AutoForm_OneStep

8/10/2019 AutoForm_OneStep

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www.alghaform.com

www.forum.alghaform.com

ALGHAFORM FORUMLARI PAYLASIMIDIR

iletisim: [email protected]


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4444 AutoFormOneStep AutoFormOneStep AutoFormOneStep AutoFormOneStep

AutoFormOneStep has been developed to recognize forming prob-lems quickly and effectively at a very early stage of product devel-opment and to modify the part geometry accordingly. The flexibleinput in AutoFormOneStep permits the creation of a binder sur-face including the punch opening line. Thus AutoFormOneStep issuited for a simple feasibility analysis and additionally for a quickverification of a tool design and the comparison of different toolconcepts. The simulation of completely designed tools can be made

in extremely short calculation times. The seamless integration ofAutoFormOneStep with the AutoFormOptimizer helps you find-ing optimized geometry and process parameters.

The inverse formulation of AutoFormOneStep allows for the sim-ple and precise determination of the blank outline and thus the min-imal material requirements. This opens new perspectives forquotations/estimations as well as for tool design considering theoptimized blank and thus the minimal material consumption.

The integration with all other AutoForm products makes manyadditional functions available such as AutoFormDieDesigner orAutoFormOptimizer for the optimization of the part geometry,

binder surfaces, addenda or process parameters.

AutoFormOneStep supports five different calculation types, whichrequire different forming knowledge of the user and are used fordifferent tasks:

Part only (1-step)Part only (1-step)Part only (1-step)Part only (1-step)The calculation is exclusively based on the part geometry; startingfrom the part geometry the flat blank is calculated (inverse calcula-tion method). The specification of the part boundary line allows forthe simple modification of the part boundary.

This simplest calculation type requires the least forming knowledgeof the user and is especially suited for forming analyses during partdesign as well as for the estimation of the forming complexity of thepart and for the determination of the minimal material consump-tion for quotation and estimation purposes. As the impact of the

addendum is only considered by restraining forces on the part


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boundary, the accuracy of a Part only calculation is coarse, espe-cially along the part boundary.

Part only (2-step)Part only (2-step)Part only (2-step)Part only (2-step)This calculation type does not directly determine the flat blank butthe curved blank, which in the real forming process conforms to theshape of the sheet after binder closure. The binder surface has to bedefined. A two step process is simulated:

Friction free binder closure involving no restraining force Deep drawing involving friction and restraining forces

The remarks of the preceding paragraph obtain indeed this cal-culation type provides more realistic results for parts withextremely curved binder surfaces. Since there is no real addendum

involved in the calculation, it is important to have an especiallyrealistic binder as used in the real tool. Yet it is sufficient if the sur-face tolerably conforms to the part contour to improve the quality ofthe calculated results.

For this reason, this method is useful for the part designer who doesnot necessarily have a deep understanding of the forming process.

Part+Binder (2-Part+Binder (2-Part+Binder (2-Part+Binder (2-step)step)step)step)

Based on the defined binder surface and punch opening line, Auto-FormOneStep automatically generates a simple addendum, run-

ning out of the part boundary tangentially and running into the binder surface on the punch opening line tangentially. The calcula-tion is based on the part and the addendum using the two stepmethod. If a realistic binder surface is available, this calculationtype improves the quality of the results considerably compared tothe Part only calculation, because a rough geometric addendum istaken into account the simulated process is thus closer to the realforming process.

This calculation type is especially wellsuited for rapid verificationand comparison of different tool concepts. Since the binder essen-tially influences the addendum and hence the results, the usershould possess the essential forming knowledge about the genera-tion of binder surfaces.

Full tool (1-step)Full tool (1-step)Full tool (1-step)Full tool (1-step)The calculation is based on the completely defined tool. The punchopening line and the flange boundary line at the end of the formingprocess have to be defined. These two lines determine the flangesurface, on which binder pressure is applied to control material

flow. The Full tool calculation type gives the most precise results ofall OneStep calculation types.

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This approach is wellsuited for the verification of tool concepts,developed e.g. in AutoFormDieDesigner. As the blank outlineafter forming (OS boundary) has to be defined due to the inversecalculation method, precise minimal precut parts can be deter-mined, which can then be used as initial blank for an incrementalsimulation. The 1-step option of the Full tool calculation is suitedfor tool with plane binder surfaces.

Full tool (2-step)Full tool (2-step)Full tool (2-step)Full tool (2-step) As for a Part only (2-step) calculation the binder surface is deter-mined at first binder closure is accomplished without friction andretraining forces.

This calculation type is used for tools with a curved binder.

As for Full tool simulations the restraining forces in the binder sur-faces are of essential importance for the results, the 2-step optionshould be preferred otherwise the simulation assumes that therestraining forces in the binder surface already apply for binder clo-sure. That does not correspond to the real forming process and maylead to a significant overestimation of strains. Besides the remarkson the Full tool (1-step) calculation type obtain.

The necessary geometric input data for the five simulation type aresummarized in the following table:

Legend :

pb line = part boundary linef line = flange line

Part onlyPart onlyPart onlyPart only

(1 - step)(1 - step)(1 - step)(1 - step)

Part onlyPart onlyPart onlyPart only


Part +Part +Part +Part + BinderBinderBinderBinder


Full toolFull toolFull toolFull tool


Full toolFull toolFull toolFull tool


Part/Tool

geometry

part part part die die

Binder surface no yes yes no yes

OS boundary pb line pb line f line f line f line

OS punchopening

no no yes yes yes



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AutoForm offers a geometry module named AutoFormPartDe-signer for the advanced use of AutoFormOneStep in feasibilityanalyses during part design. It makes possible the optimization offorming parameters in the most important geometric modificationsof the part in AutoForm:

Automatic generation of variable fillets on the productgeometry

Rapid determination of the best fillet radius for forming Determination of the die tip (drawing direction) Automatic geometry creation to fill designed holes Boundary fill by filling concave inlets: The accuracy and

usability of the Part only results increase significantly inthe outer boundary area of the part.

Modification of geometry regions by cutting and con-trolled filling Overcrowning of entire part regions Automatic and interactive development of binder surfaces:

The accuracy of the simulation increases significantly forthe Part only (2-step) calculation type.

Fully parametrized treatment of input data to facilitate theoptimization with AutoFormOptimizer

AutoFormOneStep provides five different simulationtypes.

For certain functions described in this workshop the AutoFormPartDesigner must be available. The respective functions aremarked.

