FTA (изд-во). Flexography: Principles And Practices. Vol.1-6
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PRESSES AND PRESS EQUIPMENT
INTRODUCTION 3
WIDE WEB PRESSES 5
Stack Press ..............................................................................5
Central Impression Press .......................................................7
In-Line Press ..........................................................................10
Folding Carton Press ............................................................10
Plate Cylinders ......................................................................11
Side and Circumferential Register Control .......................11
NARROW WEB PRESSES 13
Development and Growth .................................................. 13
Types of Narrow-Web Presses .............................................15
Central Impression Press...............................................15
In-Line Press ....................................................................16
Stack Press ......................................................................17
Platform Press ................................................................18
Products Printed ...................................................................18
The Narrow Web Process .....................................................19
Unwind .............................................................................19
In-Feed and Tension Control ........................................20
Print Stations ..................................................................21
Repeat Lengths ..........................................................21
Registration Adjustment...........................................21
Automatic Register Systems ...................................22
Drying and Curing ..........................................................23
Ultraviolet Curing .....................................................23
Laminating and Varnishing ......................................23
Die-cutting Stations ........................................................24
Die-cutting Basics ...........................................................25
Substrate Influence ........................................................26
Cutting Modes .................................................................28
Prescribed Shapes ..........................................................28
Specialized Tooling ........................................................28
Care and Handling of Rotary Tools ..............................29
Problem Areas ................................................................30
Waste Removal ................................................................31
Product Delivery and Collection ..................................32
TENSION SYSTEMS 34
Tension Zones ........................................................................34
Unwind .............................................................................34
Intermediate ....................................................................35
VOLUME 6
Table of Contents
FLEXOGRAPHY: PRINCIPLES & PRACTICES
Rewind .............................................................................35
Tension Drives .......................................................................35
Motors ..............................................................................35
Brakes and Clutches ......................................................36
TENSION CONTROL SYSTEMS 38
Manual Systems ....................................................................38
Roll Diameter Followers ...............................................38
Non-Contact Roll Diameter Followers ........................39
Intermediate Tension and Draw .........................................39
Automatic Controls ..............................................................39
Dancer Roll System .......................................................40
Tension Transducer Systems ........................................41
UNWIND EQUIPMENT 44
Single Position Unwind ........................................................44
Flying-Splice Unwind ...........................................................45
Unwind Tension Systems .....................................................47
In-Feed Unit ...........................................................................49
Out-Feed Unit ........................................................................49
REWIND EQUIPMENT 51
Surface Winders ....................................................................51
Double Drum ...................................................................51
Single Drum .....................................................................51
Center Winders ......................................................................52
Rewind Tension Systems .....................................................53
Power Requirement ..............................................................54
Constant Tension ............................................................55
Taper Tension ..................................................................55
Surface Rewind Tension Systems .......................................57
PNEUMATIC SHAFTS AND CHUCKS 58
Air Shafts ................................................................................58
Special Air Shafts ..................................................................59
Air Chucks .............................................................................60
WEB GUIDING 62
Web Guides ............................................................................62
Automatic Web Guiding Systems .................................64
Web Position Control .....................................................65
Sensor Installation ..........................................................65
Unwind Guiding ....................................................................65
Intermediate Web Guides ....................................................66
Steering Guides ...............................................................67
Steering Guide Operation ..............................................67
Instant Center Location ...........................................68
Entry Spans ...............................................................69
Web Plane ..................................................................69
Steering Guide Selection .........................................69
Offset Pivot Guide ..........................................................70
Rewind Guiding .....................................................................71
Rewind Operation............................................................71
WEB VIEWERS 73
Stroboscope ...........................................................................73
Oscillating Mirror ..................................................................73
Rotating Drum Mirror ..........................................................74
“Bent-Web” Feature ........................................................75
Automatic Synchronization ...........................................75
Lighting and Magnification ............................................75
Video Scanning .....................................................................75
System Configuration ....................................................76
Conclusion .............................................................................79
SUBSTRATE TREATMENT AND PROCESSING 80
Dryers......................................................................................80
How Dryers Work ...........................................................81
NFPA Guidelines .............................................................82
Cooling Rolls .........................................................................82
Heat Transfer ..................................................................82
Cooling Roll Design ........................................................83
Static Electricity ....................................................................85
Causes of Static ..............................................................85
Controlling Static ............................................................86
Conclusion..............................................................................88
SUBSTRATE CLEANING 89
Film Treating .........................................................................90
