Week 9 - Project 1 - Door Applique Design with Engineering Features

For successfully creating a component that is moldable or in other words that can be manufactured, Draft Analysis of the component should be carried out.

• What is a Draft?

Essentially, draft angles for injection molding are a design consideration that makes it much easier for a part to release cleanly from a mold. A draft angle is calculated as a degree measurement from the vertical axis of a mold, and it helps account for thermoplastic shrinkage, a practical reality of the injection molding process for most materials.

By accounting for thermoplastic shrinkage during the cooling process, draft angles greatly reduce friction between the finished, cooled part and the side of the mold. Not only does this create a much easier release process, it offers several other benefits, depending on the design of the part:

1. Reduces the chance of damage to the part due to friction during release
2. Reduces wear and tear and chances of damage to the mold
3. Ensures a uniform, smooth, unscratched finish when required
4. Ensures the integrity and uniformity of other surface finishes and textures
5. Reduces overall cooling time by lessening or eliminating the need for unconventional ejection setups
6. Most, if not all, of these benefits offer either direct or indirect overall production cost reductions

Steps for creating the Tooling Axis:

• The first and foremost step for conducting the Draft Analysis is to create the Tooling Axis. The Tooling Axis is the direction in which the mold opens and closes.
• The Tooling Axis is created along the Y direction
• Once the Tooling Axis is created, publish the Class A surface and the Tooling Axis.

Steps for Draft Analysis:

• Go to Views and Customize View Parameters. Change to material.
• Click the Draft Analysis tool and use the compass to define the draft direction as the main tooling Axis.
• Once placed correctly, lock the draft direction.
• Now, since the minimum draft angle for plastic components is 3 deg, define the value as 3 deg and select the Door Applique
• The Draft Analysis is completed

Results/ Conclusion of the Draft Analysis: By referring to the colour scale, the minimum draft angle of 3 deg is achieved and the component can be manufactured. The running point analysis tool can be used to find the value of draft angle at any point.

Steps for giving thickness:

• Creation of Class B Surface
• Creation of Class C Surface
• Creation of Closed Surface
• The following features/commands were used- Extract, Untrim, Offset, Extrapolate, Join, Trim, Boundary, Smooth Curve, Sweep, Close Surface, Thick Surface to thicken the Welding Surface which is used for Heat Staking

Heat Staking: In manufacturing products with thermoplastic components, it is often necessary to join a thermoplastic to a part of dissimilar material, whether it be metal. a dissimilar plastic, or other material

Thermal Staking is an assembly method that uses the controlled melting and reforming of a plastic stud or boss to capture or lock another plastic or metal component of an assembly in place. The plastic stud protrudes through a hole in the component to be locked in place. The heated thermal tip contacts the top of the stud, which melts and fills the volume of the tip cavity to produce a head, locking the component in place.

The progressive melting of plastic under continuous pressure forms the head. When staking, the right combination of heat and pressure for the application is critical.

Advantages:

• Simplification of machinery
• Reduced cost of machinery
• Multiple fastening points
• Allows higher density of welds compared to hot air cold form or ultrasonic welding

3-2-1 principle:

In the automotive tooling industry, Ideally 3-2-1 principle is used to locate the job. Any part which has to be fixed during welding or during machining process has to be fixed. Every object is having 12 degrees of freedom.

1. Translational movement along X-axis
2. Translational movement along Y-axis
3. Translational movement along Z-axis
4. Rotational movement along X-axis
5. Rotational movement along Y-axis
6. Rotational movement along Z-axis

The 4 Way and 2 Way Locators are used to arrest the Translational and Rotational motion along all directions except the one direction in which the component is going to be welded/fixed to other component.

Isometric View

Front View

Side View

Top View

Draft Analysis of final component:

Isometric View

Front View

Side View

Top View

Results/ Conclusion of the Draft Analysis: By referring to the colour scale, the minimum draft angle of 0.45 deg is achieved and the component can be manufactured.