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Roll Forming Handbook
DK1201_half-series-title.qxd 9/21/05 4:14 PM Page A
MANUFACTURING ENGINEERING AND MATERIALS PROCESSING
A Series of Reference Books and Textbooks
SERIES EDITOR
Geoffrey Boothroyd
Boothroyd Dewhurst, Inc.
Wakefield, Rhode Island
1. Computers in Manufacturing,
U. Rembold, M. Seth,
and J. S. Weinstein
2. Cold Rolling of Steel,
William L. Roberts
3. Strengthening of Ceramics: Treatments, Tests, and Design
Applications,
Harry P. Kirchner
4. Metal Forming: The Application of Limit Analysis,
Betzalel Avitzur
5. Improving Productivity by Classification, Coding, and Data Base
Standardization: The Key to Maximizing CAD/CAM and Group
Technology,
William F. Hyde
6. Automatic Assembly,
Geoffrey Boothroyd, Corrado Poli,
and Laurence E. Murch
7. Manufacturing Engineering Processes,
Leo Alting
8. Modern Ceramic Engineering: Properties, Processing, and Use
in Design,
David W. Richerson

9. Interface Technology for Computer-Controlled Manufacturing
Processes,
Ulrich Rembold, Karl Armbruster, and Wolfgang Ülzmann
10. Hot Rolling of Steel,
William L. Roberts
11. Adhesives in Manufacturing,
edited by Gerald L. Schneberger
12. Understanding the Manufacturing Process: Key to Successful
CAD/CAM Implementation,
Joseph Harrington, Jr.
13. Industrial Materials Science and Engineering,
edited by
Lawrence E. Murr
14. Lubricants and Lubrication in Metalworking Operations,
Elliot S. Nachtman and Serope Kalpakjian
15. Manufacturing Engineering: An Introduction to the Basic Functions,
John P. Tanner
16. Computer-Integrated Manufacturing Technology and Systems,
Ulrich Rembold, Christian Blume, and Ruediger Dillman
17. Connections in Electronic Assemblies,
Anthony J. Bilotta
18. Automation for Press Feed Operations: Applications and Economics,
Edward Walker
19. Nontraditional Manufacturing Processes,
Gary F. Benedict
20. Programmable Controllers for Factory Automation,
David G. Johnson
21. Printed Circuit Assembly Manufacturing,
Fred W. Kear
22. Manufacturing High Technology Handbook,

edited by Donatas
Tijunelis and Keith E. McKee
DK1201_half-series-title.qxd 9/21/05 4:14 PM Page B
23. Factory Information Systems: Design and Implementation for CIM
Management and Control,
John Gaylord
24. Flat Processing of Steel,
William L. Roberts
25. Soldering for Electronic Assemblies,
Leo P. Lambert
26. Flexible Manufacturing Systems in Practice: Applications, Design,
and Simulation,
Joseph Talavage and Roger G. Hannam
27. Flexible Manufacturing Systems: Benefits for the Low Inventory
Factory,
John E. Lenz
28. Fundamentals of Machining and Machine Tools: Second Edition,
Geoffrey Boothroyd and Winston A. Knight
29. Computer-Automated Process Planning for World-Class
Manufacturing,
James Nolen
30. Steel-Rolling Technology: Theory and Practice,
Vladimir B. Ginzburg
31. Computer Integrated Electronics Manufacturing and Testing,
Jack Arabian
32. In-Process Measurement and Control,
Stephan D. Murphy
33. Assembly Line Design: Methodology and Applications,
We-Min Chow
34. Robot Technology and Applications,

edited by Ulrich Rembold
35. Mechanical Deburring and Surface Finishing Technology,
Alfred F. Scheider
36. Manufacturing Engineering: An Introduction to the Basic Functions,
Second Edition, Revised and Expanded,
John P. Tanner
37. Assembly Automation and Product Design,
Geoffrey Boothroyd
38. Hybrid Assemblies and Multichip Modules,
Fred W. Kear
39. High-Quality Steel Rolling: Theory and Practice,
Vladimir B. Ginzburg
40. Manufacturing Engineering Processes: Second Edition,
Revised and Expanded,
Leo Alting
41. Metalworking Fluids,
edited by Jerry P. Byers
42. Coordinate Measuring Machines and Systems,
edited by
John A. Bosch
43. Arc Welding Automation,
Howard B. Cary
44. Facilities Planning and Materials Handling: Methods and
Requirements,
Vijay S. Sheth
45. Continuous Flow Manufacturing: Quality in Design and Processes,
Pierre C. Guerindon
46. Laser Materials Processing,
edited by Leonard Migliore
47. Re-Engineering the Manufacturing System: Applying the Theory

