Advanced Sheet Metal Design Using NX Cad Challenge_2_Box Assembly

Title

Modelling of a box assembly using Siemens NX Sheet metal

Objective

• To create a sheet metal box assembly using Siemens NX Sheet metal
• To write a detailed report on the procedure of modelling.

Introduction

Siemens NX software is a flexible and powerful integrated solution that helps us deliver better products faster and more efficiently. It is used for: Design (parametric and direct solid/surface modelling), Engineering analysis (static; dynamic; electro-magnetic; thermal, using the finite element method; and fluid, using the finite volume method) and Manufacturing finished design by using included machining modules. Here we use the feature from NX to create a casing.

Design methodology

The detailed design includes design conceptualization, prospective product drawings, sketches and geometric modelling.

Here also we use similar procedure for modelling.

Description

The tools used while the procedure is explained below. When we create a new sketch, a dialog box pop-ups asking us to define the Sketch Plane. The screen will display the sketch options. We can choose the Sketch Plane, direction of sketching and type of plane for sketching. When we create a sketch using the Create Sketch dialog box, we can choose the plane on which the sketch can be created by clicking on the coordinate frame as shown. This will highlight the plane we have selected. We use sketch curve tool bar sketch. This toolbar contains icons for creating the common types of curves and spline curves, editing, extending, trimming, filleting etc. Each type of curve has different methods of selection and methods of creation.

Line option will selectively create only straight lines.

Studio Spline can create basic spline curves with poles or through points with the desired degree of the curve.

Dimensional Constraints: The degrees of freedom can be eliminated by giving dimensions with fixed entities like axes, planes, the coordinate system or any existing solid geometries created in the model. These dimensions can be linear, radial, angular etc. We can edit the dimensional values at any time during sketching by double-clicking on the dimension.

Geometric Constraints: Besides the dimensional constraints, some geometric constraints can be given to eliminate the degrees of freedom. They include parallel, perpendicular, collinear, concentric, horizontal, vertical, equal length, etc

These are the sketch commands and feture commands used in the procedure are listed below. Afte creating thebase sketch for the box, we use tab eature for making slid sheet metal. The parameters for the sheet metal is controlled in sheet metal preference menu.

Then two flange is inserted as shown in the figure below. Using flange properties menu, we customize the diamensions.

Again two flanges are insterted normally to the previously inserted flange. But the corners remain open. so it is closed using closed corne command as shown below.

Now the gap between two flanges are closed using hem command so that it fit perfectly. The diamensions are adjusted so that it get locked.

Mirroring feature is used to replicate the other half of the box as given below.

Dimple can be inserted ater creating the respected sketch on the surface. It is also mirrored on the other side.

Bead is also created like dimple and its diamensions are controlled.

For the creation of lid for the box, a datum plane is placed accordingly so that we can create the sketch for the lid.

After creating lid, a hinge is created on the side by tab feature and it is detailed using break corner command.

Hem command help us to create a loop tab as represented below. Then it cuted normally after unbending.

Other pair of hinge is created on the top side of the lid and it is mated to other one.

Final box assembly is now created and the images are represented below.

Conclusion

Modelling and drafting of the casing was completed.