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Open Sections & Closed Sections
Trapezoidal Sections
COPRA® RF Software
User Manual  .  General Functions
 
 
© Copyright by data M Software GmbH  
 
 
© Copyright data M Software GmbH 
 
 
 
 
 
Unlawful reproduction, in any way, of this manual and its contents is strictly prohibited. 
 
data M Software GmbH makes no warranty, either expressed or implied, regarding 
these materials and makes these materials available solely on an "As is" basis. In 
no event shall data M Software GmbH be liable to anyone for special, collateral, 
incidental, or consequential damages in connection with the use of the materials 
provided. 
 
The sole liability to data M Software GmbH shall not exceed the purchase price of 
the materials described herein. 
 
Information in the manual is subject to change without notice and does not represent a 
commitment on the part of the vendor. The software described in this manual is furnished 
under a license agreement and may be used or copied only in accordance with the terms 
of the agreement. 
 
 
 
 
 
 
 
 
 
 
 
 
 
Copyright© data M Software GmbH 
All Rights Reserved 
data M Software GmbH 
Am Marschallfeld 17 
D-83626 Valley/Oberlaindern 
Germany 
www.datam.de  
 
Table of Contents 
© Copyright by data M Software GmbH  
 
I 
Table of Contents 
General Functions 
1 
1. Shortcuts 
1 
2. Entity Selection 
2 
3. COPRA® Memory 
2 
3.1. COPRA® Database 
2 
3.2. Computer RAM 
3 
3.3. The CPM File 
3 
3.4. Archive Files 
4 
4. 
The COPRA® Explorer with CADFinder 
5 
4.1. 
CADFinder/The box Project data 
5 
4.2. Flower 
6 
4.2.1. Flower data 
6 
4.2.2. Pass (x) 
6 
4.3. Rolls 
7 
4.3.1. Station 
7 
4.3.2. Axis 
7 
4.3.3. Roll Data and Attributes 
7 
COPRA® Basictools 
8 
1. The COPRA® toolbar 
8 
1.1. Starting COPRA® 
8 
1.2. Project Manager – Please do no longer use 
8 
1.2.1. Dialogue box: Project Manager 
9 
1.3. The Base Functions toolbar 
11 
1.3.1. Settings 
11 
1.3.2. 
Material Choice 
14 
1.3.3. 
Station Attributes 
15 
1.3.4. 
Roll numbering 
16 
1.3.5. COPRA® Zoom on/off! 
17 
1.3.6. Create Project Slide! 
17 
1.3.7. Save current Project! 
18 
1.3.8. Reload current Project! 
18 
1.3.9. Erase COPRA® Database 
18 
1.3.10. Erase Screen! 
18 
1.3.11. Create COPRA® Polyline 
19 
1.3.12. COPRA® Screen Menu 
19 
2. The COPRA® Database toolbar 
19 
2.1. View Flower 
19 
2.2. Get Pass 
19 
2.3. Save Pass 
20 
2.4. Delete Pass(es) 
20 
Table of Contents 
II 
 
© Copyright by data M Software GmbH  
2.5. Append Pass 
20 
2.6. Insert Pass 
20 
2.7. Fade-in Profile 
21 
2.8. Fade in Rolls 
21 
3. The COPRA® Utils toolbar 
21 
3.1. COPRA® Copy 
21 
3.2. COPRA® Paste 
21 
3.3. COPRA® DB Undo 
21 
3.4. COPRA® DB Redo 
22 
3.5. COPRA® Redraw 
22 
3.6. Entity Information 
22 
3.7. COPRA®? 
22 
4. Machine file for bearing seats 
22 
4.1. Modify 
23 
4.1.1. Pre-settings for creation of drawing 
23 
4.1.1.1. Settings Assembly Plan Dimensioning 
23 
4.1.1.2. Breakdown/Fin Pass 
24 
4.1.1.3. Intermediate/Idler Pass 
24 
4.2. Copy 
25 
4.3. Delete 
25 
4.4. Identifications 
25 
4.5. Current Machine 
25 
5. Convert Database 
25 
5.1. Action 
26 
5.2. Reference 
27 
Open & Closed Sections/Trapezoidal Sections 
28 
1. 
Profile design with COPRA® RF SpreadSheet 
28 
2. Profile Design with COPRA® RF 
28 
2.1. The Create Profile toolbar 
28 
2.1.1. Create Sections or add Entities 
28 
2.1.2. Add Entities to the Beginning 
29 
2.1.3. Mirror Profile 
29 
2.1.4. Centre 
29 
2.1.5. Delete one Entity 
29 
2.1.6. Delete a Sequence of Entities 
29 
2.1.7. Delete Current Section 
30 
2.2. The Profile Utilities toolbar 
30 
2.2.1. Edit Profile Section 
30 
2.2.2. Move Profile 
35 
2.2.3. Rotate Profile 
35 
2.2.4. Split Entity 
35 
2.2.5. Join Entities 
35 
2.2.6. Join All Entities 
36 
2.2.7. Same Number of Entities for 2 Profiles 
36 
2.3. The Profil Utils toolbar 
36 
2.3.1. Write Part of Profile to File 
36 
2.3.2. Read Part of a Profile from File 
36 
2.3.3. Write a Sequence of Passes to File 
37 
2.3.4. Read a Sequence of Passes into Flower 
37 
2.3.5. Material thickness 
38 
Table of Contents 
© Copyright by data M Software GmbH  
 
III 
3. Profile of AutoCAD 
39 
4. Strip Width Calculation 
41 
4.1. Theoretical Basis 
42 
4.1.1. Bending 
42 
4.2. Profiling/Roll forming to Shape 
46 
4.2.1. Calculation of Neutral Line 
46 
4.3. General Observations 
47 
4.4. Calculation in Accordance with German Standard DIN 6935 
49 
4.5. Algorithm according to Proksa 
51 
4.6. Algorithm in accordance with Bogojawlenskij 
55 
4.7. Calculation in accordance with VDI guideline 3389 
55 
4.7.1. Creating a Data Table of Gauge Factors 
59 
4.8. Calculation according to Oehler 
60 
4.9. Standard Formula 
61 
4.10. Table 
62 
4.11. User 
62 
5. Punching 
63 
5.1. The Punching toolbar 
63 
5.1.1. Insert Single 
63 
5.1.2. Insert Multiple 
63 
5.1.3. Delete Single 
63 
5.1.4. Delete Multiple 
64 
5.1.5. Delete All 
64 
5.1.6. Copy 
64 
5.1.7. Move 
64 
5.1.8. Property 
64 
5.1.9. Information 
65 
6. Statics 
66 
6.1. Section Characteristics 
66 
6.2. Static Values 
66 
6.2.1. Geometrical Moment of Inertia 
66 
6.2.2. Surface Centre of Gravity 
66 
6.2.3. Principal Axes 
67 
6.2.4. Torsion Moment of Inertia 
67 
6.2.5. Section Modulus 
67 
6.2.6. Maximum Distance from Edge 
67 
6.2.7. Radius of Inertia 
68 
6.2.8. Shear Centre 
68 
6.2.9. Vaulting Resistance 
68 
6.2.10. Principal Axes Angle 
68 
6.3. Abbreviation 
68 
6.3.1. COPRA® Calculated Values 
68 
6.3.2. Max. Distance from the Edge 
68 
6.3.3. Boundary Conditions 
69 
6.4. Formulas 
69 
7. Create Unfolding 
70 
7.1. 
Unfolding via Table  with COPRA® RF SpreadSheet 
70 
7.2. The Flower toolbar 
70 
7.2.1. Plane of Unfolding 
70 
7.2.2. Unfolding 
72 
7.2.3. Fold 
73 
7.2.4. Folding with Angle/Radius Calibrating Method 
73 
7.2.5. Bending Straights 
73 
Table of Contents 
IV 
 
© Copyright by data M Software GmbH  
7.2.6. Splitting Straights for Over-bending Purposes 
73 
7.2.7. Automatic Unfolding 
74 
7.2.8. Execute Unfolding 
75 
7.2.9. Dynamic Flower 
75 
7.2.10. Dynamic Unfolding 
76 
7.2.11. Dynamic Folding 
76 
7.2.12. Plane of Unfolding 
76 
7.2.13. Symmetrical Profiles 
76 
7.2.14. Calibrate 
76 
7.2.14.1. Constant Radius Method 
77 
7.2.14.2. Constant Length of Neutral Line Method 
77 
7.2.14.3. Track holding Method 
78 
7.2.14.4. Angle/Radius Method 
78 
7.2.14.5. Power Bending Method 
79 
7.2.15. Reference Point 
80 
7.3. The Profile Utilities toolbar 
81 
7.3.1. Edit Profile Section 
81 
7.3.2. Move Profile 
85 
7.3.3. Rotate Profile 
85 
7.3.4. Split Entity 
86 
7.3.5. Join Entities 
86 
7.3.6. Join All Entities 
86 
7.3.7. Same Number of Entities for 2 Profiles 
86 
7.4. The Profil Utils toolbar 
87 
7.4.1. Write Part of Profile to File 
87 
7.4.2. Read Part of a Profile from File 
87 
7.4.3. Write a Sequence of Passes to File 
88 
7.4.4. Read a Sequence of Passes into Flower 
88 
7.4.5. Material Thickness 
88 
7.5. Adapt Flower 
89 
8. COPRA® Trapezoidal Section 
90 
8.1. Manufacturing Problems 
90 
8.2. Profile Design 
91 
8.3. Bending Sequence Trapezoid 
92 
8.3.1. Run a Bending Sequence 
93 
8.4. Unfolding Flower 
94 
8.5. Outline: Wire Model 
95 
8.6. Strip Edge 
95 
8.7. Tangential Transition 
96 
 
 
General Functions 
 
Shortcuts 
© Copyright by data M Software GmbH  
 
1 
General Functions 
 You will find important tips, which you should follow under this sym-
bol. 
 Under the star symbol you find useful tips. 
 
1. Shortcuts 
In the modules Profile, Flower, Rolls and NC Data’s the shortcuts "+", "-",  
"+-", "++" and "--" are available. 
 If changes are made you will be asked whether the changes should be 
saved in the last actual pass.  
Please note that that pass number 1 is the end profile, if numbering with 
passes is chosen. If numbering with stations is chosen station number 0 or 1 
(depending on your settings) is the flat strip. You may chose the numbering 
in COPRA® Settings – Pass- and Roll-numbering. . 
 
(+) 
The shortcut "+" loads the data of the next higher pass number from the data-
base. If the current pass is the last saved in the database, then pass number one 
will be loaded. 
(-) 
The shortcut "-" loads the data of the next lower pass number from the database. 
If pass number one is the current one, the highest pass number will be loaded. 
(+-) 
The shortcut "+-" loads the data of the current pass from the database. So all not 
yet saved changes in a pass will be reserved.  
(++) 
The shortcut "++" loads the last pass / end profile of the flower from the data-
base. 
(--) 
The shortcut "--" loads the first pass / first station of the flower from the database. 
General Functions 
 
Entity Selection 
2 
 
© Copyright by data M Software GmbH  
2. Entity Selection 
Some COPRA® dialogue boxes supply a list of entities for modification purposes. 
Entities can be highlighted in the list using the crosshairs and then be modified. To 
modify multiple entities in the same way it is possible to highlight all the entities to 
be modified in the list. 
 The limits of the, from and to values, are within the filter selection set. 
 If the Use Filter for bend angle and Use Filter for Radius are both se-
lected, only those entities will be taken care of when selecting the Select! or 
Deselect!, which match both the angle and the radius of the filter selection 
set. 
 