One of the most important features of AutoFormOneStep Version.3.1 is the greatly improved userfriendliness and the ease withwhich the simulations are set up, run and evaluated. The Onestepwizard has been developed for the Part only simulation. This wiz-ard makes it possible to run feasibility studies quickly and reliablyconsidering different process parameters in a single simulation



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Contents of the Workshop AutoFormOneStepContents of the Workshop AutoFormOneStepContents of the Workshop AutoFormOneStepContents of the Workshop AutoFormOneStep

Lesson 1Lesson 1Lesson 1Lesson 1 Part only Simulation with OneStep WizardPart only Simulation with OneStep WizardPart only Simulation with OneStep WizardPart only Simulation with OneStep Wizard . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . 6 666

Importing CAD data Determining the drawing direction Defining holding conditions Evaluating the OneStep simulation

Lesson 2Lesson 2Lesson 2Lesson 2 Part only (2-step) SimulationPart only (2-step) SimulationPart only (2-step) SimulationPart only (2-step) Simulation . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . 21 212121

Variable Restraining Option Preparing the geometry Part boundary Binder surfaces

Lesson 3Lesson 3Lesson 3Lesson 3 Part + Binder (2-step) SimulationPart + Binder (2-step) SimulationPart + Binder (2-step) SimulationPart + Binder (2-step) Simulation. . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . .37 373737

Filling holes Boundary fill Automatic binder generation ( Auto Binder )

Lesson 4Lesson 4Lesson 4Lesson 4 Full tool (1-step) SimulationFull tool (1-step) SimulationFull tool (1-step) SimulationFull tool (1-step) Simulation . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . 54 545454

Full tool Tailored blank Linear weld line Material mark Material lines

Lesson 5Lesson 5Lesson 5Lesson 5 Full tool (2-step) SimulationFull tool (2-step) SimulationFull tool (2-step) SimulationFull tool (2-step) Simulation . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . 68 686868

Drawbead Symmetry Optimizing the blank Importing and exporting lines

Lesson 6Lesson 6Lesson 6Lesson 6 OptimizationOptimizationOptimizationOptimization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .78 787878

Numerical optimization Parameter study

Optimization of the force factor Optimization of the force factor of a drawbead Evaluating the optimization



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Lesson 1: Part only Simulation with OneStep WizardLesson 1: Part only Simulation with OneStep WizardLesson 1: Part only Simulation with OneStep WizardLesson 1: Part only Simulation with OneStep Wizard

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4. 14. 14. 14. 1 Lesson 1: Part only Simulation with OneStep WizardLesson 1: Part only Simulation with OneStep WizardLesson 1: Part only Simulation with OneStep WizardLesson 1: Part only Simulation with OneStep Wizard

This lesson presents a simple example for AutoFormOneStep. Using AutoForm

OneStep is it possible to run a feasibility analysis for the part geometry in a fast andstraightforward manner.

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

Geometry for the OneStep simulation

Setting up the Simulation FileSetting up the Simulation FileSetting up the Simulation FileSetting up the Simulation FileAt the start of the OneStep simulation, you have to define the simu-lation file (*.sim). This simulation file contains all the informationabout the calculation (geometric input, process parameters, numeri-cal values ...) and finally the results of the computation. Set up the

simulation file using the following command:

File > New onestep ...

The window OneStep wizard (for a OneStep Part only simulation)opens (Fig. 1.2):



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

OneStep wizardOneStep wizardOneStep wizardOneStep wizard

Importing the Part GeometryImporting the Part GeometryImporting the Part GeometryImporting the Part GeometryThe geometry import is carried out using the module afmesh , theintegrated IGES/VDAFS interface, which automatically meshes thepart geometry. The part geometry needs to be available as surfacemodel containing the inner or outer side of the part geometry. Thefollowing formats are supported for import: af , afb (binary Auto-formFormat), Nastran , Dyna and Stl .

For this lesson a VDAFS file is available. Import this file:

OneStep wizardOneStep wizardOneStep wizardOneStep wizard Import ... > VDAFS > OK > Files: os_lesson_01.vda > OK >afmesh_3.1 > OK

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

Import geometry Import geometry Import geometry Import geometry



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

Afmesh Afmesh Afmesh Afmesh

Options for meshing the CAD data

ParametersParametersParametersParameters Error tolerance : Allowable chordal error tolerance 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 errortolerance.

Max side length : Maximum element side length. Defaultsetting: 50.

FacesFacesFacesFaces Treat only : Only specified faces will be meshed. Possibleentries are e.g. 1 , 2 , 6-8.

Exclude : The specified faces are not taken into account formeshing. Possible entries are e.g. 1 , 2 , 7-9.

LayersLayersLayersLayers Treat only (for IGES import only): Only specified layerswill be meshed.

Exclude (for IGES import only): The specified layers arenot taken into account for meshing.

The meshed part geometry is immediately displayed in the maindisplay.



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

OneStep wizardOneStep wizardOneStep wizardOneStep wizard

Enter a project identifier into the field Title of the OneStep wizard.This identifier will be always be indicated in the bottom of the userinterface.

NoteNoteNoteNote: A title is automatically suggested including the current filename, the user name and the date of creation.

OneStep wizardOneStep wizardOneStep wizardOneStep wizard Title: lesson_01

The following three areas of the OneStep wizard have to be speci-fied to prepare the simulation:

Geometry Blank Process



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First, the part geometry has to be rotated such that the drawingdirection corresponds to the zaxis and no backdrafts occur in thepart. Use the buttons in the field Tip .

Checking for UndercutsChecking for UndercutsChecking for UndercutsChecking for Undercuts

Click the Backdrafts button in field Display .

Geometry > Display > Backdrafts

Faces containing undercuts will be displayed red in the main dis-play (Fig. 1.6)

The meaning of the colors:

Safe (green): Backdraft angle greater than 3 degrees Marginal (yellow): Backdraft angle between 0 and 3degrees

Severe (red): Areas containing undercuts smaller than 0degree

The part contains undercuts, thus it has to be tipped into drawingdirection. To determine a proper drawing direction we recommendusing the automatic function Min backdraft :

Geometry > Tip > Min backdraft

This function calculates a drawing direction with minimum under-cuts.

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

BackdraftsBackdraftsBackdraftsBackdrafts: Representation of areas containing undercuts



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The part contains no undercuts in the calculated drawing direction(Fig. 1.7). In case the tipping direction calculated with the automaticfunctions do not result in an acceptable drawing direction, use themanual functions ( Tip : x-axis/y-axis ) to modify the drawing direc-tion.

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

Undercut free part geometry

Having tipped the part geometry, you can now apply filleting in theareas containing sharp edges globally and fill the part boundary.

Adjust the representation in the main display as follows:

Geometry > Display > Faces

Global Filleting of all sharp edges in the part geometryGlobal Filleting of all sharp edges in the part geometryGlobal Filleting of all sharp edges in the part geometryGlobal Filleting of all sharp edges in the part geometryUse the following command to fillet sharp edges:

Geometry > Fillet > Radius: 3

Filling the Part boundaryFilling the Part boundaryFilling the Part boundaryFilling the Part boundaryGenerate the boundary fill now. Fill areas are created automaticallyalong the part boundary. The outer boundary fill line is determined

by a roll cylinder moving around the part boundary and its rollradius:

Geometry > Boundary fill > Roll radius: 100.00



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To start the global filleting and the creation of the boundary fill andthe generation of the resulting part boundary, click

Apply

The resulting geometry containing the generated part boundary isshown in Fig. 1.8. The part boundary has changed during the cre-ation of the boundary fill (see also Fig. 1.9 and Fig. 1.10).

