Week 12- Final project

                                                             DEVELOPMENT OF A DOOR TRIM PANEL

AIM:

 To design and develope vehicle interior door trim using Catia V5 with given class A surface along with Master section. Also create the Side Attachment features as per design rules.

OBJECTIVE:

• To create thickened part using master section for reference.
• To create the mounting features as per design guidelines in the industry and with master sections.
• To perform Draft analysis & Tooling analysis.

INTRODUCTION:

The door panel is the interface between the interior of the car and the inner workings of the door. Generally the door panel is divided into parts for easy designing like arm rest, map pocket, lower substrate. These require one of the toughest requirement among the interior parts of the car. This should be designed to with stand the load while being less than 2mm in thickness and also to protect the occupants during collisions.

Door currently have an inner full width panel consisting of electronic windows, central locking system and speakers. These panels typically consists of a foamed core covered with either textiles or plastics.

 

METHODOLGY:

1. Creating the Tooling Axis

The tooling direction is used to find the direction in which the part is removed from the core and cavity. The draft angle should be positive to the tooling axis to manufacture the component easily. The step by step procedure of creating the tooling axis is given below.

 (a).Creating the tooling axis for Map Pocket by create a point on surfaces respectively to the 0 value. It automatically create at mid surface and generate the line to the direction of y axis. 

(b).Creating the tooling axis for Bottle holder by create a point on surfaces respectively to the 0 value. It automatically create at mid surface and generate the line to the direction of y axis.

(c).Creating the tooling axis for Lower Substrate by create a point on surfaces respectively to the 0 value. It automatically create at mid surface and generate the line to the direction of y axis.

(d).Creating the tooling axis for Arm Rest by create a point on surfaces respectively to the 0 value. It automatically create at mid surface and generate the line to the direction of y axis. And also we need to construct a sliding axis in case of arm rest due to complex surface for manufacturing ease.

2. Creating the B surface.

Creating the B-SURFACE by extracting the class A surface, by each surfaces separately, it is offset to certain distance, making point on the master section to get the intersection as shown below.

Finally we achieved the B class surface by extracting and offset the Class A surfaces.

3. Creation of C Surfaces:

Step: 1

Extracting the boundary of Class A surface and it is make into smooth curves to sweep the curves by using support surface to the 90 degree respectively.

Once the all surface joined together it extrapolated to certain distance to trim with A Class surface to C surface. Finally we created Class C surface.

Making the Final plastic Component:

To make the final component the Class C surface is trimmed with Class B surface, the output will get the component with 2.5 mm thickness of surface and it is converted into solid body using insert body option in part design as shown below.

4. Creation of Attachment Feature to the Door Trim:

(a) Doghouse creation

Dog house is an engineering feature used in plastic trim design. Dog houses are used as supporting feature. 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 mould cavity. Dog house and other engineering components are built on B-surface

DESIGN GUIDELINES FOR DOGHOUSE.

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Procedure:

1.Creating the sketch by extracting the class A surface, by each surfaces separately, point and axis system created simultaneously on the surface. Using positioned sketch making as shown below.

2.The extruded surface is extrapolated, the extract surface from Class A has been offset to make side wall surface of dog house by trimming it.

3.The extruded surface is converted into solid by thickening the surface for 2.5mm and it is extrapolated and to make close body it is split into equal distance has shown below.It is drafted for 0.5 deg to perpendicular to the sidling axis as shown below. The edges where chamfered for 5mm to 45 Degree.

4.The undercut has been made by extrapolated surface and it is offset to the minimal value and it is trimmed to get perfect under cut.To get the proper clearance for removal of the component is drafted for 0.5 at the undercut area and it is chamfered for 1 mm to 38 deg as shown below.

5.It is union trimmed to lower substrate and it is filleted for radius 2.5mm of smooth edges as shown below.

 

(b)Creating the Heat Stake:

Heat staking is a pulsed – heat process to join two or more parts out of which one at least is made of plastic . The plastic is to deform the plastic material using the heat and foam at a set process time. The bond is made by partially de forming the plastic part in order to fix the other. Heat stakes makes it easily to bond metal to plastic is commonly used in high volume and low cost application such as Automotive, IT and consumer appliances.

DESIGN GUIDELINES:

 

PROCEDURE:

1.Creating the sketch by extracting the class A surface, by each surfaces separately, point and axis system created simultaneously on the surface. Using positioned sketch.

2.The sketch feature is then extracted to the required dimension. And it is drafted for the 0.5 deg to the sliding tooling axis, it is filleted for radius 0.25 of smooth edges as shown below.The support rib as created, where the flange will come and sits to get arrested to the heat stake.

(c) Push Pin Clip

The push pin clip has been provided as a CAT part along with suitable dimensions only we need to figure out is assembly with the doghouse attachment.

(c) 4-Way Locators.

The b-side of lower substrate has 4-way locators for the part assembly as a attachment strategy. They are basically ribs with an extended heights drafted with 0.5 degree and corner chamfererd at 45 degree and  provided with fillets of 0.5mm.

(d) Flanges.

Hence, we have made the flanges  according to master section provided.

 5. Performing 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 colour ranges identifying zones on the analysed component where the deviation from the draft direction at any point, corresponds to specified values. This rule of thumb applies to parts with mold depths of up to 2 inches. At this size, draft as low as 1½ degrees will allow for an easy, non-damaging release from the mold when the expected shrinkage of the thermoplastic material occurs.

It’s also important to remember that draft angles are just one component of an effectively designed injection molded piece. Design for manufacture is one of the easiest ways to improve the quality and efficiency of your injection molding process, and it never hurts to stay up to speed on all injection molding best practices.

Draft analysis on Door Trim Solid Body with attachment features:

PROCEDURE:

1.First we have to set the compass on the main tooling axis to get the direction of core and part moves along as shown below.Here the draft angle is given as 3 degree. Hence we achieved green colour on top surface. Hence it accepts the draft angle for the surface, so we build good quality component.

2.Now we check colour variant scale to ensure the maximum and minimum area draft angle is achieved by displaying by green, red and blue colour respectively. If the surface appears red in colour while analysing it is not accepted.We can check the angle of draft given to surface by using draft tool analysis just point the over the surface where we have check angle of given draft to the component as shown below.

A sliding axis for the Arm rest component has been done separately by using sliding tooling axis as shown below.

FINAL ASSEMBLY OF DOOR PANEL WITH ATTACHMENT FEATURES :

Front View:

Back View along with attachment features:

Conclusion:

Creation of the car interior door trim is designed using the given class A surface as the input and Class B and C surface created with the help of Class A surface. By using the given master section attachment features I.e. Heat stakes, Flanges, Dog House and Push Clips are created using the design rules. The draft analysis has been performed to analysis the draft of the component to manufacture easily applying draft to the surface by 3 degree and 0.5 degree to the attachment features. With all data and report we can conclude that draft analysis is very important to design any plastic component to mold the plastic easily. The analysis will verify that all surfaces are favorable for being pulled from a cavity. It may also highlight or given insight to defect areas.