Week 10 - Challenge 1- Attachment Feature Creation (Ribs & Screw Boss)

OBJECTIVE: 

Create the component through the given Class-A surface. the tooling axis for the given Class-A Surface should be created meeting the requirements of the draft angle and at the end perform the Draft analysis on the model. Create the rib and screw boss as by considering the design rules 

CHECKING THE INPUT - A SURFACE

Skin data will be provided to us by the styling team.The A-surface or the styling surface is first checked for any gaps and other issues in its surfaces. This Surface acts as the input surface so any correction to be done should be with approval from the styling team or done by them. A- perfect surface is the one when a boundary is created, the lines are only on the edges of a component and its holes or cutouts as shown below.

PROCEDURE FOR CREATING THE TOOLING AXIS

Tooling axis is the direction in which a core or cavity of mold opens. This Axis is very important to determine the orientation of the component in mold, core and cavity design.

The tooling axis is created by the inertia method by using the steps as follow

• Click “Measure inertia” and select the A-surface

• Click “Create geometry” in the Measure Inertia window.

• In the Creation of Geometry window, select Non-associative geometry.

• Click “Center of Gravity”

• The Inertia point is created.

• The component is viewed in all axes namely X,Y and Z.

• It is determined that the y-axis will be the direction for the Tooling axis and a line is created Using the CG point and X-direction as direction of the line

DRAFT ANALYSIS OF A SURFACE:

• Draft analysis of the surface is carried to check if the surface or part can be manufactured with the required draft angle.
• Draft angle is needed for the component to clear the core and cavity surface as it would have shrunk towards the center while cooling.
• The draft angle in this design is 3 degrees. As A surface is a single surface there won't be much difference in color. The draft analysis of A-surface is shown below

CREATION OF B-SURFACE:

The A-surface is offsetted by 3.00mm as it is the thickness required.The offset surface is the B-surface but had some issues like in some areas shown in below images.

• The Areas where the B-surface has issues are corrected by closing them using commands like Multi section,Sweep,fill area ,Offset and extract.
• Finally all the created surfaces are trimmed or joined together with offset surfaces done earlier. This created a single single surface which will act as the final B-surface

CREATION OF C-SURFACE:

• The A and B surfaces are connected by another single surface which is called the C surface.
• It is created by using sweep with A surface acting as the reference surface and curve created from the boundary of the same surface.
• Sweep with draft direction is also used to create A-surfaces.

CREATION OF CLOSED BODY:

All the surfaces (A,B,C) are joined together to form a closed body.

Boundary is selected and the body is picked. Since an error popped up it can be understood that all surfaces are joined with each other to form a proper closed surface body.

RIB DESIGN:

sketch is created for ribs

extruded and created the surface according  to the height of ribs in design rules

height -  <=5t (thickness of part)

thicken the surface using thicken surface

thickness = 0.4t (thickness of part)

rib draft >= .5degree

part is filleted (0.25mm) & timmed with main component.

SCREW BOSS

sketch is created the diameter taken (m6 bolt)  5.2mm 

The outer diameter 

Thickness -  Typically 40%* of the nominal wall at the base in one side 

40% of 2.5 =1 mm one side =7.2

paded  the sketch for height

Height to Diameter Ratio -  3:1

 Draft  - 0.5 degrees on the walls of boss

Radii - 0.25mm maximum radii. 

DRAFT ANALYSIS OF PART BODY:

 The final solid part body has to be analyzed using Draft analysis. This is done to check if all the areas of the body are satisfying the draft angle which is 3 degrees.

A draft angle is a taper applied to the vertical walls of the injection-molded component to assist with releasing the part from the mold.

Draft angles are a required feature of injection-molded custom parts. A functional part for injection molding has to have draft angles that face both the cavity and core sides. This will reduce the risk of damage to the parts and ensure that they can be ejected from the machine.

The Bumper body is checked using Analysis and images for it are shown below.