146707525 autoform incremental

iletisim: [email protected]

ALGHAFORM PAYLASIMIDIR

www.forum.alghaform.com

iletisim: [email protected]

12222 AutoFormIncrementalAutoFormIncrementalAutoFormIncrementalAutoFormIncremental

AutoFormIncremental is the AutoForm module to simulate sheet metal forming processes (conventional deep drawing, hydrome-chanical deep drawing) using the finite element method in many small steps. Using AutoFormIncremental it is possible to simulate all forming operations beginning with the plane blank sheet and ending with the finished car body part including springback calcu-lation.

In AutoFormIncremental the simulation of the following forming processes or phenomena is possible:

Impact of gravity when putting the blank sheet on the tool Binder closure (binderwrap) Drawing with/without drawbeads or lock beads Cutting Second forming Forming operations with cam slides Forming operations with die and punch inserts Springback Preforming the blank sheet by means of a fluid Hydromechanical deep drawing

Forming operations for steel and aluminum materials used in the automotive industry as well as tailored blanks can be simulated with AutoFormIncremental. In connection with the easytouse user interface the tool maker, the tool designer and the process engi-neer can quickly verify the forming process in all tools and where required optimize processes, to lay the foundations for high qual-ity parts at the computer.

When entering the simulation input data, the user is guided by the program and pointed at still necessary inputs. The movement of all tools can be checked prior to the real simulation. In general the cal-culation time for a simulation ranges from only a some minutes up to a few hours.

Color shaded post values such as sheet thickness, cracks, strain and stress as well as process parameters such as forces are available for the evaluation of the simulation. Wrinkles are identified by inspect-

www.alghaform.com

2ing the shaded representation of the model or by means of color shaded post values. These possibilities are completed by additional special evaluation criteria such as skid/impact lines.

In connection with AutoFormOptimizer, the user gets access to a numerical optimization algorithm by which process parameters such as binder force or restraining forces for drawbeads are auto-matically modified during several simulation iterations to obtain an optimally stretched part without cracks and wrinkles.


3Contents of the Workshop AutoFormIncrementalContents of the Workshop AutoFormIncrementalContents of the Workshop AutoFormIncrementalContents of the Workshop AutoFormIncremental

Lesson 1Lesson 1Lesson 1Lesson 1 DeepDrawing on Double Action PressDeepDrawing on Double Action PressDeepDrawing on Double Action PressDeepDrawing on Double Action Press . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5555

CADImportIGES Binder definition Input generator Blank definition Gravity Starting the simulation Evaluation of the simulation

Lesson 2Lesson 2Lesson 2Lesson 2 DeepDrawing on Single Action PressDeepDrawing on Single Action PressDeepDrawing on Single Action PressDeepDrawing on Single Action Press. . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . .27272727

CADImportIGES Positioning of tools Positioning the blank sheet Process definition Evaluation of the simulation

Lesson 3Lesson 3Lesson 3Lesson 3 Drawbeads and Tailored BlanksDrawbeads and Tailored BlanksDrawbeads and Tailored BlanksDrawbeads and Tailored Blanks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .47474747

Input generator Material definition Weld line Drawbead

Lesson 4Lesson 4Lesson 4Lesson 4 Drawbead generatorDrawbead generatorDrawbead generatorDrawbead generator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .64646464

Automatic determination of the width Automatic determination of the restraining force (Force-

factor) of a drawbead

Lesson 5Lesson 5Lesson 5Lesson 5 Tipping and CuttingTipping and CuttingTipping and CuttingTipping and Cutting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .70707070

Determination of the drawing direction Relief cut Trimming cut Holes Cutting direction


4Lesson 6Lesson 6Lesson 6Lesson 6OptimizationOptimizationOptimizationOptimization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91919191

Numerical optimization Parameter study Optimization of the force factor of a drawbead Evaluating the optimization

Lesson 7Lesson 7Lesson 7Lesson 7Automatic Filleting with a Constant RadiusAutomatic Filleting with a Constant RadiusAutomatic Filleting with a Constant RadiusAutomatic Filleting with a Constant Radius . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 110110110110

Automatic Filleting Defining the blank sheet by arc Restart

Lesson 8Lesson 8Lesson 8Lesson 8Multiple Step process and Starting from Restart fileMultiple Step process and Starting from Restart fileMultiple Step process and Starting from Restart fileMultiple Step process and Starting from Restart file . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 120120120120

Starting from RestartFile Definition of additional tools Definition of additional process steps Filleting radii

Lesson 9Lesson 9Lesson 9Lesson 9Using CAM ToolsUsing CAM ToolsUsing CAM ToolsUsing CAM Tools . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 141141141141

Undercuts Adding tools Changing working direction Adding a process step Process type Flanging

Lesson 10Lesson 10Lesson 10Lesson 10Use of Pad and SpringbackUse of Pad and SpringbackUse of Pad and SpringbackUse of Pad and Springback. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 154154154154

Die insert (pad) Free contours, sharp edges and undercuts Definition of an additional tool Definition of additional process steps Altering tools Positioning of tools

Lesson 11Lesson 11Lesson 11Lesson 11Hydromechanical Deep DrawingHydromechanical Deep DrawingHydromechanical Deep DrawingHydromechanical Deep Drawing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 173173173173

Symmetry Forming by means of fluids Preforming Active hydromechanical deep drawing


Lesson 1: DeepDrawing on Double Action PressLesson 1: DeepDrawing on Double Action PressLesson 1: DeepDrawing on Double Action PressLesson 1: DeepDrawing on Double Action Press

5

2. 12. 12. 12. 1 Lesson 1: DeepDrawing on Double Action PressLesson 1: DeepDrawing on Double Action PressLesson 1: DeepDrawing on Double Action PressLesson 1: DeepDrawing on Double Action Press

This lesson describes the deepdrawing process on a double action press. The CAD data of the die is available.

Fig. 1.1Fig. 1.1Fig. 1.1Fig. 1.1

Deep drawing on a double action press

Generation of a Simulation fileGeneration of a Simulation fileGeneration of a Simulation fileGeneration of a Simulation fileAt the beginning, a new simulation file (*.sim) has to be defined. The first input is the name of the simulation. During the generation of the input, this simulation file is filled with data, which is neces-sary for the simulation (geometrical data, specification of process, numerical data etc.).

The generation of the simulation file is done by the following input:

File > New ... > in_lesson_01 > OK



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Fig. 1.2Fig. 1.2Fig. 1.2Fig. 1.2

Options to create a new simulation file

File name: name of *.sim file, without extension Units: Units, which are used in this simulation file. This

should correspond to units used in CAD data. Geometric error tolerance: Acceptable chordal error of

mesh generation.

Preparation of tool geometries for the simulationPreparation of tool geometries for the simulationPreparation of tool geometries for the simulationPreparation of tool geometries for the simulationNormally the first input is the geometries of the tools used in this simulation. AutoForm requires these geometries in VDAFS or IGES format only. It is recommended that the user start with the input of the geometries, because possible errors or missing data in the CAD model can be checked and corrected early.

The tool geometries are read in VDAFS or IGES format. AutoForm automatically meshes the tool surfaces. All subsequent operations are based on this mesh. Only the mesh can be visualized in Auto-Form, not the original CAD data.



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Import and meshing of CAD dataImport and meshing of CAD dataImport and meshing of CAD dataImport and meshing of CAD dataFile > Import > IGES > OK

Fig. 1.3Fig. 1.3Fig. 1.3Fig. 1.3

Select a file: in_lesson_01.igs > OK

Fig. 1.4Fig. 1.4Fig. 1.4Fig. 1.4

Window to mesh CAD data

Start meshing with the option:

Program: afmesh_3.1 > OK



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ParametersParametersParametersParameters Error tolerance: Acceptable chordal error for the meshing. Value is taken from New file dialog (Default: 0,1) (Fig 1.1), but it can be changed. For especially small radii (equal or lesser than 2 mm) 0.05 should be used as error tolerance.

Max side length: Maximum element side length

FacesFacesFacesFaces Treat only: Only specified faces will be meshed. Exclude: The specified faces are not taken into account for

meshing.

