Week 9 - Attachment Feature Creation - Challenge 2

REPORT OF DOG HOUSE FOR THE DOOR TRIM DESIGN:

Aim :

• To create the Dog House For Door Trim Plastic component through the given Class-A surface.
• To create the tooling axis for the given Class-A Surface meeting the requirements of the draft angle and at the end perform the Draft analysis on the final model.

Introduction:

A Door Trim is an interior component attached to the inner side of the door. This product does more than merely improve the appearance of the vehicle interior. Rather, it is a vital module component that creates a more comfortable interior by providing a variety of accouterments and functions. As such, there is a necessity for balancing gap between parts, as well as an overall sense of unity between the numerous parts. They are expected to meet a variety of design specifications regarding safety, aesthetics, and functionality. Doors currently have an inner full-width panel consisting of electronic windows, central locking system, and speakers. These panels typically consist of a foamed core covered with either textiles or plastics.

Design Methodology:

The input of the product designer is in the form of the Class A Surface. The job of the product designer is to create the B and C surfaces and the create the dog houses in the required areas with keeping all the aspects for the mold.

Creation of Tooling Axis:

The tooling axis is the direction of drawing a sheet metal where the finished component is easily ejected on a particular direction and axis. In Molding, machine arrangement is given to open the mould along a direction which is known as Tooling Direction. In other words. The mould is built from two separate halves (Core and Cavity) and tooling direction basically defines the direction of mould pulls apart.

In the given model we are using the Normal To Surface method.

For creation of tooling axis, a point is inserted on one of the surface of class A through which tooling axis is drawn.

Class A surface with point on the surface:

Class A surface with Tooling Axis:

Point on extracted surface:

Material Selection

The material can be used for manufacturing Door Trim and Dog House is Acrylonitrile Butadiene Styrene (ABS). Because of its some features such as:

• The styrene provides the copolymer with a shiny, tough exterior.
• Provides quality surfaces and good resistance to chemical agents.
• A wide variety of adjustments can be made to enhance impact resistance, durability and heat resistance.

Also the Polyoxymethylene material can be used to manufacture the Door trim. It has the features called: high rigidity, yield strength and high stability in cold temperatures. Highly chemical- and fuel-resistant. Also POM is used to fabricate interior and exterior trims.

For manufacturing the component, injection molding method can be adopted. It would be the right manufacturing method. Because it is a right way to create the exact moulding for the required product. This is a common method is used to produce a high volume of plastic parts of automobiles. Products can also be made with increased flexibility to suit the needs of designers or engineers.

Class A,B & C Surface

Class A Surface:

It is the outermost aesthetic surface which is visible to customers (the outermost visible surface of a product).

Here, class A surface is given:

The class A surface is joined inorder to make it a single part and then checked the boundary to confirm that it is closed.

Class B Surface:

It is the offset of the class A surface at a particular distance. The offset distance depends on the thickness between Class A and Class B surface.

Here, the thickness given = 2.5mm.

Procedures to build class B surface:

• Offsetted the joined surfaces from class A to 2.5mm inorder to create class B surface.
• Extrapolated the offseted surfaces inorder to make sure all the surfaces are in contact.
• Trimmed the offsets to get an output same as class A surface
• Fillets are given to the required edges based on the thickness and curvature of the class A fillets.

Class C Surface:

This surface connects the Class A and Class B surfaces. (Surface in between Class A & B surfaces)

Procedure to build Class C surface:

• Boundary of class A surface is extracted and then smoothcurved the boundaries if its required
• Also here Multi-Section Surface command is used to create the Class C Surface
• Both the sweep surface and multi-section surface are joined together to form as a single one.
• Then that boundary is swept perpendicular to the Class A Surface until it gets coincided with the offseted class B surface.

Joined and Closed Class A,B & C surface:

After creating class B & C surfaces, joining operation is done between class A and class C surfaces. Then, Class B surface is trimmed with joined Class A & C surfaces to get a whole closed single surface. Then in the part workbench using closed body command, a solid body is generated.

Closed surface:

Solid Body:

DOG HOUSE CREATION:

Dog house is an engineering feature used in plastic trim design. Dog houses are used as supporting feature. Sometimes other engineering features like snaps, locators etc. are mounded on them to increase their strength. Dog houses are subjected to draft analysis to prevent breakage of the component during ejection from mould cavity. Dog house and other engineering components are built on B-surface.

Procedure for Dog House:

• C thickness should be 40% of the main wall thickness T
• Minimum width of the dog house is 12 mm.
• Height of B should be 3-6 mm
• Minimum draft for the do house is 1.5 degree to die draw.

Inserting point and Axis to create dog house sketch:

Sketches for padding the dog house:

Final Solid body of Dog House attached with part:

Draft Analysis:

In the criteria of making a plastic material, the mold should release the material when finished. if the mold surfaces are 90 degrees the material won't release from the mold because of friction due to contraction of material when cooled.The ejection of the part from mold depends on the draft. A zero draft can result in difficult or no ejection. It is recommended to add a draft of 3 degree or above inorder to remove it from the mold without any damage.

Procedure:

• Change the view mode to customize view parameters and give material as view mode.
• In the draft analysis toolbar, set the draft values and color (3 degree and above - green, 0 to 3 degree - blue, less than 0 - red).
• Drag and drop the axis system on the tooling axis and lock it.
• Perform draft analysis.

Draft analysis of Class A surface:

After applying the draft analysis, the result shows red colour in some areas of the parts. Its because the the angle is in negative direction. Hence the part is difficult to manufacture without any defect. Instead of that the class A engineer is to be modify the above part to clear the required portions in postive direction angle for manufacture the part without any defect.

Draft analysis of final plastic component:

In the above draft analysis image it is clearly shows that in the designed Class C Surface is having a negative draft. its because the draft angle can't be controlled with respected axis plane. To overcome the irregularities seen in the draft analysis the Class A Surface is to be modified.

Screenshots of the solid model with the proper colour code of the draft angle in various orientations:

Tree Structure: