AutoForm_OneStep

(1)

(2)

www.alghaform.com

www.forum.alghaform.com

ALGHAFORM FORUMLARI PAYLASIMIDIR

iletisim: [email protected]

(3)

AutoForm–OneStep 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 flexible input in AutoForm–OneStep permits the creation of a binder sur-face including the punch opening line. Thus AutoForm–OneStep is suited for a simple feasibility analysis and additionally for a quick verification of a tool design and the comparison of different tool concepts. The simulation of completely designed tools can be made in extremely short calculation times. The seamless integration of AutoForm–OneStep with the AutoForm–Optimizer helps you find-ing optimized geometry and process parameters.

The inverse formulation of AutoForm–OneStep allows for the sim-ple and precise determination of the blank outline and thus the min-imal material requirements. This opens new perspectives for quotations/estimations as well as for tool design considering the optimized blank and thus the minimal material consumption. The integration with all other AutoForm products makes many additional functions available such as AutoForm–DieDesigner or AutoForm–Optimizer for the optimization of the part geometry, binder surfaces, addenda or process parameters.

AutoForm–OneStep supports five different calculation types, which require different forming knowledge of the user and are used for different 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; starting from the part geometry the flat blank is calculated (inverse calcula-tion method). The specificacalcula-tion of the part boundary line allows for the simple modification of the part boundary.

This simplest calculation type requires the least forming knowledge of the user and is especially suited for forming analyses during part design as well as for the estimation of the forming complexity of the part and for the determination of the minimal material consump-tion for quotaconsump-tion and estimaconsump-tion purposes. As the impact of the addendum is only considered by restraining forces on the part

(4)

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 but

the curved blank, which in the real forming process conforms to the shape of the sheet after binder closure. The binder surface has to be defined. 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 with

extremely curved binder surfaces. Since there is no real addendum involved in the calculation, it is important to have an especially realistic 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 of the calculated results.

For this reason, this method is useful for the part designer who does not necessarily have a deep understanding of the forming process.

Part+Binder Part+Binder Part+Binder Part+Binder (2-step) step) step) step) Based on the defined binder surface and punch opening line,

Auto-Form–OneStep automatically generates a simple addendum, run-ning out of the part boundary tangentially and runrun-ning into the binder surface on the punch opening line tangentially. The calcula-tion is based on the part and the addendum using the two step method. If a realistic binder surface is available, this calculation type improves the quality of the results considerably compared to the Part only calculation, because a rough geometric addendum is taken into account – the simulated process is thus closer to the real forming process.

This calculation type is especially well–suited for rapid verification and comparison of different tool concepts. Since the binder essen-tially influences the addendum and hence the results, the user should 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 punch

opening line and the flange boundary line at the end of the forming process have to be defined. These two lines determine the flange surface, on which binder pressure is applied to control material flow. The Full tool calculation type gives the most precise results of all OneStep calculation types.

(5)

This approach is well–suited for the verification of tool concepts, developed e.g. in AutoForm–DieDesigner. As the blank outline after forming (OS boundary) has to be defined due to the inverse calculation method, precise minimal pre–cut parts can be deter-mined, which can then be used as initial blank for an incremental simulation. The 1-step option of the Full tool calculation is suited for 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 and retraining 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 option should be preferred – otherwise the simulation assumes that the restraining forces in the binder surface already apply for binder clo-sure. That does not correspond to the real forming process and may lead to a significant overestimation of strains. Besides the remarks on the Full tool (1-step) calculation type obtain.

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

Legend:

pb line = part boundary line f line = flange line

Part only Part only Part only Part only (1 - step) (1 - step) (1 - step) (1 - step) Part only Part only Part only Part only (2 - step) (2 - step) (2 - step) (2 - step) Part + Part + Part + Part + Binder Binder Binder Binder (2 - step) (2 - step)(2 - step) (2 - step) Full tool Full tool Full tool Full tool (1 - step) (1 - step) (1 - step) (1 - step) Full tool Full tool Full tool Full tool (2 - step) (2 - step)(2 - step) (2 - step) 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 punch

opening

(6)

analyses during part design. It makes possible the optimization of forming parameters in the most important geometric modifications of the part in AutoForm:

• Automatic generation of variable fillets on the product geometry

• 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 in the 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 for the Part only (2-step) calculation type.

• Fully parametrized treatment of input data to facilitate the optimization with AutoForm–Optimizer

• AutoForm–OneStep provides five different simulation types.