LayersLayersLayersLayers Treat only: Only specified layers will be meshed. Exclude: The specified layers are not taken into account for

meshing.



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The meshed geometry is immediately displayed and the Geometry generator automatically pops up. At first, the tool setup in the Geometry generator has to be changed, so that the die is the lower tool (right Icon in Fig. 1.5).

Fig. 1.5Fig. 1.5Fig. 1.5Fig. 1.5

In this example the CAD data is binder (binder) and punch (punch). Later the die (die) is created with Offset. The two tools have to be separated first. This is done as follows:

Select faces of binder (right mouse button or Shift right mouse button for several faces).



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Fig. 1.6Fig. 1.6Fig. 1.6Fig. 1.6

Selected faces of binder

PreparePreparePreparePrepareDefine objects: Binder

Binder is defined in Geometry generator and selected faces are put into the Binder register. The remaining unselected faces become the punch and all faces are defined as the die; hence all required tools for a standard simulation are now fully defined.

The next step is checking the geometry to see if it can be used for simulation. AutoForm can check for free edges, sharp edges or undercuts.

Control parameters can be found in Part boundary (Fig. 1.5):

Error tolerance is the acceptable chordal error of the CAD data describing the part boundary and the generated part boundary of AutoForm.

Concatenation distance is the minimum distance between points on the part boundary.



11

Use button

Generate part boundary: Apply (Fig. 1.5 bottom right)

to start automatic calculation of the part boundary (shown in blue).

Fig. 1.7Fig. 1.7Fig. 1.7Fig. 1.7

Generated part boundary

If gaps occur in the geometry, several blue lines are displayed. This is one possible way of checking for gaps and untrimmed surfaces. If the generated part boundary needs to be changed, it can be done using the option

PreparePreparePreparePrepare Outer Trim > Edit

Holes can be created with the option

Inner Trim > Add

Correction of untrimmed surfaces should be performed in CAD system. Checking for sharp edges and undercuts can also be done in Geometry generator. This is described in detail in Lessons 5 and 7.



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Check geometry for sharp edges:

FilletFilletFilletFilletGeometry generator > Fillet > Check radius: 2.00 > Check

In the logwindow, it is displayed that (no) sharp edges have been found.

Close the window using Dismiss (Fig. 1.8).

Fig. 1.8Fig. 1.8Fig. 1.8Fig. 1.8

FilletFilletFilletFillet page of Geometry generator



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Check geometry for undercuts using option:

Geometry generator > Tip (Fig. 1.9)

Fig. 1.9Fig. 1.9Fig. 1.9Fig. 1.9

TipTipTipTip page of Geometry generator

All undercuts, marginal areas and undercut free areas are calcu-lated and displayed in different color for the current drawing direc-tion when the Tip page is opened. Undercut free areas are displayed in green, marginal areas are displayed in yellow and undercuts are displayed in red. This colored display can be chosen with the option

TipTipTipTip Display > Backdrafts in the Geometry generator.



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Use the button Plot to activate the backdraft diagram (Fig. 1.9).

Generate simulation inputGenerate simulation inputGenerate simulation inputGenerate simulation inputAll further inputs are defined in the Input generator. Open the Input generator:

Model > Input generator ... > Simulation type: Incremental

Fig. 1.10Fig. 1.10Fig. 1.10Fig. 1.10

Dialog: Simulation TypeSimulation TypeSimulation TypeSimulation Type to create simulation input

Simulation type: Incremental simulation, OneStep simula-tion or Hydroforming of tubes

Tool setup: Defines the tool setup with respect to zaxis (zaxis points upward)

Sheet thickness: sheet thickness Geometry refers to: Decide which side of the tool set the

geometry refers to (punch side or die side). No offset: None of the tools automatically gets an offset. In

this case, tool offsets should be created in CAD system and different CAD geometries for punch and die should be read in.

The current file contains binder and punch geometry. Therefore, the die gets an offset (Geometry refers to: punch side).

OK opens Input generator.



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Page Title (title of simulation) has a default textstring input which can be changed. Comments is for the input of usercomments regarding the current simulation. All inputs for the simulation need to be completed before it can be executed: Inputs are missing on pages that are marked conveniently with red letters.

Fig. 1.11Fig. 1.11Fig. 1.11Fig. 1.11

Input generator

The input on pages shown in black letters are already completed. Nevertheless, all input data should be checked for meaningful val-ues for current simulation. In the following example, only pages marked with red letters are considered.

ToolsToolsToolsTools Tools are defined on Tools page. Three tools (die, punch and binder) have already been defined. The geometries of these tools have been defined in the preparation phase of tool geometries for the simulation.



16

Binder is marked in red on this page, because columns for the binder must be defined. Columns are the input points of the force for forcecontrolled tools. By default, the binder is predefined as being a forcecontrolled tool. Therefore AutoForm requires this input (see also Lessons 8 10). Columns have to be defined for every forcecontrolled tool.

Columns for binder: It is recommended to use

Tool center

BlankBlankBlankBlankOption Rectangle ... on Blank page defines a rectangular blank out-line.

TipTipTipTip: We recommend a view from positive zaxis (press CtrlCtrlCtrlCtrlZZZZ).

Fig. 1.12Fig. 1.12Fig. 1.12Fig. 1.12

BlankBlankBlankBlank page of Input generator

Outline > Rectangle ...



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Menu Blank outline - Rectangle opens:

Fig. 1.13Fig. 1.13Fig. 1.13Fig. 1.13

Blank outline - RectangleBlank outline - RectangleBlank outline - RectangleBlank outline - Rectangle

Inputs can be done by using either the right mouse button or key-board.

Use the right mouse button and sketch a rectangle to define a rect-angular blank outline. The blank outline (blue) is displayed in the main display (Fig. 1.14). In the menu Blank outline - Rectangle (Fig. 1.13) modify the values as follows:

BlankBlankBlankBlank Center x, y: 0, 0 Length X: 430 Length Y: 340

Fig. 1.14Fig. 1.14Fig. 1.14Fig. 1.14

Rectangular blank outline

Complete the definition of the blank outline by selecting

OK



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ProcessProcessProcessProcessA double action deepdrawing process is already predefined on the Process page. Double action deepdrawing process means that the binder moves until it closes with the die and then the punch moves until it is fully bottom down. The duration of the different process steps (Duration on Process page) depends on the positioning of the tools with respect each other (Move on Tools page). By default, the distances between the tools are 500 mm.

Fig. 1.15Fig. 1.15Fig. 1.15Fig. 1.15

ProcessProcessProcessProcess page of Input generator

For this example only inputs for process step named gravity are missing (Fig. 1.15):

gravity > Gravity: downwards die: Stationary



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Control Input of numerical parametersControl Input of numerical parametersControl Input of numerical parametersControl Input of numerical parametersFig. 1.16Fig. 1.16Fig. 1.16Fig. 1.16

ControlControlControlControl page of Input generator

For sheet thickness greater than 1.5 mm: select ThickSheet/Spring-back in later restart

TipTipTipTip: If button ThickSheet/SpringbackThickSheet/SpringbackThickSheet/SpringbackThickSheet/Springback in later restart is activated, thesimulation is done using 5 layers.

In addition to the preselected result variables, the following are selected:

Rslts > Contact distance aboveRslts > Contact distance belowRslts > Curvature

Start of simulationStart of simulationStart of simulationStart of simulationJob > Start simulation ... > Start job > Program: af_3.1 > Start



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Fig. 1.17Fig. 1.17Fig. 1.17Fig. 1.17

Start JobStart JobStart JobStart Job window

Only one simulation can be started with one license. Other simula-tions that are ready to start can be put into a queue (Queue). The simulation job can be put at the top or bottom of the queue.

Kinematic check only checks the tool movement only. This is com-pleted in a few seconds. This functionality helps avoid possible errors of the tool movement or tool positioning and is recognized during the simulation. If this button is activated, only the tool movements are calculated and displayed. The blank remains unde-formed.

The results are saved in the simulation file after start of the calcula-tion (Kinematic check only not activated).

File > Reopen

opens the *.sim file again, and results can be analyzed.