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

The resulting geometry and the part boundary

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

DetailDetailDetailDetail: Part boundary before boundary fill



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

DetailDetailDetailDetail: Part boundary after boundary fill

The geometry has been completely prepared for the simulation.Define the sheet thickness and select a material:

Defining Material PropertiesDefining Material PropertiesDefining Material PropertiesDefining Material PropertiesBlank > Thickness: 1

Blank > Material > Import ... > Select material > zste180bhZ_1.mat > OK

Define the restraining forces on the part boundary in the area Pro-cess . Different holding conditions can be used. The holding condi-tion Free corresponds to ideal deep drawing, e.g. for tools without a

binder. In contrast the holding condition Locked corresponds tostretch forming, e.g. for tools with extremely high binder pressure.Restraining forces, corresponding to a usual tool in which materialdrawin occurs, can be defined by means of weak , medium , strong and User defined .

The current simulation will be calculated using standard settings(Free , Medium and Locked ).

The complete input for the simulation is shown in Fig. 1.11.



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

OneStep wizardOneStep wizardOneStep wizardOneStep wizard: Prepared OneStepPart only Part only Part only Part only simulation

Store the prepared simulation and start the simulation:

File > Save as ... > os_lesson_01.sim > OK

Start ... > Program: afos_3.1 > Start

NoteNoteNoteNote: The OneStep wizard contains a number of selected functionsfor the definition of the simulation. Use the Advanced ... Advanced ... Advanced ... Advanced ... button toaccess additional functions in AutoFormOneStep. These addi-tional functions will be described in the following lessons.



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EvaluatingEvaluatingEvaluatingEvaluating Simulation ResultsSimulation ResultsSimulation ResultsSimulation ResultsThe following section describes the most important result variablesof a OneStep simulation. Having completed the calculation of thesimulation, reopen the SIM file using the command:

User interfaceUser interfaceUser interfaceUser interface File > Reopen

The main display shows the calculated part geometry. In the lowerpart of the user interface, three buttons are available: free , medium and locked . Click one of the buttons to load the results for therespective holding condition from the SIM file. Compare the results.

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

The user interface after loading the calculated simulation

FormabilityFormabilityFormabilityFormabilityThe result variable Formability gives you a general survey of thefeasibility of the part. Areas undergoing different stresses are col-ored differently on the part:

Cracks (red): Areas of cracks. These areas are above theFLC of the specified material.

Excess. Thinning (orange): In these areas, thinning is

greater than the acceptable value (default value for steel is30%).



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Risk of cracks (yellow): These areas may crack or split. Bydefault, this area is in between the FLC and 20% below theFLC.

Safe (green): All areas that have no formability problems. Insuff. Stretching (gray): Areas that have not enough

strain (default 2%) Wrinkling tendency (blue): Areas where wrinkles might

appear. In these areas, the material has compressivestresses but no compressive strains

Wrinkles (purple): Areas where wrinkles can be expected,depending on geometry curvature, thickness and tool con-tact. Material in these areas has compressive strains whichmeans the material becomes thicker during the formingprocess.

Select the result variable Formability . Compare the results for thedifferent restraining forces. The results for the holding condition

free is shown in Fig. 1.13, medium is shown in Fig. 1.14 and locked is shown in Fig. 1.15.

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

Formability Formability Formability Formability with holding condition free freefreefree



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

Formability Formability Formability Formability with holding condition mediummediummediummedium

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

Formability Formability Formability Formability with holding condition lockedlockedlockedlocked



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You can see from the figure that the part is insufficiently stretched,using the holding conditions free and medium . There are severalareas containing wrinkles (purple), wrinkling tendencies (blue) andinsufficient stretching (gray). Using the holding condition locked ,the part is sufficiently stretched. A small area of insufficient stretch-ing (gray) can be seen on the left end (Fig. 1.15).

ThinningThinningThinningThinningSwitch to the result variable Thinning (second row of icon panel inmain display, middle button). A scale is displayed in the lower partof the main display with a range of 30% thinning to 3% thickening(depending on the specified color settings) (Fig. 1.16).

Fig. 1.16Fig. 1.16Fig. 1.16Fig. 1.16

Thinning (in percentage) with the holding condition locked lockedlockedlocked

The exact thinning value (in percentage) is displayed, when youclick with the right mouse button on the geometry. Hit the Esc keyto clear these labels from the display. To find the maximum thin-ning and the maximum thickening of the part use the followingoptions

User interfaceUser interfaceUser interfaceUser interfaceResults > Show max

Results > Show min



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Fillet : The geometry is checked for sharp edges. The sharpedges are filleted by the defined radius automatically(Radius: ).

Boundary fill : Holes are filled and the boundary fill is cre-ated ( Roll radius: ).

Apply : Use the Apply button to execute all functionsdefined.

The area Blank The area Blank The area Blank The area Blank Thickness : Sheet thickness Material : Material Import ... : Import a material from the material database View ... : Shows the current material properties Input ... : Defining material properties

The area ProcessThe area ProcessThe area ProcessThe area ProcessUse the functions of this area to define the restraining forces ( Hold-ing conditions ). The following holding conditions are available:

Free : No restraining forces (ideal deep drawing) Weak (0.15): Weak restraining forces Medium (0.35): Medium restraining forces Strong (0.9): Strong restraining forces Locked : Locked (stretch forming)

Besides the above conditions, it is also possible to enter freelydefined values ( User def. ). Decide which of the holding conditionswill be used for the simulation. Click All to use all holding condi-tions, click None to use no holding condition. The simulation is cal-culated separately for each of the defined holding conditions. Bydefault the three holding conditions ( Free , Medium and Locked )are set. In version 3.1, all OneStep results are stored in a single SIMfile thus eliminating the need for manual iterations with different

conditions being stored in separate files.



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Lesson 2: Part only (2-step) SimulationLesson 2: Part only (2-step) SimulationLesson 2: Part only (2-step) SimulationLesson 2: Part only (2-step) Simulation

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4. 24. 24. 24. 2 Lesson 2: Part only (2-step) SimulationLesson 2: Part only (2-step) SimulationLesson 2: Part only (2-step) SimulationLesson 2: Part only (2-step) Simulation

The functions introduced in this lesson make possible the more precise definition of

restraining forces in AutoFormOneStep. Besides the Part only (2-step) simulation calcu-lates the developed blank more precisely. This simulation type requires the definition ofa binder surface in addition to the inputs required for a Part only (1-step) simulation.This simulation proceeds in two steps:

Simulation, in reverse, of the drawing process from binder-wrap to the final product geometry. The reverse processtakes into account friction as well as the restraints appliedto the OS boundary, and establishes the outline of thedeveloped blank mapped on to the geometry of the curved binder surface.

Simulation, in reverse, of the binderwrap process. Duringthis process, no restraints are applied on the sheet, and thedeveloped blank outline is unfolded from the curved binder surface on to the flat surface.

The above 2step approach is more representative, particularly inthe case of curved and deepdrawn parts, of the actual stampingprocess. Therefore, results of 2step simulations are more accurate

for these parts, and are closer to those of an incremental processsimulation.

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

Cross member geometry including the binder surface

Setting up a new Onestep SimulationSetting up a new Onestep SimulationSetting up a new Onestep SimulationSetting up a new Onestep SimulationUser interfaceUser interfaceUser interfaceUser interface File > New onestep to open the OneStep wizard .

