Week 8 - Challenge 3 - Coin Holder Design

AIM: To create the coin holder plastic component through the given Class A surface. To begin with the tooling axis for the given Class-A surface should be created meeting the requirements of the draft angle and at the end perform the draft analysis on the model. Take the thickness of the component to be 2.5mm.

DESCRIPTION:

Class A surface: Class-A surfaces is a term used in most in automotive design to describe a set of freedom surfaces of high efficiency and quality.

Class B surface: Class B surfaces are the secondary surfaces that you can we see sometimes but are less important.

Class C surface: Class C surface are the surfaces which connects the class A and Class B surfaces.

Draft analysis: Draft analysis is performed on components where the ejection of materials happen after the material is made inside the tools.

Design procedure:

• Checking Class A input for imperfections.

The input Class A surface is checked for the discontinuities and joined together to get complete Class A surface as one.

TOOLING AXIS CREATION: Generally tooling axis is created using bisecting line method. But in the components where it has a bin, then the tooling axis is considered as a line normal to the base surface of bin. Same is done with this component. A line normal to base surface is created and considered as tooling axis.

Draft analysis of Class A: Draft analysis is performed on Class A to check the validity of the tooling axis. During draft analysis, it was observed that bin walls are having 90 degree angle with base. There is no minimum draft given to the walls. Since we are not authorised to make changes in Class A surface, we can inform Class A designer to give minimum draft to walls.

Since we have received this surface, we will continue to design using this Class A.

B SURFACE CREATION: As usual B surface is created using standard procedure by extract, un trim, extrapolate and offset commands. B surface of this coin holder is divided as base, side walls, top wall and outer surface. B surfaces of all these sub parts are created and trimmed together to join as single surface.

The offset distance is kept 2.5mm as component thickness is 2.5mm.

CLASS C SURFACE CREATION: Class C surface for this component is created using sweep command. All the ends of component surface was facing downwards, so the C surface will created perpendicular to B surface.

To create C surface boundary of Class A surface and surfaces adjacent to boundary are extracted. Then sweep with reference surface commands is used and surface is created at 90 degrees.

Creating final closed volume, converting in solid body and draft analysis: 

Once all surface are created Class A, B and C surfaces are joined together to get the final closed volume. The closed volume is then converted into solid body using closed volume command in part design work bench.