At each timestep of the analysis, the Input generator can be opened to review or change the input or define another simulation because the input data is also saved in the *.sim file as the results.



21

Analysis of results (colored display of result vari-Analysis of results (colored display of result vari-Analysis of results (colored display of result vari-Analysis of results (colored display of result vari-ables)ables)ables)ables)In the following the analysis of the most important result variables will be discussed. These results can be displayed both as colored and shaded images.

Reopen the simulation file (*.sim) after the calculation is completed successfully.

File > Reopen

To go to the end of the simulation use

Time > End of simulation or hotkey Ctrl E.

Moving the mouse over the icon panel on the right side of the main display shows the names of each of the icons.

Activate the display of Formability results with button Formability (shown in second row of result buttons in main display).

Fig. 1.18Fig. 1.18Fig. 1.18Fig. 1.18

Result variable FormabilityFormabilityFormabilityFormability



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Cracks: Areas of cracks. These areas are above the FLC of the specified material.

Excess. Thinning: In this area, thinning is greater than the acceptable value (default value for steel is 30%).

Risk of cracks: These areas may crack or split. By default, this area is in between the FLC and 20% below the FLC.

Safe: All areas that have no formability problems. Insuff. Stretching: Areas that have not enough strain

(default 2%) Wrinkling tendency: Areas where wrinkles might appear.

In these areas, the material has compressive stresses but no compressive strains

Wrinkles: Areas where wrinkles can be expected, depend-ing on geometry curvature, thickness and tool contact. Material in these areas has compressive strains which means the material becomes thicker during the forming process.

In this example, wrinkles can be expected in the center of the part geometry and in the binder area. The part does not show any cracks or excessive thinning.

The defaultvalues of result variable Formability can be changed in the following menu:

Results > Formability

Fig. 1.19Fig. 1.19Fig. 1.19Fig. 1.19

Dialog: FormabilityFormabilityFormabilityFormability

The small plot shows the different areas with respect to the FLC.



23

Switch to result variable Thinning (second row of icon panel in main display, middle button). A scale is displayed in the lower part of the main display with a range of 30% thinning to 3% thickening colored from yellow to green (depending on the specified color set-tings). The exact thinning value (in percentage) is displayed, when you click with the right mouse button on the geometry. Hit the Esc key to clear these labels from the display. To find the maximum thinning and the maximum thickening of the part use the following options (Fig. 1.20)

Results > Show maxResults > Show min

Fig. 1.20Fig. 1.20Fig. 1.20Fig. 1.20

Display of result variable ThinningThinningThinningThinning with min and max values

To change the displayed range of the scale use the following option (Fig. 1.21)

Result > Ranges



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Fig. 1.21Fig. 1.21Fig. 1.21Fig. 1.21

Dialog: AutoForm - Min/Max EditorAutoForm - Min/Max EditorAutoForm - Min/Max EditorAutoForm - Min/Max Editor

Min/Max Simulation: Use min and max values of the whole simulation.

Min/Max Increment: Use min and max values of the cur-rent increment.

Simulation default: Use default min and max values. Manual: Use userdefined min and max values.

Change the values for the scale manually:

Manual: Min. 0.0 Max. 0.05

The display should correspond to Fig. 1.22. All areas without thick-ening are displayed in yellow.



25

Fig. 1.22Fig. 1.22Fig. 1.22Fig. 1.22

Display of result value ThinningThinningThinningThinning with min value 0.0 0.0 0.0 0.0 and max value 0.050.050.050.05

Switch to result variable Failure (maximum) (first row of icon panel in main display, middle button). Deactivate the display of the min value with following option (Fig. 1.23)

Results > Show min



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Fig. 1.23Fig. 1.23Fig. 1.23Fig. 1.23

Display of result value Failure (maximum) Failure (maximum) Failure (maximum) Failure (maximum) with max value

No values > 0.8 are shown for this example. This means that no cracks can be expected for the deep drawing of this part.

Close AutoFormUser InterfaceClose AutoFormUser InterfaceClose AutoFormUser InterfaceClose AutoFormUser InterfaceThe user interface can be closed with following option:

File > Quit or hotkey Ctrl Q.


Lesson 2: DeepDrawing on Single Action PressLesson 2: DeepDrawing on Single Action PressLesson 2: DeepDrawing on Single Action PressLesson 2: DeepDrawing on Single Action Press

27

2. 22. 22. 22. 2 Lesson 2: DeepDrawing on Single Action PressLesson 2: DeepDrawing on Single Action PressLesson 2: DeepDrawing on Single Action PressLesson 2: DeepDrawing on Single Action Press

In a single action press, the die is mounted to the ram of the press. Punch and binder are mounted on the press table. The blank lies on the binder. Sometimes the punch supports the blank, to avoid bending of the blank due to gravity. During the forming process the ram moves down and at first the die closes with the binder and the blank is fixed between these tools. The die then displaces with the binder during the ongoing movement of the ram and the part is formed over the fixed punch. The position of the tools is shown in Fig. 2.1.

Fig. 2.1Fig. 2.1Fig. 2.1Fig. 2.1

Tools in a single action press

The tool setup is the opposite of setup for deep drawing on double action presses (see Lesson 1).

For an AutoForm simulation a double action deep drawing process is predefined by default. This can be changed to a single action pro-cess. One has to adjust

Tool positioning (Tools page of Input generator) Initial position of blank (Blank page of Input generator)

and Process steps (Process page of Input generator)



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Keep in mind that for a single action process, tool geometry is always taken from CAD. In nearly all cases only one side of the tool exists and the other side is generated in AutoForm with Offset option. This means that the initial position of the tools is the same. At first the tools are opened (Tools page) and during the forming process they are closed (Process page).

For a double action process the distance at which the tools are opened does not matter because in AutoForm the tools always move in a single increment until initial sheet contact is made. Subse-quently, the incremental displacements are used only during the forming of the sheet. Using a double action process, the tools move until contact with the sheet is made without any movement of the sheet itself. The initial positioning of the tools has to be such that there is no penetration between the tools and blank.

In a single action process the positioning of the tools is very impor-tant. The distance of binder and punch has to reflect the real dis-tance in the press. The distance between binder and die does not influence the simulation. The reason is that the blank lies on the binder and the die moves initially until it comes into contact with the sheet. During drawing, the die displaces both binder and sheet and due to this movement of the sheet, AutoForm uses the incre-mental displacement. If the distance between binder and punch is too large, it can lead to long calculation time and unrealistic results.

Therefore it is important that the tool positioning for a single action process in AutoForm simulations should be the same as in the real press.

Preparation of simulationPreparation of simulationPreparation of simulationPreparation of simulationOpen a new simulation file:


Geometry generator opens.

File > Import ... > IGES > OK > in_lesson_02.igs > OK > Program: afmesh_3.1 > OK

Prepare > Select faces of binder (right mouse button) (Fig. 2.2).



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Fig. 2.2Fig. 2.2Fig. 2.2Fig. 2.2

Geometry with selected binder patches

Prepare > Define objects: Binder

Now the selected patches are defined as binder, unselected patches are defined as punch and all patches are defined as die.

Check geometry for gaps:

Geometry generator > Generate part boundary: Apply


Geometry generator > Fillet > Check radius: 2.00 > Check

A message that (no) sharp edges have been found appears in the logwindow. Close this logwindow with Dismiss.

Check geometry for undercuts:

Geometry generator > Tip

All undercuts, marginal areas and undercut free areas are calcu-lated and color displayed for the current drawing direction when Tip page is opened (see Lesson 1 for a detailed description of Tip-ping options). Undercut free areas are displayed in green, marginal areas are displayed in yellow and undercuts are displayed in red. This colored display can be switched on or off with the option

Display > Backdrafts in the Geometry generator.www.forum.alghaform.com


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Use button Plot to activate the backdraft diagram (see Lesson 1 for more details).

Generate simulation inputGenerate simulation inputGenerate simulation inputGenerate simulation inputModel > Input generator ... > Simulation type: Incremental > OK

Title is predefined but it can be changed.