Importing and Editing the CAD geometryImporting and Editing the CAD geometryImporting and Editing the CAD geometryImporting and Editing the CAD geometryUse the following commands to import the CAD data:

OneStep wizardOneStep wizardOneStep wizardOneStep wizard Import ... > VDAFS > OK > os_lesson_02.vda > OK > Program: afmesh_3.1 > OK



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The crossmember geometry is displayed in the main display, andthe OneStep wizard is filled with a few default values.

Editing Parts FacesEditing Parts FacesEditing Parts FacesEditing Parts FacesThere is an upstanding flange around one of the holes of this part. Ifthis flange were to remain on the part geometry during simulation,a prediction of cracks would result at the flange. However, sincethese flanges would be formed in a secondary operation, they may

be ignored in the OneStep simulation without any errors, and maytherefore be eliminated as follows: Hold the Shift key down anduse the right mouse button to pick the flange faces. Click the Delpicked button to remove the faces from the geometry. The remain-ing faces form the part, i.e. it is only these faces that are taken intoaccount during subsequent simulation.

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

Selected flange faces for deletion

Del picked deletes selected faces.



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

Representation of deleted faces

The deleted faces are represented as a mesh. Select the faces andsubsequently use the buttons Undel picked or Undel all to add thefaces back to the part again.

Establishing the Drawing DirectionEstablishing the Drawing DirectionEstablishing the Drawing DirectionEstablishing the Drawing DirectionIn preparation for a simulation, the imported product geometryneeds to be rotated so that the drawing direction for the product isparallel to the zaxis: There should be no backdraft faces on thegeometry relative to the zdirection. There are several manual orautomatic options that you may apply to establish the required die

tip. The ideal die tip may be established in the present case usingthe Min Backdraft option:

Display: Backdrafts shows backdrafts on the geometry.

Tip: Min backdraft reorients the product geometry such that theproduct faces, on average, have the largest possible inclination tothe zdirection.



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

Reoriented geometry with representation of backdrafts

Generating the Part BoundaryGenerating the Part BoundaryGenerating the Part BoundaryGenerating the Part Boundary(Outer boundary of the product geometry)

After editing the product geometry, the boundary of the currentgeometry may be generated automatically by clicking the Apply

button.

Display : Objects shows the geometry in colored and shaded mode.

Apply in the field Geometry generates the part boundary.



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

Geometry with part boundary

Defining the Material PropertiesDefining the Material PropertiesDefining the Material PropertiesDefining the Material PropertiesThe default material selection is FeP04; an alternate material filemay be selected from the extensive material library using theImport ... button.

Blank: Import ... to open the dialog Select material .

Use the buttons View or Preview to display the properties of theselected material: Hardening curve, forming limit curve and rval-ues.

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

Select materialSelect materialSelect materialSelect material / Preview Preview Preview Preview



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Files: zste220P_1.mat > OK

The Advanced ModeThe Advanced ModeThe Advanced ModeThe Advanced ModeAll necessary information has been entered into the OneStep wiz-ard . The settings in the area Process are left unchanged.

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

OneStep wizardOneStep wizardOneStep wizardOneStep wizard containing all information

Additional information is entered in the Advanced mode. Click

OneStep wizardOneStep wizardOneStep wizardOneStep wizardAdvanced ...

The dialog AutoForm - Question pops up:

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

AutoForm - Question AutoForm - Question AutoForm - Question AutoForm - Question

Finish closes OneStep wizard and opens AFOS input generator.



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Preparing a Binder SurfacePreparing a Binder SurfacePreparing a Binder SurfacePreparing a Binder SurfaceOpen the Geometry generator.

User interfaceUser interfaceUser interfaceUser interfaceModel > Geometry generator ...

BinderBinderBinderBinderGenerate a binder on the Binder page.

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

Geometry generator: BinderBinderBinderBinder page

BinderBinderBinderBinderAuto > Apply (Leave the default settings unchanged)



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A log window pops up containing information on the progress ofthe binder surface calculation.

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

LogLogLogLog window

The product geometry and a curved binder are shown in the maindisplay.

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

Product geometry with binder

Selecting the Geometry TypeSelecting the Geometry TypeSelecting the Geometry TypeSelecting the Geometry TypeSelect the geometry type Part only (2-step) on the Geometry pageof the Input generator.

GeometryGeometryGeometryGeometry

Part only (2-step)



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

Geometry Type Part only (2-step)Part only (2-step)Part only (2-step)Part only (2-step)

In addition to the product geometry there is a binder surface now.The OS boundary has been copied depending on the part boundary.

Variable Restraining Options Variable Restraining Options Variable Restraining Options Variable Restraining OptionsIn a lot of cases, a constant magnitude of restraining force applied tothe OS boundary in a Part only simulation does not lead to optimalpredictions of product quality. For example, localized areas may beinsufficiently stretched, or may have very large strains close to orexceeding the forming limit (leading to a prediction of cracks). Insuch cases, it would be useful to vary the holding conditionsaround the OS boundary to achieve optimal stretch conditions overthe entire product geometry without causing splits, cracks or exces-sive thinning.

ProcessProcessProcessProcessMedium > Restraining options > Variable

Enter the restr into the field Name :


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Holding condition > Name: restr

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

Restraining options VariableRestraining options VariableRestraining options VariableRestraining options Variable

Before selecting nodes along the part boundary using the functionInput points ... , we recommend to adjust the view from zdirection.

User interfaceUser interfaceUser interfaceUser interface View > From +Z (yx) andView > Fit to window

This can also be done using the keyboard by pressing Ctrl Z forthe view orientation followed by Ctrl W to fit to window.

Input generatorInput generatorInput generatorInput generator restr > Input points

The dialog for the definition of nodes opens:



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Fig. 2.15 aFig. 2.15 aFig. 2.15 aFig. 2.15 a

Definition of restraining forces

Add/edit point

Fig. 2.15 bFig. 2.15 bFig. 2.15 bFig. 2.15 b

Definition of the force factor

In the main display many nodes are shown along the part bound-ary. Select any of these nodes using the right mouse button anddefine a specific restraining force factor value at each of the selectednodes.

OK to finish the definition of nodes.

The actual restraining force variation over a segment is interpolated

linearly between values set at the nodes bounding this segment.


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The figure below shows a total of 15 restraining point defined overthe OS boundary of the cross member geometry.

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

15 nodes with different forcefactors

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

Variable restraining forces

Evaluation of the resultsEvaluation of the resultsEvaluation of the resultsEvaluation of the resultsUser interfaceUser interfaceUser interfaceUser interface File > Save as > os_lesson_03.sim to save the input data.

Job > Start simulation ... > Start to start the calculation.

File > Reopen reads the results.

To review the results for the variable restraining forces, click the button restr at the bottom of the AutoFormUser Interface.

restr



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Click the button for the result variable Formability :

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

Formability Formability Formability Formability with variable restraining forces

Besides the representation of the part with the result variable andthe developed blank the representation of the binderwrap is avail-able now.

Use the three buttons on the lower left side of the AutoFormUserInterface to select the desired representation.


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shows the binder-wrap.

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

BinderwrapBinderwrapBinderwrapBinderwrap



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shows the developed blank.

