Advanced Sheet Metal Design Using NX Cad Challenge_2_Box Assembly

Box Assembly Using NX CAD Sheet Metal Tools

OBJECTIVE:

To draw a 3D model of a sheet metal box as per the dimentions given and draft a flat pattern.

INTRODUCTION:

Sheet metal parts are widely used in machines, enclosures, brackets, and automomotive applications due to its various advantages. The parts are normally manufactured with break press, Blanking, Drawing operations. Sheet metal is a thin sheet made from metal of size ranging from 0.5 to 6mm. In this project I used NX CAD tool for designing the sheet metal bracket. NX CAD is used as design tool in more than 85% of the sheet metal industries.

DESIGN METHODOLOGY:

1. Create a rectangle of 150 x200 mm and Create a 1mm Tab. Make flanges of 10mm bend radius and 200mm length on the 200mm sides.
2. Create two flanges of 70 mm length and 10mm bend radius. Use close corner to close the gaps at the two corners.
3. To close the gap between the two flanges create flanges of 0.01 mm length and 0.5mm bend radius facing opposite sides. Then, create two flanges of 6.5 mm length and 0.51mm bend radius on both sides. Join them using an open hem of 0.5mm radius and appropriate length on both sides.
4. Mirror Body is used to mirror this component. Use unite command to join both Bodies.
5. Creat a x shaped dimple on the side face and mirror to opp. face.
6. Create an inward(inside box) dimple on the bottom face with a filleted rectangle.
7. Create a Circle on one corner of the bottom face and use bead command with depth and radius of 2mm. Mirror the bead to four corners of the bottom face using Mirror feature.
8. Create a datum plane and draw the cover of the box.
9. Create a tab on the half side face on the Box and create a circular hem for the hinge. Make a cutout of the hinge. Mirror it to the other side.
10. Create a single tab on the top cover and create a Circular hem and use cutout to fit it to the bottom hinge.

DESIGN TOOLS USED:

• Sketch - It is the basic of any design.
• Extrude - It creates a feature by extruding a section along a vector.
• Sheet Metal from solid - It builds a sheet metal model that takes its shapes from a collection of planar faces. This command is used to convert the solid body into a sheet metal body. After selecting the command and the solid body, we can also remove the edge sharpness by removing the material at these places.
• Tab - Tab is a command used to create a base for any sheet metal part that can be extruded from a sketch. The sketching plane can be selected as per the designer’s choice.
• Flange - It is used to create an extended part (bend) of a sheet metal. It is created at the edge of one side of the model. This command will allow us to select the edge of the base to create a projecting flat extruded surface. The angle, width, length, and type of flange can be determined as per the requirements.
• Jog - It modifies the model by lifting material on one side of a sketch line, adding a flange between the two sides. Jog is created at another end of the model opposite to the flange. Jog is a command to lift off one whole side of the part. By selecting a line and the plane, the material can be pushed down or lifted off depending on the situation.
• Unbend - This feature is used to unbend the adjacent bends and flatten them. Here it is used to create more features. This command is used to unbend the sheet metal parts to create geometries and work on complicated designs. In this command, we have to select a stationary face and then select the corners of flanges to unbend.
• Rebend - It is used to rebend the corners that were bent before along with any features added after the unbend feature.
• Bead - It lifts material along the contour of a sketch that simulates a stamping tool, it is used for giving strength to the sheet metal. Here two beads are created on the unbent surface. The selected sketch is lifted off from the base to provide strength to the material. Similar to dimple, the material can be removed in both directions.
• Hole - It adds a hole to one or more solid bodies in a part or an asembly with options for counterbored, countersunk and threaded. Here six simple holes are created on the unbent surface with a diameter of 10mm. It can be used to make customized or standardized holes along with a defined point or path. The dept of the hole can be controlled.
• Flat pattern - It creates a flat pattern feature from the formed sheet metal part. The user chooses this command to create a flat view of the sheet metal after unbending all the sides and faces. This view can be used in drawing the flat pattern along with the bend radius and other dimensions.

MODEL IMAGES:

Front View:

Side View:

Isometric View:

Top View:

DRAFT:

BOX Main Body:

Box Cover:

Hinge 1 Left:

Hinge 1 Right:

Hinge 2:

CONCLUSION:

Thus the design and drafting of box in sheet metal is completed using NX CAD Tools. The part file is in the attached zip folder C2. The drafted sheet metal is made in 5 sheets.