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

Objective : To create the Drill Handle plastic component through the given Class-A surface. To begin with, 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 for the Drill Handle considering the design rules.

Take the Thickness of the component to be 3 mm.

Input

• A-Surface

• Thickness of component is 3.00mm

• Draft anglre is 0.5 degrees for rib & screw boss.
• Draft angle is 3 degrees for part.
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Procedure :

A ) Verifying Class A Surface :

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.

B ) Tooling Axis Creation :

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 X-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.

Tree Structure :

C ) Draft Analysis of Class 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.

• After Tooling Axis Select the Feature Draft Analysis option from the Insert > Analysis > Feature Draft Analysis Option.

• Select the Class A Surface to analyze.
• Next click on Use the compass to define the new current draft direction option and make it align with the tooling axis by dragging it to the axis.

• Next use the lock option to lock the compass to the tooling Axis.

• If the color appears blue just click the invert option on the right side of the draft direction axis button .

Tree Structure :

D ) Creating Class B Surface Creation :

• The A-surface is offsetted by 3.00mm as it is the thickness required.

• As there are various fillets in the A surface therefore after offset they get removed.

• To correct the surface we have to do patch work using the commands Extract, Multiple-Extract, Boundary, Extrapolate, Multi-sections, Trim.

• Next Extrapolate the surface from all directions.

• This will be the final B Surface.

E ) Class C Surface Creation :

• Use the boundary command to get the edge of the class A.

• use the sweep command and give the boundary, tooling axis and draft angle as input to get the Class C Surface.

• