Week 9 - Attachment Feature Creation (Ribs & Screw Boss) - Challenge 1

Aim - This project aims to create a Door Handle plastic component along with ribs and screw bosses using the given class A surface following the OEM standard and perform the draft analysis.

Objective -

• Ensure Proper Tree Structure.
• Geometrical sets should have a proper name based on the sketches present inside them.
• All the sketches should be created under the Geometrical set.
• Use the Close Surface feature to make a solid body from the surface.
• To publish the Tooling Axis, Class A.
• To create ribs and screw bosses.

Design Methodology-

• Insert the class A surface of the Door Trim Lower in CATIA software.
• Determining the tooling axis for the Door Trim Lower.
• Creation of class B surface.
• Creation of class C surface.
• Join the Door Trim Lower's class A, class B, and class c surfaces and ensure all the surfaces are closed surfaces.
• Use the Close Surface feature to make a solid body from the surface.
• Create engineering fratures like ribs and screw bosses.

Theory -

1.Tooling Axis - Generally 3 methods used to create the tooling axis.

1.Normal to plane (Large surface avilable).
2.Bisecting the line.
3.Point and Direction.
For Door handle bisecting the line is used for tooling axis as Class A surface clears in draft analysis.

1.Normal to plane

2.Point and direction-

3.Bisecting line -

As we can see maximum surfaces are getting cleared with bisecting line method.

2.Class B Surface -

To create the class B surface, offset the class A surface inside as per our thickness requirement (here the thickness is 2.5mm, so offseted the class A to 2.5 mm ). Once the offset is created, we can observe some patches on the offset surface by taking the boundary for the offset surface, those patches are formed due to the fillets on the class A surface. We need to cover those patches with the help of the multi-section surfaces command by extracting the patch boundaries. Once all the patches on the offset are covered properly join all the patches with the offset surface, to get the replicated surface of the class A surface.

After fillinng these patches proceed with Class C surface.

3.Class C Surface -

To create the class C surface concerning the boundary of the class A surface, We used the sweep command but unable to do in one shot so did it in patches. For the surfaces almost parallel to the tooling axis used sweep with draft direction and where surface is perpendicular to the tooling axis used sweep with referance surface.

4.Final Trims -

Joining the Surface A + Surface C

Final trim with B surface.

5.Ribs and Bosses -

General Guidelines for Bosses:

• Draft - 0.5 degrees on the walls of boss
• Thickness - Typically 40%* of the nominal wall at the base.
• Height to Diameter Ratio - 3:1
• Radii - 0.25mm maximum radii.

Insection view of Ribs and bosses for diamension checking as it follows all the design rules.

Final product with engineering features -

6.Draft Analysis -

Draft Analysis is used to check the whether the minimum draft of 3deg is maintained or not. The draft analysis command enables you to detect if the part you drafted will be easily removed. This type of analysis is performed based on colour ranges identifying zones on the analyzed element where the deviation from the draft direction at any point, corresponds to specified values.