Design of backdoor
BACK DOOR DESIGN OF CAR:
Aim:
To design the complete back door by using the given styling surface of back door by appropriate methodology and providing the necessary reinforcements, emboss, hinges by using the NX CAD.
INTRODUCTION:
BACK DOOR:
Back door is the component which is situated the back side of the car, it is the opening and closing tailgate.it is covered the back side cargo space to keep the things safely in the car.it give acces to the luggage area for passengers to carry things.
Back door is also one of the most important integrated part act as a opening and closing flexibility to keep and take out the things. This door consists other different integrated parts to fix and open or closing. Like,
*Sealing flange
*Wind shield glass area
*Reinforcements like hinges for tailgates, latch and striker
*Wiper mounting unit ETC.
Back door can open and close by the gas stay cylinder fixed at the sides of the door and body frame other side. This cylinder also holds the door rigidly in open condition as well. This opening and closing actuation are controlled by the manually and automatically by providing the connection to the car main key. The door or opening of a cargo area may be hinged at the top, side, or bottom.
Latch and striker added to the body frame of the car and that locking mechanism provide in it, other side the striker provided to the back door top, latch and striker design is must follow the trajectory path to successful locking system. For the gas stay providing the hinges at the sides of door or top either side of the door at suitable position. This gas stray provided both sides of the back door.
To manufacturing the back door, need the many considerations like visibility, opening and closing, hinges and reinforcements etc. While designing the door follow the desired considerations.
This door consists also inner and outer panels with certain distance. These parts can be manufacturing by the stamping process.
MANUFACTURING PROCESS
The back door is manufacturing by the stamping process of both the outer and inner panel. For manufacturing the back door need the draft angle of minimum of 7 degrees. Door the manufacturing process the inner panel providing the gas stay, wiper motor, striker and latch mountings as well.
Between the back door and body there providing the sealing flange to make good attachment to the body with out any noise and also it provides the leakage of any water.
Foe operating the door there provides the handle system ,through which the door opening and closing is happening.
Hinges reinforcement providing on the top of the door to give the relative motion between the boy and backdoor both sides to open and close in proper manner.
MATERIAL FOR BODY PANELS
Mostly for the doors and body of the car is manufactured by the steel. Some parts are manufacture by the aluminum, there also used the plastic and fiber glass foe visibility purpose.
Materials used for the door require the certain specific characteristic to give better strength, visibility and with stand loads. This is the major challenge to the industries. The suitable material selection is very important to the stamping forming, blanking and hemming the joining of the outer and inner panel together.
While selecting the material for the door is look into the wight, cost, strength, mechanical, thermal and physical properties as well. The door should with stand the impact resistance, yielding stress, corrosion resistance, durability and reliability.
Most of the steels used in automotive application are aluminum-killed steels of about 0.7 to 0.9 mm thickness.
STAMPING PROCESS
Stamping is the major process involved in the door manufacturing. Because of the door present in the form of all curve and complex shape with certain depth, and also inner panel of the door is single component, it is possible with stamping the desire profile in the sheet in single term. Along the stamping also need the other operations like punching, piercing, Heming and trimming etc. to provide the embosses and some other cutouts on the door to force distribution diversion.
Some places need to remove the material to accommodate the other parts like wind shield glass for visibility.
1.blanking:
It is the primary process of cutting the large available sheet into the required size or cut into smaller pieces to use it as a working surface in the manufacturing process.it is done in the blanking machine consists of the is up and down, in between placed the sheet and apply the force on the sheet by moving the die.
2.piercing
This is the process need to the remove the unwanted material in the work surface and creating the hole,slots and other different profiled cutouts.it is done some time simultaneously with blanking also.
3.Drawing
This the main process in the stamping process, because here only the sheet metal gets the desired profile what we design with certain depth required to us. This is the primary process to get the sheet profile. For this process have dies with required profile, by using that die we do the drawing process by placing the sheet in between the dies.
4.Bending
Bending is the other important operation need to the bend the sheet where the bending is necessary to make component to join or fix rigidly and some cases bending is need to the to get the defined profile .it done after the drawing process.
