Week 12- Final project

DESIGN OF DOOR TRIM PANEL

AIM:

To Design a part of the Car door Plastic components placed in the car door panel by following the design standards used in the industries using Catia v5 software with the provided class A surfaces.

DOOR PANEL:

The door panel covers internal parts like the window regulator, the power window motor, and the wiring. It is attached to the sheet metal part of the door. It is designed differently based on the design of the sheet metal part of the door. Besides its aesthetic look, it also has many functional features attached to it such as an armrest, bottle holder, speaker attachment, etc. In older cars, door panels used to be made out of cardboard and upholstered with material that matches the rest of the upholstery within the cabin. On the other hand, most modern cars have door panels made from plastic. The main materials used include kenaf, which grows year-round and has excellent CO2 absorbing properties, and plant-derived plastic, making them environmentally friendly as well.

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 together to obtain the final trim

GIVEN DATA:

Class ‘A’ surfaces are primarily used in the automotive environment and refer to those surfaces which are visible in a product. In other words: A - class surfaces are those aesthetic/free-form surfaces, which are visible to us (interior/exterior), and have an optimal aesthetic shape and high surface quality.

Here, one should understand the difference between the internal or external and visible or hidden surface. The surfaces or regions which are visible nowadays are considered for Class-A modelling. It is one of the reasons why the importance of Class-A modelling is increasing day by day. Majority of the time this term is used in Plastic Part designs.

MASTER SECTION:

These are the guidelines provided to a design engineer which describe how a component would/must look like once it is modelled into a solid component from the class-A surface. For example, in this model, we have received a master-section as an input which tells us about the thickness of the component and dimensions & type of the engineering features on the component.

Given Data

TOOLING AXIS:

Tooling axis is the axis along which the core and cavity opens and closes. It is very important to define the tooling axis in the first step while designing a component as it is the main component which helps us to run draft analysis on class-A at initial stage to see if we can move ahead. Also, for later stage, tooling axis is the direction along which class-C surface and the draft to the components is given.

For the creation of tooling axis there are different methods one is the Bisecting Line method for this a suitable surface is chosen. A point is placed on the middle of that surface for creation of an axis system. A Point sketch is added on Axis system so as to intersect the surface and an intersection of the surface is made on the surface. lines which seem to create problems in the moulding are noted and an impression of it is made on the sketch and a bisecting line of the same is made. Now repeating the same procedure on the other perpendicular plane could give you another bisecting line. Now a bisecting line of the two lines obtained is created which will be our tooling axis. Another method is by choosing a suitable direction on a surface by visual analysis and doing the draft analysis for verification, this is a trial-and-error method.

Tooling axis

DRAFT ANALYSIS:

Our first step before starting the model should always be to check is the surface has enough draft that it will not create any problems while ejecting from the mould considering the tooling axis. Some components require side core where there are under undercuts, holes or projections on the side walls, so for this we need a different tooling axis and a different analysis is required to check those areas.

Draft analysis shows colour codes which are defined by the user for different values which are also user defined. These colours help us to analysis if the component is clearing. In case the component fails the analysis for class-A then we have to submit the draft analysis report to the higher authority so that the surface of the component can be improved. Failing analysis simply means that the component does not have the required draft value it must have. We have to make sure that our entire model is clearing the analysis. So, we have to run analysis for class-A, solid model and other B-side features as every single component, regardless of its size should be ejected safely from the core.

WORKINGS:

The first procedure is to check whether the provided class a is of good quality or not, for that we check the boundary of the given class A surface if it shows some boundaries other than the outer one, we have to rectify the certain problem which helps to improve the quality of the class A to get a better result.

B SURFACE CREATION:

· Offset the surfaces to 2.5 mm to create the thickness.

· Check whether all the surfaces are properly offset.

· Some edges that are not created clearly, thus the area would be created with a multiple extract and extrapolate options.

· Join all the surfaces together.

· While trimming with the class c surface some of the parts do not coincide with each other, so we will extrapolate them by selecting the outer boundary.

CLASS C SURFACE:

• Extract the boundary from the class A surface using the boundary command.
• Use sweep command > choose profile type as line > subtype as with draft direction > choose guide curve and draft direction > the minimum draft angle should be 3 degrees.
• After getting sweep extrapolate each corner to get in contact and then trim the output to create single part.
• Then join the swept part with the class A surface.

HEAT STAKES:

· 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 part.

· Heat Staking makes it easy to bond metal to plastic and is commonly used in high-volume/low-cost applications such as automotive IP, Door inner panel and also in consumer appliances.

DOG HOUSE:

· Dog house is an engineering feature used in plastic design. Which is used as support feature. Sometimes other engineering features like snaps, locators, and screw bosses are mounted on them to increase their strength and as well as the height

· Dog houses are subjected to draft analysis to prevent breakage of the component during ejection from the mould cavity. Dog house and other engineering components are built on the B-surface.

FINAL TRIM:

· Trim the class A & C joined surface with the Class B surface for getting final hollow surface.

· Check with the boundary option in the final trimmed surface, whether any extra boundaries forming or not.

CLOSED SURFACE:

· Create a closed surface in the final trim.

ADDING ENGINEERING FEATURES TO THE BODY:

The next procedure to be followed is adding engineering features to the created part the features added are

1.HEAT STAKES

· 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 stakes are created on Lower-substrate wherever the flanges are projected on the lower-substrate.

2.LOCATORS:

· Locators are the small projections place on a plastic part which helps in the proper alignment and arresting of the components for fixation. There shall be a hole in the mating part so as the locator slides inside and fits in properly with the other part

· Here we have used 4-way locators

3.PUSH CLIPS

Push clips are fixing components mount on dog house which help in clipping the part to the other body. As the push clips are manufactured elsewhere and is not in our zone of concern so we have ignored the rules while making the push clips and made a general clip of similar shape in part design without following any rules.

3.DOG HOUSE:

Primary function of the dog house is to avoid sink marks. But it also helps in other things like if the mating part is to be at a greater distance, then we cannot make the height of the screw boss of that greater height, thus we make dog house and mount screw boss on it. Hence it helps in solving the problem of screw boss and also it helps to have perpendicular screw boss.

GENERAL DESIGN GUIDELINES FOR DOG HOUSE DESIGN

1. Minimum height: Less than 6mm causes steel condition.
2. 3:1 ratio of steel width to height. But 2:1 is preferred.
3. Minimum width: 3:1 ratio of steel width to height. But 2:1 is preferred.
4. Draft: minimum 1.5deg.
5. Sink saver: height= 40% of nominal thickness. Width= 3.0mm-6.0mm.
6. Optimal radius:25mm

FINAL COMPONENT:

RENDERED VIEW

CONCLUSION:

The door trim panel was successfully created with all the design rules taken into considerations for feature attachment and the main part was created using the master section provided with the input class A.