3. COPRA® Memory 
3.1. COPRA® Database 
All data of a project are saved in the COPRA® database on the hard disk of your 
computer. This is project information, common data and the geometry of sections 
and rolls of all passes. The database covers the COPRA® work files. 
 
The database consists of the following files: 
• ALLGEM.DB  
→ Project information 
• PROFIL.DB 
 
→ Section data of all passes 
• RAHMEN.DB  
→ intern data 
• VERWTG.DB  
→ Administration of the passes 
• WALZEN.DB  
→ Roll data of all passes 
 
All database files are saved in the project directory. To modify the data of a pass, 
they need to be loaded into the computer memory. After the current pass data has 
been modified, it is written to and updated on, the hard disk database. 
 
There are various possibilities to save the data of the current pass to hard disk: 
• The current pass is saved with the Save DB option. 
• A new pass is loaded into the computer memory with the Get Show option 
and the Save current pass is selected. 
• The Save current pass option is selected when exiting a module. 
General Functions 
 
COPRA® Memory 
© Copyright by data M Software GmbH  
 
3 
3.2. Computer RAM 
In the computer memory, only the data of one individual pass are loaded. 
 Only the data of one pass can be loaded into the computer memory. 
This is the current pass. 
 In case of a computer breakdown only the modifications made to the current 
pass will be lost. 
 
Modifications made to a pass are only saved in the computer memory until a Save 
to database is being executed. 
 The design work made with COPRA® is very much faster if, in the first step, 
modifications are only made in the computer memory. 
 Exiting AutoCAD without saving the current pass may cause a loss of 
data that are only available in the computer memory. 
 
3.3. The CPM File 
When opening a new project from the project directory, a project file with the 
name "PROJECT".CPM will automatically be created. In this project directory all 5 
files of the database with the extension *.DB are saved. 
 The 5 work files *.DB of the database are saved compressed in the project 
file. This saves a lot of disk space. To have access to the project data the 
project file has to be uncompressed. The database files will be created when 
uncompressing a project file. 
 
The project file should be used to save the latest design situation. 
 
 If a project file with the latest design situation is existing, it is possible to do 
test modifications on the project. If the modifications should be discarded, the 
original design situation can be reloaded from the project file. If the modifica-
tions are OK, the new design situation can be saved in the project file. 
 
The information of the current project is saved in the project file. When fin-
ishing a project, the data of the last design situation should be saved in the 
project file. All data concerning the section, the flower or the rolls can be 
used if later modifications of the project should be necessary. 
General Functions 
 
COPRA® Memory 
4 
 
© Copyright by data M Software GmbH  
3.4. Archive Files 
 
Function: 
Important design steps should be saved in Archive files 
An Archive file has the same file format as the Project file. 
 In Archive files the 5 database files *.DB are also saved compressed and 
therefore cannot be modified directly. 
 Opposite to the one Project file, as many as necessary Archive files may be 
created. 
 
The Archive files should be used to save important steps in the design. It is like a 
snapshot of the current design situation. Especially after having worked with the 
modules Profile, Flower and Rolls it makes sense to create an Archive file. 
 Archive files can be very useful if changes need to be made to the project or 
if a similar section has to be designed later. 
 
The project file is always located in the project directory. The project file-
name cannot be changed. The location of the Archive files, as well as the 
Archive file names, are defined by the user. 
 
The COPRA® database was changed several times since the first re-
lease. Therefore it may happen that an old database would have to be 
converted first. Archive files of previous releases can always be 
loaded. Therefore all COPRA® databases should also be saved as Ar-
chive files. Before old Archive files are loaded a new project should be 
created with the Project Manager. 
General Functions 
 
The COPRA® Explorer with CADFinder 
© Copyright by data M Software GmbH  
 
5 
4. 
The COPRA® Explorer with CADFinder 
 
Function: 
Quick navigation during design 
 
The COPRA® Explorer allows a quick navigation during design and provides a 
clearly-structured overview of the existing projects. With the help of files it is pos-
sible to page between the individual stations and to determine their profile and roll 
data. Radii, angles and neutral line can be checked quickly. Furthermore, you can 
select another option by clicking the mouse, e.g. a different pass number. The 
pass number incl. the required data will then be automatically displayed as the 
current pass. COPRA® Explorer can be switched on in the toolbar COPRA® Ex-
plorer. 
 
The COPRA® Explorer is divided into the main options Flower, Project, Rolls and 
CADFinder. 
4.1. 
CADFinder/The box Project data  
All data concerning your COPRA® project are displayed in this box. It can be 
opened via the button “Projects” in Explorer. If you click the current project with 
right mouse key opens a window. Click on Properties (at the bottom of the box) to 
open the dialogue Project Properties .  
You may see and change the name of your project under Project name. Below 
the Project name is the Project path displayed. Click the button 
 in order to 
change the Project path. Next are the items Project comment and Document 
no.-prefix listed. 
A click on the button Attribute opens the dialogue Project attributes. You may 
define general Project attributes such as Company or Profile Number further 
you may modify COPRA® Project attributes as Sheet Thickness. Confirm with 
Accept for saving changes.  
What are the features of this solution? 
COPRA® CADFinder is a document management system that allows also to or-
ganise any files independent from a defined file structure on a storage device. To 
do so the user creates a nested project structure. The documents can then be 
assigned to a project in this structure via a document number. The organisation of 
the documents and the assignment to the physical file path is done by a data base 
server (e.g. MS SQL Server or an alternative data base with SQL and ODBC sup-
port for the multi user version or the MSDE data base in a single user environ-
ment). 
 
Furthermore user defined attributes can be linked with projects and documents. 
This ensures a fast retrieving of documents via specific search functions. These 
attributes in the COPRA® version of CAD-Finder may also be used to complete 
the title block information in an AutoCAD template. 
General Functions 
 
The COPRA® Explorer with CADFinder 
6 
 
© Copyright by data M Software GmbH  
Also a structured view of projects (project manager) and belonging documents as 
any number of flexible working catalogues are available for displaying different 
search results. From here the individual documents can be opened, modified, 
completed with new attributes, copied and moved very easy and comfortable. The 
design of the structured view is similar to the Microsoft Windows-Explorer in order 
to guarantee an intuitive working in a well known environment.   
 
A revision control and workflow system is also available for the individual docu-
ments. So an older version of a document may be – if desired – saved before 
modifying in order to have access to previous releases of this document. The his-
tory of a file may be saved. The link to the respective project is maintained. So for 
a document multiple work situations may be saved. The workflow system recog-
nizes if a user works on a document and sets the workflow status to "Modifica-
tion". In that case any other user may only view the document. When the modifica-
tions have been completed the status is set back and the document may be modi-
fied by another user. Any number of workflow situations maybe defined by the 
user. 
 
Please refer to the COPRA® RF CADFinder manual for a detailed explanation 
as well as further information. 
 
4.2. Flower 
By pressing the button "Flower" appears a list with all passes .  
4.2.1. Flower data 
The flower data box gives you information about the number of elements, outside 
and inside length of the profile, the length of the centre and neutral line - as well 
as the value oft strip width. 
4.2.2. Pass (x) 
All passes of the design are listed under Flower. Double click on a pass opens the 
pass automatically in model view. If you click on the + sign of any station a further 
list with all elements the profile consists of in the selected pass is displayed. You 
will get detailed information about the arcs and straight entities the profile consists 
of if you double click on any element. 
Arcs: 
Double clicking on an arc element opens a small box giving information about the 
neutral line, radii and angle. 
Lines: 
Double clicking on a line element opens a small box giving information about the 
length and the start angle of the straight element. 
General Functions 
 
The COPRA® Explorer with CADFinder 
© Copyright by data M Software GmbH  
 
7 
4.3. Rolls 
By click on "Rollers" are all Stations, their axes and rolls listed in a box. The button 
station attributes appears if you select a station and click it with right mouse key. 
Please refer to Station attributes for further information about station attributes. 
4.3.1. Station 
By double click on a station or by clicking on the + sign, all side, top and bottom 
axes are listed. 
4.3.2. Axis 
By click on Axis top/bottom/left or right opens a list with all existing rolls. The start 
and endpoint coordinates of the axis are listed. 
4.3.3. Roll Data and Attributes 
By click on any listed roll appears a list showing the following parameters under 
roll data: 
• 
Roll name 
• Maximum width 
• Maximum diameter 
• 
Number of entities 
• 
Roll type 
• Weight 
 
By click on any listed roll appears under attributes a list showing all available at-
tributes like: 
 
• Material 
• 
Roll bore 
• 
Keyway 
• 
Roll type top 
• 
Roll type bottom 
• 
Combination roll 
• 
Stamping number 
• 
Stamping groove width 
• 
Stamping groove depth 
• 
Inner diameter 
• 
Bearing 
• 
Roll number 
• 
Roll type  
COPRA® Basictools 
 
The COPRA® toolbar 
8 
 
© Copyright by data M Software GmbH  
COPRA® Basictools 
1. The COPRA® toolbar 
 
 
 
In the COPRA® toolbar the following functions are involved: 
  The icons containing a small black triangle in the lower right corner can be 
expanded with a click of the left mouse key so that additional information will 
be available.  
1.1. Starting COPRA® 
 
Function: 
Initialise the COPRA® Roll form Software, or flip back to the last, active screen menu page. 
During initialisation of COPRA®, the system checks whether the required settings 
are available. For example, all layers required by COPRA® will be created auto-
matically. If the AutoCAD commands of the Screen menu are used during design-
ing, it will always be possible to return to the last active screen menu.  
This has to be the first command after AutoCAD has been loaded or a new draw-
ing has been created. The last actual project is loaded automatically. 
1.2. Project Manager – Please do no longer use 
In previous COPRA® version was this function used to create an manage projects. 
But now COPRA®´s latest function, the COPRA® RF CADFinder may be used for 
that – see COPRA® RF CADFinder manual. The old COPRA® project manager will 
no longer be available in the next upcoming COPRA® version. . 
 If a project is set current in COPRA® CADFinder it will also be the current one 
in project manager and the other way round.  
 
 
Function: 
Create new, display or update existing projects 
The COPRA® Project Manager is a tool for easy project administration. All pro-
jects ever created with the Project Manager will appear in a project list.  
 One directory may contain one project only. 
COPRA® Basictools 
 
The COPRA® toolbar 
© Copyright by data M Software GmbH  
 
9 
1.2.1. Dialogue box: Project Manager 
Last current: 
Shows the current project and its path. 
Selected: 
Shows the selected project and its path. 
Project Mainfolder: 
Shows the selected main directory. An additional main directory for projects can 
be created. 
 COPRA® Setting files and prototype drawings should always be set.  
More: 
It can be used to reload projects, which have been removed from the project list. If 
selected, a file dialogue box for project files will be opened. Project files do have 
the extension .CPM. A double click on the filename or highlighting it and pressing 
OK, brings this project back into the project list. 
Sort Projects: 
The project list can be sorted in alphabetical, chronological order or in groups.  
New:  
A new project can be created when selecting this button. If the directory of the pro-
ject path selected does not yet exist the user has to confirm the creation of the 
directory. The project path defines the directory where the COPRA® database and 
its related files will be saved. If the directory was created, the Material’s dialogue 
box comes up and the coil material used has to be selected. It can be selected, 
either from the list box or, if a proper material is not yet available, be created by 
the user with the help of Create. The selected material is the default for all techni-
cal calculations like Spring-back and Deformation Technology. 
 
data M Software does not guarantee that the material properties 
shipped with COPRA® are correct as the natural deviations of the coil 
material may be quite high. 
 
