DELIMITATION OF THE PROBLEM

Analysis of the simulation results (part2 – punch Analysis of the simulation results (part2 – punch Analysis of the simulation results (part2 – punch contact, wrinkles, skid lines, sections, FLD, tool contact, wrinkles, skid lines, sections, FLD, tool contact, wrinkles, skid lines, sections, FLD, tool contact, wrinkles, skid lines, sections, FLD, tool forces)

forces) forces) forces)

When the calculation is finished, reopen the simulation file (*.sim) with

Lesson 2: Deep–Drawing on Single Action Press Lesson 2: Deep–Drawing on Single Action Press Lesson 2: Deep–Drawing on Single Action Press Lesson 2: Deep–Drawing on Single Action Press

File > Reopen Punch contact Punch contactPunch contact Punch contact

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

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

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

Time > closing

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

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

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

Lesson 2: Deep–Drawing on Single Action Press Lesson 2: Deep–Drawing on Single Action Press Lesson 2: Deep–Drawing on Single Action Press Lesson 2: Deep–Drawing on Single Action Press

Wrinkles

Wrinkles Wrinkles Wrinkles

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

Time > Animate start or use hotkey Ctrl – A

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

You can also use menu option Time > Times …

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

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

Surface deviation of 10 mm before bottom down

Lesson 2: Deep–Drawing on Single Action Press Lesson 2: Deep–Drawing on Single Action Press Lesson 2: Deep–Drawing on Single Action Press Lesson 2: Deep–Drawing on Single Action Press

Skidlines

SkidlinesSkidlines Skidlines

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

Skidlines can be visualized with the following option:

Results > Tool marks

In menu AutoForm - Toolmarks

File > Read from File > in_lesson_02_toolmark.af > OK Tools > Project onto > die > Accept

Define > Skid/Impact line File > Dismiss

Use menu option

Time > Simulation end or hotkey Ctrl – E

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

2.15).

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

Visualization of skid lines at simulation end

The display can be deactivated with following option:

Results > Skid/Impact line … > Select line with left mouse button

> Display > Clear all > File > Dismiss Sections

SectionsSections Sections

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

Lesson 2: Deep–Drawing on Single Action Press Lesson 2: Deep–Drawing on Single Action Press Lesson 2: Deep–Drawing on Single Action Press Lesson 2: Deep–Drawing on Single Action Press

Display > Tools … > Show all

Use hotkey Ctrl – D to open Dynamic section menu.

Define a section plane (Fig. 2.16) A x y: -200, 0 B x y: 200, 0

and select option Section in Dynamic section menu:

• Option Section displays the selected section plane as a 2D–

curve

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

Fig. 2.16

Dynamic section menu with defined section plane and activated option SectionSectionSectionSection

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

Fig. 2.17

Dynamic section with option SectionSectionSectionSection displayed in the main display

Lesson 2: Deep–Drawing on Single Action Press Lesson 2: Deep–Drawing on Single Action Press Lesson 2: Deep–Drawing on Single Action Press Lesson 2: Deep–Drawing on Single Action Press

Deactivate Dynamic section with the option:

Dismiss

Deactivate the display of all tools:

Display > Tools … > Clear all Forming Limit Diagram (FLD) Forming Limit Diagram (FLD)Forming Limit Diagram (FLD) Forming Limit Diagram (FLD)

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

Results > FLD then

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

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

Lesson 2: Deep–Drawing on Single Action Press Lesson 2: Deep–Drawing on Single Action Press Lesson 2: Deep–Drawing on Single Action Press Lesson 2: Deep–Drawing on Single Action Press

Fig. 2.18

Fig. 2.18 Fig. 2.18 Fig. 2.18

Forming Limit Diagram with all elements displayed at the simulation end

Deactivate the diagram with Dismiss

Forces Forces Forces Forces

Tool forces are of great interest for the forming simulation analysis.

In this example, the display of the punch force over punch stroke is described.

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

Activate AutoForm - Process data menu with option:

Lesson 2: Deep–Drawing on Single Action Press Lesson 2: Deep–Drawing on Single Action Press Lesson 2: Deep–Drawing on Single Action Press Lesson 2: Deep–Drawing on Single Action Press

Results > Process data …

Deactivate forces for the die and binder:

Calculated reaction forces > die Calculated reaction forces > binder

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

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

Calculated punch force over process time Deactivate the menu with

Dismiss

Close AutoForm–User Interface Close AutoForm–User Interface Close AutoForm–User Interface Close AutoForm–User Interface

The user interface can be closed with following option:

File > Quit or hotkey Ctrl – Q.

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

2. 3 2. 3

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

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

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

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

In document Initial Education of Secondary teachers in China and Spain: a comparative study under an international perspective (página 62-73)