Fig. 2.20Fig. 2.20Fig. 2.20Fig. 2.20

Developed blank Developed blank Developed blank Developed blank


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Lesson 3: Part + Binder (2-step) SimulationLesson 3: Part + Binder (2-step) SimulationLesson 3: Part + Binder (2-step) SimulationLesson 3: Part + Binder (2-step) Simulation

37

4. 34. 34. 34. 3 Lesson 3: Part + Binder (2-step) SimulationLesson 3: Part + Binder (2-step) SimulationLesson 3: Part + Binder (2-step) SimulationLesson 3: Part + Binder (2-step) Simulation

This simulation type is useful in the initial phase of methods and process planning when

only the part geometry is available. By enabling quick and interactive generation of binder surfaces based on product geometry, and by allowing the binder surface to beused in the simulation, it becomes possible to assess the influence of these tool sur-faces on feasibility, and possibly to optimize these and associated process parametersin conjunction with product geometry in early stages itself.

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

Part geometry

The procedure in creating and defining inputs and in running simu-lations of this type is as follows:

User interfaceUser interfaceUser interfaceUser interface File > New > File name: lesson_os3 Units: mm and NGeometric error tolerance: 0.1 > OK

Geometry gen-Geometry gen-Geometry gen-Geometry gen-eratoreratoreratorerator

File > Import > VDAFS > OK > File: lesson_os3.vda > OK

PreparePreparePreparePrepare Symmetry / double > x-z-plane y: 0 > OK > Apply



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

Sharp EdgesSharp EdgesSharp EdgesSharp EdgesGo to the Fillet page to determine the sharp edges of the geometry.

FilletFilletFilletFilletCheck radius: 2.00 > Check > OK

The areas on the part containing sharp edges are displayed.

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

Areas containing sharp edges

Areas in the part containing sharp edges are displayed. It is neces-sary to fillet all sharp edged areas in the part. There are two ways tofillet sharp edges: Globally with a global fillet radius or locally with


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a constant or variable radius or radius transition. We will describeall these variants.

Global FilletingGlobal FilletingGlobal FilletingGlobal FilletingGlobal fillet radius: 3.00 > Apply

All areas containing sharp edges will be filleted using a radius of 3mm.

Local Filleting by a Constant Radius (requires AutoFormPartDe-Local Filleting by a Constant Radius (requires AutoFormPartDe-Local Filleting by a Constant Radius (requires AutoFormPartDe-Local Filleting by a Constant Radius (requires AutoFormPartDe-signer license)signer license)signer license)signer license)In order to generate variable radii at individual edges, the edgesneed to be identified and the radii need to be specified. Click theAdd line ... button at the bottom of the Fillet page to identify sharp

edges.Add line ... opens the window containing the message: Markradius control edge. Finish with double click.

Selecting an edge also involves identifying the length along theedge that will be filleted. Edges have to selected one after the other,each time clicking the Add line ... button to start a new selection.

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

Local filleting



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Click once with the right mouse button to select the starting point atan edge of interest, let go the mouse button and move your mousecursor along the curved outline of the edge. This progressivelyhighlights (in yellow) the length of the edge. Double click the rightmouse button to end the edge selection.

NoteNoteNoteNote: If the run of the curve representing the edge is ambiguous(long, extremely curved edge or branchings along the curve), setintermediate points to define the run of the curve precisely. Click the right mouse button repeatedly along the curve representingthe edge.

FilletFilletFilletFilletAdd line ...

Mark the entire curve, as shown in Fig. 3.4.line1: > Constant > Constant fillet radius: 5.00 > Apply

Local Filleting by a Variable Radius (requires AutoFormPartDe-Local Filleting by a Variable Radius (requires AutoFormPartDe-Local Filleting by a Variable Radius (requires AutoFormPartDe-Local Filleting by a Variable Radius (requires AutoFormPartDe-signer license)signer license)signer license)signer license)To generate variable fillets, the edges to be filleted need to beselected as described above. Subsequently, radius control pointsare selected on each of these edges, and radius values are specifiedat each of these points.

FilletFilletFilletFilletAdd line ... > line2: > Variable > Selecting 4 radius control points >OK


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

Locally filleted edges

FilletFilletFilletFillet Assign a radius to each of the control points.

Finally click the button

Apply



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The Fillet page is as shown in Fig. 3.6:

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

FilletFilletFilletFillet page

Definition of Drawing DirectionDefinition of Drawing DirectionDefinition of Drawing DirectionDefinition of Drawing DirectionTipTipTipTipIt is necessary to rotate the imported geometry from vehicle to draw

position in order to eliminate backdraft conditions.


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

Backdraft faces on the part geometry

Incremental tipping > Y-axis > by degrees: 45 > rotate: -

The part is now free of undercuts.

Modify P page (requires AutoFormPartDesigner license)Modify P page (requires AutoFormPartDesigner license)Modify P page (requires AutoFormPartDesigner license)Modify P page (requires AutoFormPartDesigner license)Use the functions of the Modify P page to fill holes containedwithin the part geometry.

Modify PModify PModify PModify P All holes > Define holes > Min size: 1.50 > Max size: 300.00 >Apply

Use the functions of the Bndry page to fill of areas on the part

boundary:BndryBndryBndryBndry Add Bndr fill ... > Curve 1 > OK > Fill parameters: Bndry fill roll

radius: 300 > Apply

NoteNoteNoteNote: Smoothening the part boundary increases the accuracy ofthe simulation results on the part boundary, especially for concaveregions.



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

Filling holes and boundary fill

Generate the binder surface on the Binder page using the Auto-

Binder function (requires AutoFormPartDesigner).

BinderBinderBinderBinderAuto

For the binder a minimum drawing depth is required.

Drawing depth: Minimum

The main curvature direction of the binder is defined in ydirection,i.e. by an angle of 90.

Profile orientation > Angle: 90 deg


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

Auto Binder Auto Binder Auto Binder Auto Binder page

BinderBinderBinderBinder Apply

A curved binder surface has been generated. Analyze the distance between the binder and the part in the AutoFormUser Interface.

Adjust the value range of the result scale for the current example:

Geometry generator > Display > Ranges > Min/Max Simulation



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

Plot of the drawing depth distribution on the part geometry

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

Adjusting display range

Click any area of the part with the right mouse button to display theactual drawing depth value. Change the distance between binderand part using the function Binder position Shift .

The preparation of the part geometry has been finished for the sim-ulation. Define the process parameters in the Input generator:

User interfaceUser interfaceUser interfaceUser interfaceModel > Input generator > Simulation type: OneStep > OK

AFOS input generator AFOS input generator AFOS input generator AFOS input generatorTitleTitleTitleTitleEnter the title of the simulation. Enter further information on the

current simulation into the field Comment .


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GeometryGeometryGeometryGeometry Type: Part+binder (2-step) > Delete the current OS boundary line?> Delete

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

Geometry type: Part + Binder (2-step)Part + Binder (2-step)Part + Binder (2-step)Part + Binder (2-step)

The definitions of part and binder geometries have been automati-cally accomplished by transferring data of the imported part geom-etry and generated binder surface from the Geometry generator.

