Challenge

Project - Door Applique Design with Engineering Features

SSwarochi Aemula3 Jun 2021

OBJECTIVE:

Creating the Driver Door RH Applique Plastic component through the given Class-A surface. To begin with, the tooling axis for the given Class-A Surface is created to meet the requirements of the draft angle and at the end perform the Draft analysis on the model.

Creating the Heat Stakes and the locators considering the design rules mentioned in the video for the door applique.

The Thickness of the component is Considered as 2.5 mm

INTRODUCTION:

Draft:

A draft angle is a slant that is applied to each side of most features of an injection molded part. In other words Draft is providing tapers on the product features such as walls ribs posts and bosses that lie parallel to the direction of the release from the mold part ejection
The nominal draft is 3mm for plastic components and for automotive sheet metal components is 7mm

Tooling axis :

It is defined as the direction in which the molds opens or core and cavity, with the help of tooling axis created along x and Y axes are used for creating the Main Tooling axis by using bisecting method

PROCEDURE:

Connectivity of Class A surface:

The first and foremost thing to do is to check for the connectivity of the surfaces this is to ensure that there are no gaps between the surfaces if gaps are present then it should be resolved.

This can be done visually or by creating boundaries, if their gaps are present they are graphically represented by green lines. If not while performing boundary command it shows an error.

Creation of Dummy axis :

This is a normal line which we construct by analyzing the best possible direction(X/Y/Z axis) for the draft for the part, this axis is only for reference and is not used for Tooling Axis

Creation of Tooling Axis for Class A surface:

Taking the dummy axis as a reference, intersect the class A surface along the different axis (XY/YZ/ZX ) Check for the possible places where the part might face difficulties while ejecting the component from the mold.

Lines are drawn at the places where the part boundary has difficulties

Later the Tooling axis in one direction (let’s say X) is obtained by bisecting the lines drawn in the above process

In the same way, the other axis is also checked and then the Tooling axis in another direction(let’s say Y) is drawn

Now both Tooling axes are bisected and the final Tooling direction is obtained which is further used for all draft analysis axis and later unto developing Class C and Class B surfaces

Publication:

The publication is used for easy access to published components. These will come in handy while modeling (we are not required to search the entire tree structure for a particular operation)

DRAFT ANALYSIS:

Click the Inset—Analysis -- (Feature) Draft Analysis icon

If material is not on There will be a warning message is shown and then we need to select the material

The Draft Analysis dialog box is displayed. It gives information on the display (color scale), the draft direction and the direction values

DEVELOPMENT OF CLASS B SURFACE:

Class B surface is created by extracting each wall and untrimmed walls extrapolating the walls and then trimming the extra surfaces and offsetting it to certain value based upon the thickness of the component where it is 2.5 mm. The offset surface will be the B-Surface

DEVELOPMENT OF CLASS C SURFACE :

This surface is obtained by sweeping the boundaries of the Class A surface along the Tooling Axis direction, it connects A and B surfaces

Using B and C surfaces a closed surface is formed by trimming the extra surfaces

The Final trim part is converted into a solid component using closed surface command

Adding the Heat stake and locators to the Door Applique trims

3-2-1 PRINCIPLE:

It is also known as a six-pin or six-point location principle. In this, the three adjacent locating surfaces of the blank (workpiece) are resting against 3, 2, and 1 pin respectively, which prevent 9 degrees of freedom
The rest three degrees of freedom are arrested by three external forces usually provided directly by clamping.

Generally a body has 12 Degrees of freedom as shown this diagram below

Methodology of 3-2-1 Principle:

For this, refer the below figure;

[1] The workpiece is resting on three pins or Locators L1, L2, and L3 which are inserted in the base of the fixed body.
[2] The workpiece cannot rotate about the axes XX and YY and also cannot move downward.
[3] In this way, the five degrees of freedom 1,2,3,4, and 5 have been arrested.
[4] Two pins L4 and L5 are inserted in the fixed body, in a plane perpendicular to the plane containing pins L1, L2 & L3.
[5] Now the workpiece cannot rotate about the Z-axis and also it cannot move towards the left.
[6] Hence the addition of pins L4 and L5 restrict three more degrees of freedom, namely 6, 7, and 8.
[7] Another pin L6 in the second vertical face of the fixed body arrests degree of freedom 9.

The above method of locating a workpiece is called the 3-2-1 Principle.

4-way and 2-way locators:

4-way means you prevent movement at 2 axis (+X, -X, +Y and -Y) on the plane.
2-way means you prevent movement only at 1 axis on the plane

HEAT STAKING:

Thermal Heat 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 cmoponent 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

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

LOCATORS AND HEAT STAKES DESIGN PROCEDURE: