Door Trim Lower with Engineering Features using CATIA V5

AIM:

           Create the Engineering features of Heat stakes & locators for the Door Trim considering the design rules.

INTRODUCTION:

 HEAT STAKES:

          Heat staking is the process to attach two separate components together by melting the base plastic material into a shape that will hold the secondary component.

 LOCATORS:

          The devices that restrict a workpiece's movement are the locators. The locators, therefore, must be strong enough to maintain the position of the workpiece and to resist the cutting forces.

OBJECTIVE:

• Create a Tooling axis for the given CLASS -A surface.
• Create the CLASS B and C surfaces of door trim using the given CLASS-A surface.
• Create a final surface model and convert it into a solid body using the close surface command in the part design workbench.
• Create Heat Stakes & locators on the B surface.
• Perform draft analysis for both Class-A surface and Final part body.

Design Methodology

Class-A surface means visible surface. It gives the aesthetic of the component which is created by the styling team and gives to the part design engineer to create the part with all engineering aspects.

Create tooling axis:

• Check the best possible tooling direction by manually adjusting the compass.
• By analysing it is found that the y axis as tooling direction would clear most of the faces without any difficulties.
• Now extract any surface and create a mid-point on it.
• Then create a dummy axis creating a line on the point and direction along the y-axis.
• Perform draft analysis to find whether the given axis clears the draft analysis. If not create a new tooling axis.

Draft analysis of CLASS-A surface

CLASS-B surface creation:

The Class-B surface is a surface below a certain thickness from the class-A surface. This is the surface that contains engineering aspects of a model.

Create offset surface of CLASS-A about 2.5mm inward direction.

Check for discontinuity and rework on the offset surface using extract, multi-extract, multi sections surfaces.

Join the surfaces and ensure the final CLASS-B surface created has no gaps.

CLASS-C surface creation:

The surface that joins class-A and class-B surface. Class C is often specified for interior surfaces not readily visible, surfaces that will be covered by another part when assembled.

Join the sweep surfaces by using commands like extrapolate, multi-section surface.

Finally join all the sweep surfaces and ensure the continuity of the CLASS-C surface.

Creating the Final surface:

For creating the Finals door trim surface, join the CLASS-A and CLASS-C surfaces together.

Then Extrapolate the B surface a little bit outward direction to make sure that there would not be any gap when trimming with the joined surface.

Then trim the extrapolated CLASS-B surface with the Join surface (CLASS-A and CLASS-C).

Make a solid part body using the close surface command in the part design workbench

Heat Stakes Creation

To create the heat stakes, I draw a sketch on the surface. After the creation of the sketch, I pad it to 40mm height and I gave a draft angle of 0.5deg on both sides (inside and outside) and then I gave a fillet with a 0.3mm radius. After creating the heat stake, I created the ribs for supporting purposes. To create the ribs, I draw a sketch and padded it to 20mm in height and 1.5mm in thickness. After padding the ribs, I drafted 0.5deg in the tooling asix direction and filleted it with a 0.3mm radius. Finally, I union trim the ribs with a heat stake to remove the ribs, which are present inside the heat stakes.

Locators creation

To create the locators, I created a sketch on the body. After creating the sketch, I pad it 40mm in height and thicken it to 1.5mm and I drafted it with 0.5deg in the direction of the tooling axis. I gave 5mm of chamfer with 45deg of inclination and after I gave a fillet of 0.3mm radius.

3D Part model in various orientations (Isometric, Front, Side, and Top View)

DRAFT ANALYSIS:

The Draft Analysis is a command that 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 analysed element where the deviation from the draft direction at any point, corresponds to specified values.

Draft analysis is done after determining the tooling axis, draft analysis is used to check whether the minimum draft (3 degrees) is maintained or not.

Procedure for performing the draft analysis are as follows

• Change the view mode of the component to be in customized parameter mode and then select the shading mode as materials.
• Then open the featured draft analysis tool from the insert menu.
• Then click on the use the compass to define the current drafting direction and then drag and align the compass on the Tooling axis.
• Then lock the draft direction and perform draft analysis by clicking on the component.

Colour Range representation

• GREEN colour - Positive Draft
• RED colour – Zero draft 
• BLUE colour – Negative Draft

Draft analysis of final Door trim component

Conclusion:

I have successfully created CLASS B and C surfaces using the given CLASS A surface of the door trim created main tooling axis. Performed draft analysis of the final component.