Corona Discharge ...........................................................90
Typical Film Treating Applications ..............................90
Powder Spray Systems .........................................................91
Electrostatic Powder .....................................................91
Dust Control ....................................................................91
In-Line Laminating ................................................................92
Modified Press for Laminating .....................................92
Separate Laminator Section ..........................................93
Solid Adhesive Laminating ............................................94
UV/EB Varnishing ..................................................................95
Curing ...............................................................................95
Safety ................................................................................96
CORRUGATED POSTPRINT PRESSES 98
Beginnings ..............................................................................98
Evolution and Growth ..........................................................98
Markets for Flexo Printing ..................................................98
Preprinting vs. Postprinting .................................................99
Economics of Postprinting ................................................100
Range of Products ..............................................................101
POSTPRINT PRESS CONSTRUCTION 102
Sheet Feeders ......................................................................103
Kicker Feeder ................................................................103
Lead-edge Feeder .........................................................104
Print Station .........................................................................105
Top Printing vs. Bottom Printing ................................105
Plate Mounting ..............................................................107
VOLUME 6 5
FLEXOGRAPHY: PRINCIPLES & PRACTICES
Pull Bands ......................................................................107
Counter Impression Roll .............................................108
Permanent Mesh Coupling ..........................................108
Inks .................................................................................109
Anilox Rolls ...................................................................109
Sheet Transport Systems ...................................................110
Pull-roller .......................................................................110
Vacuum and Belts .........................................................111
Rollers and Vacuum .....................................................111
Printer-slotter ......................................................................112
Printer-die Cutters ..............................................................112
Flexo Folder Gluer .............................................................112
Platen Die Cutting ...............................................................117
Stacking ................................................................................117
Upstackers .....................................................................117
Downstackers ...............................................................117
Registration ...................................................................118
The Gear-driven Press ........................................................119
The Line Shaft-driven Press ........................................120
Trends in Press Design .......................................................120
Servo-drive Presses ......................................................121
Free-standing Off-line Presses ....................................122
Thinner Printing Plates ................................................123
Quick Change Anilox Roll Systems ...........................123
Dryers ...................................................................................124
Sheet Cleaners ..............................................................125
Updating and Upgrading
for Continued Development ........................................126
Job Preparation and Planning ...........................................126
Equipment Maintenance ..............................................127
Training for Continued Improvement ........................127
PRESS MECHANICS 128
Balancing Flexo Rolls ........................................................128
Static Imbalance ...........................................................129
Dynamic Imbalance ......................................................129
Forces on Bearings ......................................................129
Allowable Total Indicted Runout ...............................131
Deflection of Rolls ..............................................................131
Gear Drives ..........................................................................132
Repeat-length Increments ...........................................136
Gear Measurement – CP, DP, Module ..................137
Pitch and Bare Cylinder Diameters ......................137
Plate Squeeze Allowance .......................................137
Gear Mounting ..............................................................138
Gears and In-line Processing ......................................138
Dual Gear Systems .......................................................139
Central Impression Press Drives ................................139
Line Shaft Drives ..........................................................140
Digital-servo Drives ......................................................140
Bearings ................................................................................141
Plain Sleeve Bearings ...................................................141
Rolling Bearing .............................................................142
Needle Bearings ............................................................143
Bearing Care and Use ..................................................143
PRESS MAINTENANCE 144
Realities of Wear on Performance ....................................144
Breakdown Maintenance ...................................................144
Preventive Maintenance .....................................................145
Management Responsibility ........................................145
Comminicating Maintenance Needs ..........................146
Areas of Proper Maintenance ............................................146
Installation .....................................................................146
Utilities ...........................................................................146
Lubrication ....................................................................146
Brakes and Clutches ....................................................148
Hydraulic Cylinder and Lines .....................................149
Anilox Rolls and Fountains .........................................149
Electric Systems ...........................................................149
Dryer ..............................................................................150
Auxiliary Equipment ....................................................150
Spare Parts Inventory ..................................................150
Pressmanship and Equipment Care .................................150
Timely Clean-up ............................................................150
Handling Care ...............................................................151
The Press Operator’s Opportunity .............................151
APPENDIX 153
A. Diametric Pitch 8 ..........................................................153
Diametric Pitch 10 ........................................................154
Diametric Pitch 12 ........................................................155
Diametric Pitch 20 ........................................................156
B. Circular Pitch 0.125" .....................................................157
Circular Pitch 0.25" .......................................................158
Circular Pitch 0.5" .........................................................159
C. Module Pitch 1 ..............................................................160
Module Pitch 2 ..............................................................161
