Advanced Sheet Metal Design Using NX Cad Challenge_1_Casing Design

Sheet Metal Casing

Objective : To design a casing using the sheet metal modeling tools in NX cad.

Introduction : The sheet Metal application provides an environment for the design of sheet metal. It’s various applications are in aircraft bodies, automobiles bodies, utensils used for domestic purpose, beverage cans and many more.

We can create uniform thickness sheet metal parts using basic features such as flanges, tabs, bends, break corners, and much more. Some modeling commands are also available in the sheet metal application that can be used to create holes slots and mirror sheet metal features. In this project a sheet metal casing is made using the basic features. These are:

• Tabs.
• Normal Cutout.
• Bend.
• Flanges.
• Break Corners.
• Unbend.
• Hole.
• Dimple.
• Bead.
• Mirror feature.
• Rebend.
• Flat Pattern.

Design Methodology

Features used

Tab : This is used 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. First we have to select the curve, then we have to give the thickness for the tab.

Normal Cutout : This feature is used to cut the material by projecting the sketch onto the model and then cutting perpendicular to faces intersected by the projection. In order to use this command select the curve or sketch to extract, then if there is a problem with the cutout sketch, change options of “Limits” or “Cut Method” in the “Cutout Properties” tab and click “ok”.

Bend : This feature is used to modify the model by bending the model on one side of the sketch line. In order to use this command the line or sketch is selected, then the angle at which we want to bend the material, we can also specify the direction towards which we want the bend and increase the bend length as well.

Flanges: This command to add a flat flange at an angle to a planar face and add a bend between the two. A flange consists of a bend region and web. In the flange properties we have to select the edge where we want to create the flange , then length of the flange is given, direction and angle of the flange is set to complete the process.

Break Corners: This command is used to round or chamfer sharp corners of a tab or a flange, this done to reduce stress at the sharp edges. In order to use this command first the “Method” is given which can be “Chamfer” or “Blend” and then the radius is inserted to complete the step.

Unbend: This feature flattens a bend and the material adjacent to bend. In this we first have to select the stationary face or edge and the face we want to unbend is selected.

Hole: This feature adds hole to the model. In this we first have to specify the point where we want to create the hole in the “Hole” command tab, then specify the type of the hole we want create such as screw clearance hole, drill size hole, and many other options are available, after we have to specify the form and dimension such as screw type, size, depth limit, and finally “subtract” is selected in the boolean and the body is selected in which want to subtract the material to create the hole.

Dimple: This feature lifts the area of the model inside the sketch to simulate a stamping tool. In this feature first the sketch is selected whose shape will behave as the shape of the stamping tool then depth, side angle are given and accordingly depth reference and side walls are selected to get the desired stamping and lastly minimum tool clearance is given.

Bead: This feature lifts the material along the contour of the sketch that simulates a stamping tool. In this feature sketch is selected followed by the cross section type which can be circular, U shaped, and V shaped then the depth and radius of the cross section is selected, then we can select the “round bead edges” option followed giving the parameter of minimum tool clearance.

Mirror Features: This feature is selected to mirror only the features about a particular plane or axis. In order to use this feature we have to select the sketch and feature we want to mirror and we have to specify the plane about which we want to create the mirror.

Rebend: This feature restores the unbend feature to its previous bent state, along with any feature added after the unbend feature. Here the unbend face is selected to return it to its original state.

Flat Pattern: This creates a flat pattern feature from the formed sheet metal part. A Flat pattern is a 3D sheet metal model in a flattened state.

Model Images

Isometric view

Top view

Bottom view

Front view

Back view

Drawing sheet

Conclusion

• While creating dimple care should be taken, on which side the dimple is created and accordingly the sketch should be created so that the dimple is created on the right side.
• The rebending of the model should be done in just the reverse order of the unbending.
• In the “Mirror Features” command the sketch as well as the feature is to be selected in order to mirror the whole feature about a certain plane or line.