Design of backdoor

AUTOMOTIVE DESIGN OF CAR BACK DOOR USING NX CAD

[1] OBJECTIVE :-

1) DESIGNING OF CAR BACK DOOR FROM THE GIVEN CLASS A STYLING SURFACE USING THE APPROPRIATE DESIGNING TECHNIQUES ON CAD MODELING SOFTWARE SIEMENS NX-CAD.

2) THE OBJECTIVE OF THIS PROJECT IS TO DESIGN A BIW BACKDOOR (TAILGATE) OF A CAR  WITH AN INNER PANEL , OUTER PANEL , REINFORCEMENT FOR HINGES (LEFT,RIGHT) , LATCH AND STRIKER , GAS STAYS (LEFT,RIGHT) , WIPER MOTOR WITH ENGINEERING STANDARDS.

3) CREATION OF BACK DOOR INNER PANEL WHICH VARIFIES THE DRAFT ANALYSIS WITH RESPECT TO THE TOOLING DIRECTION CREATED FOR PHYSIBLE MANUFACTURING OF PART USING DEEP DRAWING OR VARIOUS AUTOMOTIVE COMPONENT MANUFACTURING PROCESSES.

[2] INTRODUCTION :-

Back door is also called as tailgate. Back door in a car gives the access to luggage area and few cars have passenger compartment too. In most of the cars gas stay is used to operate the back door as it reduces the effort for the person opening.

The rear door also supports the reinforcements and added weights of the Wiper Motor, Gas Stay, Tail Lamp, and Latch and Striker.The Backdoor/tailgate is one of the closure commodities in BIW sheet metal design. The backdoor 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.

Backdoor of SUV'S  are called Liftgate. The liftgate is the actual door covering the rear of the vehicle. The part is sometimes described as a panel, but most liftgates are supplied with: Built-in handles and lock mechanisms. 

 

[3] TAILGATE :-

TAILGATE IS A DOOR AT THE BACK OF A TRUCH OR CAR, THAT IS HINGED AT THE BOTTOM SO THAT IT OPEN DOWNWARDS.

[4] MAJOR PARTS AND REINFORCEMENT OF CAR BACK DOOR :-

CAR BACK DOOR CONSIST OF FOLLOWING BASICS COMPONENTS :-

1. BACKDOOR OUTER PANEL (UPPER)

2. BACKDOOR OUTER PANEL (LOWER)

3. BACKDOOR INNER PANEL

4. HINGE REINFORCEMENT (LH & RH)

5. GAS-STAY REINFORCEMENT (LH & RH)

6. LATCH AND STRIKER REINFORCEMENT

7. WIPER MOTOR REINFORCEMENT

 

[5] DESIGN INTENTION :-

THE INTENTION OF THE PROJECT IS TO DESIGN A BODY IN WHITE BACK DOOR OF THE VEHICLE CONSIDERING ALL THE ENGINEERING STANDARDS AND MANUFACTURING REQUIREMENTS WHICH SATISFY THE DEEP DRAWING PROCESS.

DEEP DRAWING PROCESS :-

Deep drawing is a cold metal forming process, in which a flat metal blank is forced into a die cavity by hydraulically driven punch.
A cup-like cylindrical part, having the depth greater than its diameter, is formed as a result of deep drawing.
The process is presented in the picture :-

[6] DESIGN CONSIDERATION OF A BACKDOOR :-

• FUNCTIONAL REQUIREMENT OF HINGE AND GAS STAYS

• REAR VISIBILITY CRITERIA

• BOOT SPACE (LUGGAGE VOLUME)

• CRASH TEST ANALYSIS

• BEND TEST , DENT TEST , TORSION TEST & ENDURANCE TEST

• REAR TEST REGULATIONS

• GAP AND FLUSHNESS REQUIREMENT

HERE , I HAD FOLLOWED TOP DOWN APPROACH FOR THE CREATION  OF BACKDOOR AND ITS CHILD COMPONENTS.