After confirmation of the material, additional project information can be entered.  
This information is optional and may be left blank. 
COPRA® Basictools 
 
The COPRA® toolbar 
10 
 
© Copyright by data M Software GmbH  
Save:  
Compresses and saves the current design data of the COPRA® database to the 
project file. When exiting the modules Profile, Flower or Rolls, the project file 
may be updated automatically by appropriate selection. 
 This function can also be used outside the Project Manager by selecting the 
Save current Project, option from the pull-down menu. 
Modify:  
Project name and project directory can be modified. 
Copy: 
Copies an existing project to another directory, which can be selected.  
Remove:  
Removes the highlighted project name from the project list. The project data it-
self are not removed from the hard disk. A project that has been removed from 
the project list can be reloaded by using the <more...> button (see <more...>). 
Info:  
Information about the highlighted project will be displayed and can be changed if 
necessary. In the headline of the box selected Project name, Project path, Pro-
ject file and Material are shown. The additional information shown can be modi-
fied and customised. The material Thickness entered is the one used when de-
signing a new section. Customer, Product, Drawing Number, Design Date, De-
signer and Comment can be entered optionally. 
Material:  
Shows the coil material used for the highlighted project.  
COPRA® Basictools 
 
The COPRA® toolbar 
© Copyright by data M Software GmbH  
 
11 
1.3. The Base Functions toolbar 
 
 
 
 
Function: 
Lists all basic functions of COPRA®. See the following descriptions: 
1.3.1. Settings 
 
Function: 
Change the default settings of COPRA®  
Language: 
The desired language can be selected in the list box. Languages are connected 
with the unit (mm) except English (US), which is connected with the unit (inch). 
Centre of Profile: 
Displays the section’s centre line. 
Split Lines in Profile: 
If toggle is set, split lines between arcs and lines will be shown. 
Automatic Zoom:  
If selected, a ZOOM EXTENTS and ZOOM <FACTOR>x is done after every 
modification. The factor may be set to values between 0.5 and 1.0. If case the fac-
tor is set to 1.0 the ZOOM <FACTOR> option will not be executed. 
Automatic redraw:  
If selected, an automatic redraw is done when loading a new module. The screen 
is updated with the current section and/or rolls. The current drawing entities will be 
erased depending on the updating screen setting in the bottom of this dialogue 
box. 
Fade out Plane of Unfolding: 
If this feature is active, the plane of unfolding will be faded out.  
Fade in next Section: 
If selected, the next section saved in the COPRA® database is also being dis-
played on the screen. 
COPRA® Basictools 
 
The COPRA® toolbar 
12 
 
© Copyright by data M Software GmbH  
Fade in previous Section:  
If selected, the previous section saved in the COPRA® database is also being dis-
played on the screen.  
Pass and Roll Numbers:  
Gives access to all options regarding pass or roll designations. By selecting the 
Fade in spacer dimensions, option the widths and diameters of the space rings 
will be faded in. 
 Please refer to chapter Rollnumbering in COPRA® Rolldesign & Rolltechnol-
ogy manual, too.  
Numbering of the different Stations: 
The numbering with station provides with further options, like separate numbering 
with station types.  
Use COPRA® Numbering: 
The standard COPRA® numbering with passes or stations will be used. 
All continuing: 
If your stations should be numbered continuously select the button next to All 
continuing.  
The resp. stations separated: 
If you would like to have a separate numbering for each station type enable the 
checkbox The resp. stations separated, please. This means that the station 
types will have an own numbering within their group e.g. Turk head 1, Turk head 2 
and so on. 
 Please refer to the in following explained point “Rollnumbering”, too. You 
have got the possibility to create individual roll numbers. 
Idlerstations: 
Enable the toggle Idlerstations if you would like to have a separate numbering for 
the intermediate stations in addition to All continuing or The resp. stations 
separated. In this case the idler stations will be as such identifiable and their 
numbering will eg. be 1-2 . 
Attach stationtype to profilenumber: 
Enable the toggle Attach stationtype to profilenumber in order to make the sta-
tion type always visible. Thereby the chosen station type (eg. calibration idler sta-
tion) will be attached to the profile number when updating screen.  
COPRA® Basictools 
 
The COPRA® toolbar 
© Copyright by data M Software GmbH  
 
13 
Layer Control: 
Allows modification of all COPRA® layers according to his/her requirements. 
COPRA® Paths:  
Provides an overview of all paths used by COPRA® for the current project. Names 
can be modified according to your requirements. 
Technology: 
Determines the decimal signs used during export. 
COPRA® Options: 
Provides the option to fade in dialogue boxes for the selection of functions. Fur-
thermore, the settings for automatic background backups can be defined. Up to 30 
archive files can be backed up, i.e. the 31st file will overwrite the first file etc.  
Contours as Polylines: 
If selected, all section and roll contours are drawn as polylines.  
Clear only COPRA® Layers when updating Screen: 
If selected, all drawing entities placed on COPRA® layers will be erased when a 
COPRA® Redraw (C Redraw) or any other updating of the screen is being made, 
e.g. when using the command Get&Show. 
If not selected, all drawing entities will be erased when a COPRA® Redraw (C Re-
draw) or any other refreshing of the screen is being made, e.g. when using the 
command Get&Show. 
This option is very useful when e.g. designing the rolls. For the construction lines a 
layer of its own can be created. If selected, all construction lines will still be visible 
after the COPRA® Redraw or Get&Show command has been executed.  
A typical example is to connect the endpoints of the roll axis with a construction 
line and use this to create the necessary offset lines to get e.g. even spacer ring 
dimensions. 
Clear also COPRA® help layers when updating screen: 
Deletes all drawn lines on COPRA® layers including the help layer during a re-
draw. 
Automatic redraw when changing project: 
A redraw will be done automatically when enabling this option and changing into 
another project and the project will be displayed. If there is actually no data in this 
project the screen will not change. It is recommendable to enable this toggle.  
COPRA® Basictools 
 
The COPRA® toolbar 
14 
 
© Copyright by data M Software GmbH  
Delete X-References: 
COPRA® works with X-references when creating assembly plans and/ or when 
defining individual roll- and station-attributes. It is recommendable to enable this 
toggle because then the external AutoCAD drawings will be only loaded as indi-
vidual roll- or station-attributes when you browse between passes. If an X-
reference is saved to network another user may have changed it, so enabling this 
toggle guarantees that you have always the latest version loaded on screen. Fur-
ther you do not have to delete the X-references from the assembly plans manually 
if you enable this toggle.  
 
The dialog box roll information: 
Show info in Rolls: 
It is possible to show raw diameter, weight, sequential number for top/bottom rolls, 
sequential number for side rolls, material and rolls type in the rolls.  
Alignment: 
Show the info on the left, right or center position. 
Description: 
The roll info described above can be set on none, as prefix or as suffix. 
 
1.3.2. 
Material Choice 
 
Function: 
Select the material you want to use 
You may choose a material in a dialogue box, further you may edit material or 
create a new one and its properties. In the past this could only be done via the 
Project Manager.   
COPRA® Basictools 
 
The COPRA® toolbar 
© Copyright by data M Software GmbH  
 
15 
1.3.3. 
Station Attributes  
 
Function: 
Station types can be individually named 
For each station can be defined which station type it is, e.g., a driven station, side 
rolls or a welding station or a drawing die and so on. 
 COPRA® takes automatically the station types from tube mill map layout eg. 
turk heads if a flower design exists. This needs to be taken into account when 
working with the COPRA® Module M3 (Automatic tubemill map. The listed 
station types can not be modified if there is data in tube mill map de-
fined. If there is no data in tubemill map COPRA® shows you in the dialogue 
box Station Attributes a hint: There is no data available in tube mill map. 
 
The single stations of your design are listed in a table. In order to link any specific 
attribute click it with left mouse key, please. At the very left of the table is the Sta-
tion numbering with COPRA® displayed, on the right next to it the numbering 
with machine. 
Station type: 
You may choose between the attributes main, idler, Turk head, welding, drawing 
die, lineal and strip guide.  
Inserted station: 
If you have later inserted a station - mark the check box Inserted station , please. 
Then already existing roll numbers will not be changed. The roll number of the 
later inserted station will be marked with an A. If you want you may adapt these 
roll numbers via the individual roll attributes.  
Station sub type: 
Depending on the chosen station type are additional attributes as pre bending, or 
calibration available that may be linked to the station.  
Station: 
You may define the corresponding number that the station has got on machine 
here.  
COPRA® Basictools 
 
The COPRA® toolbar 
16 
 
© Copyright by data M Software GmbH  
1.3.4. 
Roll numbering 
 
Function:  
Individual roll numbering global for all or for single projects 
 You may define an own roll numbering for your company here. The settings 
are either valid for all projects or for the current one – depending on your set-
tings. 
 
A dialogue opens if you click the icon Roll numbering. 
 
*ATTENTION* – Please take care whether main- or idler station is chosen (see 
left side on top of the box). Depending on your choice either the numbering for the 
main or the idler stations may be defined.  
 
The column Selection: 
Please select here which information you want to add to your individual roll num-
ber. Furthermore the option „Delimiters“ is available. You may add e.g. a hyphen 
between two chosen information in roll numbering.  
The column Format: 
Depending on your needs you may add the information complete or as short cut. 
E.g. drawing number (complete) or DNo. (abbreviated). Æ see also „Abbrevia-
tions“ 
Selected elements: 
Your selection is displayed here. The line Example at the bottom of the dialogue 
gives you a preview on how your roll number will look like later.  
 
If you need to delete an element from list mark it, please (e.g. Pass number| Ara-
bic number) and click this symbol 
, the symbol is available between the Format 
and Selected elements column. 
 
Click this symbol 
 for deleting all available elements at once the symbol is 
available between the Format and Selected elements column. 
 
For changing the sequence of two chosen elements in top direction you may use 
this symbol: 
 .The symbol is available between the Format and Selected ele-
ments column. If you want to change the sequence in bottom direction you may 
use this symbol 
. The symbol is available between the Format and Selected 
elements column.  
COPRA® Basictools 
 
The COPRA® toolbar 
© Copyright by data M Software GmbH  
 
17 
Short cuts: 
You may adapt short cuts to your needs using this function. Just click the respec-
tive button and a dialogue listing all available short cuts will open.  
User defined text: 
By right mouse key click in the column "Format" you may enter a user defined text 
if you have chosen this option. The information may then be linked to your roll 
number.  
It can be linked to roll number if you mark it and press this button
. The user 
defined text may be deleted in the column "Format" by pressing the "Delete" key.  
 
ATTENTION when deleting user defined text! 
If user defined text is deleted from "Format" column it automatically disappears at 
the right site in the column "Selected elements". 
Set as Default: 
The user defined roll number will be used global, for all projects.  
Set for Project: 
The user defined roll number will be used for the current project.  
Numbering of later inserted stations: 
Please refer to station attributes (point 1.3.2). 
 
1.3.5. COPRA® Zoom on/off! 
 
Function: 
Switches the automatic COPRA® Zoom on or off 
1.3.6. Create Project Slide! 
 
Function: 
Exchange automatically created project slide by customised one 
After the Strip Width Calculation a project slide is automatically being created 
showing the final section in the preview of the COPRA® Project Manager. With the 
Create Project Slide function this project slide can be replaced by a user defined 
one. The content of the screen is independent of any restrictions. It may be the 
flower, a 3D wire-frame model or even a roll form simulation picture including the 
rolls. 
 In case it should not be possible to create a project slide, check whether the 
project name contains a dot. 
COPRA® Basictools 
 
The COPRA® toolbar 
18 
 
© Copyright by data M Software GmbH  
1.3.7. Save current Project! 
 
