Design of backdoor

DESIGN A BACK DOOR USING NX CAD:

• OBJECTIVE:
  • To design Back Door from the given Class A Surface and to provide the necessary reinforcements and embosses.
• INTRODUCTION:
• The backdoor or tailgate is the rearmost part of the automobile which opens upwards, downwards, and sideways to give access to the luggage space or seating.In most automobiles, the backdoor opens upwards. It is hinged to the roof and a gas stay support fixed at the body side outer for keeping the backdoor in the open position as shown in fig. below.
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• Manufacturing Method:
• Deep Drawing:
• The metal deep drawing process is an effective method of manufacturing cups, cans, and other similar deep drawing products. The deep drawings having 2 main categories.
• First-stage drawing: The blank shape of metal is placed on the die and in contact with the punch. When the metal specimen is a flat piece of sheet metal is used in forming and finish the product. Initially, the punch moves in a downward direction. The outer rim of the blank is subjected to pure radial drawing (drawing toward vertical axes) between the die and blank metal. The metal becomes a bend and slides over the die and is also stretched between die and punch. The metal in the vicinity of the punch head and contact with it bend and slide over the radii and stretch over the punch head.
• Redrawing: The components drawn from the first stage again it is redrawn convert into more depth to form a cup shape in the die and punch. The second stage of drawing is called redrawing.
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• Hemming:
• The inner & outer panels are joined by the process of hemming.
• Hemming is a forming operation in which the edges of the sheet are folded over other parts in order to achieve a tight fit. Usually, hemming operations are used to connect parts together, to improve the appearance of a part, and to reinforce part edges.
• In car part production, hemming is used in assembly as a secondary operation after deep drawing, trimming & flanging operations to join two sheet metal parts together. Typical parts for this type of assembly are hoods, doors, trunk lids & fenders.
• The accuracy of the hemming operation is very important since it affects the appearance of the surface & surface quality. Material deformations, which occur while the hemming process, can lead to dimensional variations & other defects in parts. Typical hemming defects are splits and wrinkles in the flange, material overlaps in the corner areas. So, it is very important to use simulation software tools to better understand the hemming process and minimize the number of “trial & error” during the tryout.

• Design Methodolgy:
• The Outer Panel is the styling surface of the back door design. Other components of the backdoor are designed with reference to the outer panel surface. It acts as the outer cover & deals with the aesthetics of the car.
• In this design outer panel is divided into two-part.
• 1. Outer Upper Panel
• 2. Outer Lower Pane
• Outer Upper Panel:
• 1. The Outer Upper Panel Extracted from a provided styling surface.
• 2. The panel is modified for the required design with the surface tools of NX CAD.
• 3. The thickness provided to the outer panel is 0.75 mm.
• 4. Hemming is provided with corner reliefs.

Inner Panel:

• 1. The inner Panel is a component which is used for strengthening the door. It's thickness is in the range of 0.65-0.75 millimetres.
• 2. It is one of the most important components on which all accessories are mounted like Hinges, Gas Stay, Wiper Moter , Latch and Striker etc.
• 3. The possible method is the integration method. In the integration method, the part is stamped out of a single blank. This reduces the number of tools needed the assembly cost and eliminates any fit ability problem.
• 4. There are many cases where the Inner panel is subjected to stress due to frequent opening and slamming. These stress and depression factors are compensated by features like embosses and reinforcements.

DRAFT ANALYSIS:

• While designing a component must make sure that the component can produced by any means of manufacturing methods with least amount of time, material, manpower and power. So that we can reduce the overall cost of car.

• When the Back Door is considered it is manufactured by deep drawing at most of the time Deep drawing is the process where the single sheet of metal is place over a die which has the desired shape of the final output and the sheet is pressed against it with a tool. For the tool to come out from the part usually pressing relief of 5° to 9° will be provided during modelling itself.

• In NX draft analysis can be done after modelling so that we can verify whether the product is manufactured by pressing or not. One side of the surface is highlighted by green and other side by Red colour means that the model can be manufactured. Result of the draft analysis is shown in the figure below.

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Screenshots are Attached Below.

File attached below: