Advanced Sheet Metal Design Using NX Cad - Box Assembly
TITLE OF THE PROJECT: 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 one of the fundamental forms used in metal working, 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 6 mm (0.25 in) are considered plate 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 organization 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 parts 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 sheet 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 methodology 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 created in the box assembly.
Unbend:- This feature is used to unbend the adjacent bends and flatten them. Here it is used to create cut outs for the hinges.
Rebend:- It is used to rebend the corners that were bent before along with any features added after the unbend feature.
Dimple:- It lifts an area of the model inside a sketch that simulates a stamping tool. Here three dimples are created,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 feature:- It copies a feature and mirrors 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 flange:- 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. It is 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 created for hinge.
Closed corner:- It closes a corner where two adjacent flanges meet by extending 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 feature 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 the box, lid and the hinges.
Datum plane:- It creates a datum plane used to construct other features. It is created to form the lid.
Datum coordinate system:- It creates a datum coordinate system used to construct other features. It is created as a reference 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 coordinate system (Datum CSYS), flat pattern, mirror feature, mirror body, unite, normal cutout and unbend by creating a box assembly.