Advanced Sheet Metal Design Using NX Cad Challenge_6_Bracket

Project Title - DESIGN OF SHEET METAL BRACKET FROM A GIVEN 2D DRAWING USING NX SHEET METAL APPLICATION

 

Submitted By – Akhil Raj

Objective:

To develop a Sheetmetal bracket in NX sheet metal from a given 2D drawing.

SOFTWARE USED

Siemens NX 12

INTRODUCTION 

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 term sheet metal refers to a piece of metal whose thickness is between 0.15mm and 6.35mm. It is one of the fundamental forms used in metalworking and it can be cut and bent into a variety of shapes.

In NX Modeling, complex uniform thickness parts (often sheet metal) are created either by using surfacing techniques and then thickening the result, or by starting with a solid shape, blending, and then shelling the part to get uniform thickness

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. NX delivers the next generation of design, simulation, and manufacturing solutions that enable companies to realize the value of digital twin.

Here we are designing a CAD Model of a Sheetmetal bracket from a given 2D drawing using NX CAD software in sheet metal work bench and also to practice some analysis tools.

BRACKET

In mechanical engineering a bracket is any intermediate component for fixing one part to another, usually larger, part. What makes a bracket a bracket is that it is intermediate between the two and fixes the one to the other. Brackets vary widely in shape, but a prototypical bracket is the L-shaped metal piece that attaches a shelf.

These are manufactured by making use of different engineering process like die casting, stamping or forging. These brackets found their application for mounting of any products starting from antennas to TV, projectors or street lights and many more.

DESIGN METHODOLOGY FLOW CHART

The sheet-metal component was created using commands like contour flange, normal cut-out, break corners, sketch, unbend, bead, hole, rebend and flat pattern. The design methodology closely follows the industrial procedure to keep the design intent and is summarized in the flowchart below:

 

DESIGN APPROACH

• A Contour flange is created from its 2D drawing.
• Unnecessary portion of the job was removed using the normal cut out
• Sharp edges were removed using break corners
• The center line is sketched for the bead.
• Using the Unbend feature the job is flattened for further processing.
• Using bead command, the required bead is created on the sheet metal.
• Three required holes were cut at different location of job using Hole
• Using Rebend command, the sheet metal part is brought back to its initial shape.
• The final step is creating the flat-pattern for the work using Flat pattern command.

FEATURE DESCRIPTION

CONTOUR FLANGE

This is one of the types of a flange provided by NX. This would extrude a sketch along a vector or add material by sweeping a sketch along an edge or chain of edges, thereby saving the time of modelling individual flanges. In design of this metal bracket, we used the contour flange because our sketch has multiple bends.

NORMAL CUT-OUT

This feature cuts model by projecting a sketch onto model and then cutting perpendicular to faces intersected by projection. In this design we had drawn a sketch which cuts flange portion in rectangular form by normal cut-out operation.

BREAK CORNERS

This operation converts sharp corners to round or chamfer shape. We applied this operation to flange corners, four corners have radius of 25mm, internal one has 30mm radius and a extreme back has 60 mm radius.

ANALYSIS TOOLS

NX Provides tools to analyze part geometry, to measure distance between to object, for checking radius of a section, checking angle. This tool helps a lot while reverse engineering any component.

UNBEND

The Unbend feature flattens a bend and the material adjacent to the bend.

HOLES

Holes are created for fitting purpose. Various type and size of screw holes can be created through this tool. Here three holes were created.

BEAD

Lifts material along the contour of a sketch that simulates a stamping tool. Beads can also be created to stiffen sheet metal part.

REBEND

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

FLAT PATTERN

Flat pattern is the representation of the entire sheet metal component in the 2D form of the flat sheet metal with all the bends, cut-outs, holes, and additional features in the form of lines or edges. The flat pattern calculates the material and layout required to flatten a 3D sheet metal model and ensures the ability to cut the sheet metal out of the raw sheet metal plate. It removes the possible errors such as interference or collision within the same component.

DRAFTING

After the design is complete, the execution or the manufacturing of the component requires a technical drawing of the component with the provided scale and with accuracy. The necessary details such as annotations, callouts, bend tables can be added as per the requirement.

 

FINAL CAD MODEL

SHEET METAL BRACKET

(MODEL VIEWS)

Top View

Bottom View

Front View

Side View

Isometric View

Feature Tree

 

CONCLUSION:

• Successfully developed a Sheetmetal bracket from a given 2D drawing.
• Studied the work flow and to use analysis tools like local radius and distance measurement.
• Learnt the design approach and various tools used in the Sheet Metal workbench of Siemens NX.