For certain functions described in this workshop the AutoForm– PartDesigner must be available. The respective functions are marked.

One of the most important features of AutoForm–OneStep Version. 3.1 is the greatly improved user–friendliness and the ease with which the simulations are set up, run and evaluated. The Onestep wizard has been developed for the Part only simulation. This wiz-ard makes it possible to run feasibility studies quickly and reliably considering different process parameters in a single simulation

(7)

Contents of the Workshop „AutoForm–OneStep“

Lesson 1 Lesson 1 Lesson 1

Lesson 1 Part only Simulation with OneStep WizardPart only Simulation with OneStep WizardPart only Simulation with OneStep WizardPart only Simulation with OneStep Wizard . . . .. . . .. . . .. . . .6666 • Importing CAD data

• Determining the drawing direction • Defining holding conditions • Evaluating the OneStep simulation Lesson 2

Lesson 2 Lesson 2

Lesson 2 Part only (2-step) SimulationPart only (2-step) SimulationPart only (2-step) SimulationPart only (2-step) Simulation . . . .21212121 • Variable Restraining Option

• Preparing the geometry • Part boundary

• Binder surfaces Lesson 3

Lesson 3 Lesson 3

Lesson 3 Part + Binder (2-step) SimulationPart + Binder (2-step) SimulationPart + Binder (2-step) SimulationPart + Binder (2-step) Simulation. . . .. . . .. . . .. . . .37373737 • Filling holes

• Boundary fill

• Automatic binder generation (Auto Binder) Lesson 4

Lesson 4 Lesson 4

Lesson 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 5

Lesson 5 Lesson 5

Lesson 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 6

Lesson 6 Lesson 6

Lesson 6 OptimizationOptimizationOptimizationOptimization . . . .. . . .. . . .. . . .78787878 • Numerical optimization

• Parameter study

• Optimization of the force factor

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

(8)

4. 1

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

Lesson 1: Part only Simulation with OneStep Wizard

This lesson presents a simple example for AutoForm–OneStep. Using AutoForm– OneStep is it possible to run a feasibility analysis for the part geometry in a fast and straightforward manner.

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

Geometry for the OneStep simulation

Setting up the Simulation File

At the start of the OneStep simulation, you have to define the simu-lation file (*.sim). This simusimu-lation file contains all the information about 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):

(9)

Fig. 1.2 Fig. 1.2 Fig. 1.2 Fig. 1.2 OneStep wizard OneStep wizard OneStep wizard OneStep wizard

Importing the Part Geometry

The geometry import is carried out using the module afmesh, the integrated IGES–/VDAFS interface, which automatically meshes the part geometry. The part geometry needs to be available as surface model containing the inner or outer side of the part geometry. The following formats are supported for import: af, afb (binary Auto-form–Format), Nastran, Dyna and Stl.

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

OneStep wizard OneStep wizard

OneStep wizard Import ... > VDAFS > OK > Files: os_lesson_01.vda > OK >

afmesh_3.1 > OK Fig. 1.3 Fig. 1.3 Fig. 1.3 Fig. 1.3 Import geometry Import geometry Import geometry Import geometry

(10)

Fig. 1.4 Fig. 1.4 Fig. 1.4 Fig. 1.4 Afmesh AfmeshAfmesh Afmesh

Options for meshing the CAD data

Parameters Parameters Parameters Parameters • 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 error tolerance.

• Max side length: Maximum element side length. Default setting: 50.

Faces Faces Faces Faces • Treat only: Only specified faces will be meshed. Possible

entries are e.g. 1, 2, 6-8.

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

Layers Layers Layers Layers • Treat only (for IGES import only): Only specified layers

will be meshed.

• Exclude (for IGES import only): The specified layers are not taken into account for meshing.

The meshed part geometry is immediately displayed in the main display.

(11)

Fig. 1.5 Fig. 1.5 Fig. 1.5 Fig. 1.5 OneStep wizard OneStep wizard OneStep wizard OneStep 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 user interface.

Note Note Note

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

OneStep wizard OneStep wizard OneStep wizard

OneStep wizard Title: lesson_01

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

• Geometry • Blank • Process

(12)

First, the part geometry has to be rotated such that the drawing direction corresponds to the z–axis and no backdrafts occur in the part. Use the buttons in the field Tip.

