Week 9 - Attachment Feature Creation - Challenge 1

Ribs

Ribs are a feature in plastic injection moulded parts. They are thin extensions that run perpendicular from a wall or plane. They are commonly used to provide additional support and strength to a part.

It is usually trying to increase the strength of a part by making its walls thicker. Unfortunately, walls that are too thick are subject to warpage, sinking, and other defects. The advantage of using ribs is that they increase the strength of a part without increasing the thickness of its walls.

Here in CATIA V5, to create rib in a injection moulded part the surface in which the rib has to be created is extracted from the Class A surface.

A point is created on the surface.

With reference to the point on the surface, Sketch for the rib is drawn.

The line drawn is extruded to certain distance based on the rib design criteria.

Another sketch is created and with certain distance from the first rib sketch a line is drawn.

To the same length it is extruded.

The extruded surface is thickened using thick surface for 1mm.

Draft is given for 0.5mm based on the rib design criteria.

Fillets were also assigned.

Then this RIB 1 and RIB 2 Part body is assembled with the Main body.

Intersection of the whole body with the XY plane is taken.

And from the intersection sketch, the fillet part between the rib and the coin holder is projected and taken as reference and the base line of the coin holder is also taken as reference. A circle is drawn by which all these references lie tangent to the circle.

The coin holder thickness is 2.5mm and the radius of the circle drawn is 1.372mm which is approximately 1.4mm. All the criteria were noted and based on them the ribs are designed.

Front view

Side view

Top view

Isometric view