Function: 
Save the design data of the current project 
All design data of the current project can be saved in a project file. Project files 
have the extension CPM (COPRA® Project Manager). The contents are the same 
as in Archive files.  
Opposite to the Archive module the user does not have to enter a filename. The 
filename is put together automatically from the project name. 
The Project file should not be used to replace the Archive files! With the Archive 
files a history of the design process can be created. In a Project file only the last 
design situation is being saved! The Project file is only an additional option to save 
the design data. When exiting the modules Profile, Flower or Rolls the Project file 
can be updated by crossing the respective toggle. 
1.3.8. Reload current Project! 
 
Function: 
Load the design data from the Project file into the current project 
The content of the latest saved Project file is loaded into the COPRA® database. 
An existing database will be overwritten. 
1.3.9. Erase COPRA® Database 
 
Function: 
Erase the COPRA® database files from hard disk 
The design data of the current project are saved in the COPRA® database files. 
These database files are work files that should be saved as an Archive or Project 
file. Sometimes it is necessary to have more than one flower in a project. In this 
case the COPRA® database files can be erased from hard disk and a new section 
can be designed. Before the COPRA® database files are being erased their con-
tent can be saved in the Project file. If the design data are not saved in the Project 
file, an additional user confirmation is necessary. 
1.3.10. Erase Screen! 
 
Function: 
The content of the screen is erased depending on the Delete options setting 
If the Clear only COPRA® layers when updating screen is selected, then all 
drawing information placed on COPRA® layers will be erased. The names of the 
COPRA® layers are set in the Settings. If the switch is set to all active layers, all 
drawing information will be erased. 
COPRA® Basictools 
 
The COPRA® Database toolbar 
© Copyright by data M Software GmbH  
 
19 
1.3.11. Create COPRA® Polyline 
 
Function: 
Design of the outside, inside or centre section contour as a polyline 
The final section of roll formed profiles is very often dimensioned by its contour in-
tersection points. When using the standard design possibilities of a CAD system 
this can be a lot of work. The contour needs to be designed with the help of con-
struction lines and then has to be redrawn. 
1.3.12. COPRA® Screen Menu 
 
Function: 
Loading the COPRA® Screen Menu 
In contrast to the OEM standalone version, this function is currently still available 
in AutoCAD. 
 
 
2. The COPRA® Database toolbar 
 
 
 
The COPRA® database toolbar includes the following functions: 
2.1. View Flower 
 
Function: 
Display flower of the current project 
This function is an easy way to display the flower of the current project. It is avail-
able at any time and shows all passes saved in the COPRA® database. With the 
Selection of passes option the passes to be displayed can be selected. 
2.2. Get Pass 
 
Function: 
Load a new pass from the COPRA® database and save the actual one 
Before a new pass will be load from database the actual pass can be saved by 
this function. A dialogue box with all necessary information will be displayed. 
COPRA® Basictools 
 
The COPRA® Database toolbar 
20 
 
© Copyright by data M Software GmbH  
2.3. Save Pass 
 
Function: 
Save the current pass in the database 
The Save DB function saves the module specific data of a pass in the COPRA® 
database. 
2.4. Delete Pass(es) 
 
Function: 
Delete a selection of passes from the database 
The number of passes deleted will reduce the number of passes. The pass num-
bers following the deleted ones will be reduced by the number of passes deleted. 
If rolls are already available, it is for example, possible to delete the tools only. 
 
The actual pass number can only be deleted if it was selected.  
2.5. Append Pass 
 
Function: 
Append the current pass to the database 
The number of passes is increased by one. 
Example: 
The number of passes saved in the database is 5. The current pass number 3 is 
appended to the database. The new number of passes is 6 and pass number 6 
will be the current one. The contents of pass number 3 and 6 are identical. 
2.6. Insert Pass 
 
Function: 
Insert the current pass into the database 
The Insert pass function will insert the data of the current pass as a new pass in 
the COPRA® database. The number of passes is increased by one. 
Example: 
The number of passes is 5. The current pass number 4 is inserted as pass num-
ber 2 in the database. The new number of passes is 6. The new current pass is 2 
and is identical to pass number 4. The pass numbers 3 to 5 are moved one posi-
tion upwards. 
 See also station attributes for retraining of already existing roll numbers.  
COPRA® Basictools 
 
The COPRA® Utils toolbar 
© Copyright by data M Software GmbH  
 
21 
2.7. Fade-in Profile 
 
Function: 
Fade-in a selected section 
Allows to fade-in any section from the database. The current pass will thereby be 
maintained. 
2.8. Fade in Rolls 
 
Function: 
Display rolls for a station 
The rolls for the section can be faded in for any station. 
 
 
3. The COPRA® Utils toolbar 
 
 
 
3.1. COPRA® Copy 
 
Function: 
Copy rolls or sections  
Rolls or sections have not to be designed anew. Instead, existing rolls or sections 
can be copied.  
3.2. COPRA® Paste 
 
Function: 
Insert copied rolls or sections  
The copied roll or the copied section can be inserted in any pass. Rolls can be 
inserted at any position, for example, top rolls can be used as left or right rolls or 
as bottom rolls. However, you have to choose the respective COPRA® module at 
first.  
3.3. COPRA® DB Undo 
 
Function: 
Reset commands 
This function is similar to the "Undo" in AutoCAD. Up to 5 steps can be reset pro-
vided that the data was not saved beforehand. 
COPRA® Basictools 
 
Machine file for bearing seats 
22 
 
© Copyright by data M Software GmbH  
3.4. COPRA® DB Redo 
 
Function: 
Reactivate changes 
This function allows you to reactivate the last 5 steps provided that the data was 
not saved beforehand. 
3.5. COPRA® Redraw 
 
Function: 
Redraw drawing 
3.6. Entity Information 
 
Function: 
Opens a dialogue box with the entity data of a previously selected entity  
All data associated with an entity can be checked and loaded in a dialogue box. 
The roll data can be displayed on screen with function key F2 (Test Window). 
3.7. COPRA®? 
 
Function: 
Opens the Online Help. The language depends on what was selected under Settings 
If selected the Online Help will be loaded. The language thereby depends on what 
was set under Settings. 
 
4. Machine file for bearing seats 
The relation of the rolls with the machine axes is defined in machine files. 
These machine files are used in the following modules: 
• Single Roll dimension 
• Automatic contour dimensioning 
• Assembly plan 
• Dimensioned assembly plan 
The selection of the machine and modifications of the bearing seats are possible 
after selecting the Machine option in the main dialogue boxes of those modules. 
 If a machine is set as the current one in one module then this machine is 
also the current one in other modules. 
 Verify that the settings are not contradictory. For example, the diame-
ter of bore must not exceed the inner diameter of stamping groove for 
roll numbers (Settings for drawing generation). 
COPRA® Basictools 
 
Machine file for bearing seats 
© Copyright by data M Software GmbH  
 
23 
After selecting the Machine, option the Machine data dialogue box is loaded: 
Machine: 
All existing machine files are listed here. In order to set the current machine or to 
modify one, it has to be highlighted in the list. 
 
4.1. Modify 
The settings of the machine picked in the machine list can be modified. 
4.1.1. Pre-settings for creation of drawing 
After selecting the Modify..., the Settings dialogue box will be opened, in which 
the values for the borehole chamfer and stamping groove are defined. 
 
 
Fig. 1   Bore for pass number 
 
The inner ∅ of the stamping groove has to be greater or equal to the ∅ 
of the borehole plus twice the chamfer of the borehole. The ∅ of bore 
for (T/B) can be found in the Breakdown/Fin Pass. The ∅ of bore for 
(L/R) can be found in the Intermediate/Idler Pass. 
 
4.1.1.1. Settings Assembly Plan Dimensioning 
 
Illus. 2   Settings Assembly Plan Dimensioning 
COPRA® Basictools 
 
Machine file for bearing seats 
24 
 
© Copyright by data M Software GmbH  
4.1.1.2. Breakdown/Fin Pass 
Here, the details for the boreholes of the top and bottom rolls can be set. 
These are the values for the borehole details of top and bottom rolls. 
 
The inner ∅ of stamping groove (T/B) must be greater or equal to the 
∅ of the borehole in the driven passes plus twice the borehole cham-
fer.  
 
 
Illus. 3   Borehole details of the driven passes 
A:  ∅ of bore 
B:  ∅ of undercut 
C:  Supporting width (2x) 
D:  Fillet of undercut 
x:   Depth of keyway 
y:   Width of keyway 
4.1.1.3. Intermediate/Idler Pass 
These are the values of the side roll borehole details. 
 
Illus. 4   Choose the machine for single roll dimensioning 
A:  ∅ of bearing 
B:  ∅ of borehole 
C:  Depth of bearing set 
D:  Fillet of bearing set 
COPRA® Basictools 
 
Convert Database 
© Copyright by data M Software GmbH  
 
25 
 
The inner ∅ of the stamping groove (L/R) must be greater or equal to 
the ∅ of the borehole in the intermediate passes plus twice the bore-
hole chamfer. 
4.2. Copy 
The data of the machine highlighted in list are copied to a new machine. The 
name of the new machine has to match the file format. 
4.3. Delete 
The machine highlighted in the list will be removed from the list. The correspon-
ding machine file is deleted. 
4.4. Identifications 
The name of the machine has to match the file format. Only 8 characters are al-
lowed. In the identification a detailed description of the machine is possible. 
4.5. Current Machine 
Displays the designation of the current machine. 
Load of COPRA® Set: 
Loads the plant data from the COPRA® Set file. 
Save to COPRA® Set: 
Copies the machine data to the COPRA® Set directory. 
 
5. Convert Database 
 
Function:  
Modify elements of construction 
 
It can additionally convert axes or rolls for example, via a dialogue box. 
Current: 
Shows the actual pass. 
Existing Profiles: 
Provides information about the existing number of profiles. 
Axes: 
Displays the number of axes. 
COPRA® Basictools 
 
Convert Database 
26 
 
© Copyright by data M Software GmbH  
Selection: 
This opens the Selection of Stations, dialogue box. The number of existing pro-
files and axes is displayed. By Max select, the selection of single, multiple or all 
passes for a defined number of stations are possible. 
Tool: 
By Tool, it is possible to choose between top, bottom, left or right roll. Later the 
selection will be modified. 
Objects: 
By activating this toggle the profile will be modified later. 
Tool: 
Axes and rolls can be enabled for modifying here. 
 
5.1. Action 
Offers the following options: 
• Mirror horizontal 
• Mirror vertical 
• Move 
• Convert 
Depending on selected action the under objects chosen elements can be modified 
respectively the action. 
The different Actions: 
Mirror horizontal: 
The profile, axes and rolls can be mirrored horizontal. The action can be done by 
point of unfolding, plane of unfolding or free point. 
Mirror vertical: 
The profile, axes and rolls can be mirrored vertical. The unfolding point, plane of 
unfolding or free point, can do this. 
Move: 
The profile, axes and rolls can be moved. A vector of P1-P2 can be used. The 
input of the x and y co-ordinates can be done by their values or by the selection of 
the points by crosshairs. For selecting by crosshairs, use the buttons ->P1 and -
>P2. 
COPRA® Basictools 
 
Convert Database 
© Copyright by data M Software GmbH  
 
27 
Convert: 
By entering a convert factor, the profile, axes and rolls can be enlarged or made 
smaller by any value. Furthermore, conversion elements from mm to can be 
made. 
 
