Advanced Sheet Metal Design Using NX Cad Challenge_2_Box Assembly

Objective

• Learning design different component in Sheetmetal parameter and using use of heming design
• Learning about basic sheet metal features and its application to Box design.

Introduction

When molten metal is hot rolled into flat sheet which ranges from 0.5mm to 6mm thickness uniformly across the length termed as sheet metal. Below 0.5mm thickness termed as foil and above 6mm thickness categorised as steel plate. Application of sheet metal is very vast from industrial fabrication to aerospace industry. Various profile and increasing the local strength of structure is achieved by accommodating following sheet metal feature like flange, beads, coining, blanking, dimple, reliefs etc.

Here we are designing a simple case housing considering sheet metal parameter for 1mm sheet.

Design Methodology

Description of tools used

Setting Parameter:

In this section basic sheet metal parameter are set to obtain uniformity is design as per the material selection. Here all parameter are set as per the 1mm sheet metal.

Features used.

Tab Feature: It is similar feature to the extrude function but the extrude value limit to the global value set in parameters and can be edited local settings. Base sketch is required to execute this function.      

Normal Cutout : Cuts material by projecting a sketch onto the model and them cutting perpendicular to the faces intersected
by the Projection.

Flange:Adds a flat flange at an angle to a planar face and adds a bend between the two.

Closed Corner: Closes a corner where two adjacent flanges meet by extending the bends and flanges.

Unbend: Flattens a bend and the material adjacent to the bend.

Mirror body: Adds a hole to one or more solid bodies in a part or assembly with options for counterbored, countersunk and
threaded.

Dimple: Lifts an area of the model inside a sketch that simulates a stamping tool.

Bead: Lifts a material along the contour of a sketch that simulates a stamping tool.

Re-bend: Restores an unbend feature to its previous bent state, along with any features added after the unbend feature.

Unite: Combines the volume of two or more solid bodies into a single body.

Hem Flange: Modifies the model by folding the edge of sheet metal flange over onto itself for the purpose of safe handling or
to increase edge stiffness.

Datum Plane:Creates a datum plane used to construct other features.

Break Corner: Rounds or chamfers a sharp corner of a tab or flange.

Flange:

This feature used to add a flat flange at angle to planar face . Different type of flanges type are available in option to control the profile of flange. It require edge to finish command.

Creating flange on either side

Closing the open ends of flanges to the base  by close corner option

Using flange and hem command heming edge is created

Mirroring and unite command are used to mirror 1 st half of geometry

Using dimple command X pattern is create on one face and featured is mirrored to opposite face

This increase the stiffnes and rigidity of sheet.

Similar to above dimple and bead command is used to create radial rasied circular base and simple manufacturable bead to strengthen

the part.

Hemming edges are created to avoid injury to person while using the box.

Top cover of box is made with hemmed edges 

Lower portion of hinge is made by using  flange and hem flange command to achive circular profile to acomodate hinge pin. it is welded to box base by spot welding

Design of upper portion of hinge similar to lower hinge which is welded to top plate by spot welding.

full circle hem are provided with beads for easy opening and closing of box cover, here beads act as locking with the bead projection on box base face.

Bead locking from side view.

Hinge pin is a circular shaft with sphere ends lock the upper and lower hinges during the operation.

Conclusion:

Box design is completed with NX CAD in sheetmetal workbench and learnt to use different design technique to make box design.