The sheet thickness for the part is 1.2 mm. By specifying an offset of0.6 mm ( Upwards ), the simulation may be carried out on the mid-surface of the product geometry an Upwards offset is used sincethe imported surface represents the lower surface of the product.

GeometryGeometryGeometryGeometry Part > Offset: 0.6

Definition of the Punch Opening LineDefinition of the Punch Opening LineDefinition of the Punch Opening LineDefinition of the Punch Opening LineThe punch opening line is used to define areas in which the gener-ated mesh for the addendum has a tangential transition to the

binder.



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OS punch opening lineOS punch opening lineOS punch opening lineOS punch opening lineDependent ... > Bndry (Bndry) > OK

The Bndry (Bndry) line defines the part boundary including theouter boundary fill areas. It has to be adapted using the functionsExpand and Smooth of the Curve editor. The adapted line will beused as punch opening line.

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

Select CurveSelect CurveSelect CurveSelect Curve dialog

OS punch opening > Edit ... > Expand: 15 > Smooth: 0.05 > OK

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

Curve editorCurve editorCurve editorCurve editor: OSPO line

The same approach using the geometry of the Bndry (Bndry) lineas the starting point for defining another line may be employed toaccomplish the definition of the OS boundary line. This line repre-sents the outer edge of the formed sheet at the end of the forming/drawing process. Starting from the geometry of the Bndry (Bndry)line, Expand and Smooth options may be used to define the OS


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boundary line, making sure to differentiate it from the previouslydefined OS punch opening line.

OS boundary > Dependent ... > Bndry (Bndry) > OK

Edit ... > Expand: 90 > OK > Smooth: 0.1 > OK

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

OS POline and OS boundary

Blank Blank Blank Blank Thickness: 1.2 > Material: zste340_3

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

Blank Blank Blank Blank page

Definition of FrictionDefinition of FrictionDefinition of FrictionDefinition of FrictionLubeLubeLubeLube Lubrication > Constant > Standard 0.15



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

ProcessProcessProcessProcess page

Definition of the Process ParametersDefinition of the Process ParametersDefinition of the Process ParametersDefinition of the Process ParametersProcessProcessProcessProcessHolding Conditions > Type: Binder pressure

Pressure options > Pressure: 6 (default)

NoteNoteNoteNote: The binder pressure is defined relative to the final flangearea. Thus a higher pressure has to be defined than for an incre-mental simulation, for which the pressure is defined with respect tothe initial flange area.

ControlControlControlControlAccuracy > Mesh: Standard

Starting the SimulationStarting the SimulationStarting the SimulationStarting the Simulation AFOS input gen- AFOS input gen- AFOS input gen- AFOS input gen-eratoreratoreratorerator

Job > Start simulation ... > Save > Start

Evaluating the simulationEvaluating the simulationEvaluating the simulationEvaluating the simulationUser interfaceUser interfaceUser interfaceUser interfaceFile > Reopen

As a result of the simulation you can evaluate three different

phases.

Developed blankDeveloped blankDeveloped blankDeveloped blankThe outline of the developed blank is computed during the simula-tion. The edge of this blank may be exported in af, IGES or VDAFSformat, and may be used to define the blank in an AutoFormIncre-mental simulation. Blank outline may be exported as follows:

User interfaceUser interfaceUser interfaceUser interfaceFile > Export boundaries > ...


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


BinderwrapBinderwrapBinderwrapBinderwrapThe result of the OneStep calculation is iterated in the binder sur-face considering friction. Particular high strains are thus avoided forhighly curved binders.



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

Binder wrapBinder wrapBinder wrapBinder wrap

Formed sheetFormed sheetFormed sheetFormed sheetAutoFormOneStep offers among others the following results:

Distribution of strain and all dependent variables such assheet thickness, failure, wrinkling, hardening, forminglimit analysis and stress

Binder pressure distribution in the flange area Distribution of sheet reaction stress Friction shear stress Formability etc.


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

Formed sheet: Formability Formed sheet: Formability Formed sheet: Formability Formed sheet: Formability

In the example a review of the socalled Formability map of thesimulation geometry reveals a large region to be insufficientlystretched.

Do as follows to improve the predictions of uniform stretching:Modify the binder pressure value to 10 N/mm, a value suitable forthe higher thickness (1.2 mm) and higher strength sheet material.After modifying the simulation input data, save these to a new sim-ulation file, run the simulation and review the results.



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Lesson 4: Full tool (1-Step) SimulationLesson 4: Full tool (1-Step) SimulationLesson 4: Full tool (1-Step) SimulationLesson 4: Full tool (1-Step) Simulation

55

Definition of the BinderDefinition of the BinderDefinition of the BinderDefinition of the BinderThe meshed tool geometry is shown in the main display. Use theright mouse button to click on the binder surface of the tool geome-try. The selected surface is highlighted in yellow. Click on theBinder button on the Prepare page of the Geometry generator tosave these faces in the Binder register.

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

Selecting the binder surface



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Calculation of the Part boundaryCalculation of the Part boundaryCalculation of the Part boundaryCalculation of the Part boundaryPreparePreparePreparePreparePart boundary generation > Error tolerance: 0.1 > Concatenation

distance: 30.00

To confirm the above selection, click on the button

Apply

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

Geometry generator: PreparePreparePreparePrepare page


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The part boundary of the remaining tool geometry (without binder)is shown as a blue line in the main display.

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

Representation of the part boundary

User interfaceUser interfaceUser interfaceUser interface Model > Input generator ... > Simulation type: OneStep > OK

AFOS Input generator AFOS Input generator AFOS Input generator AFOS Input generatorGeometry > Type > Full tool (1-Step)

The predefined OS boundary has to be deleted.

Delete > Autoform - Question: Delete the current OS boundaryline? > Delete

ToolToolToolToolThe surfaces saved in the Part and the Binder registers are used toautomatically define the tool geometry.

Definition of the OS boundaryDefinition of the OS boundaryDefinition of the OS boundaryDefinition of the OS boundaryThis line represents the outer edge of the stamped part. Again, thismay be defined as dependent upon the punch opening line.

Dependent ... > Bndry (Pre) 1 > OK > Edit > Curve editor > Glo-bal mod > Expand: 40 > OK



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Definition of the OS punch openingDefinition of the OS punch openingDefinition of the OS punch openingDefinition of the OS punch openingThe punch opening line may be defined as dependent upon as part

boundary.

Dependent ... > Bndry (Pre) 1 > OK

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

AFOS Input generator: Geometry Geometry Geometry Geometry page


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

OS boundary OS boundary OS boundary OS boundary and OS punch openingOS punch openingOS punch openingOS punch opening

Blank Blank Blank Blank Define the sheet thickness:

Thickness: 1.0

Select the following material:

Material: Import... > Steel_General+Europe: if18_1.mat > OK

Define the weld line now:

Add weld... > Weld line > Input ...



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

Weld Weld Weld Weld dialog

The Curve editor is opened. Define the weld line by entering twopoints (x = 0/0 , y = 200/-200). The start and end point of the weld lineare positioned on the OS boundary.

NoteNoteNoteNote: To create a vertical line, press the Shift ShiftShiftShift key when setting theend point of the weld line.

