Designing of Sheet Metal Box Assembly - Using NX CAD

DESIGNING OF SHEET METAL BOX ASSEMBLY - USING “SIEMENS NX CAD”

Objective:

The main objective of this project is to design a sheet metal box assembly using the - “Siemens NX CAD” software.

Introduction:

Sheet metal:

Sheet metal is metal formed into thin, flat pieces, usually by an industrial process. Sheet metal is one of the fundamental forms used in metal working, and it can be cut and bent into a variety of shapes.

Thickness can vary significantly; extremely thin sheets are considered foil or leaf, and pieces thicker than 6mm (0.25 inch) are considered plate, such as plate steel, a class of 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 slitter.

There are many different metals that can be made into sheet metal, such as aluminium, brass, copper, steel, tin, nickel and titanium.

Sheet metal is used in automobile and truck (lorry) bodies, major appliances, airplane fuselages and wings, tinplate for tin cans, roofing for buildings and many other applications.

Box:

A box is a container used for the storage or transportation of its contents. Most boxes have flat, parallel, rectangular sides. If it is made up of sheet metal, then it is called as sheet metal box. A box assembly have different parts incorporated with it by means of mechanical or other types of joints. The parts associated with box assembly are,

• Box
• Lid and
• Hinges.

Sheet metal Box example is shown.

Design Approach:

Description:

The following tools and features of siemens NX CAD are used in the box assembly design,

Sheet metal preferences:

This feature helps to set the global parameters like material thickness, bend radius, relief depth and relief width for the design going to be created.

Sketch:

This feature is used to create 2D drawings along the required planes and faces.

Tab:

Use this command to create a base feature by extruding a sketch along a vector by a thickness value, or by adding material to existing faces and bend regions of a sheet metal part.

Flange:

This command is used to add a flat flange at an angle to a planar face and add a bend between the two edges or walls. The flange can only be made on a straight edge.

Closed corner:

Use the closed corner command to modify two flanges in one operation and to close the corner where the two flanges meet. During flattening, the corner and relief geometry are made appropriate for a flat pattern.

Hem:

Use the hem flange command to modify an edge of a sheet metal part by folding it onto itself for the purpose of safe handling or to increase edge stiffness.

The hem flange is always created as a secondary feature on a base part.

Mirror body:

Use the mirror body command to mirror an entire body across a datum plane. For example, you can use this command to form the other hand of a left hand or right-hand part. When you mirror a body, the mirror feature is associative to the original body.

Unite:

Use the unite Boolean command to combine the volume of two or more solid tool bodies into a single target body. The target body and tool body must overlap or share faces so that the result is a valid solid body. This command creates a unite feature.

Dimple:

Dimple command is used to lift an area of the model inside a sketch that simulates a stamping tool. We can create an indentation in a sheet metal part using a sketched section as the dimple outline.

Mirror feature:

Mirror feature command is used to copy a feature and mirror it across a plane.

Unbend:

Unbend command is used to flatten the model through selected bends with respect to selected face. All the flanges and bends of a model are flattened using this command to add more features.

Rebend:

Rebend command helps us to restore an unbend feature to its previous bent state, along with any features added after the unbend feature.

Bead:

Bead tool is used to create an embossed or engraved bead on sheet metal part using single entity or a set tangentially connected entities.

Datum plane:

Use the datum plane command to create a planar reference feature to help define other features, such as swept bodies and features at angles to the faces of target solids. Datum planes can be relative or fixed. Relative datum plane reference curves, faces, edges, points, and other datums.

Break corner:

Break corner command helps to create blends or chamfer on all the sharp corners or edges of a component in a single go. It simply breaks the corner into blends with some radius.

Normal cutout:

Use the normal cutout command to cut material by projecting a sketch onto the model and then cutting perpendicular to the faces intersected by the projection. You can use planar sketches or 3D curves to specify the section for the normal cutout.

Flat pattern:

Flat pattern feature is used to create another part view where the model becomes flat from the formed sheet metal part with all the details.

Box flat pattern.

Lid flat pattern.

Hinge flat patterns.

Standard views of box assembly:

Front view.

Side view.

Top view.

Isometric view.

Conclusion:

The sheet metal box assembly is designed as per the engineering standards with the help of above explained tools and features in “Siemens NX CAD” software.