[7] DESIGN OF BACKDOOR OUTER PANEL :-

THE OUTER PANEL OF BODY IN WHITE BACKDOOR IS THE STYLING SURFACE , IT ACTS AS A OUTER COVER AND DEALS WITH THE AESTHETICS OF THE CAR. OTHER COMPONENTS OF THE BACKDOOR ARE DESIGNED WITH REFERENCE TO THE OUTER PANEL.

IN THIS DESIGN THE BACKDOOR OUTER PANEL CONSIST OF TWO PARTS :-

1. OUTER UPPER PANEL

2. OUTER LOWER PANEL

(A) OUTER UPPER PANEL :-

1. EXTRACT THE UPPER OUTER PANEL FROM THE GIVEN CLASS A STYLING SURFACE.

2. MODIFY THE GIVEN CLASS A SURFACE TO PROVIDE SMOOTHNESS TO SURFACE FOR PERFECT CREATION OF THE OUTER UPPER PANEL CONSIDERING ENGINEERING STANDARDS AND DESIGN REQUIREMENTS USING VARIOUS NX-CAD TOOLS SUCH AS BRIDGE CURVE , OFFSET SURFACE , OFFSET CURVE IN FACE , EXTRACT SURFACE , THROUGH CURVES , FACE BLENDS ,TRIM SHEET , TRIM BODY ETC.

3. PROVIDE CORNOR RELIFS USING BRIDGE CURVE OR CURVE ON SURFACE AND HEMMING TO THE OUTER UPPER PANEL.

4. AFTER VARIOUS MODIFICATIONS USE EXTEND SHEET , THEN TRIM BODY, THEN USE MIRROR GEOMETRY, AFTER THIS USE SEW OPTION TO JOIN BOTH THE SURFACES.

5. THEN PROVIDE THICKNESS OF 0.75MM TO THE SURFACE TO CONVERT SURFACE INTO THE SOLID BODY.

 

(B) OUTER LOWER PANEL :-

1. EXTRACT THE UPPER LOWER PANEL FROM THE GIVEN CLASS A STYLING SURFACE.

2. MODIFY THE GIVEN CLASS A SURFACE TO PROVIDE SMOOTHNESS TO SURFACE FOR PERFECT CREATION OF THE OUTER LOWER PANEL CONSIDERING ENGINEERING STANDARDS AND DESIGN REQUIREMENTS USING VARIOUS NX-CAD TOOLS SUCH AS BRIDGE CURVE , OFFSET SURFACE , OFFSET CURVE IN FACE , EXTRACT SURFACE , THROUGH CURVES , FACE BLENDS ,TRIM SHEET , TRIM BODY ETC.

3. PROVIDE CORNOR RELIFS USING BRIDGE CURVE OR CURVE ON SURFACE AND HEMMING TO THE OUTER LOWER PANEL.

4. AFTER VARIOUS MODIFICATIONS USE EXTEND SHEET , THEN TRIM BODY, THEN USE MIRROR GEOMETRY, AFTER THIS USE SEW OPTION TO JOIN BOTH THE SURFACES.

5. THEN PROVIDE THICKNESS OF 0.75MM TO THE SURFACE TO CONVERT SURFACE INTO THE SOLID BODY.

 

(C) OUTER UPPER AND LOWER PANEL :-

 

(D) CREATION OF TOOLING DIRECTION :-

1. BEFORE STARTING TO DESIGN THE BACKDOOR INNER PANEL TOOLING DIRECTION IS NEEDED FOR THE PURPOSE OF DRAFT ANALYSIS AND FOR DEEP DRAWING PROCESS TO ACTUALLY MANUFACTURE THE COMPONENT.

2. SO TO CREATE THE TOOLING DIRECTION CREATE SKETCH ON ZC PLANE , THEN CREATE TWO LINES ONE FROM THE TOP MIDDLE CORNOR TO THE LOWER CORNOR OF THE WIND SHIELD AND ANOTHER FROM LOWER CORNOR OF WINDSHIED TO THE LOWER MIDDLE CORNOR OF THR OUTER LOWER.

3. THEN CREATE A BISECTING LINE SELECTING BOTH THE LINES CREATED PREVIOUSLY.

4. THEN BOTH THE SURFACES UPPER OUTER AND UPPER LOWER NEEDS TO BE ANALYSISED WEATHER IT CLEAR DRAFT OR NOT , FOR FURTHER REFERENCES OF INNER PANEL DRAFT.

[8] DESIGNING OF BACKDOOR INNER PANEL :-

1. EXTRACT THE UPPER AND LOWER PANEL FROM THE MODIFED CLASS A STYLING SURFACE.

2. USE OFFSET SURFACE COMMAND AND GIVE OFFSET VALUE OF 0.75+0.75+0.2 MM WHERE 0.75 MM ARE THE THICKNESS AND 0.2 MM IS FOR HEMMING CLEARENCE.

3. AFTER THIS CREATE AN EFFECTIVE SEALING FLANGE BY CHECKING ALL THE BOUNDARIES AND BY FOLLOWING THE SHAPE OF THE INNER PANEL DESIGN.

4.  THEN, CREATE MULTIPLE FLANGES SUCH AS CONNECTING FLANGE AND CONNECTING BLENDS CONSIDERING ENGINEERING STANDARDS AND DESIGN REQUIREMENTS USING VARIOUS NX-CAD TOOLS SUCH AS BRIDGE CURVE , OFFSET SURFACE , OFFSET CURVE IN FACE , EXTRACT SURFACE , THROUGH CURVES , FACE BLENDS ,TRIM SHEET , TRIM BODY ETC.

 

5. AFTER CREATION OF INNER PANEL CREATE EMBOSSES FOR CHILD COMPONENTS LIKE HINGE , LATCH, GAS STAY , WIPER MOTOR MOUNTING LOCATIONS . WHICH COMPELETS THE OVERALL DESIGN OF BACKDOOR.

6. PROVIDE EMBOSSES FOR THE MASTICS AND CUTOUTS TO THE INNER PANEL IN ‘V-Shape or Y-Shape’ SO THAT IF THE VEHICLE UNDERGOES CRASH THEN THE FORCE DISSIPATES OVER IT WHICH REDUCES THE DAMAGE TRANSFFERED TO THE BOOD SPACE AND PASSANGER COMPARTMENT .

7. PROVIDE CORNOR RELIFS USING BRIDGE CURVE OR CURVE ON SURFACE AND HEMMING TO THE OUTER LOWER PANEL.

8. AFTER VARIOUS MODIFICATIONS USE EXTEND SHEET , THEN TRIM BODY, THEN USE MIRROR GEOMETRY, AFTER THIS USE SEW OPTION TO JOIN BOTH THE SURFACES.

9. THEN PROVIDE THICKNESS OF 0.75MM TO THE SURFACE TO CONVERT SURFACE INTO THE SOLID BODY.

A. MASTIC SEALANT :-

  MASTIC SEALENT IS USED TO FIX THE INNER PANEL WITH THE OUTER PANEL WHICH INCREASES THE NVH FACTOR OF THE VEHICLE AND ALSO PROVIDE STIFFNESS TO THE BACKDOOR..

  

 

B. HINGE EMBOSS :- 

1. CREATE DATUM PLANE ON CURVE OF INNER PANEL CONSIDERING HINGE LOCATION. 

2. AFTER THIS CREATE A LINE IN SKETCH AT APPROPRIATE ANGLE SO WHILE LAW EXTENDING IT FORMS A FLAT SURFACE.

3. USE LAW EXTENSION AT THE BOUNDARIES AND PROVIDE FILLETS TO THE CORNER EDGES.

C. GAS STAY EMBOSS :-

1. CREATE DATUM PLANE ON CURVE OF INNER PANEL CONSIDERING GAS STAY LOCATION. 

2. AFTER THIS CREATE A LINE IN SKETCH AT APPROPRIATE ANGLE SO WHILE LAW EXTENDING IT FORMS A FLAT SURFACE.

3. USE LAW EXTENSION AT THE BOUNDARIES AND PROVIDE FILLETS TO THE CORNER EDGES.

D. WIPER MOTOR EMBOSS :-

1. CREATE A DATUM PLANE ON THE TOOLING CONSIDERING PROPER OFFSET VALUE FROM INNER PANEL , THEN CREATE SKETCH ON IT  CREATING REINFORCEMENT AREA.