Columns for binder has to be defined on Tools page. It is recom-mended to use:

Tool center

BlankBlankBlankBlankOption Rectangle ... on Blank page defines a rectangular blank out-line. Inputs can be made by either using the right mouse button or keyboard. Use the right mouse button and drag a rectangle to define a rectangular blank outline. The blank outline (blue) is dis-played in the main display (Fig. 2.3). In menu Blank outline Rect-angle modify the values as follows:

Center x, y: 0, 0 Length X: 430 Length Y: 340

Fig. 2.3Fig. 2.3Fig. 2.3Fig. 2.3

Rectangular blank outline

Finish the definition of the blank outline with

OK



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Adjust input for a single action processAdjust input for a single action processAdjust input for a single action processAdjust input for a single action processAll changes are done in Input generator.

Modification of tool position (Tools page)Modification of tool position (Tools page)Modification of tool position (Tools page)Modification of tool position (Tools page)The tool position has to be changed for a single action process. The punch is fixed on the press table. Therefore it is recommended to use punch position as reference.

punch > Working direction > Move: 0 (Fig. 2.4).

Fig. 2.4Fig. 2.4Fig. 2.4Fig. 2.4

Position punchpunchpunchpunch

Binder should be moved by 65 mm in working direction (Fig. 2.5). It is positioned slightly above the punch to avoid excessive bending of the sheet due to gravity. In AutoForm, the working direction is always defined with respect to the blank. It is calculated automati-cally, if the tool setup is correctly defined on the Prepare page of Geometry generator.



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Fig. 2.5Fig. 2.5Fig. 2.5Fig. 2.5

Position binderbinderbinderbinder

Any position of the die can be chosen but it is important that the die and the sheet do not intersect. In this example, the position of the die is chosen as being 565 mm opposite to working direction.

die > Working direction > Move: -565 (Fig. 2.6).

This value is used to allow 500 mm for the closing of the die and binder + 65 mm for forming.



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Fig. 2.6Fig. 2.6Fig. 2.6Fig. 2.6

Position diediediedie

These adjustments lead to following initial tool position (Fig. 2.7):



34

Fig. 2.7Fig. 2.7Fig. 2.7Fig. 2.7

Initial position of tools

Modification of initial position of blank (Blank page)Modification of initial position of blank (Blank page)Modification of initial position of blank (Blank page)Modification of initial position of blank (Blank page)The initial blank position can be modified on Blank page. For a double action process, the blank is positioned on the die. This is the AutoForm default. For a single action process, the blank has to be positioned on the binder.

Input generator > Blank > Position > On: binder (Fig. 2.8)



35

Fig. 2.8Fig. 2.8Fig. 2.8Fig. 2.8

BlankBlankBlankBlank page: Blank is positioned on binder.

Use material Zste180bhZ_1 from the database with thickness 1.0 mm:

Input generator > Blank > Properties > Thickness > 1.0

Warning: Tool offset adapted due to new average blank thickness. Select OK.

Input generator > Blank > Properties > Import ... > Steel_General+Europe > zste180bhZ_1.mat > OK

LubeLubeLubeLube Here the friction coefficient between sheet and tools can be speci-fied. By default (Standard), a single value of the friction coefficient is used for all sheet/tool contacts. It is recommended to use 0.15 for sheetsteel and 0.18 for aluminum. Different friction coefficients can be specified for tools above and below the sheet or for each of the sheet/tool contacts (Fig. 2.9).



36

Fig. 2.9Fig. 2.9Fig. 2.9Fig. 2.9

LubeLubeLubeLube page: Definition of friction coefficient Standard 0.15Standard 0.15Standard 0.15Standard 0.15

Modification of process steps (Process page)Modification of process steps (Process page)Modification of process steps (Process page)Modification of process steps (Process page)Two modifications have to be made on Process page:

tool movements and duration of process steps.

GravityGravityGravityGravitygravity > Gravity: Downwards > Tool control > Show all >die: Non-active > punch: Stationary > binder: Stationary (Fig. 2.10)



37

Fig. 2.10Fig. 2.10Fig. 2.10Fig. 2.10

Input page for gravitygravitygravitygravity

Binder WrapBinder WrapBinder WrapBinder Wrap During binder wrap, the die is moving towards the binder and the binder and the punch are stationary.

closing > Tool control > Show all > die: Displcmnt > Velocity: 1 > Set punch: Stationary > binder: Stationary

Duration of a process step depends on the distance of the contacting tools (see Tools page). In this example, the distance between the die and the binder (500 mm) determines the duration:

Duration > During time > Time: 500 (Fig. 2.11)



38

Fig. 2.11Fig. 2.11Fig. 2.11Fig. 2.11

Input for binder wrap (closingclosingclosingclosing)

DrawingDrawingDrawingDrawingDuring the drawing process, the die is moving towards the punch, the binder is forcecontrolled and it is displaced by the die. The punch is stationary.

drawing > die > Displcmnt > Velocity: 1 > Set > punch: Stationarybinder > Force > Relative tool: die > Const pressure > Value: 3 > Set

Duration of this process step depends on distance between punch and binder (65 mm):




39

Fig. 2.12Fig. 2.12Fig. 2.12Fig. 2.12

Input for drawing process step

Job > Start

Tool movement can be checked with option Kinematic check.

If the punch should support the blank during gravity, the binder position must be changed on the Tools page and duration of the drawing process step (drawing) must be changed on the Process page.

Start the SimulationStart the SimulationStart the SimulationStart the Simulation

Job > Start simulation ...

Analysis of the simulation results (part2 punch Analysis of the simulation results (part2 punch Analysis of the simulation results (part2 punch Analysis of the simulation results (part2 punch contact, wrinkles, skid lines, sections, FLD, tool contact, wrinkles, skid lines, sections, FLD, tool contact, wrinkles, skid lines, sections, FLD, tool contact, wrinkles, skid lines, sections, FLD, tool forces)forces)forces)forces)When the calculation is finished, reopen the simulation file (*.sim) with



40

File > Reopen

Punch contactPunch contactPunch contactPunch contactIn order to ensure that deep drawn parts have a high level of quality after deformation, it is important for them to have uniform initial punch contact, especially for outer panels. This can be checked as follows:

Display > Fill styles > Tools: Filled mesh > Sheet: Filled

Activate display of the punch: click the button punch in the user interface (right side, below the buttons for sheet, blank and geome-try). Set time to the end of binder wrap (closing).

Time > closing

Modify the display by clicking with the left mouse button in the scale area right of the slider and then click the right mouse button twice (Time 512).

The punch is visible through the sheet and initial punch contact can be analyzed.

Fig. 2.13Fig. 2.13Fig. 2.13Fig. 2.13



41

WrinklesWrinklesWrinklesWrinklesIt is necessary to visualize the sheet in shaded mode and to display all increments (animation) to analyze wrinkling during drawing process. Some increments have to be analyzed in detail if wrinkles occur. Deactivate the display of the punch (select the punch button in the main display again). Start the animation of the drawing pro-cess:

Time > Animate start or use hotkey Ctrl A

If a single increment needs to be analyzed in detail, stop the anima-tion using Ctrl A.

You can also use menu option

Time > Times

and then select one of the available increments in the Time menu. A surface deviation can be seen in Fig. 2.14.

Fig. 2.14Fig. 2.14Fig. 2.14Fig. 2.14

Surface deviation of 10 mm before bottom down



42

SkidlinesSkidlinesSkidlinesSkidlinesSkidlines occur, if the sheet is drawn over small radii of the tool with a certain contact pressure at a certain contact angle. Areas where skidlines occur are normally in drawing radius regions.

Skidlines can be visualized with the following option:

Results > Tool marks

In menu AutoForm - Toolmarks

File > Read from File > in_lesson_02_toolmark.af > OKTools > Project onto > die > AcceptDefine > Skid/Impact lineFile > Dismiss

Use menu option

Time > Simulation end or hotkey Ctrl E

to go to simulation end. Skidlines are now displayed as blue lines and the movement and position of these lines can be analyzed (Fig. 2.15).

Fig. 2.15Fig. 2.15Fig. 2.15Fig. 2.15

Visualization of skid lines at simulation end

The display can be deactivated with following option:

Results > Skid/Impact line > Select line with left mouse button > Display > Clear all > File > Dismiss

SectionsSectionsSectionsSectionsSometimes it is necessary to analyze the sheet/tool contact with dynamic sections. Activate display of all tools



43

Display > Tools > Show all

Use hotkey Ctrl D to open Dynamic section menu.

