B Side Attachment Feature Creation for coin holder
Objective :
To design ribs, doghouse, and Boss on coin holder.
Perform draft analysis on ribs and doghouse.
Software :
CATIA V5 (Part and Generative Shape Designworkwech).
Introduction:
CATIA V5
CATIA is a multi platform 3D software suite developed by Dassault Systèmes, encompassing CAD, CAM as well as CAE. Dassault is a French engineering giant active in the field of aviation, 3D design, 3D digital mock-ups, and product lifecycle management (PLM) software. It is also possible to generate model dimensions and create reference dimensions in the drawing views. The bi-directionally associative property of CATIA ensures that the modifications made in the model are reflected in the drawing views and vice-versa.
Generative Shape Design
It provides an extensive set of tools for creating and modifying mechanical surfaces used in the design of complex shapes or hybrid parts. Its feature-based approach offers a productive and intuitive design environment to capture and reuse design methodologies and specifications. Help to design advanced shapes that are based on a combination of wireframe and extensive multiple surfaces. It includes high-level features with full specification capture and reuse.
Dog house
Dog house is an engineering feature used in the plastic trim design. Dog houses are used as supporting features. Sometimes other engineering features like snaps; locators, etc. are mounded on them to increase their strength.
OEM Standard
Dog houses are subjected to draft analysis to prevent breakage of the component during ejection from the mould cavity. Dog house and other engineering components are built on B-surface.
Wall thickness = 0.70 x Thickness of the plastic material
Fillet on the inner side = 0.25 x Thickness of the plastic material
Fillet on the outer side = 1.25 x Thickness of the plastic material
Fillet on the coring edges = 0.25 x Thickness of the plastic material
Coring thickness = 0.40 x Thickness of the plastic material
Draft angle 2deg to 3deg
Procedure
Methodology
- To create the Screw Boss,draw a sketch on the extracted base surface with the diameter of 5mm. the thickness should be of 0.6 times the thickness of main component , so it will be 8mm.
- Make it Pad by the height/diameter ratio of 3:1 ratio.
- Draft the outer and inner walls of the pad of 0.5 degrees.
- To stiffen the screw boss add the ribs on 4 sides by drawing the sketch on the extracted base surface and Pad it to a height not more than the rib height.Draft the walls of the ribs of 0.5 degrees.
- Now add the screw boss and ribs to the main component and Unitrim the ribs which are inside the screw boss.
- Fillet the edges of walls with the radii of 0.25mm.Do the Draft Analysis for the screw boss.
- Create a sketch on the extracted base surface where the the dimensions should be more than the screw boss
- As for the Dog house one of the sides should be opened,make one side as a construction line.
- Extrude the sketch by using the Sweep option with the 1.5 degrees to the height of 20mm towards top and 1mm towards bottom.
- To cover the top surface,offset the extracted base surface to a distance of 20mm and then trim it and fillet the edges with 1mm.Pad the extruded surface to outside with the thickness of 2mm.Create the tooling axis for Side Core(Yellow).
- Cut the uneven surface at the open side by extracting the opposite surface and offset it to a distance towards the open surface and split the part in Part design by using the Split option.
- Draft the inner walls with 0.5 degrees.Now create backside contact surface by offsetting the extracted base surface to a distance in between 3 - 6mm height (B) and Sweeped surface to a distance of 40% of the main wall thickness(C).Trim the surface.
- Split the offsetted Surface with the body to get the cut on backside of Dog House.Draft the Splitted area with 0.5degrees and fillet the surface with the radii of 1mm and then translate the the Screw Boss to the top of Dog House and Add it to the Dog House and Add then component to the Main component.Do the Draft Analysis on the final component in both tooling axis.
Draft for Boss
4 way Locator
Final trim
Construction of Dog House
Draft Analysis of Dog House
Ribs
Final Output