of Constraints,
Robert E. Stein
48. Handbook of Manufacturing Engineering,
edited by Jack M. Walker
49. Metal Cutting Theory and Practice,
David A. Stephenson
and John S. Agapiou
50. Manufacturing Process Design and Optimization,
Robert F. Rhyder
51. Statistical Process Control in Manufacturing Practice
, Fred W. Kear
52. Measurement of Geometric Tolerances in Manufacturing,
James D. Meadows
53. Machining of Ceramics and Composites,
edited by Said Jahanmir,
M. Ramulu, and Philip Koshy
54. Introduction to Manufacturing Processes and Materials,
Robert C. Creese
DK1201_half-series-title.qxd 9/21/05 4:14 PM Page C
55. Computer-Aided Fixture Design,
Yiming (Kevin) Rong
and Yaoxiang (Stephens) Zhu
56. Understanding and Applying Machine Vision: Second Edition,
Revised and Expanded,
Nello Zuech
57. Flat Rolling Fundamentals,
Vladimir B. Ginzburg and Robert Ballas
58. Product Design for Manufacture and Assembly:
Second Edition, Revised and Expanded,
Geoffrey Boothroyd,

Peter Dewhurst, and Winston A. Knight
59. Process Modeling in Composites Manufacturing,
edited by
Suresh G. Advani and E. Murat Soze
r
60. Integrated Product Design and Manufacturing Using Geometric
Dimensioning and Tolerancing,
Robert Campbell
61. Handbook of Induction Heating,
edited by Valery I. Rudnev,
Don Loveless, Raymond Cook and Micah Black
62. Re-Engineering the Manufacturing System: Applying the Theory
of Constraints, Second Edition,
Robert Stein
63. Manufacturing: Design, Production, Automation, and Integration,
Beno Benhabib
64. Rod and Bar Rolling: Theory and Applications,
Youngseog Lee
65. Metallurgical Design of Flat Rolled Steels,
Vladimir B. Ginzburg
66. Assembly Automation and Product Design: Second Edition,
Geoffrey Boothroyd
67. Roll Forming Handbook,
edited by George T. Halmos
68. Metal Cutting Theory and Practice, Second Edition,
David A. Stephenson and John S. Agapiou
69. Fundamentals of Machining and Machine Tools, Third Edition,
Geoffrey Boothroyd and Winston A. Knight
DK1201_half-series-title.qxd 9/21/05 4:14 PM Page D
edited by

George T. Halmos
Delta Engineering, Inc.
Toronto, Ontario, Canada
Roll Forming
Handbook
A CRC title, part of the Taylor & Francis imprint, a member of the
Taylor & Francis Group, the academic division of T&F Informa plc.
Boca Raton London New York
DK1201_half-series-title.qxd 9/21/05 4:14 PM Page i
Published in 2006 by
CRC Press
Taylor & Francis Group
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© 2006 by Taylor & Francis Group, LLC
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No claim to original U.S. Government works
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International Standard Book Number-10: 0-8247-9563-6 (Hardcover)
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Roll forming handbook / edited by George T. Halmos.
p. cm. (Manufacturing engineering and materials processing ; 67)
Includes bibliographical references and index.
ISBN 0-8247-9563-6 (alk. paper)
1. Roll forming (Metalwork) Handbooks, manuals, etc. I. Halmos, George T. II. Series.
TS340.R5857 2005
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Preface
Roll forming has asignificant and apuzzling peculiarity. The significant aspect is that during the last
half century,roll forming has developed to be the most productive metal forming technology. About
35 to 45% of all the flat steel produced by the NorthAmerican steel mills is processed throughroll
forming mills; this is moresteel than used by the automotive industry. The puzzling aspect of roll
forming is that in spite of seeing and using hundreds of rollformed appliances,automotive,building,
agricultural, office furniture, storage, and other products, hardlyanybody outside the profession has
ever heardofroll forming.Most people havesome perception or image about forging, casting, and
welding,but not rollforming.Nopopular books or plays are about roll formers. Most importantly,
the available technical literatureislimited. Those working in the industryhaveadifficult time learning

