ENGINEERING FEATURES CREATION

OBJECTIVE: Create dog houses for the door trim considering design rules using Class A surface with the thickness of the component 2.5 mm.

DOG HOUSE:

• Dog house is an engineering feature used in plastic trim design as supporting feature.
• A Draft of 1.5 degrees per side is the maximum limit.
• In case of a slide 3 degrees of Draft can be provided
• At the intersection part dog house wall thickness must me less than or equal to 40% of the wall thickness of the component.
• It's height should be between 3 and 6 mm.

TOOLING AXIS:

• Considering the Ejection from the cavity of the mould after manufacturing the interior trim must have the nominal 3-degree draft angle.
• Hence the tooling axis is created by considering the above factor.
• The direction in which the mold or core and cavity opens is the tooling axis.
• In this case below is the tooling axis that I have used.
• The Line in the black color is our tooling axis.

SIDE AXIS:

CLASS A SURFACE:

• In automotive design, a class A surface is any of a set of freeform surfaces of high efficiency and quality.
• It is the visible aesthetic surface of any automotive component.
• Class A surface refers to those surfaces which are visible and abide to the physical meaning, in a product.
• This classification is primarily used in the automotive and increasingly in consumer goods industry.
• It is a requirement where aesthetics has a significant contribution.
• For this reason, the exterior of automobiles is deemed Class-A.
• Below is the CLASS SURFACE that I have used for this model.

CLASS B SURFACE:

• Class B surfaces are Engineering Surfaces which are invisible to the eyes or often on the back side of the Class A surfaces.
• It is mainly the thickness of the component or Class A.
• These surfaces need to be designed as per the Class A surface i.e., the continuity, thickness of the component, functionality etc should be maintained.
• These surfaces include the main engineering features such as Screw bosses, Ribs, Snaps, Stiffeners and fixations.
• B surfaces also do not contain any aesthetic styling content and textures since it is not visible to eyes.
• Below is the image of CLASS B that I have created.

CLASS C SURFACE:

• Class C surfaces are connectors between Class A and B surfaces.
• This surface connects both A and B surfaces along the Tooling Axis.
• It contains the draft as per the design.
• It is basically the thickened surface between both A and B surface.
• Below is the Class C surface that I have created for this model.

CLOSED SURFACE:

• Now the class – A and Class- C surfaces were joined together by removing the gaps in-between them with the help of extrapolation and Trim surface.
• Then, by defining the part body by using the Closed Surface command in Part Design, the component's solid body is created.

FINAL SOLID BODY:

DRAFT ANALYSIS:

• Draft Analysis is a tool in CATIA which identifies the zones which deviates from the specified values of angles along a defined draft direction using colour codes.
• It highlights the regions of draft using colours.
• Draft analysis is the first step performed after receiving the Class A of the component.
• Draft analysis should be passed in order to make the plastic component manufacturable.
• Acceptable draft angles are used as range for draft analysis that is 0 to 3 degree.
• For Heat Stakes draft given is 0.5 to 2 degree.

CONCLUSION:

This reports concludes the creation of DOG HOUSES by following all Design Consideration for this DOOR TRIM.