Fig. 4.8Fig. 4.8Fig. 4.8Fig. 4.8

Definition of the weld line position

Following the definition of the weld line, specify a new sheet thick-ness value, and then select the side of the defined weld line wherethe new thickness value applies ( Weld dialog):

Thickness: 1.5

Properties apply at > Click


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Fig. 4.9Fig. 4.9Fig. 4.9Fig. 4.9

Definition of area in the sheet with changed material properties

Using the right mouse button, click at the right side of the weld lineto which the new thickness will apply.

Finalize the weld line definition in the Weld dialog by clicking on

OK

LubeLubeLubeLube Lubrication > Constant > Constant > Standard : 0.15

ProcessProcessProcessProcess As you are preparing a Full tool OneStep simulation, it makes sense

to define a binder pressure or binder force.

Holding condition > Type: > Binder pressure > Pressure: 6 >Binder stiffness: 50



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Fig. 4.10Fig. 4.10Fig. 4.10Fig. 4.10

ProcessProcessProcessProcess page

Leave the default settings on the Control page unchanged and startthe simulation in the AFOS input generator.

Job > Start simulation ... > Save > Start job: Start

After simulation is completed, the results may be viewed and eval-uated in the AutoFormUser Interface by reopening the simulationfile:

User interfaceUser interfaceUser interfaceUser interfaceFile > Reopen


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Select the result variable Thickness .

Fig. 4.11Fig. 4.11Fig. 4.11Fig. 4.11

Distribution of thickness



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Click on the button for the developed blank :

Fig. 4.12Fig. 4.12Fig. 4.12Fig. 4.12


You realize that the original linear weld line has moved during theforming process. It is the objective now to keep the weld line posi-tion as it is and to optimize the weld line position in such a way thatthe original blank can be formed with a linear weld line.

To achieve the objective, define material marks at both ends of theweld line on the developed blank.

User interfaceUser interfaceUser interfaceUser interfaceResults > Material marks ... > Set marks


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Fig. 4.13Fig. 4.13Fig. 4.13Fig. 4.13

Coordinates of the material marks

Define the two material marks as material line. Internally additional

material marks are added along the material line.AutoForm - Material marks > Define > Material line

Click on the button Formed Sheet in the lower left area of the Auto-FormUser Interface and display the originally defined weld line.

Display > Lines ... > Weld 1 > Dismiss

You can judge from the material lines if the warped position withinthe part is still acceptable and if the weld line is still in the correctposition.



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Fig. 4.14Fig. 4.14Fig. 4.14Fig. 4.14

Different weld line positions

Use the material line on the formed part as weld line for anothersimulation. For this purpose export the material line:

User interfaceUser interfaceUser interfaceUser interfaceResults > Material lines ... > Material line 1 > File > Write selectedto file > AF Poly3D > CLOSED polylines : No > weldnew.af >OK > Material lines > File > Dismiss

Save the simulation under another name:

User interfaceUser interfaceUser interfaceUser interfaceFile > Save as > os_lesson_4b.sim > OK

Open the AFOS Input generator again.

Model > Input generator ...

Edit the weld line position on the Blank page by importing thestored material line as new weld line.

Symmetry-planes/welds/holes > Edit ... > Import ... > Delete > For-mat: af > OK > weldnew.af > OK > curve 1 > OK > OK


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Start the simulation and check whether a linear weld line is avail-able in the developed blank.

Fig. 4.15Fig. 4.15Fig. 4.15Fig. 4.15

Optimized weld line on the developed blank



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68

4. 54. 54. 54. 5 Lesson 5: Full tool (2-step) SimulationLesson 5: Full tool (2-step) SimulationLesson 5: Full tool (2-step) SimulationLesson 5: Full tool (2-step) Simulation

This lesson is based on a prepared simulation file. The tool contained in this file has

been generated with AutoFormDieDesigner. Objective of this lesson is the definition ofsymmetry conditions and drawbeads. In addition, we will also show how to optimizethe initial blank.

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

Tool geometry

Opening the prepared Simulation FileOpening the prepared Simulation FileOpening the prepared Simulation FileOpening the prepared Simulation FileOpen the prepared simulation file in the AutoFormUser Interface:

File > Open ... > Select a file: os_lesson_05.sim > OK

The AFOS input generator is opened automatically. Because theGeometry page is shown in red, you have to enter more informa-tion on the Geometry page. The following settings have already

been defined: Full tool (2-step) simulation with tools and bindersurface. Define the OS boundary by importing an existing line inAutoForm format ( .af ).


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

AFOS Input generator: Geometry Geometry Geometry Geometry page

Import OS boundaryImport OS boundaryImport OS boundaryImport OS boundaryGeometryGeometryGeometryGeometry OS boundary > Import ... > Format: af > Vertices: use all rotate >

OK > Select a file: osboundary05.af > OK > Select curve: Curve 1 >OK

Define the OS punch opening line now. This line is defined asdependent on the punch opening line as specified in the DieDe-signer tool geometry.

OS punch openingOS punch openingOS punch openingOS punch openingGeometryGeometryGeometryGeometry OS punch opening > Dependent ... > Select curve: Punch opening

1 > OK

SymmetrySymmetrySymmetrySymmetryDefine the symmetryplane on the Blank page. The sheet thickness

and the material properties have already been specified.



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Blank Blank Blank Blank Symmetry-planes/welds/holes: Add symmetry ... > Symmetry-plane: Click segment > User interface: Click the OS boundary atthe symmetry-plane > Symmetry-plane: OK

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

Symmetry plane

Defining DrawbeadsDefining DrawbeadsDefining DrawbeadsDefining DrawbeadsDrawbeads may be modeled in AutoForm using a force factor tocontrol metal flow, without having to build the detailed drawbeadgeometry into the CAD model of the tool. This gives the user flexi-

bility in using AutoForm as a tryout tool using it to quickly com-pare the performance of different drawbeads visavis feasibilityrequirements, and to identify the best bead configuration, based oncomparisons, without having to modify tool geometry to accom-plish the same.

AFOS input generator AFOS input generator AFOS input generator AFOS input generatorAdd > Drawbead > Add drawbead: Use default settings > Adddrawbead

A Drawbead ( Drwbds ) page is added to the AFOS input generator.Define the position of the drawbead:


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

AFOS Input generator: DrawbeadDrawbeadDrawbeadDrawbead page

DrwbdsDrwbdsDrwbdsDrwbds Drawbead line > Input ... > Curve editor

Move the mouse cursor into the main display. Using the rightmouse button, click three points on the geometry to create thedrawbead (see Fig. 5.5). End input of the drawbead by double clickand finally close the Curve editor by clicking

Curve editor > OK



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

Position of the drawbead

Functions for generating a drawbead:

Name : Name of a drawbead can be specified.

Input ... : Position of drawbead line can be specified (Curveeditor). 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 differentlines.

Dependent ... : Drawbead line is created from an existingline. Drawbead line is a reference to the base line. Thismeans 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

Usage tip Curve editorUsage tip Curve editorUsage tip Curve editorUsage tip Curve editorA curve closed or open may be created using the Curve editor byadding control points (or nodes). Each new control point creates anew curve segment running from the last point to the new one.Curve segments may be linear or curved. It is possible to toggle

between two types of segments using the Ctrl key. Holding the Ctrl key down while creating a point with the right mouse button cre-ates a linear segment.