the trade and in explaining to others what their profession is, what they are doing,and, indeed, what
roll forming is.
During the 100-year historyofroll forming, thousands of knowledgeable tool, equipment, and
product designers and users haveworkedand are still working in this industry. Unfortunately,most of
the experience gained by those roll former operators, setup personnel, and designers has never been
documented in anymeaningful way, and it remains the secret of the individuals. Of all the published
papers and researchreports, only alimited number can be readily interpreted and applied in roll
forming plants.
The aim of this handbook is to fill this gap in knowledge and to provide comprehensiveinformation
about roll forming equipment to operators, supervisors, engineers, and tool and equipment designers, as
well as to students interested in this trade. The text is based on the authors’ own experience,enriched
with the experience of other individuals willing to share their knowledge with them.
Roll forming is acomplex subject. It is possible that readers willsearchfor and cannot find certain
missing details. As editor and author,Ichose to include those subjects that Ithought would be most
relevant to both novices and experiencedpractitioners. Nobody knows everything about roll forming;
readers’ experiences maydiffer from those described in this book because of the multitude of factors
influencing the qualityand quantityofrollformed products. Therefore, readers are encouraged to send
their comments, observations, and data to the editor and authors of this book. Certainly,their criticism
and the new information will enrich subsequent editions of this handbook.
Iwas introduced to roll forming by my former boss in the late 1950s. On my first day on the job,he
pointed to an uncoiler and explained, “There’s wherethe material comes from, it’s formed in the next
equipment, which is the mill and then it is cut to length. The rest of it you will learn.”And Ilearned the
hard way, by trying to understand the process, reading the few papers on the subject that were available
at that time, and taking coursesprovided by FMA, SME, and afew other organizations. Admittedly,my
most valuable experiencestems from setting up mills with rolls Idesigned and operating the rollforming
line. Inever forgot the mistakes Imade. However,alifetime would not be enoughtogain all of the
iii
experience that Ilearned from mill operators, setup personnel, suppliers, colleagues, and friends who
were willing to share their “hard learned” knowledge with me.
Special acknowledgment to Andy Baird, To ny Srnec, and to along list of co-speakers at rollforming

conferences: TimGutowski, Don Hill,Joe Ivaska, Barlow Brooks, Leo Gale, and manyothers. Ialso
learned alot fromthe comments and questions of the audience at my presentations.
Thanks to those experts who took the time to read and correct parts of my original manuscript:
RollDesign —TonyRhodes, Fred Gradous; Materials —Shrikant Bhat, Jim Cran, SteveForrest,
Gil Kaufman, Alan Pearson, Paul Schurter,and others.
The writing of this book was also made possible by the understanding and supportofmyfamily,
including the correctionofmyEnglish grammar by my children, typing of the text by my efficient
secretaryFannyTam, the preparation of drawings by George A. Dobrevand several other engineers, and
the kind cooperation of about 30 companies.
George T. Halmos
Prefaceiv
Editor
George T. Halmos,consulting engineer,has been the president of Delta Engineering Inc. in Toronto,
Canada since1979. He graduated as amechanical engineer from the Technical UniversityofBudapest in
1950. He worked for 4years as aresearch engineer and was head of the largest material testing laboratory
in middle Europe. He was also alecturer at the Te chnical University of Budapest from 1950 to 1956. In
1957, he joined asubsidiaryofAlcan in To ronto as adesign engineer.For the next 17 years, he worked
for the largest sheet metal manufacturing companyinCanada (Westeel-RoscoLtd.) in the positions
of project engineer,then works manager and chief engineer.In1976, he joined B&K Machinery
International Ltd. as general manager of the Roll Forming Division. He has participated in the
engineering committees of the Canadian Steel Sheet Building Institute, the Canadian Steel Pipe Institute,
and the Canadian Standards Association Metric Committee. He is amember of several professional
associations and is aregistered consulting engineer.Heauthored approximately 50 technical papers and
has made over 100 presentations on various subjects on rollforming.
Currently,heprovides consulting and troubleshooting services, conducts management and operator
training courses, and carries out research and development in all aspects of sheet metal manufacturing
technologies, with special emphasis on roll forming; customers range from the smallest shops to the
word’slargest manufacturing companies.
v