Define a section plane (Fig. 2.16)

A x y: -200, 0 B x y: 200, 0

and select option Section in Dynamic section menu:

Option Section displays the selected section plane as a 2Dcurve

Option Clipping displays 3D geometry with the selected section plane as a clipping plane.

Fig. 2.16Fig. 2.16Fig. 2.16Fig. 2.16

Dynamic sectionDynamic sectionDynamic sectionDynamic section menu with defined section plane and activated option SectionSectionSectionSection

Press the button Apply in the Dynamic section menu. The 2D sec-tion is displayed in the main display (Fig. 2.17).

Fig. 2.17Fig. 2.17Fig. 2.17Fig. 2.17

Dynamic sectionDynamic sectionDynamic sectionDynamic section with option SectionSectionSectionSection displayed in the main display



44

Deactivate Dynamic section with the option:

Dismiss

Deactivate the display of all tools:

Display > Tools > Clear all

Forming Limit Diagram (FLD)Forming Limit Diagram (FLD)Forming Limit Diagram (FLD)Forming Limit Diagram (FLD)The Forming Limit Diagram (FLD) is a method to predict material failures. The Forming Limit Curve (FLC) (measured strains above which cracks occur) is displayed in black in the FLD. Major/minor strains of all finite elements are shown in this diagram. Cracks and process stability can now be analyzed. This diagram is activated with the option:

Results > FLD then

Time > Simulation end or hotkey Ctrl E to go to the simulation end.

Strains of all elements are displayed in the FLC diagram by select-ing the Show all button (top right see Fig. 2.18). In this example all elements are far away from the FLC, which means that no cracks or splits are predicted and the process is quite stable.



45

Fig. 2.18Fig. 2.18Fig. 2.18Fig. 2.18

Forming Limit Diagram with all elements displayed at the simulation end

Deactivate the diagram with

Dismiss

ForcesForcesForcesForcesTool forces are of great interest for the forming simulation analysis. In this example, the display of the punch force over punch stroke is described.

Keep in mind that the calculated force is only a rough estimation of the actual force, because friction forces of the press and coining effects are not taken into account. As a rule of thumb, the calculated forces should be multiplied with a factor of 2 to 2.5 for the actual force.

Activate AutoForm - Process data menu with option:



46

Results > Process data

Deactivate forces for the die and binder:

Calculated reaction forces > dieCalculated reaction forces > binder

A calculated punch force of about 300000 N is necessary at bottom down (Fig. 2.19) to form the part. This would mean in reality a punch force of about 75 tons.

Fig. 2.19Fig. 2.19Fig. 2.19Fig. 2.19

Calculated punch force over process time

Deactivate the menu with

Dismiss

Close AutoFormUser InterfaceClose AutoFormUser InterfaceClose AutoFormUser InterfaceClose AutoFormUser InterfaceThe user interface can be closed with following option:

File > Quit or hotkey Ctrl Q.


Lesson 3: Drawbeads and Tailored BlanksLesson 3: Drawbeads and Tailored BlanksLesson 3: Drawbeads and Tailored BlanksLesson 3: Drawbeads and Tailored Blanks

47

2. 32. 32. 32. 3 Lesson 3: Drawbeads and Tailored BlanksLesson 3: Drawbeads and Tailored BlanksLesson 3: Drawbeads and Tailored BlanksLesson 3: Drawbeads and Tailored Blanks

This lesson mainly covers drawbeads and tailorwelded blanks. In AutoForm you can define any number of drawbeads or weld lines.

Fig. 3.1Fig. 3.1Fig. 3.1Fig. 3.1

Drawbeads (red lines) and weld lines (blue lines)

Tailored BlanksTailored BlanksTailored BlanksTailored BlanksIn AutoForm you can define any number of weld lines. This defini-tion is done in the Input generator. Weld lines can have the follow-ing shapes:

Simple joint (weld line from one blank boundary to another blank boundary) (Weld line 1 in Fig. 3.1)

Tjoint (weld line from weld line to blank boundary) (Weld line 2 in Fig. 3.1) and

Patch (closed weld line, patch is welded into a blank) (Weld line 3 in Fig. 3.1)

A new simulation is created for this lesson, similar to Lesson 1.

Generation of a Simulation fileGeneration of a Simulation fileGeneration of a Simulation fileGeneration of a Simulation fileThe generation of the simulation file is done with the following input:




48

Preparation of tool geometries for the simulationPreparation of tool geometries for the simulationPreparation of tool geometries for the simulationPreparation of tool geometries for the simulationReading and meshing CAD model:

File > Import ... > VDAFS > OK > in_lesson_03.vda > OK > Program: afmesh_3.1 > OK

The meshed geometry is immediately displayed and the Geometry generator automatically pops up. At first the tool setup in the Geometry generator has to be changed, so that the die is the lower tool (right icon in Fig. 3.2).

Fig. 3.2Fig. 3.2Fig. 3.2Fig. 3.2

PreparePreparePreparePrepare page of the Geometry generator



49

Now the binder has to be defined in order to separate the geometry into punch, die and binder.

Select faces of binder (right mouse button or Shift + right mouse button for several faces).

Fig. 3.3Fig. 3.3Fig. 3.3Fig. 3.3

Selected faces of binder

Prepare > Define objects: Binder

All tools are now defined (see Lesson 1 for details). Now the blank boundary has to be generated. Use the button

Generate part boundary: Apply (right bottom in Fig. 3.2)

to start automatic generation of part boundary. Part boundary is displayed in blue (Fig. 3.4).



50

Fig. 3.4Fig. 3.4Fig. 3.4Fig. 3.4

Generated part boundary


Geometry generator > Fillet > Check radius: 2.00 > Check

In the logwindow it is displayed that (no) sharp edges have been found. Close this window using Dismiss.

Check geometry for undercuts using option:

Geometry generator > Tip

All undercuts, marginal areas and undercut free areas are calcu-lated and displayed in different color for the current drawing direc-tion when the Tip page is opened (see Lesson 1 for more details on using the Tip function). Undercut free areas are displayed in green, marginal areas are displayed in yellow and undercuts are displayed in red. This colored display can be chosen with the option

Display > Backdrafts in the Geometry generator.

Use the button Plot to activate the backdraft diagram.

Generate simulation input Generate simulation input Generate simulation input Generate simulation input All further inputs are defined in the Input generator. Open the Input generator:

Model > Input generator ... > Simulation type: Incremental > OK

ToolsToolsToolsToolsBinder is marked in red on this page, because columns must be defined.



51

Columns for binder: It is recommended to use

Tool center

BlankBlankBlankBlank Outline > Copy from... > Select curve (Fig. 3.5) > Bndry (Pre) 1 > OK

This option on Blank page creates a blank outline which is identical to the part boundary (Fig. 3.4).

Fig. 3.5Fig. 3.5Fig. 3.5Fig. 3.5

The menu Select curve shows all generated lines here the part boundary should be selected to generate a blank boundary that is identical to the part boundary.

Edit the blank boundary now:

Outline > Edit ... > Curve editor (Fig. 3.6) > Global mod > Convex > move slider to max. value (right side) > Expand: 40 > OK

Fig. 3.6Fig. 3.6Fig. 3.6Fig. 3.6

Settings on Global modGlobal modGlobal modGlobal mod in Curve editorCurve editorCurve editorCurve editormenu

Definition of a Definition of a Definition of a Definition of a weld lineweld lineweld lineweld line

On the Blank page, several modifications have to be made to define a tailorwelded blank. Weld lines are always added in lower section of the Blank page (Fig. 3.7).



52

Fig. 3.7Fig. 3.7Fig. 3.7Fig. 3.7

BlankBlankBlankBlank page: Add weld ...Add weld ...Add weld ...Add weld ...

Weld menu opens, for which inputs have to be completed.

Fig. 3.8Fig. 3.8Fig. 3.8Fig. 3.8

WeldWeldWeldWeld menu



53

Options for generating a tailorweld blank:

Weld line: Position and orientation of the weldline is defined here.