Checking for Undercuts Checking for UndercutsChecking for Undercuts Checking 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 3

degrees

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

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

Geometry > Tip > Min backdraft

This function calculates a drawing direction with minimum under-cuts. Fig. 1.6 Fig. 1.6 Fig. 1.6 Fig. 1.6 Backdrafts BackdraftsBackdrafts

(13)

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

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

Undercut free part geometry

Having tipped the part geometry, you can now apply filleting in the areas 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 geometry Global Filleting of all sharp edges in the part geometry Global Filleting of all sharp edges in the part geometry Global Filleting of all sharp edges in the part geometry Use the following command to fillet sharp edges:

Geometry > Fillet > Radius: 3

Filling the Part boundary Filling the Part boundary Filling the Part boundary Filling the Part boundary

Generate the boundary fill now. Fill areas are created automatically along the part boundary. The outer boundary fill line is determined by a roll cylinder moving around the part boundary and its roll radius:

(14)

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

Apply

The resulting geometry containing the generated part boundary is shown 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. 1.8 Fig. 1.8 Fig. 1.8 Fig. 1.8

The resulting geometry and the part boundary

Fig. 1.9 Fig. 1.9 Fig. 1.9 Fig. 1.9 Detail DetailDetail

(15)

Fig. 1.10 Fig. 1.10 Fig. 1.10 Fig. 1.10 Detail Detail Detail

Detail: Part boundary – after boundary fill

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

Defining Material Properties Defining Material Properties Defining Material Properties Defining Material Properties Blank > 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 to stretch forming, e.g. for tools with extremely high binder pressure. Restraining forces, corresponding to a usual tool in which material draw–in 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).

(16)

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

OneStep wizard OneStep wizardOneStep wizard

OneStep wizard: Prepared OneStep–Part onlyPart onlyPart only simulation Part only Store the prepared simulation and start the simulation:

File > Save as ... > os_lesson_01.sim > OK Start ... > Program: afos_3.1 > Start

Note NoteNote

Note: The OneStep wizard contains a number of selected functions for the definition of the simulation. Use the Advanced ...Advanced ...Advanced ...Advanced ... button to access additional functions in AutoForm–OneStep. These addi-tional functions will be described in the following lessons.

(17)

Evaluating

Evaluating Simulation Results

Simulation Results

The following section describes the most important result variables of a OneStep simulation. Having completed the calculation of the simulation, re–open the SIM file using the command:

User interface User interface User interface

User interface File > Reopen

The main display shows the calculated part geometry. In the lower part of the user interface, three buttons are available: free, medium and locked. Click one of the buttons to load the results for the respective holding condition from the SIM file. Compare the results. Fig. 1.12

Fig. 1.12 Fig. 1.12 Fig. 1.12

The user interface after loading the calculated simulation Formability

Formability Formability Formability

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

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

• Excess. Thinning (orange): In these areas, thinning is greater than the acceptable value (default value for steel is 30%).

(18)

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

• 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 compressive stresses 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 which means the material becomes thicker during the forming process.

Select the result variable Formability. Compare the results for the different 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. 1.13 Fig. 1.13 Fig. 1.13 Fig. 1.13 Formability FormabilityFormability

(19)

Fig. 1.14 Fig. 1.14 Fig. 1.14 Fig. 1.14 Formability Formability Formability

Formability with holding condition mediummediummediummedium Fig. 1.15 Fig. 1.15 Fig. 1.15 Fig. 1.15 Formability Formability Formability

(20)

You can see from the figure that the part is insufficiently stretched, using the holding conditions free and medium. There are several areas containing wrinkles (purple), wrinkling tendencies (blue) and insufficient 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).

Thinning ThinningThinning Thinning

Switch to the 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 (depending on the specified color settings) (Fig. 1.16).

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

Thinning (in percentage) with the holding condition lockedlockedlockedlocked 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 thin-ning and the maximum thickethin-ning of the part use the following options

User interface User interface User interface User interface

Results > Show max Results > Show min

(21)

Close AutoForm–User Interface

The user interface can be closed with following option:

File > Quitor hotkey Ctrl – Q.

The area Geometry (OneStep wizard)

Use the functions of this area to check if the meshed part geometry is suitable for the simulation (undercuts and sharp edges) and to prepare the geometry for the simulation. The following functions are available:

• Symmetry: Define the symmetry plane for symmetrical parts. This definition is possible for the values X = 0, Y = 0 or no symmetry.

• Tip: Determines the drawing direction of the part.

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

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

• Reset: Uses the original axis of CAD data (z–axis) as draw-ing direction.