Contributors
vii
GeorgeT.Halmos
Delta EngineeringInc.
Ontario,Canada
Joseph Horvath
Retired
Joseph Ivaska
Tower Oil &Technology Co.
205 W. Randolph St.
Chicago,IL60606
Manabu Kiuchi
Faculty of Informatics
Institute of Industrial Sciences
TeikyoHeisei University
Tokyo, Japan
Ashok Shah
The LockformerCompany
GerardInternationalCorporation
Naperville, IL

Contents
1 Introduction to Roll Forming George T. Halmos 1-1
1.1 Introduction to Roll Forming 1-1
2 Roll Forming Mill George T. Halmos 2-1
2.1 General 2-1
2.2 Mill Types 2-1
2.3 Mill Components 2-18
References 2-32
3 Presses and Die Accelerators George T. Halmos 3-1

3.1 General 3-1
3.2 Mechanical Presses 3-6
3.3 Pneumatic Presses 3-10
3.4 Hydraulic Presses 3-12
3.5 Information and Dimensions for Press/Die Purchasing and Installation 3-15
3.6 Rotaryand Other Cutting,Punching Equipment 3-15
3.7 Flying Die Accelerators 3-20
4 SecondaryOperations in the Roll Forming Line George T. Halmos 4-1
4.1 SecondaryOperations 4-2
4.2 Straightening 4-3
4.3 Tight or Loose Line: Cutting Before, In-Between, or After Roll Forming 4-9
4.4 Location of the SecondaryOperations 4-14
4.5 Stationaryand Flying Dies 4-14
4.6 Punching, Perforating,Notching,and Mitering 4-16
4.7 Piercing and Partial Punching 4-19
4.8 Flanging,Louvering, and Lancing 4-20
4.9 Embossing and Drawing 4-20
4.10 Bending 4-22
4.11 Curving (Sweeping) 4-24
4.12 Marking 4-46
4.13 Swedging (OffSetting) 4-46
4.14 RotaryDies 4-46
ix
4.15 Mechanical Joining of DifferentStrips or Parts 4-56
4.16 Adhesive Bonding 4-60
4.17 Soldering and Brazing 4-60
4.18 Resistance Welding 4-60
4.19 Painting 4-62
4.20 Foaming 4-62
4.21 Packaging 4-62

References 4-62
5 Roll Design George T. Halmos 5-1
5.1 Roll Design Process 5-2
5.2 Cross-Section 5-4
5.3 Product Orientation and Other Operations in the Line 5-13
5.4 Materials 5-19
5.5 Roll Forming Mill 5-28
5.6 Other Tool Design Considerations 5-40
5.7 Spacersand Shims 5-48
5.8 Calculating Strip Width 5-52
5.9 Bend Lines 5-55
5.10 Number of Passes 5-64
5.11 Flower Diagram 5-73
5.12 Roll Design 5-78
5.13 Calculating Roll Dimensions Manually 5-94
5.14 Computer-Aided Roll Design 5-95
5.15 Examples 5-100
5.16 Roll MarkingSystem 5-103
5.17 Roll Orientation 5-107
5.18 Setup Charts 5-107
References 5-111
6 Materials George T. Halmos 6-1
6.1 Design Considerations 6-1
6.2 Mechanical Properties 6-2
6.3 Crystalline StructureofMetals 6-7
6.4 Forming Metals 6-7
6.5 Increasing the Strength of Metals by Cold Working 6-10
6.6 HotRolling 6-10
6.7 H.R. and H.R.P.O.Steels 6-12
6.8 Cold Rolled Steel 6-12

6.9 Carbon Steel 6-12
6.10 Alloyed Steel 6-13
6.11 Stainless Steel 6-15
6.12 Metallic Coatings 6-16
6.13 Nonmetallic Coating and Laminating 6-17
6.14 Joining Different Materials in the Roll Forming Process 6-18
6.15 Aluminum 6-18
6.16 Other Metals and Materials 6-20
Contentsx
6.17 Influence of PrimaryMetal Processes on Roll Forming 6-20
6.18 Guideline to Steel Prices 6-24
References 6-24
7 Lubrication Joseph Ivaska 7-1
7.1 TribologyofLubrication 7-1
7.2 Selection of Lubricants 7-5
7.3 SurfaceProperties of Formed Material 7-8
7.4 Lubricants for the SecondaryOperations 7-10
7.5 Application Techniques 7-11
7.6 Preparation and Maintenance of Lubricants 7-12
7.7 Operating Problems during Production 7-18
8 Coil Processing ,Material Handling, and Plant Layout
George T. Halmos and Joseph Horvath 8-1
8.1 Flow of Material 8-2
8.2 Coil Handling and Storage 8-3
8.3 Sheet Handling and Storage 8-6
8.4 In-Line Coil Handling 8-9
8.5 Coil End Welding 8-14
8.6 Strip (Coil) Accumulators 8-16
8.7 Flattening and Leveling 8-19
8.8 In-Line Sheet Handling 8-22