Properties: These are the properties of one part of blank, which can be changed in comparison to the basic or refer-ence blank (At least one of these properties has to be changed.).

Thickness: Thickness of the blank Material: Material of the blank Angle: Rolling direction Properties apply at: A right mouse button click on one of

the blank regions, which are joined with the weld line, defines the region for which the new properties (i.e., thick-ness, material and angle) are valid.

Weld line > Input > Curve editor > Define weld line with right mouse button (the start and end points lie on the blank boundary) > OK

Weld line is accepted (Fig. 3.1 Weld line 1).

A weld line joins two different parts of a blank. Properties of one part of blank are already defined on Blank page. Properties for the other part of the blank have to be defined on the Weld page. In this example the thickness of the two halves is different (0.8 mm and 1 mm):

Properties > Thickness: 1 (Fig. 3.9)

Fig. 3.9Fig. 3.9Fig. 3.9Fig. 3.9

Definition of new thickness



54

Click > A right mouse button clicks on the blank region, for which the new properties are valid (right part) > OK

After pressing OK button, a dialog (Fig. 3.10) asks if the automatic tool offset should be calculated based on the average thickness.

Fig. 3.10Fig. 3.10Fig. 3.10Fig. 3.10

Dialog to adjust automatically offset to average thickness

OK (on Tools page the offset is 0.9 =(0.8+1.0)/ 2) (Fig. 3.11).

Fig. 3.11Fig. 3.11Fig. 3.11Fig. 3.11

ToolsToolsToolsTools page new offset is automatically used

Definition of a TDefinition of a TDefinition of a TDefinition of a TJointJointJointJoint

To define a second weld line, select the Add weld ... button on the Blank page again (Fig. 3.7). The Weldmenu appears again. Now the properties of the second weld line have to be completed.

Add weld ... on Blank page

Weld line > Input > Define weld line using right mouse button (start point lies on the first weld line and the end point lies on the blank boundary) (Fig. 3.1 Weld line 2) > OK

Properties > Thickness: 2 (Fig. 3.12)

Click > A right mouse button click on the blank region, for which the new properties are valid > OK



55

Fig. 3.12Fig. 3.12Fig. 3.12Fig. 3.12

New thickness will be defined

Again the dialog appears which asks if the automatic offset should be calculated as the mathematical average of the three thickness val-ues (see Fig. 3.10)

OK on Tools page the offset is 1.2667 ((0.8 + 1 + 2) / 3)

Definition of a Definition of a Definition of a Definition of a closed weld line closed weld line closed weld line closed weld line (patchwork)(patchwork)(patchwork)(patchwork)

Menu to add a weld line

Add weld ... on the Blank page

Weld line > Input > Define a closed weld line using the right mouse button (Fig. 3.1 Weld line 3)

Properties > Material > Import ... > zste180bhZ_1.mat > OK (Fig. 3.13)

Click > A right mouse button click on the blank region, for which the new properties are valid (new material) > OK



56

Fig. 3.13Fig. 3.13Fig. 3.13Fig. 3.13

The new material will be defined

Using this procedure, any number of weld lines can be defined for a simulation. After launching the simulation, AutoForm will create the blank and the properties of the defined areas can be examined. This examination is not possible prior the launch of the simulation since (before the simulation) only the boundaries are defined and the blank does not exist yet.

DrawbeadDrawbeadDrawbeadDrawbeadIn AutoForm a drawbead is defined using only a bead centerline and not with the real beadprofile geometry. This line specifies the position of the drawbead. Furthermore a restraining force is speci-fied which depends on the real profile geometry.

It is also possible to use the geometry of the drawbead, but that is not recommended. Advantages of the drawbead model are:

Simulation time is shorter, because the drawbead geome-try with its small radii does not need to be geometrically formed by the mesh (hence fewer elements are necessary).

Changes or optimization of the drawbead position or drawbead force can be achieved easily and quickly within AutoForm directly. In contrast, changes to the real profile geometry of the drawbead have to be made in a CAD sys-tem which takes much more time and effort.



57

Fig. 3.14Fig. 3.14Fig. 3.14Fig. 3.14

AutoForm now offers a Drawbead generator for the correlation of the real profile geometry of drawbeads and drawbead force. With the Drawbead generator the real geometry of the drawbead can be specified and the force factor is automatically calculated by Auto-Form. If the force factor is known, the Drawbead generator will determine the real geometry of the drawbead. Use of the Drawbead generator is described in Lesson 4.

To define a draw bead an additional page has to be added to the Input generator.

Add > Drawbead ... (Fig. 3.14) > Add drawbead > OK

A new page is added to Input generator (Fig. 3.15).

Fig. 3.15Fig. 3.15Fig. 3.15Fig. 3.15

Drawbead page (DrwbdsDrwbdsDrwbdsDrwbds)



58

Functions for generating a drawbead:

Name: Name of a drawbead can be specified. Tools: Tools are defined; drawbead is active when these

tools are closed. Input ...: Position of drawbead line can be specified (Curve

editor). Import ...: Drawbead line is imported from CAD. Copy from ...: Drawbead line is copied from an existing

line. Base line and drawbead line are treated as different lines.

Dependent ...: Drawbead line is created from an existing line. Drawbead line is a reference to the base line. This means only the base line can be changed and the depen-dent drawbead line will also change correspondingly.

Position: Displacement of drawbead line in xy plane Width: Width of a drawbead Forcefactor: Force factor of a drawbead

Drwbds > Name: bead1 > Above: binder > Below: die

Drawbead line > Input ... > Define drawbead line using the right mouse button (Fig. 3.1 bead 1) (For symmetrical parts drawbead lines should intersect the symmetry line) > OK

Width: 15 Forcefactor: Medium: 0.35

An additional page has to be opened on the Drwbds page to add a second drawbead. This can be done in the Input generator with the menu option:

Add > Drawbead ... > Add drawbead > OK

or on Drwbds page using button

Add Drawbead ... (Fig. 3.15 left lower corner) > OK

A dialog asks if the new drawbead should be generated with parameters of an existing drawbead. Fig. 3.16 shows that parame-ters of bead1 are used. Only the drawbead line has to be specified for bead 2. All other input parameters are automatically taken from bead 1 (Fig. 3.17).



59

Fig. 3.16Fig. 3.16Fig. 3.16Fig. 3.16

Dialog asking for reference beads

Fig. 3.17Fig. 3.17Fig. 3.17Fig. 3.17

Only the line needs to be defined for the second bead

The position and length of the second drawbead line will be defined using existing part boundary (Bndry (Pre)1).

Drawbead line > Copy from ... > Select curve > Bndry (Pre) 1 (Fig. 3.18) > OK


60

Fig. 3.18Fig. 3.18Fig. 3.18Fig. 3.18

Select curveSelect curveSelect curveSelect curvemenu

The second drawbead line is modified:

Drawbead line > Edit ... > Curve editor > Global mod > Expand: 20 > Trim (Fig. 3.20) (Length of a drawbead will be defined. Start point is defined using the right mouse button (Fig. 3.21) and end point is defined using Shift right mouse button (Fig. 3.22)) > OK

Fig. 3.19Fig. 3.19Fig. 3.19Fig. 3.19

Drawbead line is expanded on the Global modGlobal modGlobal modGlobal modpage in Curve Curve Curve Curve editormenu.

Fig. 3.20Fig. 3.20Fig. 3.20Fig. 3.20

TrimTrimTrimTrim page in Curve editorCurve editorCurve editorCurve editormenu



61

Fig. 3.21Fig. 3.21Fig. 3.21Fig. 3.21

Start point of a drawbead line

Fig. 3.22Fig. 3.22Fig. 3.22Fig. 3.22

End point of a drawbead line

ProcessProcessProcessProcess Only inputs for process step gravity are missing on Process page (Fig. 3.23):

Process > gravity > Gravity: Downwards

Tool control > die: Stationary



62

Fig. 3.23Fig. 3.23Fig. 3.23Fig. 3.23

Definition of process step gravitygravitygravitygravity

Control Input of numerical ParameterControl Input of numerical ParameterControl Input of numerical ParameterControl Input of numerical ParameterWriteRestart > off (Fig. 3.24)

WriteRestart ON means that a restart file (*.rst) is created. This file contains all data that is necessary to restart the simulation from a particular time.

