Advanced Sheet Metal Design Using NX Cad Challenge_6_Bracket
Tittle : To design and modelled Bracket using siemens NX-CAD
Objective :
1.) To understand the concept behind design
2.) To get familiar with NX-CAD sheet metal workbench
Introduction :
Sheet Metal : It is a comprehensive cold working process for sheet metal (Usually below 6mm).Thicknesses of this sheet can vary significantly extremely thin to the thicker sheets, thinner sheets are generally considered as foil or leaf and pieces thicker than 6 mm (0.25 in) are considered plate steel. There are many different metals that can be made into sheet metal, such as aluminium, brass, copper, steel, tin, nickel and titanium. Sheet metal is used in automobile and truck (lorry) bodies, airplane fuselages and wings, medical tables, roofs for buildings (architecture), and many other applications. Generally there are two types of region in any sheet metal are web and bend region. COMMON BENDING OPERATIONS GENERALLY used are Press brake forming, Air bending ,Roller bending , Beading,Flanging , Hemming , Roll forming , Stretch forming,Deep drawing.
NX-CAD Sheet metal Workbench : With Sheet metal CAD tools, you can apply standard values, such as material thicknesses and bend radii, based on industry or company best practices. With folding and unfolding capabilities, you can work with models at any stage of the fabrication process. Sheet metal parameters create accurate flat patterns for documentation and manufacturing.
Methodology :
To achieve a final product the methodology is followed is
Features Used :
1.Contour Flange: Usually this feature can be used as first feature to create a base feature by extruding a sketch along a vector by a length value or adding a material to a plane face. The sketch can be of any shape only if it has to be open profile. The thickness to the base plate is automatically determined by the metal parameters which in sheetmetal workbench it refers to as a global value, we can add different thickness manually as a local value.
2.NORMAL CUTOUT: It cuts the sheet metal part by sketching the profile for cutout and then it cuts the sheet perpendicular direction to the sketch plane.
3.BREAK CORNER: For better manufacturing process and to make part more handy.In this it Rounds a sharp corner by selecting an edge and then specifying the radius of it.
4.UNBEND: Usually this feature is used to create some additional features on the flanges by flattening a bend by first selecting the flat surface and then clicking on the bend region. 
5.Hole : First step is to locate the point by sketching on the plane the points are the centre of the hole. Then click on hole feature on the ribbon tab and select the point that you sketch earlier and give the diameter.
6.BEAD: It is a stamping tool that lifts a material along a counter of a sketch that simulates stamping a tool. In these parameters like depth of the stamping, radius of the stamping and die radius need to be specify correctly in order to work on this properly.
7.REBEND: Once all the features are done on the flanges then in order to rollback this command is used.It restores the bend by just selecting the bend region.
8.FLAT PATTERN: Creates flat pattern feature from the formed sheet metal part. It is generally used for adding a flattern view of this sheet on the drafting environment.So that when the part is ready the manufacturer will have an idea of cutting the shape of sheet that needs to be cut and its dimensions.
Step wise explanation :
Step 1 :
To start with double click on NX-Cad software icon and open it,once all the modules loaded click on new then select sheet metal module. Select sketch and then click on y-z plane to draw a new profile. To create the base plate I sketched a profile. By right clicking on any empty space in the working area one command pops up to finish the sketch. Once the sketch is done now we have to add sheet metal parameters. This is done by clicking menu-preferences-sheetmetal and then setting up the values of sheet metal parameters.
Step 2 :
Select the sketch and click on the contour flange tool to add its base plate with the thickness value that we specified earlier as 3mm.
Step 3 :
Select top plane to sketch the profile to cutout the material once the sketch profile is done make sure it is fully closed then constraint the profile for accurate dimension. Finish the sketch and select the cutout command on the top of the ribbon toolbar.
Step 4 :
If you will look closely at the part we will notice that there are some sharp edges, to convert it into round edges there is a command called “Break Corner”. Click on the break corner and select the edges and specify the appropriate radius value to round the edges.
Step 5 :
To add some additional features such as hole, bead cutouts etc the sheet metal part is being unbend to get its flatten view. To flatten the geometry click on unbend select the base tab and select on the all the bend region.
Step 6:
Now the sheet is being flattened to apply some additional features like bead and hole. For the bead make a sketch of the profile that we want the material to lift and then click on finish the sketch. Click on bead tools located in the punch group. In the cross-section select circular and make sure that the radius is greater than the depth value. Next feature to be added is to click on hole and then specify the point which is centre of the hole define the screw size and fit type which is generally normal and then click on “ok”.
Step 7 :
Now whole other features are added on the part so here we need to rebend the sheet. So, select the rebbend feature on the top and select the bend region that needs to be bent. And flat pattern the sheet to use unbend view while the drafting.
Step 8 :
In the file tab select the new part option and select drawing and define the sheet size of the drawing view, now select base view from there click on flat pattern view and specify the appropriate scale in which the whole flatten sheet must fit in.
Standard Views :
Conclusion :
Henceforth, the bracket is being modelled using sheetmetal tools and drafted in NX-Cad drawing.