8.9 Finished Product Handling 8-23
8.10 Finished Product Storage 8-31
8.11 Material Handling Equipment 8-34
8.12 Material Handling Accessories 8-38
8.13 Crane Controls 8-40
8.14 Plant Layout 8-41
References 8-43
9 Designing Products for Roll Forming George T. Halmos 9-1
9.1 Developing Light Gage Products 9-1
9.2 Design Considerations 9-2
9.3 SecondaryOperations 9-10
9.4 Profiles Manufactured in Different Sizes 9-20
9.5 Design of Specific Products 9-22
9.6 Dimensioning and Tolerancing 9-22
References 9-29
10 Equipment Installation, Roll Setup,Maintenance, and Troubleshooting
George T. Halmos 10-1
10.1 Installation of Roll Forming Lines 10-1
10.2 Roll Installation and Setup 10-8
10.3 Maintenanceand Spare Parts 10-14
10.4 Troubleshooting and Trou ble Prevention 10-32
Contents xi
11 Behavior of Metal Strip during Roll Forming Manabu Kiuchi 11-1
11.1 Various Types of Deformations 11-1
11.2 Causes of Redundant Deformations 11-3
11.3 Effects of Redundant Deformations on Product Defects 11-6
11.4 Mathematical Simulation of the Deformation of aMetal Strip 11-19
11.5 Computerized Design System for Roll Profiles 11-29
11.6 CAE for Roll Forming 11-34
12 Acquiring Roll Forming Lines, Education, and Training George T. Halmos 12-1

12.1 WhyRoll Form Products? 12-1
12.2 DifferentPaths to StartRollForming 12-2
12.3 Evaluating the Product 12-3
12.4 Selecting Line Components 12-4
12.5 Procuring Roll Forming Tooling 12-7
12.6 Equipment and Tool Specifications 12-7
12.7 AcceptanceTest 12-7
12.8 Education and Training 12-7
12.9 Motivation 12-11
References 12-11
13 Safety Ashok Shah 13-1
13.1 Safety 13-1
13.2 Common Safety-Related Definitions 13-2
13.3 SafetyDesign Procedure 13-2
13.4 Determining Limits of the MachineryorSystem 13-3
13.5 Determining Hazards/Risk Estimation 13-3
13.6 Risk Reduction by Design 13-8
13.7 Safeguarding 13-9
13.8 Selection of Guards and ProtectiveDevices 13-13
13.9 Required Characteristics of Guards and Protection Devices 13-13
13.10 Signals and Warning Devices 13-14
13.11 Personal ProtectiveEquipment 13-14
13.12 Training 13-14
13.13 Summary 13-15
References 13-16
14 Increasing Efficiency of Roll Forming Lines and Case Studies George T. Halmos 14-1
14.1 Output, Productivity, and Efficiency 14-1
14.2 Line Utilization 14-2
14.3 Improving Productivity 14-3
14.4 Case Studies 14-4

14.5 PreliminaryTool and Equipment Cost Analysis 14-10
14.6 PreliminaryCost Analysis 14-10
15 Unusual, New, and Future Roll Forming Technologies George T. Halmos 15-1
15.1 The Last 100 Years 15-2
15.2 The Future of Roll Forming 15-2
Contentsxii
15.3 Pull-ThroughMills: Nondriven Rolls 15-5
15.4 Tension Roll Forming 15-6
15.5 Combining Roll Forming and Cold Drawing 15-7
15.6 Developing NewRollForming Methods 15-7
15.7 Roll Forming Tools 15-9
15.8 Reducing the Thickness of the Starting Material 15-10
15.9 Forming at Elevated Temperature 15-11
15.10 Hot Roll Forming Variable Cross-Sections 15-11
15.11 Hot Thickness Reduction along the Length of the Strip 15-12
15.12 Welding Hot Roll Formed Sections 15-12
15.13 Other “Hot”Processes 15-13
15.14 In-Line Soldering,Brazing,and HeatTreating 15-13
15.15 Equipment and Tooling Requirements for Hot Roll Forming 15-14
15.16 Press Tooling for Conventional Roll Forming Lines 15-16
15.17 Computer-Controlled Roll Forming Lines 15-16
References 15-17
Appendices A-1
References R-1
Index I-1
Contents xiii

