Design of backdoor
OBJECTIVE:-
- The objective of the project is to design a BIW back door of car with inner panel, outer panel and reinforcement for hinges, gas stay, wiper motor and latch by following the engineering standards.
- The inner panel must be subjected to draft analysis for verifying whether its satisfy the deep drawing requirement for the tooling direction created in the design.
- The given styling surface develop a back door using appropriate design methodologies.
SOFTWARE:-
- Siemens NX CAD.
INTRODUCTION:-
- The back door is the rearmost car portion which is known by also dikki. the vehicle which gives access to the trunk space of the vehicle. The rear door also supports the reinforcement and added weight of the wiper motor, gas stay, tail lamp and latch striker.
- The tail gate is one of the closer commodities in BIW sheet metal design. the back door has a lot of components inside and is designed to incorporate them easily. it affects the rear visibility and luggage area.
- The material used for door manufacturing depends on the budget and performance of the vehicle mostly aluminium and steel will be used whereas low budget vehicles use steel which makes the manufacturing process easy and cost efficient since it follows the stamping of moulds.
- The backdoor consists of the following basic components:
DESIGN CONSIDERATION OF A BACKDOOR:-
- Functional Requirement of Hinge and gas stay
- Rear Visibility Criteria
- Luggage Volume
- Crash Analysis
- Bend Test, Dent Test, Torsion Test & Endurance Test
- Rear Crash Regulation
- Gap and Flushpess Requirements
DESIGN OF BACKDOOR OUTER PANEL:-
The Outer Panel is the styling surface of the back door Other components of the backdoor are designed with reference to the outer panel. It acts as the outer cover and deals with the aesthetics of the car.
In this design outer panel is divided into two parts:
1. Outer Upper Panel.
2. Outer Lower Panel.
1. Outer Upper Panel:
The Outer Upper Panel extracted from a styling surface. The panel is altered for the required design with the surface tools of NX CAD. The thickness provided for the outer panel is 0.75 mm hemming is provided with the corner relief.
2. Outer Lower Panel:
The Outer Upper Panel extracted from a styling surface. The panel is altered for the required design with the surface tools of NX CAD. The thickness provided for the outer panel is 0.75 mm hemming is provided with the corner relief.
TOOLING DIRECTION:-
- Before starting to design the inner panel of the back door tolling direction for deep drawing purpose should be created.
- Then the styling surface needs to be and analysis since it might have irregularities, hence it must be fixed first.
- Then the back door was designed Top to down approach.
DESIGN OF BACKDOOR INNER PANEL:-
- The Inner Panel extracted from a styling surface.
- The panel is altered for the required design with the surface tools of NX CAD.
- The thickness provided for the outer panel is 0.75 mm.
After creating the tooling direction the design of the inner panel will begin where we will first develop an effective sealing flange by checking all the boundaries and by following the shape of ths inner panel design. By creating multiple flanges and by using surface modeling techniques the concept design of the inner panel was created.
- After the concept of the inner panel is developed, then the child components like a hinge, latch, gas-stay locations and their reinforcements must be designed. Which completes the overall design of the tailgate. (Highlighted view:-sealing emboss)
MASTIC SEALANT:-
Mastic sealant is used to joint inner panel with outer panel which increase the NVH factor and stiffness to the back door.
HINGE, GAS STAY & WIPER MOTOR EMBOSS:-
The green circle denotes the hinge emboss which was created using the datum plane and emboss feature in NX. It was also designed in a way that the emboss should have a flat surface for assembling the hinges using it. The orange circle denotes the gas stay emboss which was created using the surface of the connecting flange. The brown circle denotes the Wiper motor emboss which was created using the surface of the connecting flange.
HEMMING:-
Hemming and seaming are two similar metalworking processes in which a sheet metal edge is rolled over onto itself. Hemming process in which the edge is rolled to itself.
CORNER RELIEF:-
During the hemming process, when giving the corner relief helps to control sheet metal material behaviour and to prevent unwanted deformation during unbend operations also helps to reduce the number of passes in hemming.
DESIGN THE REINFORCEMENT:-
The thickness provided for all reinforcements is 1mm.
1. Hinge reinforcement
2. Gas stay reinforcement
3. Wiper motor reinforcement
4. Latch reinforcement
All the reinforcements were created using the same method, first, the linked pody was created separately for each with the help of extract geometry and then the required portion was trimmed out and then thickened,
1. Hinge reinforcement:
Hinges enable the opening and closing of the back door. One end of the hinge is fixed on the backdoor and the other end on the Roof on both sides. Hinges can be placed outside or inside the backdoor. The hinge reinforcements are added to compensate for the weak region due to the acting load over it.
2. Gas Stay Reinforcement:
Gas Stay is a device used for supporting the back door in its open position. Gas stay requires no manpower and is engaged into support position automatically as the back door opens. One end of the gas stay is fixed on the backdoor and the other end on the body side or on the back door stationary area. Embossing is provided at the gas stay mounting area to compensate for weakness and improve strength.
3. Wiper motor reinforcement:
It is useed to mount the wiper motor assembly.
4. Latch and Striker Reinforcement:
The Latch & Striker forms the locking mechanism of the backdoor with the car. Due to regular opening, closing and over slamming of the backdoor, there is stress developed in the latch and striker area. To compensate for the same reinforcements are added in this area.
DRAFT ANALYSIS:-
- The draft analysis will be performed for the tooling direction created at first and checked that the model is suitable for manufacturing.
- Then to get complete green portion the necessary changes to the draft angle of the embosses were carried out by optimizing the model
- The Draft Analysis command enables us to detect that the part drafted will be easily removed or not.
- This type of analysis is performed based on color ranges icentifying zones on the analyzed element where the deviation from the draft direction at any point, corresponds to specified values.