• X- and Y-axis: Allows for the manual rotation by a defined angle about the x– or y–axis.

• Del picked: Removes selected faces from the meshed geometry.

• Del backdraft: Removes faces containing undercuts from the geometry.

• Undel picked: Deleted faces are restored. • Undel all: All deleted faces are restored. • Display: Switch for the representation

• Faces: Each face is represented by another color. • Objects: The geometry is represented by a single color. • Backdraft: The geometry is automatically checked for faces

containing undercuts. The faces are colored green for safe areas, yellow for areas with marginal undercuts and red for areas containing severe undercuts.

• Deleted: Deleted faces are displayed again.

• Part boundary: The part boundary needed for the simula-tion is generated.

• Error tolerance: Acceptable chordal error for the part boundary. The value can be changed. For especially small radii (equal or lesser than 2 mm) 0.05 should be used as error tolerance.

(22)

• Fillet: The geometry is checked for sharp edges. The sharp edges 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 functions defined.

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 Process

Use the functions of this area to define the restraining forces (Hold-ing conditions). The follow(Hold-ing hold(Hold-ing 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 freely defined values (User def.). Decide which of the holding conditions will 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. By default the three holding conditions (Free, Medium and Locked) are set. In version 3.1, all OneStep results are stored in a single SIM file thus eliminating the need for manual iterations with different conditions being stored in separate files.

(23)

4. 2

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

Lesson 2: Part only (2-step) Simulation

The functions introduced in this lesson make possible the more precise definition of restraining forces in AutoForm–OneStep. Besides the Part only (2-step) simulation calcu-lates the developed blank more precisely. This simulation type requires the definition of a 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 process takes into account friction as well as the restraints applied to the OS boundary, and establishes the outline of the developed blank mapped on to the geometry of the curved binder surface.

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

The above 2–step approach is more representative, particularly in the case of curved and deep–drawn parts, of the actual stamping process. Therefore, results of 2–step simulations are more accurate for these parts, and are closer to those of an incremental process simulation.

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

Cross member geometry including the binder surface

Setting up a new Onestep Simulation

User interface

User interface User interface

User interface File > New onestep … to open the OneStep wizard.

Importing and Editing the CAD geometry

Use the following commands to import the CAD data: OneStep wizard

OneStep wizard OneStep wizard

OneStep wizard Import ... > VDAFS > OK > os_lesson_02.vda > OK > Program:

(24)

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

Editing Parts Faces

There is an upstanding flange around one of the holes of this part. If this flange were to remain on the part geometry during simulation, a prediction of cracks would result at the flange. However, since these flanges would be formed in a secondary operation, they may be ignored in the OneStep simulation without any errors, and may therefore be eliminated as follows: Hold the Shift key down and use the right mouse button to pick the flange faces. Click the Del picked 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 into account during subsequent simulation.

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

Selected flange faces for deletion

(25)

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

Representation of deleted faces

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

Establishing the Drawing Direction

In preparation for a simulation, the imported product geometry needs to be rotated so that the drawing direction for the product is parallel to the z–axis: There should be no backdraft faces on the geometry relative to the z–direction. There are several manual or automatic options that you may apply to establish the required die tip. The ideal die tip may be established in the present case using the Min Backdraft option:

Display: Backdrafts shows backdrafts on the geometry.

Tip: Min backdraft re–orients the product geometry such that the product faces, on average, have the largest possible inclination to the z–direction.

(26)

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

Re–oriented geometry with representation of backdrafts

Generating the Part Boundary

(Outer boundary of the product geometry)

After editing the product geometry, the boundary of the current geometry may be generated automatically by clicking the Apply button.

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

(27)

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

Geometry with part boundary

Defining the Material Properties

The default material selection is FeP04; an alternate material file may be selected from the extensive material library using the Import ... button.

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

Use the buttons View or Preview to display the properties of the selected material: Hardening curve, forming limit curve and r–val-ues. Fig. 2.6 Fig. 2.6 Fig. 2.6 Fig. 2.6 Select material Select material Select material

(28)

Files: zste220P_1.mat > OK

The Advanced Mode

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

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

OneStep wizard OneStep wizardOneStep wizard

OneStep wizard containing all information

Additional information is entered in the Advanced mode. Click

OneStep wizard OneStep wizard OneStep wizard OneStep wizard

Advanced ...