1
Introduction to Roll
Forming

GeorgeT.Halmos
Delta Engineering Inc.
1.1 Introduction to Roll Forming 1 -1
AShort History of Using Metals
†
Forming of Sheet
Metals
†
What is Roll Forming?
†
Basic Requirements
1.1 Introduction to Roll Forming
1.1.1 AShortHistoryofUsing Metals
Our ancestors used wood and stone tools for over 1.7 million years, give or take afew hundred thousand
years, beforemaking use of metals. It was only around 6000 B.C. when naturally available gold (and later
copper), meteorite iron, and afew other metals were shaped by hammering to makeornaments, tools,
and weapons. Afterwards, our forefathers discovered how to reduceores, melt and alloymetals, and
utilize them for moreelaborate products.
Gold was mainly used for jewelrybecause it is too soft for implements. Copper was only slightly
harder,but by adding arsenic and tin to copper,the early Bronze Age smiths could produce good-quality
axes and other articles. Gradually,more and morebronze articles were used and the Bronze Age
superseded the Stone Age.
Gold, copper,tin, lead, silver,iron, and mercurywere the only seven known and used metals until the
thirteenth centuryand only five more metals werediscovered up until the seventeenth century. Today, we
knowthat about twothirds of all known elements are metals.
The first iron products dated back to 3000 to 4000 B.C., but they werescarceand expensive. The edges
of iron implements were too soft; therefore, iron articles weresuitable for ornaments but not for tool and
weapons. The discovery of carbonizing around 1200 to 1300 B.C. brought major change and heralded the
beginning of the Iron Age. Steel products became better for tools and weapons. Transition was slow,but
eventually cast and forged iron products replaced bronze in most areas. Furnaces became larger and steel

became better.The early smiths producedexcellent qualityaxes, chisels, hoes, swords, and other
implements. In 1350, the ironmakers of central Europe succeeded in melting and casting iron troughthe
use of primitiveblast furnaces [438].
Making complex items, such as body armor assembled fromhundreds of matching pieces of
hammeredplates and wires, required considerable skill and experience. The process was extremely
labor-intensive because of the long hours of hammering required. Actually,uptothe seventeenth
century, to the dawn of the Industrial Revolution, everynoncast item, from ornamental to utilitywas
made by hand, through labor-intensive forging.Not manypeople could afford to own metal products.
1 -1
During the Industrial Revolution of the eighteenth and nineteenth centuries, manyofthe handtools
used in metal manufacturing were gradually replaced by power-driven machinery. Water wheels, steam
engines, and, later on, electrical motors provided an abundant quantityofpower. In 1855, Bessemer
patented the first modern steel-making method in England, aprocess that provided large quantities of
better qualitysteel. Originally,steel was intended for castings (canons), but eventually most of it was
processed by forging, using big,powered presses.
One of the most significant and least-heralded achievements of the Industrial Revolution was
the replacement of the ancient artofhammering (forging) with pairs of rotating rollstochange the shape
or the thickness of the metals. Based on the forging experience, and knowing that steel is more
pliable when it is hot, the rolling process was completed at hightemperatures. Rolling reduced
the thickness and increased the surface area in contact with air.The rapid cooling of the large
surfaceslimits the minimum thickness achievable by hot rolling.The introduction of flywheels, clutches,
reversible steam engines, and electrical motors contributed to faster steel forming processes, permitting
further reduction of the minimum thickness of the rolled products. However,the thinner the metal gets,
the larger its surface and the faster the rate of cooling. Therefore,evenwiththe most modern equipment,
the minimum thickness of commercially available hot rolled steel is still about 0.060 to 0.070 in.
(1.5 to 1.8 mm).
Rolling at room temperatureisnot anew technology. Primitivecold rolling was used in the
fourteenth centuryfor gold and silver. The first true rolling mills of which anyrecordexists were
designed by Leonardo da Vinci in 1480 [437]. In the late sixteenth and early seventeenth centuries,
pairs of rolls were used to rollflats from soft materials such as gold, lead, and tin, probably at room

