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

AIM -

To create a solid body of a given Door Applique and to create the Locators and Heat Stakes on it as per design standards.

INTRODUCTION -

Heat Staking-
Heat Staking is a pulsed-heat process to join two or more parts out of which one at least is made of plastic. The process is to deform the plastic material using heat and force at a set process time. The bond is made by partially de-forming the plastic part in order to fix the other.

Heat Staking makes it easy to bond metal to plastic and is commonly used in high volumes/low-cost applications such as automotive, IT and consumer appliances.

In the Manufacturing Of thermoplastic components, it is often necessary to join the thermoplastic to a part of dissimilar material, whether it can be a metal, dissimilar material 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 a metal component of an assembly in place. The plastic studs protrude through the holes in a component to be locked in a place. the heated thermal tip contacts the top of the stud, which melts and fills the volume of the tip cavity to produce the head, locking the component in a place. The progressive melting of the plastic under continuous pressure forms the head. When Staking, the right combination of heat and pressure for the applications is critical.

Advantages of Heat Stakes-

Similar and dissimilar materials may be joined: metal to metal, plastic to plastic, metal to plastic.
Accurate control operating within a small process window.
Local heating results in no damage to surrounding materials.
Processing of glass-filled materials.
No mechanical vibration.
Many heat-stake shapes are possible through custom-designed tools.

2 and 4-way locators-
In any kind of assembly before fixing the part to the mating part we need to fix the position of the part with respect to the mating part. In these cases, we need to follow some engineering principles. In this project, we are going to follow the 3-2-1 Principle. Any Part which has to be fixed during the welding or machining process has to be fixed is having 12 degrees of freedom.

Translation Movement along X-Axis
Translation Movement along Y-Axis
Translation Movement along Z-Axis
Rotational Movement along X-Axis
Rotational Movement along Y-Axis
Rotational Movement along Z-Axis

INPUT-

Tooling Axis-

- Check the Connectivity of class A Surface: these can be done by creating boundaries or by joining command if there are any gaps or openings they will be easily visualized.

-Visually analyse the best possible tooling axis.

-the clearance checking along all the axis on the plane with the model and constructing two lines contact with the walls, the line bisecting the two lines and passing through the point will be the tooling Axis.

but for this cat part, the bisecting method is not required because every part of the cat can be cleared throw the Z direction only easily.

The tooling axis is nothing but the direction in which the core and cavity open and close. The design engineer works are to analyse the Class-A surface and find out the best possible tooling direction keeping in mind all the draft angle is with respect to the tooling axis so that the component can be easily ejected from the moulds.

Class A surface-

In automotive design, a class A surface is any of a set of freeform surfaces of high efficiency and quality. Although strictly, it is nothing more than saying the surfaces have curvature and tangency alignment – to ideal aesthetical reflection quality, many people interpret class A surfaces to have G2 (or even G3) curvature continuity to one another. Class A surfacing is done using computer-aided industrial design applications. Class A surface modellers are also called "digital sculptors" in the industry. Industrial designers develop their design styling through the A-Surface, the physical surface the end-user can feel, touch, see etc. and the class A surface is created in the software called ALIAS.

Draft Analysis on Class A surface-

Draft analysis compass is used to define the draft direction.

check whether the minimum draft of 3deg is assumed or not. the minimum draft of 3 deg is provided with the whole component changes into green colour.

Class B Surface Creation-

Represent internal and/or functional surfaces. This cluster exemplary includes derived surfaces created by offset operations from class A surfaces to define the thickness of the material (2.5mm). In this file, it is important to link class B surfaces geometrically to enable an adaptation to class A surfaces automatically in case of styling change.

After creating the tooling axis, a B surface is to be created which is nothing but the surface parallel to the A surface. B surface contains all the fillets and the edges which the A surface contains.

Class C Surface Creation-

Class C Surface is swept along the boundary of Class A at an angle perpendicular to the CLASS A surface with respect to the tooling axis direction with a draft angle of 3 degrees.

Joining CLASS A, B and C Surfaces to get Closed Surfaces-

After finishing all the 3 surfaces, join the class A and class C surfaces together using the Join command. Now, the joined surfaces are then trimmed with a class B surface to form a closed surface.

Making of the solid part using the class surface command-

after the completion of joining the class A, B, C surfaces ensure that the surface has no gaps between then using the boundary command if it did not form the boundary then the surface is closed switch to the part design and insert the new part body and use the close surface command to gat the solid part.

Draft Analysis-

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

Draft angles are very important in thermoforming product design. If the product is formed onto a female or negative mould, it shrinks away from the mould sidewalls. As a result, true female or negative products can be thermoformed with vertical walls having zero draft angles.

Creating 2 and 4-way locators and Heat stakes-

4-way locators mean you prevent movement at 2 axis (+X, -X, +Y and -Y) on the plane. Generally, you have a cylindrical pin on the fixture and a circular hole at the workpiece part.

Sketch 1-

2-way locators -

2-way locators mean you prevent movement only at 1 axis on the plane.

While creating the locators we need to follow the design rules to create the ribs in order to avoid the sink marks on the components.

Sketch 2-

Heat Staking

Heat Staking is a pulsed-heat process to join two or more parts out of which one at least is made of plastic. The process is to deform the plastic material using heat and force at a set process time. The bond is made by partially de-forming the plastic part in order to fix the other.

Once done with the design of locators and the heat stakes we need to design the counter holes in the mating parts with standard clearances as shown in the picture below.

Sketch 3-

Applique with 2 and 4-way locators and Heat stakes-

Applique with the counterpart clearance-

Draft analysis for the final output-