Module Pitch 3 ..............................................................162
Module Pitch 4 ..............................................................163
PRESSROOM PRACTICES
INTRODUCTION 167
PERSONAL AND PRESSROOM SAFETY 169
Proper Dress ........................................................................169
Common Sense ....................................................................169
Safety Signage .....................................................................170
Emergency Equipment .......................................................171
Flammable Materials ..........................................................173
VOLUME 6
FLEXOGRAPHY: PRINCIPLES & PRACTICES
Hazardous Materials ...........................................................174
Disposal of Hazardours Materials ..............................175
Right-to-Know Law .......................................................175
Tool Safety ...........................................................................175
Doctor Blades ...............................................................176
Use of Rags ....................................................................176
Die-cutting Saftey .........................................................176
NARROW-WEB PRESS PROCEDURES 177
Press Setup ..........................................................................177
Select the Print Stations ..............................................177
Prepare the Dies ...........................................................177
Inspect the Mounted Plates ........................................177
Change the Anilox Rolls ..............................................178
Die Installation and Setup ...........................................179
Use of Setup Stock .......................................................181
Set Edge Guides ............................................................181
Set Auxiliary Stations ..................................................181
Dry Registration ............................................................181
Set Ink Distribution ......................................................183
Set the Fountain Roll and/or Doctor Blade ..............183
Set Impression, Inking and Registration ...................184
Check Colors to Standard ...........................................185
Approval Form ..............................................................185
Press Run Procedures ....................................................... 185
Ink Viscosity and pH ................................................... 185
Adding Ink to the Fountain .........................................187
Inspection Quality and Checks ...................................188
Quality Awareness ........................................................189
Shipping Preparation .................................................. 189
Preparing for the Next Job ..........................................189
Cleanup Procedures ...........................................................190
Cleanup Steps .............................................................. 190
Clean the Plates ............................................................191
Remove and Clean the Cutting Die ............................191
Label Ink Containers ...................................................191
Remove Unprinted Stock ............................................191
Clean Tools and Press Area ........................................191
Clean Ultraviolet (UV) Curing Units ......................... 192
WIDE-WEB PRESS PROCEDURES 193
Press Setup ..........................................................................193
Select the Print Stations ..............................................193
Determine the Substrate Wind ...................................193
Install Cylinder Hardware ...........................................194
Change Anilox Rolls .....................................................194
Anilox Roll Selection Guidelines ................................195
Load Cylinders into the Print Stations ......................195
Ink the Print Stations ...................................................196
Set the Fountain Roll and/or Doctor Blade ..............196
Set Impression, Inking and Registration ...................197
Check Colors to Standard ...........................................197
Approval Forms ............................................................198
Press Run Procedures ........................................................198
Ink Viscosity and pH ....................................................198
Adding Ink to the Fountain .........................................200
Inspection and Quality Checks ...................................201
Quality Awareness ........................................................202
Preparing for the Next Job ..........................................203
Cleanup Procedures ...........................................................203
Preliminary Cleanup Steps ..........................................203
Two-roll Station Cleanup .............................................203
Chamber-bladed Station Cleanup ...............................204
Cleaning the Plates .......................................................204
Doctor-blade Assembly Cleanup ................................205
Replacing a Doctor Blade ............................................205
Cleanup Ink Pans ..........................................................205
Label Ink Containers ....................................................206
Remove Unprinted Stock ............................................206
Clean Tools and Press Area ........................................206
Clean the Pumps ...........................................................206
CORRUGATED PRESS PROCEDURES 207
Press Setup ..........................................................................207
Supply Assurance Precheck ........................................207
Set the Feed Mechanism .............................................207
Set the Feed Gates .......................................................209
Set the Feed Device .....................................................209
Check Plates to Print Card ..........................................210
Select the Print Stations ..............................................210
Mounting the Plates to the Print Cylinder ................210
Set the Pull Rolls ..........................................................211
Set the Ink Distribution System .................................211
Ink the Print Stations....................................................211
Set the Fountain Roll and/or Doctor Blade ..............212
Adjust Print Impression ...............................................213
Check Colors to Standard ...........................................214
Press Setup Checklist ..................................................214
Pressrun Procedures ..........................................................214
Monitor Ink pH and Viscosity .....................................214
Adding Ink to the Fountain .........................................215
Checking Quality ..........................................................216
General Housekeeping .................................................217
Prepare for the Next Job .............................................217
Cleanup Procedures ...........................................................217
Cleaning Equipment and Materials ............................218
Opening the Machine ...................................................218
Conserve Ink .................................................................218
Manual Cleanup ............................................................218
Cleaning the Plates .......................................................219
Chamber-bladed Station Cleanup ...............................219
Doctor-blade Assembly Cleanup ................................219
Ink Pan Cleanup ...........................................................220
VOLUME 6
FLEXOGRAPHY: PRINCIPLES & PRACTICES
Automatic Washups ......................................................220
Mark Ink Containers ....................................................220
Weekly Cleanups ..........................................................221
APPENDIX
Pressroom Troubleshooting Chart ...................................223
INDEX 233
CHAPTER 1
Presses & Press Equipment