Design of backdoor

          Drawing is a process of forming flat sheets blanks into hollow shapes by means of a punch that causes the metal to be formed into the die cavity. If the depth is one or more times the diameter of the final shape, then the process is called deep drawing. The deformation limit or the limiting draw ratio (LDR) is the maximum blank diameter that can be drawn into a cup without failure. The draw ratio or the percentage reduction up to 48% on first draw, are considerd achiveable is most ductile material. Embossing the bases of deep drawn components with beads adds rigidity and strength and prevents the phenomenon of dishpanning Mainly mechanical presses up to 1000 tons in capacity are used for deep drawing. 

              Hemming is a sheet metal forming process in which sheets are joined by bending it usually to 180*

Automotive body panels and automotive parts such as deck-lids, trunk-lids,door,hoods and tailgates are formed by hemming process. The simplest form of hemming set up is combining two different setups. The first is an acute setup, where the 30deg bend is created using standard tooling. Once the first bend is made the part is either transferred bar and is closed. This setup doesn't require any special tooling and may be preferable for short runs, prototypes or job shops which will need to form a variety of hem lenths. As individual pieces of break press tooling the acute tooling and flattening bar are very verstile and value outside of hemming. The draw backs to this system is the obvious requirements is the obvious requirements of two unique setups, as well there is no thrust control in the flattening process.

3. Embosing

       The metal sheet embossing operation is commonly accomplished with a combination of heat and pressure on the sheet metal, depending on what type of embossing is required. Theoretically, with any of these procedures, the metal thickness is changed in its composition.

              Metal sheet is drawn through the male and female roller dies, producing a pattern or design on the metal sheet. Depending on the roller dies used, different patterns can be produced on the metal sheet. The pressure and a combination of heat actually "irons" while raising the level of the image higher than the substrate to make it smooth.       

          The term"impressing" refers to an image lowered into the surface of a material, in distinction to an image raised out of the surface of a material.In most of the pressure embossing operation machines, the upper roll blocks are stationary, while the bottom roll blocks are movable. The pressure with which the bottom roll is raised is referred to as the tonnage capacity.

        Embossing machines are generally sized to give 2 inches (5 cm) of strip clearance on each side of an engraved embossing roll. Many embossing machines are custom-manufactured, so there are no industry-standard widths. It is not uncommon to find embossing machines in operation producing patterns less than 6 inches (15 cm) wide all the way up to machines producing patterns 70 inches (180 cm) wide or more.

4. Trimming operation-

            The shaving operation is another name for trimming. It is a finishing technique that involves removing burrs from cut edges in order to smooth them down and improve dimensional accuracy.

5.Punching operation-

        A punch and die technique is used to create circular holes in a sheet of metal. Although this is the polar opposite of blanking, the process is essentially identical. Blanking processes, for example, require the employment of a punch and die.

• Before starting to design the inner panel of the back door the tooling direction for deep drawing purpose should be created.
• The back door was designed using a top down approach.