temperature.Cold rolling was also used to planish tin plates. Room temperature (cold) rolling of steel
commenced in the late eighteenth centuryand became more widely used in the nineteenth century. By
the late nineteenth and in the twentieth centuries, an immense varietyofhot and cold rolled
aluminum,copper,brass,lead, tin, titanium,zirconium,and specialtyalloys sheetbecame
commercially available. Without these rolled flat products, our current life and our living standard
would be unimaginable.
1.1.2 Forming of Sheet Metals
The name “manufacturing”originates from the Latin manu (hand) and factura (making). When flat-
rolled sheets became commercially available,for along time, the final products were manufactured,
formed, and shaped by hand. Gradually,machines, particularly presses, substituted for most of the hand
forming.
Avarietyofmechanical presses (single-action screw,friction, link-and-crank, and different double-
action drawpresses)and hydraulic presses were used almost exclusively to blank, form, or drawall sheet
metal products until the early twentieth century. Other processes, such as curving, profiledrawing,
stretch bending, spinning, winding,beading,explosiveforming,electromagnetic forming, and hydro
forming are also used for forming sheets and plates. However,the combined output of these processes is
considerably less than that produced by the presses and later on by roll formers.
Althoughroll forming was already used in the early 1900s, it was only after the Second Word Warwhen
it took over asignificant percentage of the fabrication of sheet metal products from press brakes and
other types of forming.Owing to the highefficiency of roll forming,the labor content of manyproducts
was drastically reduced.
Roofing,siding,farm buildings, grain storage bins (silos), shelving,storage racks, fluorescent light
fixtures, electrical products, refrigeration, heating,ventilation, railwaycars, powerplants, doors,
windows, toilet partitions, bicyclewheels, fireplaces, furniture, appliances, airplanes, spacecraft,
swimming pools, and countless other products haveall been efficiently roll formed.
In the 1950s and 1960s, rotaryencoders were introduced and the applications of pneumatic presses,
in-line welding, prepunching, and rollforming prepainted metals spread widely.Eventually,moreand
moreother operations were incorporated into the roll forming lines.
Roll Forming Handbook1 -2
In the 1970s and 1980s, prepunching became moresophisticated through the use of differentcontrols

and gagged punches. Innovations wereintroduced to reduce tool changeover time using rafted
construction,
1
side-by-side rolls and other devices. Die accelerating systems became more sophisticated
and lengths moreaccurate. Steels with up to 200,000 psi (1960 MPa) yield strength and manyexotic
metals were successfully rollformed. In the late 1970s and early 1980s, computer-aided rolldesign
systems were introduced.
In the 1990s, an increased number of programmable controllers and computers havebeen added to
control the lines. The product, as well as the material tolerances, has become tighter and the demand for
manufacturing flexibilityhas increased. Customers pressed equipment suppliers for better qualityand
moreefficient lines, including automated finished-product handling.Competitiveness has necessitated
the reduction of the number of operators and in some cases one operator to run two or more lines, at an
increased speed, and at ahigher utilization rate.
By the 1970s, about 35 to 40% of all sheet products produced by the NorthAmerican steel mills were
processed through roll formers. In the last decades of the twentieth century, rollforming of automotive
products became the fastest growing segment of the industry.
The roll forming industryisstill growing strongly in the twenty-first century.
1.1.3 What is Roll Forming?
It is not asimple task to describe or explain the concept of rollforming.Afrequently used definition
demonstrates the complexity:
To form sheet metal strip along straight, longitudinal, parallel bend lines with multiple pairs of
contoured rolls without changing the thickness of the material at room temperature.
Similar to manyother definitions, the above one also has exceptions.
To form sheet metal strip along straight, longitudinal, parallel bend lines, but
*
The products often exit the roll former curvedorinaspiral form
*
The products can havebend lines 908 to the longitudinal bend line
*
The bend lines are not always parallel (intentionally)