The dialog AutoForm - Question pops up:

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

AutoForm - Question AutoForm - QuestionAutoForm - Question AutoForm - Question

(29)

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

AFOS Input generator AFOS Input generator AFOS Input generator AFOS Input generator

The full function range of the AFOS input generator will be

described in one of the following lessons. For this example only the pages Geometry and Process are used. For the following steps, we require a license for AutoForm–PartDesigner.

(30)

Preparing a Binder Surface

Open the Geometry generator.

Model > Geometry generator ...

Binder Binder Binder Binder Generate a binder on the Binder page.

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

Geometry generator: BinderBinderBinder pageBinder

Binder Binder Binder Binder

(31)

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

Fig. 2.11 Fig. 2.11 Fig. 2.11 Fig. 2.11 Log Log Log Log window

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

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

Product geometry with binder

Selecting the Geometry Type

Select the geometry type Part only (2-step) on the Geometry page of the Input generator.

Geometry Geometry Geometry Geometry

(32)

Fig. 2.13 Fig. 2.13 Fig. 2.13 Fig. 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

In a lot of cases, a constant magnitude of restraining force applied to the OS boundary in a Part only simulation does not lead to optimal predictions of product quality. For example, localized areas may be insufficiently stretched, or may have very large strains close to or exceeding the forming limit (leading to a prediction of cracks). In such cases, it would be useful to vary the holding conditions around the OS boundary to achieve optimal stretch conditions over the entire product geometry without causing splits, cracks or exces-sive thinning.

Process Process Process Process

Medium > Restraining options > Variable

(33)

Holding condition > Name: restr

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

Restraining options Variable Restraining options Variable Restraining options Variable Restraining options Variable

Before selecting nodes along the part boundary using the function Input points ..., we recommend to adjust the view from z–direction. User interface

User interface View > From +Z (yx) and

View > Fit to window

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

Input generator Input generator

Input generator restr > Input points …

(34)

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

Definition of restraining forces

Add/edit point

Fig. 2.15 b Fig. 2.15 b Fig. 2.15 b Fig. 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 and define a specific restraining force factor value at each of the selected nodes.

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.

(35)

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

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

15 nodes with different force–factors Fig. 2.17

Fig. 2.17 Fig. 2.17 Fig. 2.17

Variable restraining forces

Evaluation of the results

User interface

User 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 AutoForm–User Interface.

(36)

Click the button for the result variable Formability: Fig. 2.18 Fig. 2.18 Fig. 2.18 Fig. 2.18 Formability FormabilityFormability

Formability with variable restraining forces

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

Use the three buttons on the lower left side of the AutoForm–User Interface to select the desired representation.

(37)

shows the binder-wrap. Fig. 2.19 Fig. 2.19 Fig. 2.19 Fig. 2.19 Binderwrap Binderwrap Binderwrap Binderwrap

(38)

shows the developed blank. Fig. 2.20 Fig. 2.20 Fig. 2.20 Fig. 2.20 Developed blank Developed blankDeveloped blank Developed blank

(39)

4. 3

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

Lesson 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 be used 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 parameters in conjunction with product geometry in early stages itself.

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

Part geometry

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

User interface File > New > File name: lesson_os3

Units: mm and N

Geometric error tolerance: 0.1 > OK

Geometry Geometry Geometry Geometry gen-erator erator erator

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

Prepare Prepare

(40)

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

Sharp Edges

Go to the Fillet page to determine the sharp edges of the geometry.

Fillet Fillet Fillet Fillet Check radius: 2.00 > Check > OK

The areas on the part containing sharp edges are displayed.

Fig. 3.3 Fig. 3.3 Fig. 3.3 Fig. 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 to fillet sharp edges: Globally with a global fillet radius or locally with

(41)

a constant or variable radius or radius transition. We will describe all these variants.

Global Filleting Global Filleting Global Filleting Global Filleting

Global fillet radius: 3.00 > Apply

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

Local Filleting by a Constant Radius (requires Local Filleting by a Constant Radius (requires Local Filleting by a Constant Radius (requires Local Filleting by a Constant Radius (requires AutoForm–PartDe-signer license)

signer license) signer license) signer license)

In order to generate variable radii at individual edges, the edges need to be identified and the radii need to be specified. Click the Add line ... button at the bottom of the Fillet page to identify sharp edges.

Add line ... opens the window containing the message: Mark radius control edge. Finish with double click.

