Week 8 - Challenge 1 - Draft Analysis on a Fan Cover
AIM-
Draft analysis on a fan cover
Objective-
The objective of this project is to know how to create a tooling axis and perform a draft analysis.
Theory
Draft analysis
The draft analysis helps to detect if your draft part is easily removable from the mold (in case of plastic component) or die (in case of sheet metal). All plastic components will have a minimum draft of 0.5to 3 deg. And for automotive sheet metal parts, the draft will be 7 deg or more. If a mold wall is perpendicular to the part ejection there is simple friction or interference between the mold and the part which will not allow one to release from the other. This is why design engineers give a minimum draft to the part.
The Draft Analysis dialog box is displayed. It gives information on the display (color scale), the draft direction and the direction values.
Mode option
The mode option lets you choose between a quick and a full analysis mode. These two modes are completely independent.
The default mode is the quick mode. It simplifies the analysis in that it displays only three color ranges.
Quick mode:
Full mode:
Double-click on the value in the color scale to display the Value Edition dialog box.
Enter a new value (negative values are allowed) to redefine the color scale, or use the slider to position the distance value within the allowed range, and click ok.
The value is then frozen, and displayed in a green rectangle.
The color scale settings (colors and graduated values) are saved when exiting the command, meaning the same settings will be applied when you will edit a draft analysis. New settings are created with each new draft analysis.
When the draft angle value of the surface is equal or smaller than a graduated value, the colour below the graduated value is applied.
When the draft angle value of the surface is greater than the greatest graduated value, the colour above this graduated value is applied.
Display option
Uncheck the Colour Scale checkbox to hide the Draft Analysis.1 dialog box, this dialog box only appears in edition mode.
Activate the On the fly checkbox and move the pointer over the surface. This option enables you to perform a local analysis.
Arrows are displayed under the pointer, identifying the normal to the surface at the pointer location (green arrow), the draft direction (red arrow), and the tangent (blue arrow). As you move the pointer over the surface, the display is dynamically updated. Furthermore, circles are displayed indicating the plane tangent to the surface at this point.
The On-the-fly analysis can only be performed on the elements of the current part.
Click the No Highlight Representations button to set the display option of highlight effect sources as "on/off". When checked "On" the surfaces are selected but they will not be seen in the specification tree.
Click the Light Effect button and the colors of the analyzed elements react to the light source.
Direction
The first chek box is locked direction icon which is used to lock the direction of the compass after selecting the specified direction.
Click on the compass icon to specify the new pulling direction to remove the part.
Click the inverse button to automatically reverse the draft direction . when several elements are selected for analysis, the draft direction is inverted for each element when the button is clicked.
Tooling direction
The tooling direction is basically the direction that the mold pills apart. The mold is built in two separate pieces basically. You have a cavity side and you have the core side. The core pulls apart from the cavity and that is the dyeline or the tooling direction.
PROCEDURE
The procedure is divided in to two parts first creating the tooling axis then perform the draft analysis.
Creating tooling axis using the bisecting method
The first thing to do is finding out the possible tooling direction by visually checking the part. Rotate the part in all directions and find out the most suitable direction for tooling. Here in case of fan cover viewing from Z direction, we can clear the face in tooling.
Then we create a point on the surface of the part, we can create the point anywhere on the surface but usually, we take CG point or take a point near to the center. On this point we put a new axis system.
Then we are finding out the tooling axis in X direction. For that intersect command is used to get the boundary in X direction or XZ plane.
Extending the drafted face using point to point line command. Then using bisecting line command bisect both extended lines to get the tooling axis in X direction.
Next we have to find out the tooling axis in Y direction. For that intersect command is used to get boundary in Y direction with YZ plane as reference.
Extending the drafted face using a point to point line command. Then using bisecting line command bisect both extended lines to get the tooling axis in y direction.
After creating the tooling axis along X and Y direction bisect both the lines and create the actual tooling axis.
Performing the draft analysis
Open feature draft analysis option from insert>Analysis>Feature draft analysis.
A new window pop up by default it will be in quick analysis mode. Change the range to 3 deg.
Next you have to position the compass on the tooling axis by dragging the compass from the top right corner of the working area.
Then you have to define the compass by click on the compass icon on the draft analysis window.Then lock the position of the compass by clicking the lock icon.
After that select the surface and the whole surface will show a colour range. Here the fan cover surface is fully in green colour, which means all faces are having a minimum draft angle and its good for manufacturing. If any face is showing blue or red colour we have to work on that face to give a good draft.
RESULT
Front view
Right view
Top view
Bottom view
Isometric view
