Challenge

Week 9 - Attachment Feature Creation - Challenge 1

MM.Dinesh Kumar14 Jan 2022

DESIGN

AIM:

To create ribs for the given Centre console coin holder by following the design rules.

CREATION OF TOOLING AXIS:

Step 1: Extract the top surface of the coin holder which represents the class A surface.

Step 2: Check the boundary of the class A surface and ensure there is no gap in between the surface.

Step 3: Create an axis system on the class A surface by creating a point on it.

Step 4: Draw a sketch by intersecting class A surface with YZ plane.

Step 5: Since the edges are parallel to the YZ plane, a perpendicular line is drawn to the base surface and it is taken as tooling axis.

DRAFT ANALYSIS ON CLASS A SURFACE:

Step 1: Change the view to customized view and enable the material in shading option.

Step 2: Insert the feature draft analysis.

Step 3: Click the compass icon and place the compass along the tooling direction.

Step 4: Lock the draft direction and select the component to draft.

Step 5: Enable the color scale and change the draft value as required. Here 3 degree is given as draft angle.

Step 6: The green color indicates that the surface is more than 3 degree from the tooling direction. The blue color indicates that the surface is 0 to 3 degree from tooling direction. Red color indicates that the surface is less than 0 degree from tooling direction which indicates the negative draft.

DESIGN RULES FOR RIB:

Consider ‘t’ as the wall thickness of the component.

Draft - 0.5 degree per side minimum
Rib thickness, w = 0.4 * t (resin dependent factor)
Rib thickness at the tip – 0.75mm minimum
Rib fillet radius - 0.25mm maximum
Rib height – 5 x t
Height/width – 3:1 steel

2:1 preferred

RIB DESIGN:

Step 1: Extract the bottom surface of the coin holder on which the ribs are going to be created.

Step 2: Create a point in the middle of the surface and insert an axis system at that point.

Step 3: Create a sketch on ZX plane by drawing lines (ribs) as required. The height of the ribs and spacing between the ribs should be in the ratio of 3:1 (steel height/width ratio maximum). So, the distance between the lines should satisfy this condition after thickening ribs. Here,

Y/X < 3

12.5/X < 3

X = 12.5/3

X = 4.2

So, spacing between the ribs should be greater than or equal to 4.2mm.

Step 4: Extrude the lines to a height of 12.5mm as the wall thickness of the component is 2.5mm, along the tooling direction.

Y = 0.5 x t

Y = 0.5x 2.5

Y = 12.5mm

Step 5: Thicken the extruded surface to 1mm.

w = 0.4 x t

w = 0.4 x 2.5

w = 1mm

Step 6: Provide draft to the sides of the ribs for 0.5 degree along the tooling direction.

Step 7: Assemble these ribs to the main body and give fillets for 0.25mm to all edges of the ribs.

Step 8: Create an intersect between XY plane and the component.

Step 9: Draw tri-tangent circles at the bottom of the ribs as shown in figure and measure the diameter of the circles. It should not exceed ± 30% of the wall thickness. In this design, the diameter should be 1.75mm – 3.25mm.