Selecting an edge also involves identifying the length along the edge 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. 3.4

Fig. 3.4 Fig. 3.4 Fig. 3.4

(42)

Click once with the right mouse button to select the starting point at an edge of interest, let go the mouse button and move your mouse cursor along the curved outline of the edge. This progressively highlights (in yellow) the length of the edge. Double click the right mouse button to end the edge selection.

Note NoteNote

Note: If the run of the curve representing the edge is ambiguous (long, extremely curved edge or branchings along the curve), set intermediate points to define the run of the curve precisely. Click the right mouse button repeatedly along the curve representing the edge. Fillet Fillet Fillet Fillet Add 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 AutoForm–PartDe-Local Filleting by a Variable Radius (requires AutoForm–PartDe-Local Filleting by a Variable Radius (requires Local Filleting by a Variable Radius (requires AutoForm–PartDe-signer license)

signer license)signer license) signer license)

To generate variable fillets, the edges to be filleted need to be selected as described above. Subsequently, „radius control“ points are selected on each of these edges, and radius values are specified at each of these points.

Fillet Fillet Fillet Fillet

Add line ... > line2: > Variable > Selecting 4 radius control points >

(43)

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

Locally filleted edges Fillet

Fillet Fillet

Fillet Assign a radius to each of the control points. Finally click the button

(44)

The Fillet page is as shown in Fig. 3.6: Fig. 3.6 Fig. 3.6 Fig. 3.6 Fig. 3.6 Fillet FilletFillet Fillet page

Definition of Drawing Direction

Tip Tip Tip Tip It is necessary to rotate the imported geometry from vehicle to draw position in order to eliminate backdraft conditions.

(45)

Fig. 3.7 Fig. 3.7 Fig. 3.7 Fig. 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 AutoForm–PartDesigner license) Modify P page (requires AutoForm–PartDesigner license) Modify P page (requires AutoForm–PartDesigner license) Modify P page (requires AutoForm–PartDesigner license) Use the functions of the Modify P page to fill holes contained within the part geometry.

Modify P Modify P Modify P

Modify 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:

Bndry Bndry Bndry

Bndry Add Bndr fill ... > Curve 1 > OK > Fill parameters: Bndry fill roll radius: 300 > Apply

Note Note Note

Note: Smoothening the part boundary increases the accuracy of the simulation results on the part boundary, especially for concave regions.

(46)

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

Filling holes and boundary fill

Generate the binder surface on the Binder page using the Auto-Binder function (requires AutoForm–PartDesigner).

Binder Binder Binder Binder

Auto

For the binder a minimum drawing depth is required. Drawing depth: Minimum

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

(47)

Fig. 3.9 Fig. 3.9 Fig. 3.9 Fig. 3.9 Auto Binder Auto Binder Auto Binder Auto Binder page Binder

Binder Binder

Binder Apply

A curved binder surface has been generated. Analyze the distance between the binder and the part in the AutoForm–User Interface. Adjust the value range of the result scale for the current example: Geometry generator > Display > Ranges > Min/Max Simulation

(48)

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

Plot of the drawing depth distribution on the part geometry

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

Adjusting display range

Click any area of the part with the right mouse button to display the actual drawing depth value. Change the distance between binder and 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:

Model > Input generator > Simulation type: OneStep > OK

AFOS input generator AFOS input generatorAFOS input generator AFOS input generator

Title Title Title Title Enter the title of the simulation. Enter further information on the

(49)

Geometry Geometry Geometry

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

Fig. 3.12 Fig. 3.12 Fig. 3.12 Fig. 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 Geomgeom-etry generator. The sheet thickness for the part is 1.2 mm. By specifying an offset of 0.6 mm (Upwards), the simulation may be carried out on the mid-surface of the product geometry – an Upwards offset is used since the imported surface represents the lower surface of the product. Geometry

Geometry Geometry

Geometry Part > Offset: 0.6

Definition of the Punch Opening Line Definition of the Punch Opening Line Definition of the Punch Opening Line Definition of the Punch Opening Line

The punch opening line is used to define areas in which the gener-ated mesh for the addendum has a tangential transition to the binder.