2. PROJECT THE SKETCH ON INNER PANEL THEN USE EMBOSS OPTION AND SELECT END CAP AS DATUM PLANE FOR FLAT SURFACE.

 

E. LATCH AND STRIKER EMBOSS :-

FOLLOW THE SAME PROCEDURE AS EXPLAINED ABOVE OF VARIOUS REINFORCEMENTS.

HERE I HAD CHOSEN THE EMBOSS DIRECTION ACCORDING TO MY VARIATIONS AS WE DONT HAVE HINGE AXIS HERE BUT THE DIRECTION OF EMBOSS SHOULD BE TAKEN AS ACCORDING TO THE LATCH TRAJECTORY AND THE FLAT SURFACE MUST FOLLOW THE PERPENDICULAR TANGENTIAL DIRECTION OF THE TRAJECTORY CIRCLE.

 

[9] STRIKER POSITIONING ( LATCH TRAJECTORY ) :-

THE POSITION OF HINGE SHOULD BE PERPENDICULAR TO THE LATCH WHEN THE LATCH AND STRIKER MEETS.

SO TO FIND THE LATCH TRAJECTORY WE DRAW A CIRCLE CONSIDERING CENTER AS HINGE AXIS IN SKETCH ON ZC PLANE . 

THEN DRAW A TANGENTIAL PERPENDICULAR LINE FROM THE CIRCLE WHERE THE LATCH AND STRIKER MEETS . SO THAT IT CAN FOLLOW ITS TRAJECTORY.

[10] HEMMING PROCESS :-

Hemming is a sheet metal forming process in which sheets are joined by bending it to 180°. Automotive body panels and automotive parts such as deck-lids, trunk-lids, doors, hoods and tailgates are formed by hemming process. In this process, usually a sheet is bent with the help of inner sheet in three different stages.

 

• AFTER THE DESIGNING OF BOTH OUTER UPPER AND LOWER PANEL HEMMEING IS CREATED USING OFFSET SURFACE AT APPROPRIATE DISTANCE  , LAW EXTENDING CORNOR EDGES AND PROVIDE THREE FACE BLEND.

• THE TWO SEPERATE OUTER PANELS WILL BE JOINED USING BLANKING.

[11] CORNER RELIEF'S :-

DURING THE HEMMING PROCESS, CORNOR RELIFS HELPS TO CONTROL SHEET METAL MATERIAL BEHAVIOUS AND TO PREVENT UNWANTED DEFORMATION DURING UNBEND OPERATIONS AND IT ALSO HELP TO REDUCE NUMBER OF PASSES IN HEMMING.

 

[12] DESIGNING THE REINFORCEMENTS :-

THICKNESS PROVIDED TO ALL THE REINFORCEMENT IS 1 MM.

 

1. HINGE REINFORCEMENT (LH,RH)

2. GAS STAY REINFORCEMENT (LH,RH)

3. WIPER MOTOR REINFORCEMENT

4. LATCH REINFORCEMENT

PROCEDURE :-

ALL THE REINFORCEMENTS ARE CREATED USING SAME METHOD FIRST CREATE A SEPERATE PART FOR ALL THE REINFORCEMENT THEN EXTRACT THE FLAT SURFACES OF ALL THE REINFORCEMENT EMBOSSES USING WAVE GEOMETERY LINKER AS WE ARE FOLLOWING TOP DOWN APPROCH. THEN MODIFY THE SURFACE WHERE REQUIRED . AFTER THIS PROVIDE THICKNESS OF 1MM TO THE SURFACETO CONVERT THE SURFACE INTO SOLID BODY.

