Week 12- Final project

                                         Project Report On Development of a Door Trim panel

AIM: To design the car door inner panel with reference to given Class-A surface by using given mastersection, creating attachment features and performing draft analysis to check the manufacturing feasibility of the component by using software CATIA V5.

OBJECTIVES: 

• To create individual tooling axis for the parts and perform draft analysis on the class A surface
• To create the class B and class C surfaces from the given class A surface
• To form a solid geometry by combining all the surfaces
• To decide an attachment strategy for the part and create engineering features in reference from the master section provided
• To perform draft analysis on the solid part model with all engineering features
• To assemble all the components togehter to obtain the final trim

INTRODUCTION:

Door panels serve as an interface between the interior of the car and the inner workings of the door, and between vehicle occupants and the door. They are expected to meet a variety of design specifications regarding safety, aesthetics, and functionality. In addition, they are expected to continue the material theme of the dashboard and pillars while concealing intricate electrical and mechanical components for operating locks, windows, and other features. The door panel has evolved from a simple two-part system of latch and simple winding mechanism to a more sophisticated enclosure. Doors currently have an inner full-width panel consisting of electronic windows, central locking system, and speakers. These panels typically consist of a foamed core covered with either textiles or plastics.

• Class-A surface:

       The Class-A surface is the outermost surface of the plastic component which is also looks fine surface and it is the                   aesthetic surface that the designer creates as an input part for the design work.

• Class-B surface:

       The Class-B finish is a quality finish with only minimal imperfections. A Class-B finish is the most common finish for                 exterior surfaces. It is normally specified on surfaces such as external covers, panels, and parts that are fairly prominent.

• Class-C surface:

       The Class-C finish allows more imperfections than Class-A or Class-B. Class-C is often specified for interior surfaces not           readily visible, surfaces that will be covered by another part when assembled, or surfaces which the Customer feels do             not need to meet a high cosmetic finish.

• Tooling Axis:

      In Molding, machine arrangement is given to open the mold along a direction which is known as Tooling Direction. In              other words. The mold is built from two separate halves (Core and Cavity) and tooling direction basically defines the                direction of mold or core pulls apart.

• 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 color ranges identifying zones on the analysed element where the deviation from the draft direction         at any point, corresponds to specified values. Most parts or applications require minimum of 1/2 to 1 degree, however 3         degrees is widely accepted as the norm.

GIVEN DATA:

Class A Surfaces with Master sections

• Components of Door Trim Panel:

       1. Arm Rest

       2. Map Pocket

       3. Bottle Holder

       4. Lower Substrate         

                                                             ARM REST

• Input:

• Check the given class A surface for improvements

Given class A surafce is not as good as needed . we have to informed styling team for improvement.         

As shown in above image I have improved given class A surface in surafce workbench by using surafce operation such as extract, extrapolation , trim etc.

• Creation of Tooling Axis For Arm Rest:

Here for moulding of Arm Rest we need two tooling axis. Some area get cleared with first tooling axis and reamaining with second one.

• Draft Analysis:

From above draft analysis we noticed that there is lot of space for improvement of class A surafce. We have to request stlyling team for class A modification.

 

• Class B Surface:

Class B surface is created by offseting class A surafce by 2.5 mm as per the mastersection. After offseting some area not get offseted , there patches formed. This patches are closed by surface creation features such as fill , multisection , blend etc.

• Class C Surface:

C surface is the connecting surface of Class A and Class B surface. By using Sweep we created the Class C surface. For that first we have to extract Class A boundary and then with draft direction at angle 3 degree we have sweep the class A extracted boundary. And we get the Class - C surface.

By trimming join of Class A ,C with Class B surface we get close body.

• Solid Body of Arm Rest:

• Creation of Flanges on Arm Rest:

From mastersection we get the idea of flanges . I have created flanges on Arm Rest by considering counterpart (Lower Substrate) position.