*
The bend lines are not always straight (occasionally unintentionally)
with multiple pairs of contoured rolls, but
*
To achieve the desiredshape, the roll formers mayapply bronze shoes, plastic guides and,
especially during setup,2£ 4s. If the wood pieces are effective during the setup,then they are
clamped to the machine. Once the clamps are taken away,the 2 £ 4s are strapped to the
equipment. If they are still functioning well after amonth or so,then they are painted in green and
became partofthe line [431]
without changing the thickness of the material, but
*
The thickness is almost always reduced at the bend lines
*
In thin curvedproducts, the outside fibers are thinner than the inside ones
*
Mills are built with special passes to reducethe strip thickness at specified locations
*
Contrarytogood practice, the thickness of the material is occasionally
reduced by bent shafts, and far too frequently by the operators
1
Raftedw Rollformer is aregisteredtrade name of The BradburyGroup.
Introduction to Roll Forming 1 -3
at room temperature, but
*
To eliminate the cracking of paint at the bend lines, the material can be preheated just before
forming
*
Plastic can be roll formed at elevated temperature
*
In-line soldering, brazing, or annealing requires elevating the temperature of metal while

processingthrough the equipment
*
Titanium was hot roll formed in the late 1960s
*
Hot rollforming is apotential new technology.
Rollforming is aflexible process, whereboth the fundamental rules and the exceptions can be utilized. It
has been provenseveral times that even seemingly impossible roll forming tasks can be accomplished,
althoughitmay take alonger time and much moremoney.Onthe other hand, it has also been shown
that plans to roll form simple shapes can create disastrous results if the basic rules of rollforming are not
followed.
1.1.4 Basic Requirements
1.1.4.1 Satisfying Customers
Rollformed products are sold to customers in an extremely competitive market. Customers are always
looking for manufacturers who can repeatedly meet with their basic requirements. They are expecting to
receive:
*
The right quality
*
The right quantity of products
*
At the right time
*
Forthe right price
Companies not able to supply the right qualityorthe right quantity, at the right time for the right price
will lose their customers. However,not consistently meeting customers’expectations or having
manufacturing problems is not always the plant’s fault. The plant cannot manufacturegood-quality
products at the right time for the right price if they are not provided with the basic mechanisms to fulfill
their obligations.
1.1.4.2 Basic Requirements of the Manufacturing Plant
To successfully meet the demands and outperform the competitors, manufacturing plants must have:

*
Good design (product drawings) to be manufactured
*
Sufficient run quantities
*
The right material to be formed
*
Proper equipment
*
Good tooling and
*
Knowledgeable, motivated workforce
Good design (products that can be manufactured without extreme hardship).Most plants haveexperience
with products that cannot be efficiently roll formed, or sometimes not roll formed at all. The product can
be too complicated for the available equipment, or the dimensions or tolerances are beyond the
capabilities of the equipment or tooling.
Sufficient run quantities.Ifthe run quantities are belowaneconomical minimum level, then highsetup
cost can reduceefficiency unless the plant has aspecial-purpose line set up for that specific product. Very
highrun quantities may reduceproduct costs but can increase inventory, product-handling cost, and
storage space requirement.
Acceptable quality material.Running across “bad material” is not arare occurrence. Perhaps the
supplied material was either unsuitable for the product, or it could havebeen incorrectly specified.
Roll Forming Handbook1 -4
However,when troubleshooting of the equipment and tooling does not yield quick results,the material is
far too frequently,and often incorrectly,blamed for the bad products.
Proper equipment suitable for forming the product.There is no plant without complaints about the roll
forming lines. Frequently,the complaints are justified; sometimes, it is the results of procuring aline of
insufficient capacityorbad quality, or of neglected maintenanceorabusive usage by the operator.The life
of agood-quality, reasonably well-maintained rollformer can be over 50 years. Most malfunctioning
equipment problems are corrected in the first year,and the mill will operate with reasonable reliability.

However,incorrectly specified, slow,weak, or low-qualitylines cannot be made competitive against faster
and better lines.
Good tooling.Roll forming lines are equipped with several sets of tooling during their lifetime. Good-
quality, operator-friendly,properly set up tooling is essential to produce good-qualityproducts at
reasonable price.
Knowledgeable, motivated work force.Ithas been stated repeatedly that the greatest asset of acompany
is its people. Acompanycan haveanexcellent product, good material, the best equipment and tooling,
but is still unable to produce competitivelywithout knowledgeable people. Continuous education of the
operators and other employees, combined with motivation, is crucial to good productivityand profit.
Introduction to Roll Forming 1 -5