Restarts can be used to save time, e.g. for multi stage processes, the different forming processes can be simulated one after the other. The disadvantage is the size of the *.rst file which requires greater disk space.

Taking into account the speed of AutoForm, the restart option is only useful for large parts (e.g. side panel, floor panel). In Lesson 8 (Multiple Step process and Starting from Restart File), this option is described in complete detail.



63

Fig. 3.24Fig. 3.24Fig. 3.24Fig. 3.24

ControlControlControlControl page of Input generator WriteRestartWriteRestartWriteRestartWriteRestart disabled

Following results variables are switched off on Rslts page:

Rslts > Contact distance aboveRslts > Contact distance belowRslts > Curvature

Start of simulationStart of simulationStart of simulationStart of simulationJob > Start simulation ... > Start job > Program: af_3.1 > Start

File > Reopen


Lesson 4: Drawbead generatorLesson 4: Drawbead generatorLesson 4: Drawbead generatorLesson 4: Drawbead generator

64

2. 42. 42. 42. 4 Lesson 4: Drawbead generatorLesson 4: Drawbead generatorLesson 4: Drawbead generatorLesson 4: Drawbead generator

This lesson describes in detail how the width, the force factor and the restraining forces of a drawbead are determined automatically. The values are determined in the Draw-bead generator and have to be input manually in the Input generator.

Drawbead generator calculates the values Width and Forcefactor for a defined drawbead. These are dependent on

geometry of the drawbead, sheet thickness, friction, forming velocity and material

These two values have to be specified manually in the Input genera-tor (Drawbead page > Width and Forcefactor).

WarningWarningWarningWarning: The function is currently a BetaVersion. This is mainly dueto insufficient comparisons between the results of Drawbead gen-erator and actual stampings at present.

First a simulation file has to be created to use the Drawbead genera-tor, as was done in previous lessons.

Open example simulation file in_lesson_04.sim:

File > Open ... > Select a file > in_lesson_04.sim > OK

The drawbead generator is opened with

Model > Drawbead generator ...


65

Fig. 4.1Fig. 4.1Fig. 4.1Fig. 4.1

Drawbead generator

First the name of the drawbead is necessary (Name:). This name has to be the same as the drawbead defined in the Input generator.

Then the type of drawbead has to be specified. The Drawbead gen-erator offers three options: drawbead, lock bead and lock step.

The drawbead type is specified with the buttons shown in Fig. 4.2.

Fig. 4.2Fig. 4.2Fig. 4.2Fig. 4.2

Menu for selecting drawbead, lock bead or lock step



66

Different geometrical parameters are necessary for the different drawbead types.

Drawbead geometry (Shape)Drawbead geometry (Shape)Drawbead geometry (Shape)Drawbead geometry (Shape)DrawbeadDrawbeadDrawbeadDrawbeadA drawbead is defined with the following parameters (Fig. 4.3):

Radius R: Draw in radius Height h: Height of drawbead Radius r: Radius of drawbead Clearance c: Clearance

These parameters can be changed graphically by moving the dashed lines (Fig. 4.3) or directly with the input fields for the parameters.

The dashed lines can be moved with the left or right mouse button. Use the middle mouse button to zoom in and out. Click once with the middle mouse button to fit to window.

Fig. 4.3 Fig. 4.3 Fig. 4.3 Fig. 4.3

Parameters to describe a drawbead

Lock beadLock beadLock beadLock beadA lock bead is defined with the following parameters (Fig. 4.4):

Radius R: Draw in radius Height h: Height of lock bead Radius r: Radii of lock bead Clearance c: Clearance Width b: Width of lock bead



67

The parameters can be changed graphically by moving the dashed lines (Fig. 4.4) or directly with the input fields for the parameters.

Fig. 4.4Fig. 4.4Fig. 4.4Fig. 4.4

Parameters to describe a lock bead

Lock StepLock StepLock StepLock StepA lock step is defined with the following parameters (Fig. 4.5):

Radius R: Draw in radius Height h: Height of lock step Radius r: Radius of lock step Clearance c: Clearance

Fig. 4.5 Fig. 4.5 Fig. 4.5 Fig. 4.5

Parameters to describe a lock step

The parameters can be changed graphically by moving the dashed lines (Fig. 4.5) or directly with the input fields for the parameters.



68

ForcesForcesForcesForcesThe middle part of the Drawbead generator window shows results of the calculation of restraining forces and hold down force (Fig. 4.6) and the diagram allows the user to determine the profile geom-etry of the bead for a given restraining force.

Fig. 4.6 Fig. 4.6 Fig. 4.6 Fig. 4.6

Forces

Under the Result option, the user can decide whether the Force fac-tor (forces with respect to yield stress and thickness) or the Line force (forces in N/mm for a 1 mm line) is to be calculated. These cal-culated forces (Restraining force and Hold down force) are shown below.

The drawbead graphics window shows calculated forces based on the specified geometric parameters (R, h, r, c and B). The vertical line can be moved (with right or left mouse button) and the calcu-lated forces are updated immediately. Depending on the specified geometric parameter, (e.g. r) the geometry of the drawbead profile also changes. With this option the user can find the geometry profile of the drawbead for a given force (e.g. a result of an optimization run).

Parameters for processParameters for processParameters for processParameters for processIn the lower part of the Drawbead generator, parameters for the process can be specified which influence the calculated forces (Fig. 4.7).



69

Necessary inputs are for

Sheet Thickness Friction Forming Velocity Material One drawbead or outer drawbead (single) or inner draw-

beads (double)

Fig. 4.7 Fig. 4.7 Fig. 4.7 Fig. 4.7

Inputs for process parameters

If double drawbead are used, the button named double is used to specify the inner drawbead of these two. The outer drawbead can be specified by selecting outer DB:.

If one of the process inputs in the Drawbead generator window is changed, the forces are recalculated.

More drawbeads can be created with the Add button while the Delete button (Fig. 4.1) removes existing drawbead geometries.

Working with Drawbead generatorWorking with Drawbead generatorWorking with Drawbead generatorWorking with Drawbead generatorThe following parameters from Drawbead generator have to be used Drwbds page of the Input generator:

Since the Drawbead generator is currently a BetaVersion, the cal-culated values for Width and Restraining have to be input manu-ally in the Input generator. This will be done automatically in the next version.

Drawbead generatorDrawbead generatorDrawbead generatorDrawbead generator Input generatorInput generatorInput generatorInput generator

Shape Width w Width

Forces Restraining, if Force fac-tor button is active

Forcefactor


Lesson 5: Tipping and CuttingLesson 5: Tipping and CuttingLesson 5: Tipping and CuttingLesson 5: Tipping and Cutting

70

2. 52. 52. 52. 5 Lesson 5: Tipping and CuttingLesson 5: Tipping and CuttingLesson 5: Tipping and CuttingLesson 5: Tipping and Cutting

This lesson describes tipping and cutting operations in AutoForm.

Fig. 5.1Fig. 5.1Fig. 5.1Fig. 5.1

Tool geometry of Lesson 5 with cutting lines

The drawing direction in AutoForm is always zdirection. The geometry must be always checked for undercuts. If undercuts exist, the geometry has to be tipped (using the Tip page) to find a good drawing direction.

Preparation of SimulationPreparation of SimulationPreparation of SimulationPreparation of SimulationOpen a new simulation:

File > New ... > File name: in_lesson_05 > OK

Geometry generator window is opened

File > Import ... > af > OK > in_lesson_05.af > OK

Drawing direction is modified from Tip page (Fig. 5.2).



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Fig. 5.2Fig. 5.2Fig. 5.2Fig. 5.2

TipTipTipTip page of Geometry generator

Double attached: Various options to tip double attached parts

Define...: Definition of a new center of rotation for tipping the part

Total TippingTotal TippingTotal TippingTotal Tipping Average Normal: Uses normal vector of geometry as draw-ing direction.

