Advanced Sheet Metal Design Using NX Cad Challenge_2_Box Assembly
PROJECT REPORT
TITLE: DESIGN OF SHEET METAL BOX ASSEMBLY IN NX CAD
OBJECTIVE: To design and model the box assembly in sheet metal workbench of NX CAD version 11.
INTRODUCTION: NX is a 3D CAD CAM software developed by Siemens. The Casing will be designed and modelled in the sheet metal workbench of the NX.
Sheet Metal is a metal formed by an industrial process into thin, flat pieces. It is one of the fundamental forms used in metal working and it can be bent into variety of shapes. Countless everyday objects are fabricated from sheet metal. The thickness can vary significantly, extremely thin sheets are called foils and sheets having thickness greater than 6mm are called plates.
DESIGN METHODOLOGY:
DESCRIPTION:
The tools and features used in the design and modelling of the casing are:
Tab:
It is the first basic feature of the sheet metal design. It is actually the base of the model on which additional features are added. First the profile for the tab is generated and by using the tab command the tab is created.
Fig 1. Generation of Tab
Flange:
Flange is a projecting rim on a flat object. Flanges can be given to the edges of the model by using the flange command available n the sheet metal workbench. Flanges are given to all the 4 edges and the parameters are changed accordingly.
Fig 2. Flanges
Closed Corners:
It is the command which helps to manipulate the corners created by flanges and bends according to our requirements. The corners can be closed and kept open or given smooth edges. The parameters can be changed according to the requirements of the model in the closed corner command.
Fig 3. Closed Corner
Additional Flanges are created at the open side by using the flange command available in the sheet metal workbench. The parameters are changed accordingly.
Fig 4. Flanges
Hem Flanges:
Hem Flanges command is available in the sheet metal workbench. This flange is created to give smooth finish to the sharp edges. Different options like openloop, closed, closed loop hem flanges are available. The parameters can be changed according to the requirements.
Fig 5. Hem Flanges.
Mirror Body:
It is the feature which helps to create to exact copies of the body by selecting a reference axis or plane. Mirror option is available in the sheet metal workbench of the NX CAD.
Select the bodies or features which are to be mirrored and select a plane or axis about which the feature or body is to be mirrored.
Fig 6. Mirror Body
Beads and Dimples:
Beads and dimples are given in the sheet metal to provide strength to the sheet metal parts. The sketch profile for the bead and dimples are created on the required sketch plane.
The options for the bead and dimple are available in the sheet metal workbench. The required parameters are entered and thus bead and dimples are created.
The dimple feature is also mirrored using mirror feature onto the opposite face.
Fig 7. Dimple
Another dimple and beads are also created on the bottom plane to strengthen the sheet metal
Fig 8. Dimple and Beads
Hem Flanges are given at the top surface all the edges to give it a smooth finish.
Fig 9. Hem Flanges
Lid:
The datum plane is moved to a certain height and a profile for tab is generated on that plane. Using tab command and giving the required thickness the lid is created.
Fig 10. Lid
Additional Flanges are created at the edges of the lid.
Fig 11. Flanges
For the creation of hinges a tab is created.
Fig 12. Tab
Break Corners:
It is to give smooth finish to the sharp corners.
Fig 13. Break Corners
Flanges are given at the edges of the newly created tab. The angle and the other parameters are changed.
Fig 14. Flanges.
Open Loop Hem Flange is created. The material thickness and inste are changed accordingly to get the required result.
Fig 15. Hem Flange.
Unbend:
The part is unbend to create additional features such as hole, dimple, beads which otherwise cannot be created if it not unbend. Moreover it also helps to check whether the part is a sheet metal or not. If the part is unbending then it is a sheet metal otherwise it is still a solid body or dumb body.
Fig 16. Unbend
Normal Cut Out:
It is the type of cut out which is mainly preferred in sheet metal design. The advantage this type of cut out has over the extrude cut out is that normal cut out removes the material perpendicular to the surface of our model rather than plane.
First the sketch is generated and using the normal cut out the material is removed from the part.
Fig 17. Normal Cut Out
Rebend:
After creation of additional features the part is rebend back to get our required product.
Fig 18. Rebend
The feature is mirrored by selecting the sketch feature and the plane.
Fig 19. Mirror
To create a hinge, again a tab is created on the top surface, flanges are created and normal cut out is applied and at last the part is rebend to get the required result.
Fig 20. Final Result
MODEL VIEWS:
Fig 21. Front View
Fig 22. Top View
Fig 23. Side View
Fig 24. Isometric View
CONCLUSION:
- This project helped me to understand the basic features of the sheet metal workbench in NX CAD.
- Got familiarised with the user interface of the NX CAD.
- Understood the various terminologies related to the sheet metal design.
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