5.2. Reference 
Here is the reference point for the selected action, thus, different reference points 
are offered. Refer to the next point for a detailed description. 
The different References: 
Unfolding Point: 
The unfolding point is used as the actions basic point. 
Unfolding Plane: 
The unfolding plane is the actions basis. 
Free Point P1: 
By defining the x and y co-ordinates any point can be selected as the actions ba-
sic point. 
Vector P1-P2: 
Two points that define the basis of the action can be selected with are two possi-
bilities: 
1. By P1 (x1) (y1) to define the co-ordinates of the first point, and P2 (x2) (y2) 
to define the co-ordinates of the second point. 
2. Or click at the buttons ->P1 and ->P2. Then the points can be selected by 
crosshairs. The co-ordinates of the selected points are automatically taken 
into the dialogue box. 
Convert Factor: 
By entering a convert factor, objects can be made larger or smaller, or be con-
verted from mm to inches. 
Open & Closed Sections/Trapezoidal Sections Profile design with COPRA® RF SpreadSheet 
28 
 
© Copyright by data M Software GmbH  
Open & Closed Sections/Trapezoidal Sections 
1. 
Profile design with COPRA® RF SpreadSheet 
Please refer to the COPRA® RF SpreadSheet user manual for further information. 
Profile design an unfolding can easily be done in a table using COPRA® RF 
SpreadSheet.  
 
2. Profile Design with COPRA® RF 
 
Function: 
Create a section with the help of macros 
This feature allows creating sections on the basis of entered parameters. By se-
lecting this icon, three toolbars are opened which will be described below.  
 
2.1. The Create Profile toolbar 
 
 
2.1.1. Create Sections or add Entities 
 
Function: 
New sections or entities can be added to the existing end of the section 
After selection, a dialogue box with the respective section macros is opened. 
Next: 
Jumps to the next page with section macros. 
Previous: 
Jumps to the previous selection. 
After selecting a section, a dialogue box is opened. Here, the section’s dimensions 
can be entered with the help of parameters. 
OK and new Entity: 
Allows adding another entity to the end of the profile. As a section is existing, an 
additional page with macros is provided. 
OK and Section: 
Creates the selected section. 
Open & Closed Sections/Trapezoidal Sections  
Profile Design with COPRA® RF 
© Copyright by data M Software GmbH  
 
29 
When recalling the function, another entity can be added to the end of the section, 
i.e. at the right end. At the highest entity number, COPRA® numbers the entities 
from left to right. 
2.1.2. Add Entities to the Beginning 
 
Function: 
New entities can be added to the beginning of the section  
If selected, the same dialogue boxes as with the previous command are available. 
The new entities will be automatically added to entity number 1. COPRA® num-
bers the entities from left to right.  
2.1.3. Mirror Profile 
 
Function: 
Mirrors a section 
This is a useful function for symmetrical sections. All entities will be mirrored. The 
mirror line is the material thickness displayed at entity no.1 (the beginning of the 
section) or at the last entity (the end of the section). All entities are mirrored in-
stantaneously. Entities of the same type will automatically be joined if chaining is 
not set to off. If the valid number of entities is exceeded, a warning is shown in the 
status line. To create e.g. trapezoidal sections, the Mirror option can be used 
several times. Using the Mirror option a second time will cause all existing entities 
to be mirrored. 
2.1.4. Centre 
 
Function: 
Moves the centre of gravity of a section to the point 0,0 
If a section was moved to another location or rotated by using the function, the 
centre of gravity can be moved back to the point 0.0. 
2.1.5. Delete one Entity 
 
Function: 
Remove one entity from the section 
2.1.6. Delete a Sequence of Entities 
 
Function: 
Remove a sequence of entities from the section 
A sequence of entities may be deleted by picking the first and last entity of the 
sequence. All entities between the picked ones including these will be removed. 
The remaining entities will automatically be chained again. 
Open & Closed Sections/Trapezoidal Sections  
Profile Design with COPRA® RF 
30 
 
© Copyright by data M Software GmbH  
2.1.7. Delete Current Section 
 
Function: 
Deletes the current section data from memory 
Entering the Del Curr, function will remove all entity data from memory. As a re-
sult you will get a blank screen. This function does not affect the content of the 
COPRA® database. The shortcut +- allows resetting the changes. Another possi-
bility to reset the changes offers the COPRA®DB Undo, function from the  
COPRA® Utils toolbar. 
 
 
2.2. The Profile Utilities toolbar 
 
 
2.2.1. Edit Profile Section 
 
Function:  
Modify dimensions and geometry’s of the section  
Normally, it is not necessary to modify a section within a flower. This can be done 
with the standard COPRA® functions. There are only a few cases where function 
is required. 
 
This function allows modifying the calculated length of the neutral 
line. Be careful with this function as it may give rise to problems.  
Pass Data: 
Supplies information about the current flower 
• 
Number of passes saved in the data base 
• 
Current pass number to be modified 
• 
Number of entities in the current section 
• Material thickness 
Flower Data: 
Provides a list of data for all sections within a flower. 
Open & Closed Sections/Trapezoidal Sections  
Profile Design with COPRA® RF 
© Copyright by data M Software GmbH  
 
31 
Strip Width: 
Supplies information about changes of the originally calculated strip width 
• Original (old) strip width left of the section forming point 
• Original (old) strip width right of the section forming point 
• 
Current strip width left of the section forming point 
• 
Current strip width right of the section forming point 
• 
Difference between original and current strip width left of the section form-
ing point 
• 
Difference between original and current strip width right of the section form-
ing point 
• 
The differences between the strip widths are provided for verification of the 
changes. 
Listbox: 
If selection with the crosshairs highlights an entity, its geometry data are trans-
ferred to the edit boxes at the bottom of the window. The values can be modified. 
Selecting the OK button will make the changes permanent. The entities at the sec-
tion forming point (FP) are marked with an asterisk. 
Radio Button S: 
Enabled by COPRA®, if only a straight entity in the list is highlighted. A straight en-
tity can be changed into an arc entity by selecting B, and the previous data of the 
straight are saved. If the arc entity is converted back to a straight, the previous 
data will be restored. 
Radio Button B: 
Enabled by COPRA®, if only an arc entity in the list is highlighted. An arc entity 
can be changed into a straight entity by selecting S, and the previous data of the 
arc are saved. If the straight entity is converted back to an arc, the previous data 
will be restored.  
Bend Angle: 
The angle of all entities selected in the list is set to the pre-set value. Depending 
on the selected procedure, the radii and lengths of the entities will be adjusted or 
a length compensation is applied. This function is especially helpful if, for exam-
ple, not the inner radius but the outer radius is used as a basis. 
Inside Radius: 
The inner radius of all entities selected in the list is set to the pre-set value. De-
pending on the selected procedure, the angles and length of the entities are ad-
justed or a length compensation is applied. 
Open & Closed Sections/Trapezoidal Sections  
Profile Design with COPRA® RF 
32 
 
© Copyright by data M Software GmbH  
Contour Radius: 
The contour radius of all entities selected in the list is set to the pre-set value. De-
pending on the selected method the angles and lengths of the entities are ad-
justed or a length compensation is applied.  
Length: 
The length of the neutral line of all entities selected in the list is set to the pre-set 
value. Depending on the selected procedure the angles and radii of the entities 
are adjusted or a length compensation is applied. 
% New: 
The percentage of the neutral line with regard to the entire original strip width of all 
entities selected in the list is set to the pre-set value. The lengths of the neutral 
line are recalculated. Depending on the selected procedure, the angles and radii 
of the entities are adjusted or a length compensation is applied.  
 For a description of how to select entities refer to General Information. 
Profile Entity: 
Here the number of entities in a section can be changed. In combination with the 
function, dispense length compensation to selection, it is also possible to 
separate entities. 
Add: 
If only one entity is highlighted in the list, it can be copied by using the, Add! op-
tion. The new entity will be inserted after the selected entity. If the copied entity is 
a straight it can be converted to an arc if A is selected. If the copied entity is an 
arc it may be converted to a straight. 
 The entity data of the new entity are similar to those of the copied entity. 
Strip width differs by the length of the copied entity. 
Remove: 
All highlighted entities will be removed from the list.  
Modification Procedures: 
The different procedures have different effects on the section when changing an-
gle, radius or length of an entity. Several types of length compensations can be 
applied.  
Open & Closed Sections/Trapezoidal Sections  
Profile Design with COPRA® RF 
© Copyright by data M Software GmbH  
 
33 
Free: 
This procedure is equal to the COPRA® calibration method Angle/Radii. 
 
Change 
Angle 
Radius 
Length 
Length compensation 
Angle 
 
Unchanged 
Is adjusted 
None 
Radius 
unchanged 
 
Is adjusted 
None 
Length 
Option: Adjust Option: Adjust 
 
None 
 
Constant Length/Adjust: 
This procedure is equal to the COPRA® calibration method Angle/Radii. 
 
Change 
Angle 
Radius 
Length 
Length compensation 
Angle 
 
Unchanged 
Is adjusted 
None 
Radius 
unchanged 
 
Is adjusted 
None 
Length 
Option: Adjust Option: Adjust 
 
None 
 
Compensation with Straights only: 
This procedure is equal to the COPRA® calibration method Constant Radius.  
Length compensation is done with straight entities only. If an adjacent entity of the 
modified entity is not a straight entity, a new straight entity will be created auto-
matically. 
 
Change 
Angle 
Radius 
Length 
Length compensation 
Angle 
 
Unchanged 
Is adjusted 
With straights only 
Radius 
Unchanged 
 
Is adjusted 
With straights only 
Length 
Option: Adjust  Option: Adjust 
 
With straights only 
 
Compensation in Adjacent Entities: 
This procedure is equal to the COPRA® calibration method Tube Profiling. Length 
compensation is done with the adjacent entities of the modified entity, no matter 
whether the adjacent entities are straight or arc entities. 
 
Change 
Angle 
Radius 
Length 
Length compensation 
Angle 
 
Unchanged 
Is adjusted 
Adjacent entities 
Radius 
Unchanged 
 
Is adjusted 
Adjacent entities 
Length 
Option: Adjust Option: Adjust 
 
Adjacent entities 
Open & Closed Sections/Trapezoidal Sections  
Profile Design with COPRA® RF 
34 
 
© Copyright by data M Software GmbH  
Length Compensation: 
If the selected procedure is based on direct length compensation, it can be de-
fined how the lengths are to be distributed at the right or left of the modified entity. 
Outside: 
Outside is the entity next to the modified entity, which is further away from the 
point of unfolding and closer to the end of the section or, in case of closed sec-
tions, is closer to the welding point. 
Inside: 
Inside is the entity next to the modified entity, which is closer to the point of un-
folding and further away from the end of the profile or, in case of closed sections, 
is further away to the welding point.  
Adjust: 
If changing the length of an arc or if an arc is used as a length compensation en-
tity, either the radius or the angle can be adjusted to the new length. 
Angle: 
If required, the angle of an arc entity is adjusted to the new length. 
Radius: 
If required, the radius of an arc entity is adjusted to the new length. 
Length Difference: 
After user-defined editing of the section data, a difference between the original 
strip width and the new strip width may occur. This difference can be distributed to 
the entities selected in the list. 
Even: 
The difference is divided by the number of selected entities. The resulting value is 
added to each entity.  
Percentage: 
The difference is distributed as a percentage of the length of the entity. A longer 
entity gets a higher percentage of the total difference and vice versa. 
Open & Closed Sections/Trapezoidal Sections  
Profile Design with COPRA® RF 
© Copyright by data M Software GmbH  
 
35 
2.2.2. Move Profile 
 
Function: 
Move section 
This function allows moving a selection of sections by defining reference and tar-
get points. The sections to be moved are displayed in the same colour. Optionally, 
additional sections can be displayed which will be listed in a different colour. The 
changes will be automatically saved to the database. If only one section was 
moved, it could be saved optionally. 
2.2.3. Rotate Profile 
 
Function: 
Rotate section 
This function allows rotating a section as desired by selecting reference points. 
The sections to be rotated are displayed in the same colour. Optionally, additional 
sections can be displayed which are listed in a different colour. The changes are 
automatically saved to the database. If only one section was moved, it could be 
saved optionally. 
2.2.4. Split Entity 
 
Function: 
Split one entity into two parts 
Sometime it may be necessary to insert an entity where it cannot be done be-
cause of an existing entity. In this case the Split entity function can be used to 
break an entity. The entity to be split has to be picked with the crosshairs. The 
entity data will be displayed and the entity selection has to be confirmed. In case 
of a straight the length to the break point has to be entered, in case of an arc the 
including angle has to be entered. If the break position is valid, the entity will be 
split in the position defined and the new section will be displayed. 
2.2.5. Join Entities 
 
Function: 
Join split entities 
If selected, two adjacent equal entities can be joined.  
To do so, pick the entities with the crosshairs. All entities between, which have the 
same geometrical values, will be automatically joined. In case of arcs, the inner 
radii have to be equal.  
Open & Closed Sections/Trapezoidal Sections  
Profile Design with COPRA® RF 
36 
 
© Copyright by data M Software GmbH  
2.2.6. Join All Entities 
 
Function: 
Join separate entities 
If selected, all adjacent equal entities are joined within the section. In case of arcs, 
the inner radii have to be equal. 
2.2.7. Same Number of Entities for 2 Profiles 
 
Function: 
Adjust number of entities of two sections  
The number of entities of the current pass and a second pass is adjusted. In the 
occurring dialogue box the second pass has to be selected respectively. 
 