(50)

OS punch opening line OS punch opening lineOS punch opening line OS punch opening line

Dependent ... > Bndry (Bndry) > OK

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

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

Select Curve Select CurveSelect Curve

Select Curve dialog

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

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

Curve editor Curve editorCurve editor

Curve editor: OS–PO line

The same approach – using the geometry of the Bndry (Bndry) line as the starting point for defining another line may be employed to accomplish 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

(51)

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

OS boundary > Dependent ... > Bndry (Bndry) > OK Edit ... > Expand: 90 > OK > Smooth: 0.1 > OK

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

OS PO–line and OS boundary Blank

Blank Blank

Blank Thickness: 1.2 > Material: zste340_3 Fig. 3.16 Fig. 3.16 Fig. 3.16 Fig. 3.16 Blank Blank Blank Blank page

Definition of Friction

Lube Lube Lube

(52)

Fig. 3.17 Fig. 3.17 Fig. 3.17 Fig. 3.17 Process ProcessProcess Process page

Definition of the Process Parameters

Process Process Process Process Holding Conditions > Type: Binder pressure

Pressure options > Pressure: 6 (default) Note

NoteNote

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

Control Control Control Control Accuracy > Mesh: Standard

Starting the Simulation Starting the SimulationStarting the Simulation Starting the Simulation

AFOS input AFOS input AFOS input AFOS input gen-erator

erator erator erator

Job > Start simulation ... > Save > Start

Evaluating the simulation

File > Reopen

As a result of the simulation you can evaluate three different phases.

Developed blank Developed blank Developed blank Developed blank

The outline of the developed blank is computed during the simula-tion. The edge of this blank may be exported in af, IGES or VDAFS format, and may be used to define the blank in an AutoForm–Incre-mental simulation. Blank outline may be exported as follows:

(53)

Fig. 3.18 Fig. 3.18 Fig. 3.18 Fig. 3.18 Developed blank Developed blank Developed blank Developed blank Binderwrap Binderwrap Binderwrap Binderwrap

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

(54)

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

Binder wrap Binder wrapBinder wrap Binder wrap Formed sheet Formed sheet Formed sheet Formed sheet

AutoForm–OneStep offers among others the following results: • Distribution of strain and all dependent variables such as

sheet thickness, failure, wrinkling, hardening, forming limit analysis and stress

• Binder pressure distribution in the flange area • Distribution of sheet reaction stress

• Friction shear stress • Formability etc.

(55)

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

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

In the example a review of the so–called Formability map of the simulation geometry reveals a large region to be insufficiently stretched.

Do as follows to improve the predictions of uniform stretching: Modify the binder pressure value to 10 N/mm², a value suitable for the 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 simsim-ulation and review the results.

(56)

4. 4

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

Lesson 4: Full tool (1-Step) Simulation

This lesson describes a OneStep simulation based on a tool geometry with a tailored blank. In addition, that the weld line position is optimized in such a way that the original blank contains a linear weld line – thus reducing costs for the blank.

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

Tool geometry

Setting up a new Simulation

File > New … > File name: os_lesson_4 >Length: mm > Force: N > Geometric error tolerance: 0.1

Geometry Geometry Geometry Geometry gen-erator erator erator erator

File > Import... > VDAFS > OK > Files: os_lesson_4.vda > OK

AF–Mesh window AF–Mesh window AF–Mesh window AF–Mesh window Error tolerance: 0.1 > Max side length: 50 > OK

(57)

Definition of the Binder

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

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

(58)

Calculation of the Part boundary

Prepare Prepare Prepare Prepare Part boundary generation > Error tolerance: 0.1 > Concatenation

distance: 30.00

To confirm the above selection, click on the button

Apply

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

(59)

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

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

Representation of the part boundary User interface

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

AFOS Input generator AFOS Input generator AFOS Input generator AFOS Input generator

Geometry > Type > Full tool (1-Step)

The pre–defined OS boundary has to be deleted.

Delete > Autoform - Question: Delete the current OS boundary line? > Delete

Tool Tool Tool Tool

The surfaces saved in the Part and the Binder registers are used to automatically define the tool geometry.

Definition of the OS boundary Definition of the OS boundary Definition of the OS boundary Definition of the OS boundary

This line represents the outer edge of the stamped part. Again, this may be defined as dependent upon the punch opening line.

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

(60)

Definition of the OS punch opening Definition of the OS punch openingDefinition of the OS punch opening Definition of the OS punch opening

The punch opening line may be defined as dependent upon as part boundary.

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

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

(61)

Fig. 4.6 Fig. 4.6 Fig. 4.6 Fig. 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:

(62)

Fig. 4.7 Fig. 4.7 Fig. 4.7 Fig. 4.7 Weld WeldWeld Weld dialog

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

Note NoteNote

Note: To create a vertical line, press the ShiftShiftShiftShift key when setting the end point of the weld line.