Min draw depth: Calculates a drawing direction with min-imum drawing depth.

Min backdraft: Calculates a drawing direction with mini-mum undercuts.

Screen axes: Uses the normal of the display as drawing direction.



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Set draw dir ...: Definition of drawing direction with two points or one line

Reference ...: The drawing direction of the active tool is adapted to the drawing direction of a selected reference tool (e.g. helpful for multistage process, to adapt the draw-ing direction of the different stages).

Sync: Mirrors drawing direction for double attached parts. Reset: Uses the original axis of CAD data (zaxis) as draw-

ing direction. Import ...: Reads in a rotation matrix. Export ...: Write out a rotation matrix in VDAFS, IGES or

AutoFormformat. Incremental tipping: Allows rotation by a specific angle

around x, y or zaxis or around a user defined axis. by degrees: Specific angle by dx dy dz: distance in x,y and zdirection, to move the

geometry. rotate +/-: Start rotation. move +/-: Start displacement. Backdraft diagram: All possible undercutfree drawing

directions are calculated (using Plot) and displayed in the diagram.

If the center of the plot is completely within the green circle the geometry is undercut free (default: Safe > 3); if the center is between green and red circles, geometry is in marginal area (default: Marginal: 0 ~ 3); if the center is outside the red circle, geometry has undercuts (default: Severe: 0).

This diagram helps to find an undercut free drawing direction:

X-/Y-/Z-Axis: Shows the rotation matrix of the part. Current transformation: Real transformation (rotation

around x,y and zaxis and displacement at x,y and zdirection)



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Display > Backdrafts (Fig. 5.3).

Fig. 5.3Fig. 5.3Fig. 5.3Fig. 5.3

Tool geometry of Lesson 5 with undercuts

Fig. 5.4Fig. 5.4Fig. 5.4Fig. 5.4

Display menu of Geometry generator with Backdrafts switched on

To find a good drawing direction it is recommended to use the option Average normal and then rotate manually until an undercut free drawing direction is found.

In this example we use the option named Min backdraft. Here the geometry is rotated about the zaxis by +65 degrees to align the geometry with the xaxis.

The current rotation (Tip page bottom) should read X = -71.58, Y = -50.66, Z = 65 degree.



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Fig. 5.5Fig. 5.5Fig. 5.5Fig. 5.5

Tipped geometry

Definition of tools Definition of tools Definition of tools Definition of tools PreparePreparePreparePrepareSelect faces of binder surface (right mouse button or Shift right

mouse button for selecting multiple faces)

Define objects: Binder

Input generationInput generationInput generationInput generationModel > Input generator ... > Simulation type: Incremental > OK

The title is already predefined. On Tools page Columns have to be defined for the binder. It is recommended to use

Tool center

Complete input using tabs from left to right. Since it is a single action process, use the following position values for the tools:

Tools > punch > Move: 0 > binder > Move: 30 Columns > None > die >Move: -530



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Fig. 5.6Fig. 5.6Fig. 5.6Fig. 5.6

Position of tools

BlankBlankBlankBlank The blank is first created in CAD and imported to AutoForm:

Blank > Import ... > af > Use all > Rotate > OK (Fig. 5.7)

Fig. 5.7Fig. 5.7Fig. 5.7Fig. 5.7

Dialog: Import line(s)Import line(s)Import line(s)Import line(s)

Select a file > In_lesson_05_crv.af > OK

File named in_lesson_05_crv.af contains all curves which are used in this lesson (cutting lines, cutting directions, blank).

Select curve > Curve 1 > OK (Fig. 5.8).



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Fig. 5.8Fig. 5.8Fig. 5.8Fig. 5.8

Dialog: Select curveSelect curveSelect curveSelect curve with selected curve Curve 1Curve 1Curve 1Curve 1

For a single action process, the blank has to be positioned on the binder.

BlankBlankBlankBlankPosition > On: binder

Add a drawbead with a force factor of 0.35:

Add > Drawbead > Use default settings > Add drawbeadDrwbds > Tools > Above: die > Below: binderDrawbead line > Copy From > Bndry (Pre) 1 > OKDrawbead line > Edit > Global mod > Expand: 20 > OKWidth: 15 > Forcefactor: Medium 0.35

Drwbds page should look like fig. 5.9.



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Fig. 5.9Fig. 5.9Fig. 5.9Fig. 5.9

DrwbdsDrwbdsDrwbdsDrwbds page

The main display with punch and binder switched on should look like fig. 5.10

Fig. 5.10Fig. 5.10Fig. 5.10Fig. 5.10

Punch and binder with blank and drawbead



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Complete single action process definition on the Process page:

GravityGravityGravityGravitygravity > Gravity: Downwards > Tool control: Show all >die: Non-activepunch: Stationarybinder: Stationary (Fig. 5.11)

Fig. 5.11Fig. 5.11Fig. 5.11Fig. 5.11

Input for gravitygravitygravitygravity

Binder wrapBinder wrapBinder wrapBinder wrapDuring binder wrap phase, the die moves towards the binder, and the binder and the punch are stationary.

closing > Tool control: die > Displcmnt > Velocity: 1 > Set > punch: Stationary > binder: Stationary




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Fig. 5.12Fig. 5.12Fig. 5.12Fig. 5.12

Input for binder wrap

DrawingDrawingDrawingDrawingDuring the drawing phase, the die moves over the punch, the binder is forcecontrolled and is displaced by the die, while the punch is stationary.

drawing > Tool control: die > Displcmnt > Velocity: 1 > Set > punch: Stationary > binder > Force > Relative tool: > die > Const pressure > Value: 3 > Set




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Fig. 5.13Fig. 5.13Fig. 5.13Fig. 5.13

Input for drawing

Definition of different cutting process typesDefinition of different cutting process typesDefinition of different cutting process typesDefinition of different cutting process typesThe definition of cutting processes is always done on Process page of the Input generator. In AutoForm different cutting types can be defined:

Relief cut Trimming cut Hole

Definition of a relief cut 5 mm before bottom downDefinition of a relief cut 5 mm before bottom downDefinition of a relief cut 5 mm before bottom downDefinition of a relief cut 5 mm before bottom downThe following steps have to be defined:

Drawing process (existing process drawing) must be stopped 5mm before bottom down.

Cutting line for relief cut must be defined. Drawing process must continue until bottom down.



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Stop drawing process 5mm before bottom downStop drawing process 5mm before bottom downStop drawing process 5mm before bottom downStop drawing process 5mm before bottom downSelect process step drawing on Process page. Duration of drawing is 30. This value must be changed to stop the process 5mm before bottom down.

drawing > Duration > During time > Time: 25

Change the name of this process step:

drawing > Name: drawing1 (Fig. 5.14)

Fig. 5.14Fig. 5.14Fig. 5.14Fig. 5.14

Drawing until 5mm before bottom down



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Definition of a relief cutDefinition of a relief cutDefinition of a relief cutDefinition of a relief cutA new process step has to be added to define a relief cut.

Add process step ... > Cutting > Insert position: Insert after > drawing1 > Add process step

On Process page a new subpage is created (Fig. 5.15), which must be completed:

Fig. 5.15Fig. 5.15Fig. 5.15Fig. 5.15

Input for definition of relief cut

Process step > Name: cutting1 > Cut 2D > Cut Contour: Copy from > Select curve > Curve 4 > OK > Cutting type: Open cut



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The geometry (punch and binder switched on) should look like fig. 5.16.

Fig. 5.16Fig. 5.16Fig. 5.16Fig. 5.16

Punch and binder with defined relief cut

Finishing deep drawing process (last 5 mm)Finishing deep drawing process (last 5 mm)Finishing deep drawing process (last 5 mm)Finishing deep drawing process (last 5 mm)Now the deep drawing process must be completed (last 5 mm). A new process step has to be added again:

Add process step ... > Forming > Insert position: Insert after > cutting1 > Add process step (Fig. 5.17)

Fig. 5.17Fig. 5.17Fig.

146707525 autoform incremental

Documents

double action pressdeepdrawing

single action pressdeepdrawing

simulation evaluation

plane blank sheet

simulation ranges

real simulation

simulation iterations

following forming processes