile
0.4
0.5m
)
A B M Y Z
0.2
0.3
Tens
ion
(kN
/m A B M Y Z
0
0.1
0 50 100 150 200
CD position (inches)
CD Position (inches)
Worst Roll for Bagginess
PaperCon 2011 Page 2471
Case studies: correction of baggy edges
PaperCon 2011 Page 2472
Case study #1: Baggy edge (newsprint)
Tension profiles of edge rolls of paper machine0.5
B k dFront edge
0.3
0.4
(kN
/m)
Back edgeFront edge
0.1
0.2
Tens
ion
Tension diff between the 2
sides is 0.3 kN/m
00 10 20 30 40 50 60 70 80 90 100 110 120 130
CD Position (inches) PM front edge PM back edge
Significant baggy edge at the back of the machine
PaperCon 2011 Page 2473
Case study #1: Correcting the drying history
Tension profiles comparison of edge rolls of paper machine0.5
Before correction After correction
0.3
0.4
n (k
N/m
)
Before correction After correction
Tension diff between the 2
sides is reduced to 0.1 kN/m
Back edgeFront edge
0.1
0.2
Tens
ion
00 10 20 30 40 50 60 70 80 90 100 110 120 130
CD Position (inches) PM front edge PM back edge
Changing the drying history (press + dryers) allowed to reducethe tension non-uniformity at the back edge
PaperCon 2011 Page 2474
Case study #2: Baggy edge (directory grade)
CD tension profile (STD production)2.5
1.5
2
n ST
(pli)
Front edge roll Back edge roll
0.5
1
Tens
io
00 20 40 60 80 100
CD Position (in)
Significant baggy edge at both edges of the machine
PaperCon 2011 Page 2475
Case study #2: Application of moisture bias
Moisture bias at the edges
0 51
1.52
2.5
as (%
)
Moisture bias(-2% gradual bias
-2-1.5
-1-0.5
00.5
Moi
stur
e bi
a
( gover 50” wide)
-2.50 25 50 75 100 125 150 175 200 225
CD position (inch)
T i fil ith i t bi 2% B k f PM1Tension profile with moisture bias -2% - Back of PM1
2
2.5
3
No bias
With biasTension profile in CD
0.5
1
1.5
Tens
ion
(pli)profile in CD
increases at the edges
0
0 5
0 10 20 30 40 50CD Position (inch) Back PM1 >
PaperCon 2011 Page 2476
Case study #2: Correcting the tension profile with moisture bias
• No biasCD tension profile (STD production)
2
2.5
Front d
Back d- The tension profiles
were not uniform at the edges
0 5
1
1.5
Tens
ion
ST (p
li) edge roll
edge roll
0
0.5
0 20 40 60 80 100
CD Position (in)
• With bias- Tension profiles are
CD tension profile with moisture and caliper bias
2
2.5
li)
Front edge
Back edge- Tension profiles are
improved, especially at the back
0.5
1
1.5
Tens
ion
ST (p
edgeroll
edge roll
00 20 40 60 80 100
CD position (in)
PaperCon 2011 Page 2477
Case study #3: Inverse baggy edge (fine paper)
Tension profiles of edge rolls0.5
d
0.3
0.4
kN/m
)
Tension diff between the 2
Back edgeFront edge
0.1
0.2
Tens
ion
(k between the 2 sides is 0.2
kN/m
00 10 20 30 40 50 60 70 80 90 100 110 120 130
CD position (inches) PM front edge PM back edge
Inverse baggy edges at each edge of the machineThe customers see baggy edgesggy g
PaperCon 2011 Page 2478
Case study #3: Correcting CD moisture profilesM i t fil t d llMoisture profiles at edges rolls
0.1
0.2
0.3
0.4
vari
atio
n (%
)
-0.3
-0.2
-0.1
0
Moi
stur
e co
nten
t v
Relationship between moisture and CD tension
-0.40 10 20 30 40 50 60 70 80 90 100 110 120 130
CD position (inches)
R2 = 0.7329
0.3
0.4
0.5
kN/m
)Inverse correlation between CD tension and CD moisture profiles(higher moisture = lower tension)
0.1
0.2
Tens
ion
(k
( g )
Correction of CD moisture profiles is underway
0-0.4 -0.3 -0.2 -0.1 0 0.1 0.2 0.3
Moisture variation (%)
PaperCon 2011 Page 2479
What can be achieved
Measurements on any grade of paper Base sheet/coated/laminated Base sheet/coated/laminated
After conversion/print
Different CD positions and sets on paper machinesp p p
Quantification of CD tension profile Quantify how severe is actual bagginess
Comparison with database
Corrections suggested
Analysis and follow-up of machine changes
PaperCon 2011 Page 2480
Conclusions
• A tension beam was developed to quantify CD tension profile of paper web• high accuracy (<5% error)• high accuracy (<5% error)• high resolution (50 units over 127 cm width)
• This new tool was successful in measuring the tensionThis new tool was successful in measuring the tension non-uniformity of different types of paper grades.
• Bagginess and baggy edge can now be quantified at low cost
• Corrections can be made by changing the drying history of the web from the press section to the reelthe web from the press section to the reel.
• The tension beam can be used to monitor the tension profiles corrections and later to ensure the uniformity of the profiles with time.
PaperCon 2011 Page 2481