2.3. The Profil Utils toolbar 
 
2.3.1. Write Part of Profile to File 
 
Function: 
Writes a part of a profile for copying purposes to hard disk 
In some types of sections there are repeated shapes. To avoid a new design of 
these shapes they can be written to file with the Write PP option and copied with 
the Read PP option. 
A typical example would be stiffing ribs in a trapezoidal section. 
Simply pick the first and last entity of the entities to be copied and enter a filename 
describing that part. The entity data are written to file and are ready to be copied. 
2.3.2. Read Part of a Profile from File 
 
Function: 
Reads a part of a profile from hard disk and inserts it in the current section 
Each part of a profile written to hard disk can be inserted into the current section 
with various options. After entering the filename these options are listed in the 
status line: 
Option 1: A - insert Part of Profile at the Beginning of the Section 
Entering the option A causes the part of profile to be added to the beginning of the 
section. The beginning of the section is at entity no. 1. The entity picked first when 
writing the part of profile will be added to entity no. 1 as the first one. 
Open & Closed Sections/Trapezoidal Sections  
Profile Design with COPRA® RF 
© Copyright by data M Software GmbH  
 
37 
Option 2: E - insert Part of Profile at the End of the Section 
Entering the option E causes the part of profile to be added to the end of the sec-
tion. The end of the section is at the entity with the highest number. The entity 
picked first when writing the part of profile will be added to that entity as the first 
one. 
Option 3: G - insert Part of Profile at a Location picked by Crosshairs 
Entering the option G causes the part of profile to be added at a position picked by 
crosshairs. The part of profile will be added before the entity picked by the cross-
hairs. The entity picked first when writing the part of profile will be added to that 
entity as the first one. 
Option 4: N - insert Part of Profile at a Location defined by an Entity Number 
Entering the option N causes the part of profile to be added at a position defined 
by an entity number. The part of profile will be added before the entity number 
entered. The entity picked first when writing the part of profile will be added to that 
entity as the first one. 
 
2.3.3. Write a Sequence of Passes to File 
 
Function: 
Write flower to file 
This function allows saving a flower or part of a flower to a file.  
2.3.4. Read a Sequence of Passes into Flower 
 
Function: 
Read flower from file 
This function allows reading a flower or part of a flower from a file.  
Open & Closed Sections/Trapezoidal Sections  
Profile Design with COPRA® RF 
38 
 
© Copyright by data M Software GmbH  
2.3.5. Material thickness 
 
Function: 
Change material thickness subsequently 
This function allows to subsequently change the sheet thickness for a complete 
flower. In the occurring dialogue box you can choose between several methods. 
After having selected a method, a slide provides a preview of how sheet thickness 
will change. 
Select: 
Select the passes, whose material thickness is to be changed. 
Plate Thickness old: 
Information on the old material thickness. 
Plate Thickness new: 
Dialogue field for the new sheet thickness value. 
Datum Line: 
Defines the reference line for the modification of sheet thickness. 
Iternal Radius constantly: 
The inner radius of the section remains constant. 
Outer Radius constanty: 
The outer radius of the section remains constant. 
Outer Contour constantly: 
The outer contour of the section remains constant. 
Centre Line constantly: 
The centre line of the section remains constant. 
Iternal Contour constantly: 
The inner contour of the section remains constant. 
Open & Closed Sections/Trapezoidal Sections  
Profile of AutoCAD 
© Copyright by data M Software GmbH  
 
39 
3. Profile of AutoCAD 
 
Function: 
Creating a profile by AutoCAD polyline 
The first step when designing a new roll set is the definition of the final section 
shape. This can either be done with the COPRA® Profile Module or by designing 
the section with the help of the CAD system. The handling is very easy. The final 
shape of the section is designed and drawn with CAD functions. For the conver-
sion of the shape from a CAD drawing to a COPRA® section the CAD Profile 
Module has to be loaded and the contour polyline has to be picked with the 
crosshairs. In terms of AutoCAD, the design of the section has to fulfil the follow-
ing conditions: 
Conditions: 
• 
COPRA® has to be initialised 
• 
Polyline from a contour or centre line of the profile must be on the screen 
• 
The contour has to be drawn as a polyline 
• Only inside, outside or centre line contour are necessary for the conversion 
• 
If the section is designed with material thickness, COPRA® will cancel the 
conversion. 
• 
The intersection points between arcs and lines must be tangent 
• 
The inside radius of the section may not be smaller than 0 during the con-
version 
 
One of the following Options can be selected:  
Erase Database: 
The COPRA® database in the current project path will be removed. The number of 
sections and passes will be zero. A completely new section can be created. 
Continue: 
The COPRA® database in the current project path will not be removed. After the 
conversion of the contour the new contour may be added to the existing section. 
Cancel: 
Exits the CAD Profile module. No data will be removed and no conversion is done. 
After having identified the polyline, a dialogue box appears allowing you to define 
the settings for section conversion. 
Material Thickness : 
The material thickness for the profile can be entered. 
Open & Closed Sections/Trapezoidal Sections  
Profile of AutoCAD 
40 
 
© Copyright by data M Software GmbH  
Centre Line: 
The centre line is the reference for sheet thickness. 
Contour Line: 
The contour line is the reference for sheet thickness. 
Centre of Gravity in 0.0: 
If toggle is crossed, the centre of gravity of the section will be moved to the point 
0.0 after the conversion of the polyline. 
If there is already a section saved in the COPRA® database, which has not been 
removed when loading the program, a dialogue box comes up offering various op-
tions. 
Append: 
The converted section will be appended to the database. If one pass was existing, 
the new section will be saved as pass no. 2. 
Overwrite: 
The current pass, which is pass 1, will be overwritten with the converted contour. 
Insert: 
The converted section can be inserted in the COPRA® database. The respective 
pass number has to be user-defined. The definition can be done in an extra dia-
logue box. 
No: 
The converted section will not be saved in the COPRA® database. 
Open & Closed Sections/Trapezoidal Sections  
Strip Width Calculation 
© Copyright by data M Software GmbH  
 
41 
4. Strip Width Calculation  
 
Function: 
Calculation of theoretical strip width 
The strip width calculation takes into account the stretching of the material during 
the forming process. The inside radius of the material will be compressed and the 
outside radius will be stretched. The neutral line of the material moves towards the 
inside of the radius during being bent. This causes the length of the geometric 
centre line to be different from the actual strip width. 
After having selected the Strip Width function, a dialogue box appears which will 
be described below. 
Window: 
The dialogue box appears, showing a list of all elements. Including, entity no., 
bend angle, the inside radius, the ratio inner radius/material thickness Ri/s0, the 
length of the geometric centre line, the length of the calculated neutral line, the 
calculation method used for a bend, a correction factor being dependent on the 
calculation method and the difference between centre line and neutral line deltaB. 
Calculation Method: 
Allows selecting the method for strip width calculation. 
Factor: 
Enter the factor for defining the position of the neutral line.  
Bend Selection: 
The options Select, Deselect, Inverse, Filter and Crosshairs allow selecting 
several arc entities to which the respective calculation methods can be assigned. 
Calculation Methods: 
Shows the selected formula or the value from the used table. 
Section Data: 
Shows the current data of the section as well as the calculated strip width. 
Results: 
The calculated strip width can be saved to a file. The name of the file can be se-
lected independently. The file is copied to the Project Directory, Info directory. 
Open & Closed Sections/Trapezoidal Sections  
Strip Width Calculation 
42 
 
© Copyright by data M Software GmbH  
4.1. Theoretical Basis 
4.1.1. Bending 
Bending is a process of cold forming which industrial engineering often applies. 
Leaving aside edge deformation, the process of bending is limited to a 2D reflec-
tion, which allows a ratio of unbent length b, and material thickness t, of more than 
5. Thus, for the major part of all bending applications, we can use this simplifica-
tion. 
Due to the elasticity of the material, the actually given bending angle of a finished 
piece is inferior to the originally bent angle. The importance of the spring-back de-
pends on the amount of residual elastic stress before relief. 
 
 
Fig.  5  Stress and strain condition with bent parts of different curvature 
a  
: Stress value at yielding point  
b  
: Stress value in plastic zone 
I 
 
: Major bending angle; here we only have residual elastic strain. 
II 
: Sharply bent metal; here we have besides residual elastic stress tensions in the plastic  
 
  zone accounting for the major share. 
 
Hardly bent sheet metal with a much higher bending radius r, compared to its 
thickness s, will therefore show a considerable tendency to spring-back into its 
original position. The higher the ratio ri/s0, the higher the share of residual elastic 
stress will be. This means that a square-edged curvature has a minor tendency to 
spring back compared to metal with a significant bending radius. 
The spring-back which first of all depends on the ratio of bending radius rI, and 
material thickness s0, will in addition be influenced by the hardness and the mate-
rial micro-structure, however it is not influenced by the load period. 
Open & Closed Sections/Trapezoidal Sections  
Strip Width Calculation 
© Copyright by data M Software GmbH  
 
43 
For an exact determination of the spring-back, the gauge factor k has been intro-
duced; k can be determined by tests. The spring-back ratio K is the ratio of bend-
ing angle after spring-back and bending angle before spring-back. 
 
K r
s
r
s
=
+
⋅
+
⋅
=
1
2
2
1
0 5
0 5
,
,
α
α
 
The spring-back angle ρ therefore is: 
2
2
1
1
1
α
α
α
ρ
⋅






−
=
−
=
K
 
 
 
Fig. 6   Spring-back diagram to determinate the value K 
K : Spring-back relation 
r1 : Inner bending radius 
r2 : Inner bending radius after spring-back 
s : Sheet thickness 
α2 : Bending angle after spring-back 
α1 : Set bending angle during the bending process 
ρ : Spring-back angle 
 
Exact values regarding the spring-back behaviour are indispensable if tool design 
depends on the bending angle, e.g. in case of positive locking bending to shape. 
During the forming of edged profiles, the spring-back can be compensated by a 
deeper lowering of the bending rail with a greater side-angle of the bending de-
vice. 
The process of bending causes a shift of the material towards the bending zone. 
Due to the compressive stress in the inner zone of the curvature, the material is 
upset and the layers of material will become thicker. In the external zone the ma-
terial will be lengthened due to tensile stress and the layers will accordingly be-
come thinner. 
Open & Closed Sections/Trapezoidal Sections  
Strip Width Calculation 
44 
 
© Copyright by data M Software GmbH  
 
Fig. 7 Sheaf of lines in an arc of circle 
The curvature can be subdivided in two zones in which only tensile stress or com-
pressive stress occurs. 
A third zone has to be introduced in which the material is first upset and after-
wards stretched again. A limit elongation fibre has been defined as delimitation. 
This is a fibre where no more alterations due to stretch will occur. At the beginning 
of the bending process, it is identical to the median fibre and moves during the 
bending process towards the inner side passing the whole range of the final inter-
mediate zone. 
The fibre, which at the end of the bending process has the same length as before 
shaping, is the so-called neutral line. 
 
