Week 11 - Final project

AIM - To create the Door trim panel's CAD model considering the inputs given to me following the design rules and OEM standards.

ABSTRACT - The project deals with the explanation of steps and procedures followed while developing the Door Trim Panel of a car using CATIA V5. Using the class A surface I was able to create the tooling axis, class B surface, class C surface, and after forming the solid body from that I was able to create the flanges and the B side features such as Dog house, push pins, Heat stakes, etc. And finally, the draft analysis is also done on the components to check the manufacturability of the components.

INTRODUCTION - The door panel will usually match the rest of the vehicle's interior. Door panels were formerly made of cardboard with an upholstered interior finish of vinyl, leather, cloth, carpet, or other materials for the decorative trim. Modern cars typically have door cards made of plastic, most often using injection molding, as well as incorporating other decorative materials.

The design should incorporate both the necessary service amount and the functional unit (such as "it is strong" and "it looks and feels good") so that a given car door panel "would service a car body's life span of 200,000 kilometers (124,274 mi)." The door panel typically incorporates other parts that contribute to the appearance, functionality, and ergonomics of the vehicle. These include armrests, switches, or other controls for windows and the locking mechanism, convenience lights, Map pockets, lower substrate, storage compartments, and other features. An image of the door trim panel is shown below:

The steps that I followed for this project is mentioned below:

1) Extracting the class A surface from the input

2) Draft Analysis of class A

3) Creation of Class B and Class C surface from Class A

4) Created the solid body and performed the draft analysis on the solid body

5) created the flanges

6) Created the Engineering features

7) Draft analysis of the component with Engineering features.

PROCEDURE - Here the input which is given to me is below:

In the above fig., u can see that the surfaces along with the master section are given to me.

Master section - Master section are the guides for a design that shapes the component after technical styling of class A surface. The Master section is parameterized model of the vehicle body that outlines the guidelines for the NPD team.

so here I have to create three parts that are mentioned below:

1) Lower substrate

2) Map pocket

3) Door Armrest

Then I have to create the attachment features that are required for the assembly of the parts.

First I have started by creating the lower substrate. For this, I have extracted the class A surface of the lower substrate from the input that is given. The extract is shown below:

Tooling axis - The tooling axis is defined as the direction in which the mold opens or core and cavity opens and closes. The selection of the correct tooling axis is important to ensure the component is taken out perfectly and also the cost of the component should be less.

Draft analysis - Draft analysis is a technique to analyze whether the component created is manufacturable or not based on the draft conditions applied. So here I will provide the direction in which the component should be ejected to get the easy removal. My dirction will be the tooling axis that I have created.

The minimum draft value for the Automotive plastic component is 3 degrees and those for the texture faces 7 degrees of the draft is suitable. The draft is provided to the component for easy removal from the mold in the case of the plastic components.

So here I will change the customize view parameters and will select the material mode.

Then I will go insert and select the analysis and in the analysis, I will select the draft analysis. The draft analysis block is shown below:

In the above fig. under the display, the section selects the color scale and turns on the light effect for proper visualization. then under the direction section, I will click on the compass and will drag the compass from vehicle zero to my tooling axis. and then I will click on the lock feature and will select the class on the surface. The result is shown below:

The color scale shown above denotes the following:

The Green color denotes that the draft provided is above 2.9 degrees.

The Blue color denotes that the draft provided is between o and 2.9 degrees.

The Red color denotes that the draft provided is negative.

After performing the draft analysis I have made sure that the proper draft is provided on the component and now I can create the further surfaces which are class B and Class C surfaces.

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FLANGES - Flanges are the elements that are needed to join different components together. So here I have to make flanges on the door armrest and the map pocket. Following the master section, given as the input basically the measurements and location of the flange. I have created the flanges.

Dog House - Dog house is an engineering feature used in the plastic trim design. Doghouses are used as supporting features. 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 the mold cavity. Dog house and other engineering components are built on B-surface.

Here the dog house is required for lower substrate only. So for creating the dog house I have extracted the base surface of the lower substrate and made a point on that extracted surface and sketched on it. The sketch is shown below:

Then I have swept the above sketch along the tooling axis of the lower substrate giving 1.5 degrees of the draft. The sweep is shown below:

Now according to this tooling axis, I have drafted the inner portion of the dog house. the draft value I have given is 0.5 degrees. Actually, I have given the draft before giving the inner fillets and that is the correct method to do it later u can give fillets. The draft is shown below:

Now for avoiding the sink mark I have followed the design rule for it which is shown below:

For this purpose, I have just offset the base of the lower substrate to a height of 4mm the value could be anything between 3 - 6 mm. and then I have extracted the inside portion of the dog house. The offset and extraction of surfaces are shown below:

After trimming I have the trim to 1 mm considering the design rule that it should be 40 % of the thickness of the component. The thickness of the component is 2.5 mm so 40% of 2.5 is 1mm. After offsetting it to 1mm I have split the offset surface with the dog house body. the split is shown below:

Then I have used the copy and paste special option and translated the dog house along with a push pin to different locations on the lower substrate in which I want the dog house. so basically I have created points on the lower substrate and used the point-to-point translation. After doing the translation I have just added all the dog houses to the lower substrate. The result is shown below:

Heat staking - Heat staking also known as thermoplastic staking is the process of joining two dissimilar materials together. In heat staking, we use local heating and cooling to raise the temperature of plastic components and allow plastic reforming to be carried out. This reforming can be used in a wide variety of applications.

Applications range from staking plastic bosses for assembly of car door panels to joining PCBs to plastic housings. Benefits of this technique include; no vibration damage, no particulates, the ability to stake metalized coated applications, and the capability to stake in difficult to access or restricted areas.

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.

The advantages of Heat staking are as follows:

1) simplification of the machinery

2) Reduced cost of machinery

3)Multiple fastening points

4) Allows higher density of welds compared to hot air cold form or ultrasonic welding.

Before creating the heat stakes I have created the holes on all the flanges that I created earlier. For the hole, I have created one point on the upper face of the flange and created a sketch on it. The sketch is shown below:

CONCLUSION - This concludes the creation of the Door Trim Panel along with engineering features using the master section given as the input and the draft analysis has also been performed on the component.