Backdoor Design

BACK DOOR DESIGN

Aim: To design a back door and its reinforcement. Perform draft analysis on all parts of assembly.

Software: NX Siemens

What is Back Door?

Back door are the type of door which are on the rear of the car and also not every car has a back door, sometimes it has trunk for car like sedan. Back door enable accesses to luggage room.

Parts of Back Door:

1. Outer Pannel Upper:

This is the outer upper panel of the back door we design this in NX Siemens. The base design of the outer panel is given is to us which look like this from which we created the above upper panel.

Procedure for design:

• Check the surface can be sewed or not and if not fix the surfaces using bridge curves and through curve mesh, we can also give it to manufacture for creating proper surface but usually we fixed it and mentioned it to the provider
• Divided parts in NX assembly
• Create outer panel with proper hemming clearance using Offset Surface
• Create Law extension at the surface and make a 3 Face blend
• Make a mirror geometry and if get some error then extend the surface and trim the extra edges to get clean mirror geometry and then Sew the surface
• Give thickness of 0.75mm to the panel

The panel should look like this

• Do the draft analysis to check whether the part is feasible to manufacture or not
• For draft analysis give the tooling direction

Draft Analysis:

• Brow line at the center is tooling direction

This is outer panne upper is created

2. Outer Pannel Bottom

This is the outer panel bottom part and it is not necessary that we always have two panel for outer door but in our project we have two panel.

Procedure for design:

• Design procedure is same as the upper panel
• Create the flange using offset surface
• Give thickness of 0.75mm

Draft Analysis:

3. Inner panel:

The inner panel of the back door is kind of the main part of the back door as it covers the door and hold all the part that are going to connected to the back door like gas stay, latch and striker, mounting of the rear light space, viper motor, hinges to connect the door and roof, etc., that why this part is need to be designed with proper accuracy and methodology.

Procedure for Inner Panel:

• We need to create the connecting flange using Offset Surface from main body
• Then create Bridge Curves and Through Curves Mesh to create connection between upper and lower Offset Surfaces
• From here we have to create the surface of the inner body using same Bridge Curves and Through Curve Mesh
• We have to give reinforcement place for different reinforcements that we will be giving to the part
• Reinforcements are given using Emboss command or by making Offset Surface and then making Trim and Extend command we have used both command
• While making inner panel we have to keep checking if the panel can be thickened or not because some time it won’t thicken because of some emboss error
• After all emboss places are created we have to Mirror Geometry and also Thickened the Inner Panel

Draft Analysis:

• Again draft analysis is done in a tooling direction and as we can see that the draft analysis is giving the positive draft to Inner Panel so the design is good

4. Hinge Reinforcement:

These reinforcements are given at the inner panel to provide more strength to the connection between roof and back door

Procedure for Reinforcement:

• Copy the inner body and past at the hinge reinforcement part and put it into a feature group
• Offset the surface which you want for hinge reinforcement
• Make proper cut on the surface and give thickness

Draft Analysis:

• The parts are green, that means draft angle is positive and can be manufacture

5. Gas Stay Reinforcement:

These reinforcements are also for increasing the strength of the gas stay which will connect with the body. The gas stays will hold the door in upward direction.

Procedure for GSR:

• Just like last reinforcement we copy and paste the inner body because on that body we have reinforcements grooves
• Offset the surface we want and trim extra parts and apply thickness to it

Draft Analysis:

• The parts are green, that means draft angle is positive and can be manufacture

6. Latch and Striker:

The latch and Striker are the mechanism used to close the door and hold it closed. Here we need reinforcement as this part may be used a little hard or rough as when people close door, they mostly used to slam the door so that why this reinforcement is necessary.

Procedure for L&S:

• Just as all reinforcement copy and past the inner panel and create the feature group
• Offset the surface we needed for L&S
• Trim extra portion
• Give the thickness to part

Draft Analysis:

• The parts are green, that means draft angle is positive and can be manufacture

7. Viper motor reinforcement:

The VMR (Viper Motor Reinforcement) is given for mounting the motor to it. This is also only available in some car not all cars have rear viper.

Procedure for VMR:

• copy and paste inner panel into the model
• offset surfaces that are required
• trim extra surfaces and give proper thickness

Draft Analysis:

• The parts are green, that means draft angle is positive and can be manufacture

Conclusion:

The Back Door has been properly designed and all the parts are properly assembled and also the draft analysis of all parts are done so the model can also me manufactured.