DESIGN OF INTERIOR DOOR TRIM OF A CAR

DESIGN AND DEVELOPMENT OF INTERIOR DOOR TRIM OF CAR:

AIM:

    To design a car door trim with all necessary attachments using styling surfaces and master sections.

 

ABSTRACT:

    This project consists of the process of designing and developing an interior door trim of a car from scratch after the styling surfaces (Class A Surfaces) and master sections were provided for references. From the Class A surfaces, Class B and C surface were created and it is made into a solid. After this, some necessary features like flanges, heat stakes, ribs and dog houses were created according to the master section given. Finally Push pins/clips were attached to the dog house using constraints to complete the interior door trim.

 

CLASS A SURFACES GIVEN FOR:

• Lower Substrate.

• Arm Rest.

• Map Pocket (Lower)

• Map Pocket (Upper)

 

With all these given, the overall view of the door trim at first would look like,

 

REQUIREMENTS:

• Creation of Solid from Class A surfaces.
• Tooling axis and side core axis for every component if necessary.
• Creation of mounting features (DogHouse, HeatStakes, Flanges)
• Draft Analysis of components.
• Proper assembly with constraints.

 

Creation Of Solid From Class A Surfaces:

    To begin with, The solid to form needs three surfaces namely Class A, B and C surfaces. These surfaces combine to form a closed body which helps us to create a solid part out of it.

    Class A surface is nothing but the given styling surface. Note that there should not be any modification in the class A by the design engineer while developing any component since it may change or interfere with the environment. But if there is a patch in class A which has been created while extracting the data, there is an exception. Still it is advised to contact the Styling Team and ask them for a proper class A surface.

    Class B surface is the offsetted surface with an offset value of the thickness of the component. This surface is usually extended from the sides in order to trim it with other surfaces. Here either the surface is created directly using offset command or it can be created by extracting each and every surface of Class A and the trim with nearby surfaces with an offset value.

    Class C surface is the joining surface which connects both A and B surface so that it would be easier to trim and make a solid out of it. All these surfaces will be intersecting with each other hence providing an easy way to trim with each other. After all these surfaces are trimmed together, the surface wont have any boundaries and it will become a closed surface.

 

CLASS A,B and C SURFACE OF RESPECTIVE COMPONENTS:

LOWER SUBSTRATE:

Class A surface:

Class B surface:

Class C surface:

Finally, the solid part:

ARM REST:

Class A surface:

Class B surface:

Class C surface:

Now, the solid part,

MAP POCKET (LOWER):

Class A surface:

Class B surface:

Class c surface:

Hence, the final part,

MAP POCKET (UPPER):

Class A surface:

Class B surface:

Class C surface:

Finally, the solid part,

 

TOOLING AXIS AND SIDE CORE AXIS:

Tooling Axis:

    Tooling axis is the direction where the core and cavity part in molding process moves. this direction is to be verified before creating the solid part since it play an important role in the manufacturing process. Since no component can be removed from the cavity in 90 degress, it is a must to proide draft to the components for east removal of the components with respect to tooling direction. hence the direction or axis in which the core and cavity moves is known as Tooling Axis.

    This tooling axis is created in every component and it should be made sure that it can practically clear most of the region during manufacturing.

 

Lower Substrate:

Arm Rest:

Map Pocket (Lower):

Map Pocket (Upper):

    Though we have created the tooling axis, Luck wont be always with us. There will still be some areas which wont clear with the main tooling axis. Hence the Side core axis is introduced.

 

SIDE CORE AXIS:

    Side Core Axis is another axis created for the component if it fails to clear which the already created tooling axi. Obvious that complex parts wont be cleared in just a single tooling axis. Hence an axis which can clear the part side ways is known as side core axis.

    Note here that creation of side core axis is easy but it will increase the price of component since this process needs another mold for the side core to pass in. Hence it is usually recommended to make use of the main tooling axis and clear the maximum area. so that the component cost and time during molding can be reduced.

    (Practical example representing side core axis will be shown in the "Draft Analysis of components" section for better understanding.)

