Advanced Sheet Metal Design Using NX Cad Challenge_2_Box Assembly
ADVANCED SHEET METAL DESIGN USING SIEMENS NX CAD – BOX ASSEMBLY
Objective:
To design a box assembly and create a draft of it using siemens NX sheet metal application.
Introduction:
Sheet metal is metal formed by an industrial process into thin, flat pieces. Sheet metal is on of the fundamental forms used in metal workng, and it can be cut and bent into a variety of shapes. Countless everyday objects are fabricated from sheet metal. Thicknesses can vary significantly; extremely thin sheets are considered foil or leaf, and pieces thicker than 6mm (0.25 in) are considered plates steel or “structural steel”.
Sheet metal is available in flat pieces or coiled strips. The coils are formed by running a continuous sheet of metal through a roll sitter.
NX sheet metal:
Creating fast, accurate flat patterns is the goal of any organisation that manufactures products which contain sheet metal parts. NX sheet metal provides a set of tools within the NX design environment that allows for simple and fast design of sheet metal parts, dependent on their material and manufacturing process, the most common of which is straight brake sheet metal forming.
With NX sheet metal, formed and unformed representations of the pats are created closely following the industry workflows and best practices for bending calculations, tooling and sheet metal features. The value lies in improving quality and reducing cost of shheet metal parts by producing an accurate sheet metal pattern as the correct input for part manufacture, whether internally or to a supplier.
Design Methodology:
Design methodlogy is explained by the flow chart as follows;
Description:
Sketch – It is the basic of any design.
Tab – It is used to create base feature of a sheet metal by extruding a sketch along a vector by a thickness value. here tabs were created as the base of the top and bottom hinges as well as the base of the box.
Flange – It is used to create an extended part (bend) of a sheet metal. There are total twelve flanges creeated in the box assembly.
Unbend – it is used to rebend the corners that were bent before along with any features added after the unbend feature.
Dimple – It lifts an aea of the model inside a sketch that simulates a stamping too. Here three dimples are ceated i.e., in the middle of the base and two at the sides of the box.
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. There are total four beads created around the dimple at the base.
Normal cutout – it cuts the material by projecting a sketch onto the model and then cutting perpendicular to the faces intersected by the projection. Here a rectangular shaped cutout was created to create the top and bottom hinges.
Mirror features – it copies a feature and mirror it across a plane. Here the dimple on the side wall and beads on the bottom of the tab are created using this feature.
Hem flanges – it modifies the model by folding the edge of a sheet metal flange over onto itself for the purpose of safe handling or to increase edge stiffness used to create flanges on the walls of the box, on the sides of the lid and also on the hinges.
Break corner – it rounds or chamfers a sharp corner of a tab or flange. It is used in the tab craeted for hinge.
Closed corner – it closes a corner where two adjacent flanges meet by extend the bends and flanges. It is used to close the gap between the flanges used to create the walls of the box.
Mirror body – it copies a body and mirrors it across a plane. Box, lid and hinges are mirrored as a body using this command.
Unite – it combines the volume of two or more bodies into a single body. Two box and lid parts are combined using this features to create a single body.
Flat pattern – it creates a flat pattern feature from the formed sheet metal part, separate flat patterns are created for th box, lid and the hinges.
Datum planes – it creates a datum plane used to construct other features. It is created to form the lid.
Datum coordinate system – it creates a datum cordinate system used to construct other features. It is created as a refernce to mirror the bodies and the features.
IMAGES:
Following are the images of box assembly in different views;
Front view
Back view
Top view
Bottom view
Left side view
Right side view
Isometric view
Draft(drawing sheet):
Lid
Hinges
Top hinge
Bottom hinge
Box
Conclusion:
By performing this task, I have learned how to use features like tab, flange, break corner, closed corner, dimple, hem flange, bead, rebend, datum plane, datum cordinate system, flat pattern, mirror feature, mirror body, unite, normal cutout and unbend by creating a box assembly.