Guidelines for Allowable Roller Misalignment

Transcription

1 Web SM When to Move, How Close to Move Guidelines for Allowable Roller Misalignment 2013 David Roisum, Ph.D. Finishing Technologies, Inc. 77.1

2 Why is Alignment So Important? Affects the Web: Flatness: Bagginess and apparent Bagginess Position: Path and Registration (e.g. Printing) Runnability (Web Breaks) Winding: Roll Quality Wrinkles Costs money if standards are: Too loose or Too tight 77.2

3 Two Views of Alignment Mechanical Level Square Common Centerlines Web Handling In-plane (bending) Path control Web breaks Wrinkles Out-of-plane (twisting) Web damage/breaks at edges Center wrinkle Offset Centerlines Guide runs off center Web runs off center 72.3

4 Hand Tools - Types microns / meter Pi Tape Figures Courtesy of Oasis Alignment Services 72.4

5 Hand Tool - Limitations Level At best good to /foot (100 microns per meter) (Optics can be 20X tighter) Square There is no squaring tool Parallelism Problems Doesn t help square vertical spans (1-2 and 3-4) Accumulation of error Level and Square Large Tendency to Sloppiness

6 Hand Tool Application Step 1 I might have an alignment related problem Path Control Printer Registration Wound Roll Edge Web Breaks (Diagonal) Wrinkling Step 2 Verify working hypothesis that problem might be exacerbated by misalignment Level by level Parallel by Pi Tape Step 3 Align rollers using precision tooling That specific area or Entire machine 72.6

7 Optical Tooling Similar to surveying equipment, but > 10X more precise Figures Courtesy of Oasis Alignment Services 72.7

8 Baseline Installation Alignment means Establishing offset centerline for alignments Look for monuments (small plugs) in floor Figure Courtesy of Oasis Alignment Services 72.8

9 Centerline Survey Alignment means Level, Square, AND Middle of Rollers on Same Centerline Figure Courtesy of Oasis Alignment Services 72.9

10 Squaring With Optics Precision Square w.r.t. Baseline Uses a pair of TTS Precision right angles Figure Courtesy of Oasis Alignment Services 72.10

11 Other High Tech Alignment Tools Laser Shaft Alignment The standard for motor to roller alignment Laser Trackers Gyroscope Coordinate Measuring Total Station Gyro Fast setup and position readout Figures Courtesy of Oasis Alignment Services 72.11

12 Alignment Details - Preparation $$$ for Downtime Machine Builder Standards & Instructions Alignability Maintenance Remove Excess Rollers Roller Maintenance Dowel/Mark Align Crew Plug Lines Report with before & after readings Design for Service (alignability) Dowel Pin Shear Ledge Individual rollers easily moved Preserve Level Shear ledge Jack bolts Match Drilled Frames? Dunn, Jim M. Precision Alignment of Winders. Tappi J., vol 79, no 6, pp 67-71, June 1996 Williams, Fritz (OASIS). Alignment Methods and Best Practices for Cost Effective Alignment of Production Equipment. AIMCAL AWEB, Charlotte, May 7-10,

13 Alignment Challenges Bearing Housings At an angle Bolt bound designs (e.g., match drilled frames) No shear ledge Rollers - General Flimsy frames Flimsy foundations Loose mounting Rollers Specific Pivoting / translating Skewable Curved axis (bowed spreaders) Segmented Alignment No line of sight Flimsy floors Hand tools Procedural Lack of guidance Which rollers How close Not enough time Special Foil Close packed rollers Narrow rollers (wheels) 72.13

14 Two Views of Alignment Mechanical Level Square Common Centerlines See Web Roller Alignment - Mechanics Web Handling In-plane (bending) Path control Web breaks Wrinkles Out-of-plane (twisting) Web damage or breaks at edges Center wrinkle Offset Centerlines Guide runs off center Web runs off center 73.14

15 In-Plane Bending a.k.a, i.e. Not parallel Not trammed THE MOST SERIOUS RISK Path Control Web breaks Wrinkling etc 73.15

16 In-Plane Bending: Stresses-Strains Physics: Explains Normal Entry Law: Web enters a roller in traction at a right (normal) angle Guides Roller Misalignment Spreaders etc Can Cause Web Breaks Slack Web Wrinkles Path Change etc Tract ion 73.16

17 Out-of-Plane Twisting a.k.a, i.e. Twist Very Tolerant Difficult to Overstress No path change Applications: Pivot Pt 2 3 Displacement Guide 2 3 Sensor Some Dual Spreaders 1 L1 Correction Span 4 L2 Twist 73.17

18 Out-of-Plane Twisting: Stresses-Strains No Path Change High Stresses at Edges Center MD Bagginess/Wrinkle possible 73.18

19 Emergency Alignment Wrinkles are found at roller #3 and cause the web to break Question: Which roller (1-4) should be moved in which direction (horizontal, vertical, other)? 2 Wrinkle Dryer Hint: Unwind Ctr Winder 73.19

20 Smart Alignment Which rollers and directions is alignment most needed? Level easy Square requires optics 73.20

21 Two Views of Alignment Mechanical Level Square Common Centerlines Web Handling In-plane (bending) Path control Web breaks Wrinkles Out-of-plane (twisting) Web damage or breaks at edges Center wrinkle Offset Centerlines Guide runs off center Web runs off center 73.21

22 Current Art/Craft/Science Paper Industry: or per 100 width, maximum Converting Industry: / foot Most Common By Far: nothing whatsoever inch 125 micron Models for wrinkling and web breaks Commercial tolerances that are relatively easy to Despite decades of research, most everyone is getting the achieve with a bit of care answer wrong 77.22

23 In-Plane Bending a.k.a, i.e. Not parallel Not trammed THE MOST SERIOUS RISK Path Control Web breaks Wrinkling etc 77.23

24 In-Plane Bending: Stresses-Strains Physics: Explains Normal Entry Law: Web enters a roller in traction at a right (normal) angle Guides Roller Misalignment Spreaders etc Can Cause Web Breaks Slack Web Wrinkles Path Change etc Tract ion 77.24

25 Out-of-Plane Twisting a.k.a, i.e. Twist Very Tolerant Difficult to Overstress No path change Applications: Pivot Pt 2 3 Displacement Guide 2 3 Sensor Some Dual Spreaders 1 L1 Correction Span 4 L2 Twist 77.25

26 Practical Alignment One number for maximum allowable Worst case for a machine or plant In-plane bending (versus out-of-plane, level and square) Material (thin, high modulus) Machine (short spans, short L/W span ratios) Rollers (traction) With Practical Exceptions such as 77.26

27 Calculation Based For Each Critical/Typical Roller, Web and Direction Path Control Web Breaks (Critical Angle to Inside Edge Slackness) Web Tension Flat Align + t, E Wrinkled Slack Misalignment Angle Wrinkling (Critical Gehlbach, Lars S. and Good, Angle to Diagonal J.K and Kedl, Douglas M. Prediction of Shear Wrinkles in Shear Wrinkle) Web Spans. Tappi J., vol 72, no. 8, pp , Aug 1989

28 TopWeb Roller Align etc 77.28

29 WP AbbottApp Wrinkle Predictor AbbottApp Wrinkle Predictor runs on any computer and smartphone that has a modern browser 77.29

30 Empirical For Each Critical/Typical Roller, Web and Direction Wrinkling (Critical Angle) Move roller while running, observe when diagonal wrinkle starts Walks Uphill Points to Narrow side 73.30

31 Parametric Analysis: 36 cases from paper, paperboard, PET, PE and AL foil Allowable Misalignment per WP AbbottApp Hair' s Case Describe Brea Misalig dth n Misalig n Tension Width Span Diameter Wrap Friction Thickness Modulus Slack Notes microra dians mils lbs in in in degrees mil MPSI Wrinkle 1.00 Paper Machine Wrinkle Board 2.00 Machine Wrinkle Board 3.00 Rewinder Slack Paper 4.00 Rewinder Both 4.01 Tension Study X Wrinkle 4.02 Tension Study X Slack Low tension worst 4.03 L/W Study X Slack 4.04 L/W Study X Slack Short L/W worst 4.05 Diameter X Both 4.06 Diameter X Both NC 4.07 Wrap X Both NC 4.08 Friction Study X Both NC 4.09 Friction Study X Both Thick Caliper 4.10 Caliper Study X 2X Slack Worst* 4.11 Caliper Study X 0.5X Wrinkle Modulus High mod 4.12 Study X Both worst Modulus 4.13 Study X Both Paper Worst low tension, short span, 4.14 Case Slack high mod Paper Worst 4.15 Case Both PET Machine Wrinkle 12.0PET 0 Rewinder Slack Tension Study X 0.4 Slack 12.0 Low tension 2 Tension Study X 0.4 Slack worst L/W Study X 0.4 Slack 12.0 Short L/Q 4 L/W Study X 0.4 Slack worst 12.0 Thick Caliper 5 Caliper Study X 5X Slack Worst* Caliper Study X 0.1X Slack 12.0Modulus 7 Study X Slack 12.0Modulus 8 Study X Slack 12.0PET Worst worst 9 Case Slack case 12.1PET Worst 0 Case Both Foil Machine Wrinkle Foil Converter Sack Foil Converter Both worst case worst case PE Rewinder Slack 31.0PE Rewinder 1 Worst Case Slack 31.0PE Rewinder 2 Worst Case Both worst case worst case 77.31

32 Paper/Paperboard - PM Winder & Converting Rewinder Paper is fussier than paperboard Narrow converting rewinder fussier than full width PM winder Case Describe Hair's Bread th Misalign Misalign Tension Width Span Diameter Wrap Friction Thickness Modulus Slack Notes microradi ans mils lbs in in in degrees mil MPSI Wrinkle 1.00 Paper Machine Wrinkle 2.00 Board Machine Wrinkle 3.00 Board Rewinder Slack 4.00 Paper Rewinder Both 77.32

33 Converting Rewinder - Other Tension, Width, Span, Wrap, Friction, Caliper, Modulus, Slack or Wrinkle Case Describe Hair' s Brea dth Tensio Misalign Misalign n Diamete r Wrap Frictio Thicknes n s Modulus Slack Notes Width Span microrad ians mils lbs in in in degrees mil MPSI Wrinkle 4.00 Paper Rewinder Both 4.01 Tension Study X Wrinkle 4.02 Tension Study X Slack Low tension worst 4.03 L/W Study X Slack 4.04 L/W Study X Slack Short L/W worst 4.05 Diameter X Both 4.06 Diameter X Both NC 4.07 Wrap X Both NC 4.08 Friction Study X Both NC 4.09 Friction Study X Both 4.10 Caliper Study X 2X Slack Thick Caliper Worst* 4.11 Caliper Study X 0.5X Wrinkle 4.12 Modulus Study X Both High mod worst 4.13 Modulus Study X Both Paper Worst 4.14 Case Slack low tension, short span, high mod Paper Worst 4.15 Case Both 77.33

34 Paper Industry Summary ½ Hair s breadth good enough for most of the rollers in the paper industry* ½ Hair s breadth is the VERY tight end of commercial tolerances Irony: the paper mill winder (where tight tolerances originated) can tolerate 100X** converting winder (which has no specs) * Sectional roller gaps and other special situations excepted ** Guide roller can be misaligned 300 mils 77.34

35 Industry Summary Hair s Breadth Board Mill 50 Paper Mill 1.0 PE Convert 0.5 Paper Convert 0.2 Foil Convert* 0.1 PET Convert *Walker s foil study indicates models are too conservative Large difference between needs and practice in converting Education Tolerance Few rollers Slippery surfaces Light wrap angles 77.35

36 Outgoing Suggestions Outgoing (Should rollers be moved?) Response to known misalignment problems Path Web Breaks Wrinkles (diagonal) Calculate or Measure threshold of pain Safety factor of 4-10 Similar to tension Classes A < 20 micro-radian tooling, brittle webs B 20 micro-radian paper, metal C 100 micro-radian converting D 1000 micro-radian rubber, textiles F - > 1000 micro-radian web handling fail 77.36

37 Questions? Answers: David Roisum, Ph.D office cell 77.37