5.Hemming
Heming is the process used to the join the two are more different parts together to get required part.in this process we are going to join the inner and outer panel of the back door rigidly. The inner panel is covered the outer panel at the periphery of the sheet by bending the outer panel sheet and taking it other side as a folding cover and bind together.in automotive industries the roller hemming is used majorly for join the components.
Hemming is give good joining technology and gives the good appearance to the customer and is done in the different stages as follow.
BACK DOOR DESIGN procedure:
PARTS OF BACKDOOR
*Back door outer panel
*Back door inner panel with different reinforcements
*Hinge reinforcements
*Gas stays reinforcements
*Latch and striker mounting
*Wiper motor mounting
1. BACK DOOR OUTER PANEL
This is the visible surface to the outers is manufactured with two different components like upper and lower panel. This part can extract from the skin data provide by the styling surface given to the back door designer. For this panel we are just providing the extra end surface to bend and fold the ends to hemming with inner panel. After that will give the thickness about the 0.75mm.
2.BACK DOOR INNER PANEL
Back door inner panel situated at the some distance to the outer panel. The outer panel is extracting and offset it to the certain distance. After that we are provide the sealing flange on the inner panel to place the sealing rubber between the inner panel and body of the car. For that we provide the groove like structure on inner panel by using suitable commands.
At the top of the inner panel provide the some gap to the wind shield .along that on inner panel also provide the hinge reinforcements mountings and gas stay, latch and striker mountings also.by drawing the desired sketch and Crete the emboss with some holes to hinge mounting.
At the middle of the inner panel design the some embosses and cut outs to the good strength capable and force distribution outwardly. There also need one mastic area to join the inner and outer panel rigidly for that also provided that vertical flange structed.
sealing flange:
emboss and cut outs:
final part:
Mastic Area
This area is provided fo the joining of the outer and inner panel.it increase the strength and maintain the good NVH.so that created the mastic are between the outer and inner by extending the sheet and offset the surface to the some distance from inner panel and cut it into required.
Mastics sealants used for joining of outer panel and inner panel. It increases the strength of back door and good NVH. So accurate clearance given for mastic sealant.
After design total profile thicken the sheet about the 0.75mm inwards.
Reinforcements in inner panel
Hinge reinforcement
In back door design there nee the hinge reinforcements to fix the back door to the body to move up and down with hinge help.so for offset the required surface to about the 1.9mm from the inner panel and cut it into the up to require, make it into thick part of 0.75mm and mirror it for other side hinge.
Gas stay reinforcement
Gas stay is the air cylinder which helps to the opening and closing the door and hold it in opening time fixedly and carry the load of the entire back door. For that we design the gas stay reinforcement at the side of the inner panel as similar to hinge reinforcement.it also design the as per required length.
It also fixed by spot weld to the inner panel for that provide the some clearness.
Wiper motor reinforcement
This is designed parallel to the inner panel by offsetting the surface at a distance to the inner panel and provide the some cut outs to fix the motor to the reinforcement. The motor will fixed to this part inside.
It also thicken about 0.75 mm and mirror it to full reinforcement either side.
Latch and striker reinforcement
This part designed to locking the door into the provided latch on body. For that define the trajectory path along its moving direction after that design the part as per trajectory path direction.
Apply the thickness of 0.75mm
Hemming
Heming is done after completing the total back door. Extend the outer panel and apply the sweep over it to bend and fold the sheet at desired location and required form to join the inner panel with the outer panel. After hemming need to provide the stress reliefs on the hemming region to give more strength to the outer panel to avoid stress concentration.
Then apply the thicken 0.75 mm of outer panel.
Draft Analysis
Draft analysis is performed while sending the design to the manufacturing team to check the minimum draft angle provided or not to the inner panel. Because in stamping process the draft angle is most important to avoid the damage of the stamped part during removing from the die.
If we not provide the proper draft angle it leads to damage the part and tool wearing also.
For that we provide the tooling axis to the part and checking the draft angle with respect to the tooling axis. If it is green color then it satisfy the draft angle for stamping the part.
CONCLUSION:
Finaly the back door design is completed by all necessary sealing flanges a reinforcement on the inner panel. The draft analysis also performed on the inner panel and it is satisfied successfully.
BACK DOOR DRIVE LINK:
https://drive.google.com/file/d/1b8ZJ8bQ9-JVOUuR056xIvJYp6C5hwcQM/view?usp=drive_link