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Using just the right mouse button would create a curved segment. Itis possible to switch the mode of an existing segment betweencurved and linear modes by holding the Ctrl key down while click-ing (anywhere) on the segment with the right mouse button.

Starting the SimulationStarting the SimulationStarting the SimulationStarting the SimulationJob > Start simulation ... > Start job: Start

After simulation is completed, the results may be viewed and eval-uated in the AutoFormUser Interface by reopening the simulationfile:

User interfaceUser interfaceUser interfaceUser interface File > Reopen

The simulation results are shown by the result variable Formability in Fig. 5.6.

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

Simulation results



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The initial blank will be optimized now, i.e. as a result a rectangularor trapezoidal blank will be determined. Click the button Devel-oped blank.

User interfaceUser interfaceUser interfaceUser interfaceProcess > Process stage: Developed blank

The initial blank as calculated on the basis of the OS boundary isshown. Generate a trapezoidal blank on the initial blank usingmaterial marks. These material marks are completely connected tothe blank and will be defined as a material line.

Results > Material marks ... > AutoForm - Material marks: Setmarks

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

Position of the material marks

Having defined four points on the blank, define these points asmaterial line.


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

Coordinates of the material marks

AutoForm - Material marks > Define > Material line

Activate the process stage containing the actual results of theOneStep simulation.

Process > Process stage: Formed sheet



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

Material line at process stage Formed sheetFormed sheetFormed sheetFormed sheet

The material line defined above is now shown on the decklid geom-etry. Use this line as OS boundary for another Full tool (2-step) sim-ulation. For this export the material line in the process stage Formedsheet :

Results > Material lines ... > AutoForm - Material lines: Materialline 1 > File > Write selected to file ... > AF Poly3D > Should thedata written as CLOSED polylines: Yes > Select a file: Selection:osboundarynew.af > OK

Save the simulation under another name. A new simulation file isset up, containing the input data of the existing simulation file.

User interfaceUser interfaceUser interfaceUser interfaceFile > Save as ... > Save as: Selection: os_lesson_05b.sim > OK

Open the Input generator and go to the Geometry page:

Model > Input generator ... > Geometry


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Import the new OS boundary now:

OS boundary: Import ... > AutoForm - Question: Delete the cur-rent os boundary? Delete > AutoForm - Question: Delete currentlydefined symmetry plane(s)? Delete > Import line(s): Format: af >OK

Select a file: osboundarynew.af > OK > Select curve: Pick or selectfrom list: Curve 1 > OK

Attention Attention Attention Attention: The existing symmetryplane has been deleted by theimport of the new OS boundary. Go to the Blank Blank Blank Blank page of the Inputgenerator and redefine the symmetryplane.

Start the new simulation and check both the forming results and theshape of the initial blank.

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

Optimized trapezoid blank



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Lesson 6: OptimizationLesson 6: OptimizationLesson 6: OptimizationLesson 6: Optimization

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4. 64. 64. 64. 6 Lesson 6: OptimizationLesson 6: OptimizationLesson 6: OptimizationLesson 6: Optimization

This lesson describes in a simple example how process parameters can be automati-

cally optimized using the optimization algorithm of AutoForm. Process parameters inOneStep can be the restraining forces at the part boundary.

Fig. 6.1Fig. 6.1Fig. 6.1Fig. 6.1

Geometry of optimization example

AutoForm offers an optimization algorithm that is fully integratedinto the user interface. It allows the user to optimize various inputparameters, so that a robust and highquality part can be producedconsistently. Optimization criteria can be defined by the user by

using the different FLD zones. In most cases, the criteria will beused to produce a part without any cracks/splits and wrinkles, andhaving a uniform thickness strain (e.g. 2%) in all areas. Inputparameters, which are available for an optimization can be binderforces, drawbead force factors, blank size or tool geometry (usingAutoFormDieDesigner). For all these optimization parameters, theuser defines (a) the parameters and (b) the allowable minimum andmaximum values of these parameters. Selected optimization param-eters are marked in the Input and Geometry generator in yellow(highlighted).

Parameter studies are also possible with AutoFormOptimizer.Input parameters can be automatically varied and the result varia-tions can be analyzed to determine the process sensitivity anddependence on the parameters. The goal is to find the dependencyof the results of the drawing process on the parameters and todetermine a process window.

In the following example an optimization of restraining forces at the

part boundary is defined which is based on a completed OneStepsimulation.


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Open the simulation file os_lesson_06_basis.sim :

File > Open > os_lesson_06_basis.sim > OK

Create an optimization:

Model > Input generator > Create > Optimization

First the design variables have to be defined, which will automati-cally be varied by the optimization algorithm, to achieve better partquality. The restraining forces on the part boundary ( RestrainingConstant ) will be optimized. Proceed as follows:

ProcessProcessProcessProcess Restraining > Constant

Click with the right mouse button the yellow framed input field ofthe restraining force. A menu titled Add/edit design variable willopen (Fig. 6.2).

Fig. 6.2Fig. 6.2Fig. 6.2Fig. 6.2

Menu to define design variable

Name : Name of the design variable

Dependent : Name of a previously defined design variable:This defines a dependent design variable, which means thevalue of this parameter depends on the previous one.

Independent : Definition of a fully independent designvariable

Start : Starting value of design variable to use Min : Minimum allowable value of design variable Max : Maximum allowable value of design variable

The optimization range of restraining force is between a free part boundary ( Forcefactor = 0.0 ) and a fixed or fully locked part bound-



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ary ( Forcefactor = 2.0 ). The start value for the restraining force is afree part boundary ( Forcefactor = 0.0 ).

Complete the input for force factor of the first restraining force(design variable) by using the submenu titled Design variabledefinition of the menu Add/edit design variable as follows:

Name: rest > Dependent: Independent > Start: 0 > Min: 0 > Max: 2 (Fig. 6.2) > OK

Now the background color of input field has changed to yellow.This means the parameter is to be used as a design variable. Thename of this variable is displayed in the input field (Fig. 6.3).

Fig. 6.3Fig. 6.3Fig. 6.3Fig. 6.3

Menu to define restraining forces

ProcessProcessProcessProcessRestraining > Constant > The design variable rest (force factor) isdefined

All design variables have been defined now. Complete the input onOptimize page of Input generator. Switch to this page (Fig. 6.4).


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Fig. 6.4Fig. 6.4Fig. 6.4Fig. 6.4

Optimize Design v.Optimize Design v.Optimize Design v.Optimize Design v. page of Input generator

Design variablesDesign variablesDesign variablesDesign variables Optimization/Parameter study : Definition of optimizationor parameter study

Optimization : Optimization will be performed. Normal random : Parameter study; variables will have a

Gaussian distribution around a defined center in parame-ter range.

Uniform random : Parameter study; variables will have an

arbitrary distribution in parameter range. Regular grid : Parameter study; variables will have a regu-lar distribution in parameter range with a specified number of calculations.

Name : Name of design variable Current : Current value of design variable for the open

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