 
Fig. 8   Total elongation of individual layers depending on the edge elongation ea 
Open & Closed Sections/Trapezoidal Sections  
Strip Width Calculation 
© Copyright by data M Software GmbH  
 
45 
 
Fig. 9   Bending radii shown at a shaped sheet metal 
ra:    outside radius 
rmo: radius of the original centre fibre 
rm:   radius of the centre fibre 
ru:    radius of the neutral line 
rg:    radius of the limit elongation fibre 
ri:      inner radius 
 
The non-lengthened fibre does not coincide with the centre fibre of the curvature. 
This is due to the change in sheet thickness in the bending zone. The curves of 
tensile and compressive yield stress are usually not the same for one material and 
the influence of lateral strain should not be underestimated. The thicker is the 
sheet and the smaller is the bending radius the more differs the position of the 
neutral line from the centre fibre. 
The micro-graph section of a square-edged aluminium sheet shows the actual 
course of the fibre. 
 
Fig. 10  Micro-graph of Al 99 h 
Because of elongation the external fibre is subject to a smoothing of the curvature 
so that in the centre of the curvature the external radius of curvature will be supe-
rior to the one of the lateral zones of curvature. Due to compressive stress in the 
interior of the curvature, the margin texture might break down so that one cannot 
classify it as a useful internal radius of curvature. Besides, the illustration shows 
that because of the material shifts the fibres do no longer follow concentric circles. 
Open & Closed Sections/Trapezoidal Sections  
Strip Width Calculation 
46 
 
© Copyright by data M Software GmbH  
During the bending of thick sheets with small bending radii, those edge deforma-
tions occur frequently. Because of the pressure the material on the inside is even 
subject to lateral yielding. The fibres on the outside, however, are lengthened, 
which causes a weakening of the sheet; it not only decreases the original thick-
ness but also the original width in the external zones. 
4.2. Profiling/Roll forming to Shape 
As for shaping, the roll forming or profiling technique is quite similar to the bending 
process. Due to its continuous process, however, not only the desired changes in 
shape appear but also undesired longitudinal deformations, which influence the 
shaping behaviour unfavourably. 
In calculating the position of the neutral line those longitudinal deformations are 
disregarded. 
Exact calculation of the coil stock width is required in order to guarantee stability 
of dimension within given tolerance limits of a profile to be designed.  
There are different methods to determine longitudinal modifications in the curva-
ture zones. Those methods often use different physical mathematical approaches. 
 
4.2.1. Calculation of Neutral Line 
Introduction 
In order to take alterations appearing within the curvature zone during the bending 
process into account one starts with a neutral line, which is neither lengthened nor 
upset by the bending process. In unbent condition the length of this fibre corre-
sponds to the length of the work-piece that is to be bent. In bent condition the po-
sition of the neutral line defines the dimensions. The greater the distance to the 
centre fibre in direction of the centre of the curvature, the shorter will be the neu-
tral line and the shorter will be the unbent length. The length of an arc is calcu-
lated as follows: ϕ
π
⋅ ⋅
r
180
 
In practical life, compensation factors or gauge factors were introduced for differ-
ent materials so as to calculate the length in unbent condition. First a work-piece 
to be shaped is designed in unbent condition. Thus the final dimensions are de-
fined. Tables and diagrams indicating the gauge factor for a certain material, de-
pending on sheet thickness and bending radius, were created in order to obtain 
the dimensions for cutting to size of sheets. We only have to add this value to the 
longitudinal dimensions of each curvature so as to receive the length in an unbent 
condition. Those tables and diagrams were generated during tests with different 
materials. Since the bending programme only uses contours and curvatures, the 
dimensions always refer to them.  
 
Thus, the coefficient of the position of the neutral line is used to calculate the 
length of the bending zones; the coefficient can be deduced from the compensa-
tion factors. The gauge factors could be converted at once and be stored in a new 
table for the position of the neutral line. 
Open & Closed Sections/Trapezoidal Sections  
Strip Width Calculation 
© Copyright by data M Software GmbH  
 
47 
Nevertheless, the table of the gauge values was chosen as a basis for the calcu-
lation of the programme, in order to get easy control of the values. It is highly 
probable that gauge factors for new materials will also be defined by tests so that 
they can directly be included in the table. In addition, recalculating the gauge fac-
tor for each curvature does not involve major efforts. 
With the present bending programme the position of the neutral line was entered 
as a coefficient in relation to the thickness. For defining a curvature this coefficient 
is automatically pre-set to 0.5 in order to provide for a minimum of changes in ex-
isting programmes. 
Only during positioning of a piece, i.e. in calculating and appending the individual 
elements of the work-piece the coefficient is calculated according to the material 
and depending on the bending radius and sheet thickness and the pre-set value 
will be overwritten. That enables you to proceed with the positioning of a new ma-
terial at any moment. The coefficients will be redefined. 
4.3. General Observations 
Calculating the coil stock width is mainly based on the following assumption: due 
to deformation and constriction of material, see Fig. 11, in the bending area con-
nected with it, there will be a lengthening of the latitude co-ordinate of the work-
piece with given retention of volume. 
In order to produce an arc element with a defined opening angle, and a median 
length of arc b, as necessary for the production of a profile required, you have to 
envisage a length element of the unformed material that corresponds to the me-
dian length of the arc of the finished profile, minus lengthening. 
The value for the coil stock width of any profile required, results from the length of 
unfolding of a finished profile minus the total of elongation’s that occurred in the 
bending areas. 
 
Fig. 11   Constriction in bending areas 
Open & Closed Sections/Trapezoidal Sections  
Strip Width Calculation 
48 
 
© Copyright by data M Software GmbH  
All methods divide the profile into straights and arc elements for calculation. The 
calculation of the initial width according to methods 1 to 3 is done in two steps. 
First the theoretical lengthening is defined for each arc element of the profile, fol-
lowing the respective calculation rules of the chosen method. The total of those 
lengthened is subtracted from the length of the profile after unfolding. And the re-
sult will be the coil stock width required, as the total of those lengthened of all ref-
erence zones, is the dimension by which the latitude co-ordinate of the material 
will be increased due to the shaping process. 
 
Fig. 12   Lengthening ∆b in a bending area 
A model depiction of the lengthened ∆b in a bending zone is shown in Fig. 12. It is 
supposed that the dimensions of straight sections will not change during shaping. 
These reflections will lead to an inconsistent alteration of material thickness within 
the transition zone between straight and arc elements. Nevertheless this approach 
should be maintained provided the following points are taken into consideration. It 
is known from studies that the material thickness s of bending areas reaches its 
minimum at the vertex of the curve and will only reach the original material thick-
ness so far out at the adjacent side. We can assume that the surfaces between 
the real and the imaginary course of the external borderline have the same di-
mension at each side of the transition in question. See also Fig 13. 
 
Fig. 13   Transition from straight to arc 
Thus, the transverse strain may be still defined on the basis of volume retention. 
The method according to S+B proceeds slightly different in detail. 
Open & Closed Sections/Trapezoidal Sections  
Strip Width Calculation 
© Copyright by data M Software GmbH  
 
49 
It approaches the arc elements with straight elements following certain rules. In 
combination with further gauge values depending on the bending angle one ob-
tains the production width necessary for the arc element. Using the S+B method, 
the coil stock width for a profile, results from the total of the defined production 
widths for arc and straight elements. 
4.4. Calculation in Accordance with German Standard DIN 6935 
The German standard DIN 6935 on cold forming to shape includes a gauge factor 
K, which takes the longitudinal alterations, based on the bending process into ac-
count. 
This factor indicates the difference between unbent fibre and centre fibre of an arc 
element and thus makes the calculations of the unbent fibre possible. 
1
lg
2
1
65
.
0
≤




⋅
+
=
k
s
r
k
 
This standard is valid for bent pieces of flat steels dedicated to the use in  
mechanic engineering. 
 
Fig. 14   Position of the neutral line according to German standard DIN 6935 
r 
: internal radius of the curvature 
s 
: material thickness 
β 
: opening angle 
a, b 
: leg length 
v 
: gauge factor 
L 
: stretched length 
 
 
 
 
L a b v
= + +
 
 
Thus, k/2 results for the coefficient of the position of the neutral line, since this 
coefficient refers to the thickness s. 
 
 
 
 
s k
s
2
= ⋅ Koeff.
 
The DIN standard uses the factor k to calculate the gauge value. In the pro-
gramme however, you can immediately use the formula for calculation, since even 
the choice of a certain dimensioning method does not allow the generating of a 
homogenous table of gauge factors between German standard DIN and VDI 
guidelines. 
Open & Closed Sections/Trapezoidal Sections  
Strip Width Calculation 
50 
 
© Copyright by data M Software GmbH  
The conditions of this method which are to be taken into account regarding mate-
rial and bending radii admitted are shown in DIN standard 6935. The table 15 
shows a material key list that is to be used for calculations according to DIN 6935. 
 
 
steels with guaranteed minimum tensile strength 
steels 
up to 390N/mm2 over 390 up to 490 
N/mm2 
over 490 up to 640 
N/mm2 
gen. 
structural 
steels 
QST 34-2 
QST 42-2 
QST 52-e 
according to DIN 
17100 
QST 37-2 
QST 42-3 
 
 
QST 37-3 
QST 46-2 
 
  Table 15 
Table 16 lists minimum the bending radii (internal radius) admitted for the choice 
of certain material thickness values and materials. The indicated values are valid 
for bending angles α <=120°. For α >120° the following value in the table is to be 
inserted. 
 
Steels 
with 
during 
bending  
smallest bending radius r admitted for thickness s 
A guar-
anteed 
cross-
wise or 
 
over over over over over over over over over over over over over over
L mini-
mum 
parallel 
to 
1 
1 
1.5 2.5 3 
4 
5 
6 
7 
8 
10 
12 
14 
16 
18 
Tensile 
strength 
direc-
tion 
 
up 
to 
up 
to 
up 
to 
up 
to 
up 
to 
up 
to 
up 
to 
up 
to 
up 
to 
up 
to 
up 
to 
up 
to 
up 
to 
up 
to 
N/mm2 of 
roll-
ing 
 
1.5 
2.5 3 
4 
5 
6 
7 
8 
10 
12 
14 
16 
18 
20 
up 
to 
390 
cross 
wise 
1 
1.6 
2.5 3 
5 
6 
8 
10 
12 
16 
20 
25 
28 
36 
40 
 
parallel 1 
1.6 
2.5 3 
6 
8 
10 
12 
16 
20 
25 
28 
32 
40 
45 
Over 
390 up 
to 490 
cross 
wise 
1.2 2 
3 
4 
5 
8 
10 
12 
16 
20 
25 
28 
32 
40 
45 
 
parallel 1.2 2 
3 
4 
6 
10 
12 
16 
20 
25 
32 
36 
40 
45 
50 
over 
490 up 
to 640 
cross 
wise 
1.6 2.5 
4 
5 
6 
8 
10 
12 
16 
20 
25 
32 
36 
45 
50 
 
parallel 1.6 2.5 
4 
5 
8 
10 
12 
16 
20 
25 
32 
36 
40 
50 
63 
Table 16 
The lengthening of a bending zone is calculated with a non-dimensional correction 
factor K with a value between zero and one. This factor indicates the deviation 
towards the median line of an arc element and thus allows defining of the non-
lengthened fibre. 
Open & Closed Sections/Trapezoidal Sections  
Strip Width Calculation 
© Copyright by data M Software GmbH  
 
51 
 
Fig. 17   Graphical depiction of the correction factor K 
The delta value for the bending zone is calculated with the following equation: 
∆b a
s
K
=
⋅
⋅
⋅
−
π
0 1
360
(
)  
 
opening angle  α in (degrees) 
 
Depending on the specific inner radius R ( := inner radius/material thickness ), the 
calculation is subdivided into several process parts which deliver different values 
for the correction factor K. 
 
