Design of backdoor
REPORT:
AUTOMATIVE DESIGN OF CAR BACK DOOR USING NX CAD
OBJECTIVE:
1)From the given class A surface, develop a back door using appropreiate design methodoliges.
2) The objective of the this project is to design a back door of a car with an inner pannel, outer pannel and reinforcement for the Hinges, Gas stay, Wiper motor, and latch by following the standards.
3) The inner panel must be subjected to draft analysis for verifying whether it satisfies The deep darwing requirements for the requirements for the tooling direction created in the design.
SOFWARE USED:
siemens NX CAD
INTRODUCTION:
The Back door of a car is the rearmost part of the vechicle which gives acess to the trunk space of the vecicle. The rear door also supports the reinforcements and added weight of wiper motor, Gas stay, tail limp , Latch and striker.
The backdoor/ tailgate is one of the closure commodities in BIW sheet metal design. The backdoor has a lot of components in it and its designed to incroperate them easily. it affects the rear visbility and lugagge area.
The material used for door manufacturing depends on the budget and performance of the vechicle. Mostly Aluminium and steel used where as low budget vechicles use steel which makes The manufacturing process easy and cost-efficient since it follows the stamping of mould.
Major Parts and Reinforcments.
The backdoor consists of the following components:
1. Back door outer panel (upper)
2. Back door outer panel (lower)
3. Back door inner panel
4. Hing reinforcement (RH& LH)
5. Gas stay reinforcements (LH&RH)
6.Latch and striker Reinforcemnt
7.Wiper motor reinforcement
TAILGATE:
Tailgate is the door at the back of the truck or car,that is hinged at the bottom so that it open downwards.
DESIGN INTENT:
The intent of the project is to design a body in white back door of the vechicle considering the engineering standards and manufacturing requirements which satisfies the deep drawing process.
DESIGN CONSIDERATION OF BACKDOOR:
1.Functional requirements of hinge and gas stay.
2.Rear visiblity criteria.
3.Luggage space.
4.Crash analysis.
5.Bend test, dent test, torsion test and Endurance test.
6.Gap and flushness requirements.
DESIGN OF BACKDOOR OUTER PANEL:
The outer panel is the class A surface of the back door. other components of back door are designed with referance to the outer panel it acts as outer cover and deals with aesthetic of the car.
In this design outer panel designed into two parts.
1.Outerupper panel
2.Outerlower panel
Outer upper panel :
1.The outer upper panel is extracted from Class A surface.
2.The panel is altred for the required design with the surface tools of Nx Cad.
3.The thickness provided for outer panel is 0.75mm.
4.Hemming is provided with the corner relif.
Outer Lower panel :
1.The outer lower panel is extracted from ClassA surface.
2.The panel is altred for the required design with the surface tools of Nx Cad.
3.The thickness provided for outer panel is 0.75mm.
4.Hemming is provided with the corner relif.
Lower and upper panel:
Tooling direction:
1.Before starting to design the inner panel of back door the tooling direction for deep drawing purpose sholud be created.
2.Then the styling surface needs to checked and analyzed since it might have irregularities, hence its must fixed first.
3.Then the back door was design by top down approach.
Design of back door inner panel:
1.The inner panel extracted from the styling surface.
2.The panel is altred for required design.
3.The thickness provided for outer panel is 0.75mm.
After creating tooling direction The design of inner of inner panel will being were we will first develop an effective sealing Flange by checking all the boundries and by following the shape of inner panel design.By creating a multiple flanges and by using surface modeling techniquces the concept design of inner pannel was created.
1. After the concept of inner panel is develop, Then the child components like hinge, latch, gas stay locations and there reinforcement must be designed. which complete the over all design of the component (back door).
2. The embosses were created so that if the vechicle undergoes the crash then the force dissapates over it which reduces the damage transfered to the trunk space.
MASTIC SEALENT:
The mastic sealent is used to fix inner panel and outer panel togeather which increases the NVH factor and stifness of the back door.
Hing, gas stay and wiper motor:
The hing emboss which was created using the datum plane and the emboss feature in NX. It was also design in the way that the emboss should have a flat surface for assembling the hinges by using it.
The gas stay emboss which was created using surface of the connecting flange.
The wiper motor emboss was created using the surface of the flange.
LATCH AND STRICKER EMBOSS:
The latch and striker which is designed by creating a trajectory that follows the opening and closing of the back door with respect to the hing axis.
STRIKER POSSITION:
The position of hing should be perpendicular to the latch when the latch and striker meets. The circle is drawn from the center of the hing axis to find the path of striker and positioned perpendicular to the path.
HEMMING:
Hemming and seamming are two similar metal working process in which a sheet metal edge is rolled over on its self. hemming is the process in which the edge is rolled flush to itself.
1. The outer panel has designed as two parts named as outer panel upper and lower.
2.After designing the outer panel the hemming was created by offsetting the surface with the help of blend and swept surface
3.The Two separate outer panels will be joined.
CORNER RELIEF:
During the hemming process, when giving the corner relif helps to control sheet metal material behaviour and to prevented unwanted deformation during the unbending operation and also helps to reduce the number of pasess in hemming.
DESIGINING THE REINFORCEMENT:
The thickness provided for reinforcement is 1.5mm
1.Hing reinforcement
2.Gas stay reinforcement
3.wiper motor reinforcement
4.latch reinforcement
All reinforcements were created using the same method first the linked body was created separatly for each with the help of extract geometry and then the required portion was trimmed out and thickned.
Hing reinforcement :
Hinges enabling the closeing and opening of the tail gate . one end of hing is fixed on the back door and the other end on the roof, on both sides. Hinges can be placed on out side or inside of the back door.
The hing reinforcement are added to compensate for weak region due to the acting load over it.
Gas stay reinforcement:
Gas stay is a device used for supporting the back door in its opening position. Gas will work individually and its engagged in to support position automatically as the back door opens. one end of the gas stay is fixedon the back door and the other end on the body side or on the back door stationary.
Embossing is provided at the gas stay mounting area to compensate for weakness and improve strength.
Wiper Motor reinforcement:
Wiper motor reinforcement is created to mount the wiper motor assembly.
Latch and striker reinfrocement:
The latch and striker forms the locking mechanism of the back door with the car. Due to the constant opening, closing and over slamming of the back door, there is stress developed in the latch and striker area. To compensate for the same, reinforcements are added in the area
DRAFT ANALYSIS:
1.The draft analysis will be performed for the tooling direction created at first and checked that the model is suitable for manufacturing.
2.Then to get a complete a green portion the necessary changes to the draft angle of embosses were carried out by obtimizing the model.
3.The draft Analysis command enables us to detect that the part drafted will be easily removed or not
4.This type of analysis is performed based on colour range identifying zones on the analyzed element where the deviation from draft direction at any point, corresponds to specified values.
VIEWS OF DESIGNED DOOR:
CONCLUSION:
Thus the body in white Back door of a car was designed following the engineering standards also the deep drawing requirements were also satisfied.