Sheet Metal Bracket II Design using Siemens NX CAD

• Objective - To learn the sheet metal design process and to design a sheet metal bracket II in Siemens NX CAD following industrial workflow.

• Introduction - Sheet Metal is metal formed by an industrial process into thin, flat pieces OR Sheetmetal is a comprehensive cold working process for metal sheets usually below 6mm, including shearing, punching/cutting/folding, riveting, splicing, etc.

• Sheetmetal is one of the fundamental forms used in metalworking and it can be cut and bent into a variety of shapes. Countless everyday objects are fabricated from sheetmetal. Thickness can vary significantly; extremely thin sheets are considered foil or leaf, and pieces thicker than 6mm are considered plate steel or structured steel.

• In sheet metal, a constant called the k factor rules the bend parameters of all the bends in the part. It is the ratio of the length of the neutral axis to the thickness of the sheet metal.

• In this project, a bracket is designed in Siemens NX CAD software following the industrial approach. The use of a parametric modeling environment is the main use made in this project. This project focuses on the stiffening process of a bracket with the application of advanced flanges. All the sheet metal design considerations are carefully considered while completing this project.

• Design Methodology -

• Description - Sketch in the YZ Plane.

In order to create a couple of normal cutouts in the bracket, the sketch is initially created keeping the profile accurately.

• Sketch for Contour Flange - For this bracket, the sketch is created in an XZ plane with the following dimensions.

• Contour Flange - A contour flange is created using the open sketch created in a plane. It is different from regular flanges because it can be created in any shape and it does not require choosing the edge of any tab or existing flange.

• Normal Cut Out - It cuts away the material at the right angle with respect to the sketch plane.

• Break Corner - This feature breaks the sharp edges in the corners and makes it round or adds chamfer. It is like the fillet feature in some other CAD software.

• Unbend - This is a very powerful and very useful tool in NXCAD. It allows all the bends made by various features to the unbend state at once.

• Normal Cutout - It cuts away the material at the right angle with respect to the sketch plane.

• Rebend - All the features added after the unbend feature are added in the unbend state itself. After adding sketches and additional features are completed, the sheetmetal component has to be rebent to the required position. This is done using the rebend feature and selecting all the bends in order or by box selection.

• Break Corner - This feature breaks the sharp edges in the corners and makes it round or adds chamfer. It is like the fillet feature in some other CAD software.

• Advanced Flange - Unlike base simple flange, the advanced flange can create a flange from any edge which can be either curved or straight line, open or closed profile. This allows the creation of a flange with a matching face also. The advanced flange is created at the upper portion with proper parameters for this bracket.

• Unbend - Again the unbend feature is applied after which a couple of features are applied.

• Hole -The hole feature in sheet metal is similar to solid modeling. Here two general holes of 6mm radius are created while in the unbent state.

• Normal Cutout- Again, a couple of normal cutouts are carried out in the unbend state as shown below.

• Advanced Flange - Again, an advanced flange is applied at the edge of the normal cut out in the above step.

• Rebend - All the features added after the unbend feature are added in the unbend state itself. After adding sketches and additional features are completed, the sheetmetal component has to be rebent to the required position.

• Gussets - Gussets are basically supporting features that provide the structure of the part of the product from the base tab or flange wherever the bend exists. These are stiffening features applied at the bends.

• Flat Pattern - This feature is used to create an automatically flattened version of sheet metal parts and prepare the model for the manufacturing process. This flat pattern remains the last feature in the model tree. A flat pattern ensures the manufacturability of components.

• Drafting -
• It is possible to create a 2D drawing from a 3D model using the NX Drafting application. With the 3D model opened in NX, go to application > Drafting, this disables the sheet metal application and starts the drafting application.
• Setting Required - Select the Base view command to show the view of the sheetmetal. Set the scale to 1:1.

• Model View -

• Front View-

• Top View -

• Bottom View-

• Side View-

• Isometric View-

• Conclusion - In this project, a sheet metal bracket is successfully designed from a solid body in the sheet metal workbench of NX CAD.