Fig. 4.8 Fig. 4.8 Fig. 4.8 Fig. 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 where the new thickness value applies (Weld dialog):

Thickness: 1.5

(63)

Fig. 4.9 Fig. 4.9 Fig. 4.9 Fig. 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 line to which the new thickness will apply.

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

OK

Lube Lube Lube

Lube Lubrication > Constant > Constant > Standard: 0.15 Process

Process Process

Process 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

(64)

Fig. 4.10 Fig. 4.10 Fig. 4.10 Fig. 4.10 Process ProcessProcess Process page

Leave the default settings on the Control page unchanged and start the 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 AutoForm–User Interface by reopening the simulation file: User interface User interface User interface User interface File > Reopen

(65)

Select the result variable Thickness. Fig. 4.11 Fig. 4.11 Fig. 4.11 Fig. 4.11 Distribution of thickness

(66)

Click on the button for the developed blank : Fig. 4.12 Fig. 4.12 Fig. 4.12 Fig. 4.12 Developed blank Developed blankDeveloped blank Developed blank

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

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

(67)

Fig. 4.13 Fig. 4.13 Fig. 4.13 Fig. 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-Form–User Interface and display the originally defined weld line.

Display > Lines ... > Weld 1 > Dismiss

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

(68)

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

Different weld line positions

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

Results > Material lines ... > Material line 1 > File > Write selected to file … > AF Poly3D > CLOSED polylines: No > weldnew.af >

OK > Material lines > File > Dismiss

Save the simulation under another name:

File > 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 the stored material line as new weld line.

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

(69)

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

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

(70)

4. 5

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

Lesson 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 AutoForm–DieDesigner. Objective of this lesson is the definition of symmetry conditions and drawbeads. In addition, we will also show how to optimize the initial blank.

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

Tool geometry

Opening the prepared Simulation File

Open the prepared simulation file in the AutoForm–User Interface:

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

The AFOS input generator is opened automatically. Because the Geometry 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 binder surface. Define the OS boundary by importing an existing line in AutoForm format (.af).

(71)

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

AFOS Input generator: GeometryGeometryGeometryGeometry page

Import OS boundary

Geometry 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 as dependent on the punch opening line as specified in the DieDe-signer tool geometry.

OS punch opening

Geometry OS punch opening > Dependent ... > Select curve: Punch opening 1 > OK

Symmetry

Define the symmetry–plane on the Blank page. The sheet thickness and the material properties have already been specified.

(72)

Blank Blank Blank Blank Symmetry-planes/welds/holes: Add symmetry ... >

Symmetry-plane: Click segment > User interface: Click the OS boundary at the symmetry-plane > Symmetry-plane: OK

Fig. 5.3 Fig. 5.3 Fig. 5.3 Fig. 5.3 Symmetry plane

Defining Drawbeads

Drawbeads may be modeled in AutoForm using a force factor to control metal flow, without having to build the detailed drawbead geometry 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 vis–a–vis feasibility requirements, and to identify the best bead configuration, based on comparisons, without having to modify tool geometry to accom-plish the same.

AFOS input generator AFOS input generatorAFOS input generator AFOS input generator

Add > Drawbead > Add drawbead: Use default settings > Add drawbead

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

(73)

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

AFOS Input generator: DrawbeadDrawbeadDrawbeadDrawbead page Drwbds

Drwbds Drwbds

Drwbds Drawbead line > Input ... > Curve editor

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

(74)

Fig. 5.5 Fig. 5.5 Fig. 5.5 Fig. 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 (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 x–y plane • Width: Width of a drawbead

• Forcefactor: Force factor of a drawbead Usage tip – Curve editor

Usage tip – Curve editorUsage tip – Curve editor Usage tip – Curve editor

A curve – closed or open – may be created using the Curve editor by adding control points (or nodes). Each new control point creates a new 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.

(75)

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

Starting the Simulation Starting the Simulation Starting the Simulation

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

After simulation is completed, the results may be viewed and eval-uated in the AutoForm–User Interface by re–opening the simulation file:

User interface File > Reopen

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

(76)

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

Process > Process stage:Developed blank

The initial blank as calculated on the basis of the OS boundary is shown. Generate a trapezoidal blank on the initial blank using material marks. These material marks are completely connected to the blank and will be defined as a material line.

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

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

Position of the material marks

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

(77)

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

Coordinates of the material marks

AutoForm - Material marks > Define > Material line

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