Week 8 - Challenge 3 - Switch Bezel Design

Objective:- Objective of this challenge is to do a Draft analysis of a BASE BRACKET using CATIA Software. And also create Class A surface, Class B surface and Class C surface and Solid Pattern for manufacturing.

Draft Analysis:

Draft analysis helps to detect if your drafted 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 0.5 to 3deg. And for automotive sheet metal parts, the draft will be 7deg or more. If a mold wall is perpendicular to the part ejection, there is ample 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. In CATIA V5 the feature draft analysis dialog box looks like this:

Direction:
• The first check box is the 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.

Class A Surface:- It is a surface that we get as input from Alias software.

Class B Surface:- It is a surface that we create at offset thickness from Class A surface.

Class C Surface:- It is a surface that we create to join Surface A and Surface B.

 we import Class A surface in Catia. That Class A surface may be in the different part surfaces, so we join them using JOIN Command in CATIA. For confirmation of joining we use BOUNDARY command, If boundary shows no error then we go for phase 

Analyze the model and focus on the surfaces which will create problems. Like in the image below, surfaces marked with black pen might create problem while tooling so we will focus on them and make axis in their respective direction

we have two lines. We will get our tooling axis by bisecting them. Note here that, the tooling axis when viewed from the direction, we should see the surfaces which we thought might create problems, like shown in the image below.   

DRAFT ANALYSIS ON CLASS-A SURFACE:

1. Go to insert< analysis< feature draft analysis.
2. Align the tooling axis with the compass.
3. Click on the surface and see that the surface is within the permissible limit of the draft values.
4. The surface should be green and in the column proper value (3deg) should be inserted.
5. If any surface is not green then we have to edit our tooling axis. We just have to edit the above dimension which we mentioned till we get all the surfaces in green.

 start with, the top rest surface is extracted and untrimmed and extrapolated, so that this can be used to trim with other surface to form the class B surface.other surfaces are also taken, untrimmed and extracted to trim with the adjoint surfaces. the requirement, the fillets are given. In order to given the fillets it is not exactly equal to class A. Along with the fillet radius, part thickness has to be added.

 class C surface it is necessary to sweep it to the required length. However for this as the border formed is having number of small sections the border curve can be smoothened and then swept or else done in parts.

Solid formed after the class A,B & C surface

it can be seen that one wall of the part fails in the feasibility check, this happened due to the draft angle which is given to the axis at the beginning. To avoid this, again the angle has to be increased and update has to be done.

 standard views

Feature trees