Week 9 - Attachment Feature Creation - Challenge 1

Aim

To Create the rib for the Centre console coin holder considering the design rules in catia V5.

Rib design factors

• Thickness
• Height
• Location
• Quantity
• Moldability

Ribs Functions

• Act as stop or guide for the mechanisms
• Provide alignment in assembly parts.
• Locate and captivate components in assembly
• Augment strength locally without increasing the wall thickness.

Rib Design Rules input

Draft

Draft is the amount of taper for molded or cast parts perpendicular to the parting line. It also a slant that is applied to each side of most features of an injection molded part By applying appropriate draft angle the mold will be easier to remove and it also accounts for thermoplastic shrinkage in Injection molding. The draft may also alter the form and fit of the part during assembly.

A draft of minimum of 0.5 degree draft per side is recommended. For textured sidewalls use an additional 0.4 degree draft per 0.1mm depth of texture. But maintaning the minimum draft could be costly during manufacturing hence an optimum draft angle of 3 degree could be maintained.

Tree structure

Check the class A surface

• The input class A surface is checked for any gaps or disjoints using the join or boundary commands.
• If there is any Minor error the it can be rectified or else send back to the Class A surface designer to make the necessary modifications properly.

In this case we can see that the Class A surface does not have any gaps or disjoints and has smooth and continuous boundary.

Create the Tooling axis

The tooling axis is the direction in which the core and cavity opens and closes. In this case we can see that the bin area surface can be used as tooling axis center point. The intersecting lines can be drawn to identify the surfaces which could not be cleared in tooling axis.

Bisecting line tooling axis

The bisecting line is used to create a line bisecting the two reference lines created in normal direction. The bisecting lines helps us to achieve the average draft angle between the two reference lines.

Publish

In the next step publish the tooling axis and Class A,B,C surfaces so that we can access it easily and use it for further creation of surfaces or thick body.

Draft Analysis

Once the tooling axis is created the draft analysis can be done. For viewing the draft analysis results we need to change the view parameters into customise mode enabling only the material.

Go to insert-analysis-feature draft analysis.

The compass option is used to choose the tooling axis. The color coding shows the result of the draft analysis done. The limits of the draft angle can be changes according to the needs.

Types of the modes in the analysis

A single limt can be chosen to show the positive or negative draft

Multiple limits can also be set based on the requirements

The draft angle value can be found at any given point of the surface. for the ribs 0.5 degree is optimum and we can see that the some parts of the model has positive draft angle highlighted in green color and some parts with zero draft highlighted in blue color. The negative draft is shown in red color.

We can see that the rib satisy the tooling direction and can be cleared in the cavity side.

Rib creation

Extract the top surface and draw the rib sketch

Then the sketch is extruded and thickend

The draft of 0.5 degree and fillet of 0.25 mm radius is added.

we can measure and check the dimensions of the ribs by taking an interesection.

Then the rib is assembled on the coin holder body.

Conclusion

Thus the rib is created for the Centre console coin holder considering the design rules in catia V5.