A. HINGE REINFORCEMENT :-

HINGES ENABLES THE OPENING AND CLOSING OF THE BACKDOOR. ONE END OF HINGE IS FIXED ON THE BACKDOOR AND THE OTHER END ON THE ROOF . HINGES CAN BE PLACED OUTSIDE OR INSIDE THE BACKDOOR .

HINGE REINFORCEMENT ARE ADDED TO COMPENSATE FOR THE WEAK REGION DUE TO THE LOAD ACTING OVER IT.

 

B. GAS STAY REINFORCEMENT :-

GAS STAY REINFORCEMENT IS PROVIDED FOR GIVING STRENGTH TO THE INNER PANEL AND FASTENING CAN TIGHT PROPERLY SO THAT THE GAS STAY RODS CAN BE ATTACHED. ONE END IS CONNECTED TO THE CAR CHASSIS AND ANOTHER END IS CONNECTED TO THE BACKDOOR.

EMBOSSING IS PROVIDED AT THE GAS STAY MOUNTING AREA TO COMPENSATE FOR WEAKNESS AND IMPROVE STRENGTH.

 

C. WIPER MOTOR REINFORCEMENT :-

  WIPER MOTOR REINFORCEMENT ARE CREATED TO MOUNT AND PROPER HOLDING OF THE WIPER MOTOR ASSEMBLY AS REINFORCEMENT ALSO PROVIDE SUPPORT TO THE ASSEMBLY.

 

D. LATCH AND STRIKER REINFORCEMENT :-

THE LATCH AND STRIKER FORMS THE LOCKING MECHANISM OF THE BACKDOOR WITH THE CAR. DUE TO REGULAR OPENING , CLOSING AND OVER SLAMMING OF THE BACKDOOR , STRESSES ARE DEVELOPED IN THE LATCH AND STRIKER AREA. SO TO COMPENSATE FOR THE SAME , REINFORCEMENT ARE ADDED TO THIS AREA.

 

[13] DRAFT ANALYSIS :-

THE  DRAFT ANALYSIS  WILL BE PERFORMED FOR THE TOOLING DIRECTION CREATED AT FIRST AND CHECKED WEATHER  THE MODEL IS SUITABLE FOR DEEP DRAW AND MANUFACTURING.

• Then to get a complete green portion the necessary changes to the draft angle of the embosses were carried out by optimizing the model.

• Here we have taken the draft angle of 7 degrees to verify the draft analysis of the design.

• 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 identifying zones on the analyzed element where the deviation from the draft direction at any point, corresponds to specified values.

A) INNER PANEL :-

 

B) HINGE REINFORCEMENT :-

C) GAS STAY REINFORCEMENT :-

D) LATCH AND STRIKER REINFORCEMENT :-

E) WIPER MOTOR REINFORCEMENT :-

[14] BACK DOOR DESIGN IN VARIOUS ORIENTATIONS :-

A) FRONT VIEW :-

 

B) SIDE VIEW :

 

C) TOP VIEW :-

 

D) ISOMETRIC VIEW :-

 

[15] BACKDOOR INNER PANEL IN VARIOUS ORIENTATIONS :-

A) FRONT VIEW :-

 

B) SIDE VIEW :

 

C) TOP VIEW :-

 

D) ISOMETRIC VIEW :-

[16] CONCLUSION :-

THUS, I GOT KNOWLEGE ON HOW TO DESIGN THE BODY IN WHITE BACK DOOR (TAILGATE) FOLLOWING ENGINEERING STANDARDS AND ALSO THE DEEP DRAWING REQUIREMENTS FOR PHYSIBLE MANUFACTURING OF THE COMPONENT.

GOOGLE DRIVE LINK FOR BACK DOOR :-

AS I WAS NO ABLE TO UPLOAD DATA MORE THEN 20 MB.

https://drive.google.com/file/d/1sm6YwuN5kyvrG_BX2__zYWh08vegUXvE/view?usp=drive_link