1. 
R > 5 
  K = 1.0 
2. 
5 0
0 05
,
,
≥ >
R
 
  K = 0.65 + 0.5 * log(R) 
3. 
0 05
0
,
≥ ≥
R
 
  K = 0.0 
4. 
0.0 > R 
  impossible after def of R 
This division allows covering all possibilities of an arc element regarding bending 
radius and opening angle relevant in practical life. Thus, the total of all calculated 
Db values has to be subtracted from the unfolding of the finished profile in order to 
define the coil stock width. 
4.5. Algorithm according to Proksa 
In order to allow for an overall application, the calculation according to Proksa is 
subdivided into three calculation parts which are chosen and dependent on the 
specific inner radius R (:= inner radius/material thickness). The lengthening ∆b, 
which occurs in the zone of deformation due to the bending process, is calculated 
respectively. 
 
1. 
R >5 
  ∆B = 0.0 
2. 
5 0
0 1
,
,
≥ ≥
R
 
    
(
)
[
]
2
0
360
1
)
1
(
2
s
s
s
r
b
i
−
⋅
+
−
⋅
⋅
⋅
=
∆
π
α
 
3. 
0 1
0 0
,
,
≥ ≥
R
 
  ∆b
s
=
+ ⋅
⋅
α
π
360
0 0 12
,
 
4. 
0.0 >R 
  impossible after def of R 
The division method shown in the second line is based on calculation rules de-
veloped by Proksa. 
Open & Closed Sections/Trapezoidal Sections  
Strip Width Calculation 
52 
 
© Copyright by data M Software GmbH  
In this formula the specific material thickness S (= current material thickness/initial 
material thickness) is used. Proksa uses a differential equation to calculate the 
specific sheet thickness S and for the modification to material thickness he uses S 
=s /so as a function of the specific internal radius R. 
(
)
(
)1
1
+
⋅
+
−
⋅
=
−
−
A
A
e
R
s
e
S
dR
dS
 
with 
 
 






⋅
−
⋅
+
⋅






⋅
−
⋅
=
χ
χ
χ
5
.0
1
5
.
0
1
ln
25
.
0
1
ln
2
2
S
K
A
 
it is valid 
 
χ =
⋅
⋅ +
2
2
S
R S
 :curvature 
 
 
 
K
k
k
v
=
⋅2
0
 
:material factor 
 
 
 
 
kv 
:coefficient of hardening 
 
 
 
 
ko 
:yield point in shear 
The solution of this non-linear differential equation of first order is only possible 
with the numerical method of approximation. Here we chose the method of 
Runge-Kutta. For plane metal (condition before shaping) the value for the specific 
inner radius R = ri/so approaches the infinite set. As there is no constriction, the 
specific sheet thickness = 1.0. For practical calculation R has to be chosen high 
enough to be able to define a problem of initial value. In this application the values 
have been set in the following way. 
 
independent variable: 
R = 10.0 
 
dependent variable: 
S =   1.0 
The choice we made for the specific inner radius R is in any case sufficient be-
cause even calculations with a much higher initial value for R confirm our choice. 
In order to proceed to a numerical solution we use an initial step of -1.0, which will 
be commanded variably during the calculation programme so as to reduce the 
error to a minimum. The solution range of the differential equation is also limited 
by the abscissa value R = 0.01 to the amount of values relevant for the calculation 
of the material width requested according to Proksa. 
Fig. 14 shows a depiction of these solutions for several material factors K. The 
solution curves are ending in the straight S = 1.0 with increasing R. 
As comparison the curves for ideal plastic-rigid (kv = 0.0) and ideal elastic material 
(ko = 0.0) are marked. 
Open & Closed Sections/Trapezoidal Sections  
Strip Width Calculation 
© Copyright by data M Software GmbH  
 
53 
 
Fig.  18   Alteration of material thickness s/so as function of specific inner radius ri/so 
The material factor K is a parameter of this differential equation and specifies the 
given characteristics of the material used for production. The definition of factor K 
requires the definition of the values kv and ko. For this purpose the yielding curve 
of the material is replaced by a straight. However, you have to make sure that the 
slope of this straight corresponds approximately to the slope of the yielding curve 
in the middle of the zone of adaptation. Also, you have to make sure that the sur-
faces below the yielding curve and of the substitute straights are nearly of the 
same size in the middle of the zone, see Fig 19. It is useful to carry out this ap-
proximation of the yielding curve with several straights, see Fig 20. 
 
Fig.  19   Approximation to the real yielding curve by a straight 
Using the example of the material UQST36, the determination of the factor K is to 
be shown. First of all the appropriate areas are defined. The curve sections of the 
different areas are approximated each by a straight in accordance with the above 
mentioned criteria. From a depiction as shown in Fig. 16, you can get the values 
required for the calculation of K. 
Open & Closed Sections/Trapezoidal Sections  
Strip Width Calculation 
54 
 
© Copyright by data M Software GmbH  
 
Fig. 20   Yielding curve for material UQST36 with substitute straights approximated for different areas 
 
The following interrelations are valid 
k
k
k
r
v
0
0
3
0 66
=
=
⋅
,
tanβ
 
 
 
 
 
β : slope angle of substitute straights 
 
Now you may define the individual part of material K1 to K3 for the three areas in 
our example. You will obtain: 
K1 = 2.128 
K2 = 1.021 
K3 = 0.647 
The arithmetic average of these three values is the material factor that is to be 
used for the material UQST36. 
KUQST36 = 1.27 
With the information now available concerning material factor and differential 
equation, the latter can be solved. The result will be a table with the solution points 
(S; R) from which you can get the dependence of R and the value for the modifi-
cation of material thickness S. With acceptable exactitude a linear interpolation 
can be used for intermediate points. The specific sheet thickness S has two appli-
cations in the above method of calculating the ∆b value. 
As for the method in accordance with DIN standard 6935, all possibilities for an 
arc element regarding bending radius and opening angle, relevant in practical life, 
are covered by a sub-division into three steps. For the definition of the coil stock 
width the total of all calculated ∆b values is subtracted from the unfolding of the 
finished profile here. 
Open & Closed Sections/Trapezoidal Sections  
Strip Width Calculation 
© Copyright by data M Software GmbH  
 
55 
4.6. Algorithm in accordance with Bogojawlenskij 
The method according to Bogojawlenskij is based on the method of mathematical 
statistics. The measured values necessary for this purpose have been obtained 
especially from angle and U profiles. 
As explained in the previous section, the calculation of the coil stock width is 
based on the determination of the ∆b values for the individual bending areas. 
For carbon and low-alloy steels this value is obtained as a result of the following 
formulae which are chosen depending on the specific internal radius R. 
 
1. 
R >5 
  ∆b = 0.0 
2. 
5 0
0 1
,
,
≥ >
R
 
  ∆
∆
b
n
S
B
=
⋅
⋅
0 1172
0 1157
,
,
 (mm) 
3. 
0 1
0 0
,
,
≥ ≥
R
(Falzung)  
  ∆b
s
=
⋅
⋅
⋅
α
π
/
,
360
0 12
0
 
4. 
0.0 >R 
  impossible after def of R 
 
nB : number of bending areas of a profile 
∆s = so * 0.0032 * α0.53 * 1.26 * R-0.55 
α : opening angle in degrees 
R : specific internal radius ri/so 
The equations mentioned under 2, and the formula for the determination if the ∆s 
value, have been developed by Bogojawlenskij only for applications with so = 1-
8mm, R = 5-35mm. α = 0-90° and material widths between 100mm and 350mm. 
The deduction is based on angles and U profiles as already mentioned. For this 
reason application is not recommended for all profiles. 
According to literature this method obtained very good calculation results for angle 
and U profiles. 
In accordance with the methods explained, the coil stock width results from the 
difference between unfolding of finished profile and total of all ∆b values. 
4.7. Calculation in accordance with VDI guideline 3389 
The VDI guideline 3389 page 3 deals with forming under bending conditions by 
wedge shaped tool with 90°. The indications of the document are especially des-
tined to meet with high demands of 90° wedge-shaped bending and to forward 
tested standard values to practise. Those standard values were derived from re-
sults of long-term statistical interpretation. The deviations of bent pieces caused 
by unequal quality within one kind of material can be neglected in practical life. 
Since each curvature is treated separately by the bending programme, it is suffi-
cient to take V bending into account disregarding e.g. U shaping, since the pro-
gramme interprets both curvatures as two V curvatures. 
Due to material strain during shaping, the non-lengthened fibre is placed in a posi-
tion, which is not coaxial to the bending radius. Since the position cannot be de-
fined in geometrical terms and thus is of no use in determining the stretched 
length, the gauge factors for bending angles of 90° have been determined by trial 
and error by bending tests. 
Open & Closed Sections/Trapezoidal Sections  
Strip Width Calculation 
56 
 
© Copyright by data M Software GmbH  
They are shown in diagrams in the VDI guideline 3389 page 3. On the basis of 
these gauge values the position of a theoretical neutral line required by the bend-
ing programme is to be calculated. 
 
 
Fig.  21   Stretched length according to VDI 
s        : thickness of the work-piece 
ri 
: internal radius of the curvature 
l1, l2 
: internal side length  
L 
: stretched length 
x 
: gauge values 
 
 
 
L
l
l
x
= + +
1
2
 
 
 
Fig. 22   Stretched length according to the position of the neutral line 
a, b: 
lengths of the unmodified areas 
Koeff.: position of the neutral line 
 
 
 
(
)
(
)1
1
+
⋅
+
−
⋅
=
−
−
A
A
e
R
s
e
S
dR
dS
 
Open & Closed Sections/Trapezoidal Sections  
Strip Width Calculation 
© Copyright by data M Software GmbH  
 
57 
The arc of the circle is calculated by 
ϕ
π
⋅r
180
 
 
The radius of the neutral fibre results from the internal radius. By equating the two 
equations you will get an equation for the coefficient depending on the gauge fac-
tor. As the gauge factors for an angle of 90° are included in the VDI guidelines, ϕ  
equals 90°. 
(
)
(
)1
1
+
⋅
+
−
⋅
=
−
−
A
A
e
R
s
e
S
dR
dS
 
 
Fig. 23   Dimensioning according to VDI 
l1 and l2 can geometrically be divided into a, b and 2 * ri. 
Thus for the first equation is: 
L a b
r
x
i
= + +
+
2
 
 
By equating results: 
(
)
2
Koeff.
2
π
⋅
⋅
+
+
+
=
+
+
+
s
r
b
a
x
r
b
a
i
i
 
 
 
 
 
 
Resolution for the coefficient: 
This equation allows calculating a single valued coefficient using the values of 
bending radius, thickness of work-piece and material, as the gauge factor x is a 
function of these three values and no other parameter appears. If the material is in 
addition, compressed in the bending area, you will have to consider the stretching 
stress for each zone of shaping.  
2
Koeff.
2
2
⋅
⋅
+
=
+
π
π
s
r
x
r
i
i
π
π
⋅
+
−
⋅
=
s
x
ri
2
)
4
(
Koeff.