Advanced Sheet Metal Design Using NX Cad Challenge_7_ Metal bracket-II
METAL BRACKET DESIGN BY USING CATIA V5
OBJECTIVE:
The aim of this project to design a metal bracket and create a detailed drawing for manufacture siemens Nx sheet metal application.
INTRODUCTION:
Sheet metal fabrication is the process of forming parts from a metal sheet by punching, cutting, stamping and bending.
3D CAD files are converted into machine code, which code, wich controls a machine to precisly cut and form the sheets into the final part.
sheet metal parts are known for their durability, which makes them great for end use applications (e.g. chassis). parts used for low volume prototypes, and high volume production runs are most cost- effective due to large intiall setup and material costs.
Because parts are formed from a single sheet of metal, designs must maintain a uniform thickness. Hence the designer must be sure to follow the design reruirements and tolerances to ensure parts fall closer to design intent and cutting sheets of metal.
CRITICAL DIMENSIONS
The following are some terminology that are used in sheet metal Deigners need to adhere to machinery guidelines when designing for bending. Bends can be deifned by these parameters. Some critical dimensions that need to be considered when setting up shetting up sheet metal design in CAD software are sheet metal thickness, the k-factor and bend radius. one needs to check that these factors are consistent with the tooling that will be used in maufacturing.
Bend line-The straight line on the surface of the sheet, on either side of the bend, that defines the end of the level flange/ web and the start of the bend.
Bend radius- The distance from the bend axis to the inside surface of the material, between the bend lines.
Bend angle- The angle of the bend, measured between the bent flange and its original position, or as the included angle between perpendicular lines drawn from the bend lines. sometimes specified as the inside bend radius. The outside bend radius is equal to the inside bend radius plus the sheet thickness.
Neutal axis- The location in the sheet that is neither streched nor compressed, and therefore remains at a constant length.
K-Factor - The locaton of the neutal axis in the material, calculated as ratio of the distance of the neutal axis T , to the material thickness t. The K-factor is dependent upon several factors ( material, bending operation, bend angle, etc.) and is greater than 0.25, but cannot exceed 0.50. k factor = T/t
Bend allowance - The length of the neutal axis between the bend lines or the arc length of the bend. The bend allownce added to the flange lengths is equal to the total flat length.
DESIGN METHODOLOGY:
Workflow to design a sheet metal part
DESIGN FEATURES:
The following features are used in the project. This project was designed in sheet metal module of the siemens NX CAD.
SKETCH - This command is used the draw the shape of the design.
CONTOUR FLANGE -This command is used to create the bse feature by extruding the sketch along a vector. Here the sketch is extruded to 158mm long.
NORMAL CUTOUT - This command is used to create a cutout by projecting a sketch onto the model and then cutting perpendicular to the face intersected by the projection.
BREAK CORNER - This command is udes to round the edges of the flanges or tab, in this project it was used to round the edges of the flanges.
UNBEND - This command was used to unbend the bent areas in the sheet metal to get the flattened sheet metal.
ADVANCED FLANGE - This command is used to add flanges along an edge using a bend angle or a referance face.
GUSSETS - This command is used to create stiffening gussets on the part.
HOLE - This command is used to create holes at desired location.
REBEND- This command is used to rebend the unbend areas to obtain the bend features and also to obtain the final sheet metal part.
FLAT PATTERN- This command to create the flat pettern view which is needed for drafting and later manufacturing purpose for a sheet metal.
FINAL DESIGNED MODEL:
DRAWING SHEET:
CONCLUSION:
Thus the objective of designing a metal bracket in the NX CAD sheet metal application is done successfully.