Design of backdoor
AIM- DESIGN OF BACK DOOR WITH GIVEN STLYING SURFACE AS PER THE OEM SATNDARDS.
DESIGN-Design of back door inner panel ,outer panel upper & lower saperately with hemming flange & reinforcements of the hinge reinforcement ,gas stay reinforcement,stricker reinforcement,wipermoter etc
BACK DOOR is the part of the BIW car body acts as closing at the rear side.covering the storage compartment.
it is also called as tailgate body.
The working principle of car back door how it is opened it consists of gas stays (hydraulic pumps) which is attached to the one end to the body side feature biw & other end to the back door assembly which wiil be explained detailed below by placing the images & hinges joined to the biw & back door on the top side & in the bottom side latch & stricker is fixed which acts as the locking the back door after it closed.the back door contains the wiper fpor cleaning the glass while raining & as per the requiremenyt conditions registration no plate rear lamps like indicators car brand logo,etc to be assumed the location & WHWRE THEY WILL BE PLACED & TO BE DESIGNED THE BACK DOOR.
THE HIGHLIGHTED IN YELLOW COLOUR IS THE BACK DOOR PART OF THE CAR BODY.
The designed back door has 1 inner panel & 2 outer panels.joined togeather by hemming & spot welding at required places.
MATERIAL USAGE FOR BACK DOOR
at present all the premium cars like high class brand cars are using the aluminium material to manufacture the part to reduce the weight of the part model as compared with the sheet metal part body.but the cost of the aluminium is very high except the cost all the features are high like easy to manufacture ,only single part of completeback door no reinforcement are required for given the strength to the model.
THE OPENING WAY OF BACK DOOR
the back door is opened in the three steps like when we lift the back door by unlocking it it wiill open at certain angle ,stops & opens completly ,this is because it gives good fell to the passange & no need to apply more energy to open it completly tec .
BACK DOOR AS TYPES OF OPENING
- TOP MOUNTED
- SIDE MOUNTED
DESIGN CONSIDERATIONS OF BACK DOOR ASSEMBLY
- Rear visibility
- Support structures like hinges,gas stays,latch & stricker,wiper etc.
- Mountings for wiper moter,tail lamps, & other wiring loops.
- Boot space
- Rear crash regulations
- sealing flange(black dolour rubber sealing support flange)
- joining of upper & inner panel hemming & specified sopt weld joints.
BACK DOOR ASSEMBLY PARTS WHICH I HAVE DESIGNED IN THIS CHALLANGE.
COMODITIES OF BACK DOOR
INNER PANEL
the above image is inner panel of the car back door it consists embosses ,mounting of hinges,gas stays,stricker,wiper motor etc ,it acts as support to the outer panel of back door upper & lower the outer panel & inner panel is joined with the hemming operation ,where the sheet is folded mainting the required gap.
THE HIGHLIGHTED POINTS ARE THE MOUNTING WHERE THE ASSEMBLY PARTS WHERE FITTED AT THET POINTS WITH NUT & BOLTS OR SPOT WELD AS PER THE OEM REQUIREMENTS
spot welding process of automotive sheet metal
At this point spot welding is done to join the two outerpanels upper & lower.
In order to avoid these limitations, friction stir spot welding (FSSW) process is the competent solid state process to weld the low carbon steel automotive steel. FSSW is a single spot joining process, in which a solid-state joining is made between adjacent materials at overlap configuration.Spot welding (also known as resistance spot welding) is a resistance welding process. This welding process is used primarily for welding two or more metal sheets together by applying pressure and heat from an electric current to the weld area. It works by contacting copper alloy electrodes to the sheet surfaces.
the above highlighted part acts as the suppport to the outer panel in middle of the panel the gap b/w the outer & inner panel is 5 mm where the rubber mastics material is used here to join there because the outer panel can,t be joined with spot welding or any other operation which damages the look effect of the stlyoing surface from out side, thats the reason the rubber mastics are used to give support b/w them.
here the sheet metal is trimmed & folded at required shape the folded matel is the part of inner part itself no extra material is added there.
OUTER PANEL UPPER
It acts as the stlying of the car body backside it consists of rear lamp mounting indicators & car no lamp
HEMMING SURFACE
DRAFT ANALYSIS OF BACK DOOR OUTER PANEL UPPER
OUTER PANEL LOWER
FOR SOME CARS TO HIS PART REGISTRATION NO IS FIXED. THIS PART ACTS AS THE OUTER PANEL STLYING IN THE BOTTOM SIE.OF THE CAR BODY.
DRAFT ANAYSIS 
REINFORCEMENTS
The purpose of the reinforcements is giving the additionl strength to the mounting features which are in the inner panel the additional assembly part are joined to that mountings the strength at that particular point will be reduced to avoid that & given strength this reinforcement is added.
the thickness 1.5MM TOTAL.
YELLOW COLOUR PARTS ARE THE REINFORCEMENT OF HINGE,GAS STAYS,WIPER MOTOR,STRICKER.
HINGE REINFORCEMENT
ONE END OF THE HINGE IS JOINED AT THIS POINT WITH THAT HOLES REQUIRED JOINING METHODS AS PER THE OEMS
GAS STAY REINFORCEMENT
ONE END OF THE GAS STAY IS JOINED AT THIS POINT
WIPER MOTOR REINFORCEMENT
STRICKER REINFORCEMENT
BACK DOOR ASSEMBLY RED COLOUR IS INNER PANEL & GRAY COLOUR IS THE OUTER PANEL
THICKNESS OF THE MATERIAL
INNER PANEL 0.75
OUTER PANEL 0.75
REINFORCEMENT 0.75 ( I HAVE GIVEN)
DRAFT ANALYSIS ANGLE min is 7 deg (performed 9 deg)
GAP BETWEEN THE OUTER PANEL & INNER PANEL CLEARANCE IS 0.2mm because the glove is added to join the gap so that it is fixed strongly to avoid stress consentration and tearing posibilities of material.
stricker attchment axis(just for referance)
GIVEN RELIEFS AT EDGES TO AVOID TEARING OF THE PART WHILE MANUFACTURING
COMPLETE ASSEMBLY INSIDE VIEW
OUT SIDE VIEW
CONCLUSION
DESIGN OF BACK DOOR OUTER PANEL ,REINFORCEMENTS, MOUNTING FEATURES IS DONE FOLLOWING THE DESIGN CONSIDERATIONS AS PER THE OEM STANDARDS.& PERFORMED DRAFT ANALYSIS IS OK.ALL THE RELEVENT IMAGES & FILES ARE ATTACHED IN THE ANSWER BOX.