 

CREATION OF MOUNTING FEATURES:

    After the solid part has been produced and necessary tooling axes were created, This plastic part which is going to get fitted with the sheet metal needs Mountings to be created.

    Here Master Sections will be useful since we can take these as reference to easily create any feature.

Given Master Sections Are:

For Example, a section view:

The necessary mounting which should be created in the components are,

• Flanges.

• Heat Stakes.

• Ribs.

• Dog House.

    After the mounting features has been created, The components come to their final stage, which is assembly.

 

Components with mounting features:

Lower Substrate:

Arm Rest:

Map Pocket (Lower):

Map Pocket (Upper):

 

DRAFT ANALYSIS OF COMPONENTS:

Draft Analysis:

    Draft Analysis is a process of visualizing whether the created components can be manufactured using the tooling axis as well as the side core axis we created. It is always advised to keep a draft of 0.5-3.0 DEG for every component so that while in the mafucturing area, these components can be taken out nicely and clean without any damage.

   Here we created Tooling axis as well as Side core axis. Hence we should check the draft using both axes in order to satisfy the clearance. And if any of the region is not able to clear itself, we should make contact with the respective styling team for further modification and then try to clear those regions again.

    We have to make sure the draft analysis should show us a green color which means the specified component can be cleared using the tooling axis easily. other colors represent the inability to produce the components without any damage causing to it.

Draft Analysis of components:

LOWER SUBSTRATE:

    Here, As you can see, the draft analysis using Main tooling axis shows green color and is pretty much approximate to clear the region. Hence there wont be any modification for the lower substrate class A and the design can be done easily.

    But still the mounting feature such as Dog House is not able to clear the main tooling axis and it show a red color. Hence we provide side core axis to clear those regions.

Side Core Axis for Dog House:

    Here, using side core axis, the dog house is cleared and shows green in color.

ARM REST:

    The arm rest has most of the regions but stlll there are some areas which cant be cleared using the tooling axis. hence we can have two options here.

1. A side core axis can be created and can be used to clear the remaining regions but it will be cost consuming hence it wont be recommend as long as there is an urgent need.
2. In other case, this CAD can be sent to the styling team again and ask for remodification due to clearance issues. so by that, the team will try to modify the CAD for best results and resend to design engineers. and even if still the modification is not enough to clear the part using main tooling axis, then we are recommended to use side core axis.

MAP POCKET (Lower):

    From the draft analysis, it is shown that here as well the tooling axis direction finds it difficult to clear some areas. Henec we can either change the direction of tooling axis or consult the styling team for remodification.

    But even if the tooling axis can be changed to satisfy the part, it is not recommended to change the direction other than the natural axis direction which in our case, it is Y-Axis. 

    This is beacause different parts will be manufactured by different team in companies and each and every team cant focus on other team's tooling axis for reference other than natural axis since it may lead to clashing of components and it will interfere with the fits.

MAP POCKET (Upper):

    From these two images, there is only one area which is not clearing along the axis. It can be cleared if we slightly modify the Class A surface but as we already discussed, it is strictly not advised to do so since there may be interference with the environment caused by these modification.

    Hence It is usually done by the styling team so make contact with the styling team and ask for modification. So that the part can be cleared and no interference will be produced.

 

PROPER ASSEMBLY WITH CONSTRAINTS:

    Since the parts were created with reference with other parts, there is no use of assembling with constraints. However, the Push pin has to be assembled in order to make the product whole since it is created seperately.

PUSH PIN:

After Assembling the push pins the lower substrate would look like,

 

FINAL ASSEMBLY OF INTERIOR DOOR TRIM (FINISHED PART):

PART VIEWS:

 

CONCLUSION:

    As a result, as per the given output requirements, the Interior door trim of car has been designed and developed with all necessary mountings and draft analysis were made satisfactorily. Yet there might be some modification to be done in some components to ensure proper manufacturability and feasability. It depends on the styling team anyway, so from a design engineer perspective, Proper consideration were made sucessfully.