• Draft Analysis:

Follow the below steps for coeerct analysis

select Feature Draf Analysis cammand from Toolbar

change to material mode

Drag the compass and aligne it with the tooling axis and lock it.

Provide the nominal draft value of 3 degree and do the analysis each surface meets the feasibility.

From above draft analysis we notice that given part is not as good to manufcature. There is lot of modification needed. We have to request styling team to improvement in class A at particular areas.

                                                                     MAP POCKET

• Given Input:

• Tooling Axis:

• Class B:

Class B surface is created by offseting class A surafce by 2.5 mm as per the mastersection. After offseting some area not get offseted , there patches formed. This patches are closed by surface creation features such as fill , multisection , blend etc.

• Class C:

C surface is the connecting surface of Class A and Class B surface. By using Sweep we created the Class C surface. For that first we have to extract Class A boundary and then with draft direction at angle 3 degree we have sweep the class A extracted boundary. And we get the Class - C surface.

• Flanges:

From mastersection we get the idea of flanges . I have created flanges on Arm Rest by considering counterpart (Lower Substrate) position.

• Draft Analysis:

Follow the same steps as we did for Arm Rest.

• Assembly:

                                                                             BOTTLE HOLDER

• Input Class A Surface:

• To Check Quality of Class A:

The quality of class A surface is not good enough need to be modified.

• Draft Analysis on Class A:

Follow the same steps as we did for Arm Rest.

 For creating Class B surface we have to offset it by 2.5 mm as shown in above image.

• Creation of Flanges/ Mounting Brackets:

• Draft Analysis:

Follow the same steps as we did for Arm Rest.

                                                                  LOWER SUBSTRATE

• Input:

For creating Class B surface we have to offset it by 2.5 mm as shown in above image.

• Creation of Dog House:

• The two main purposes of a dog house are to avoid sink marks and to house various other engineering features like screw boss, locators, push clips etc.
• In this case, the dog house is designed to house the push clips and the 4 way locator. The dog house designed for the push clip features a slot on the top face to accommodate the push clip
• The dog house should follow certain design rules which are stated below

• Doghouse wall thickness at the intersection of the part wall (C) should be 40% or less than the main wall stock (T).
• The height of ( B ) should be between 3.0 – 6.0 mm
• Outer surface of dog house must have a draft angle of 3 degrees
• Inner surface of dog house must have a draft angle of 0.5 degrees

• Draft Analysis:

 

•  Creration of Heat stake:

• Heat stakes are used in thermoplastics to assemble two parts together by locally heating and cooling the plastic material and allowing it to reform itself and act as a joint for the two materials.
• We have placed 9 heat stakes in the model based on the reference points created by estimation.
• One of the important factor to be considered while designing the heat skates is the height of the heat skates. It should always be less than the height of the locators.

• Creation of Locators:

• The main purpose of locators is to facilitate proper locking of two components together while assembling and arrest the maximum degrees of freedom possible.
• These locators are similar to guide pins provided in mould.
• The two types of locators used are two way locator and four way locator.
• We have positioned three 4 way locators in our model which meet the rib design criteria.

From above image we can see the position of all heat stake , locators and dog house. This all feature created on lower substrate by considering position of its counter parts.

• Push Pin:

 Push pins are used for joining one component to another . These are basically attached to the doghouse. For creating the push pins the following reference was taken for dimensions.

• Final Assembly:

For final assembly of door trim panel we have to constarin all parts together. 

Following image shows the  assembly of push pin with dog house.

Following tree structure shows the how all part are constrained.

CONCLUSION:

In this way, From this project I have leraned how to create CAD model for plastics parts by considering design rule. By doing this project on Catia V5 , I got very well familier with part workbench ,surface workbench , Assembly workbench. Also I get confidence in handling different features of all workbenches. Along with this , I get idea of how to design a part by considering manufacturing and assembly aspects also i get to know how actual door trims got created and lots of other things too.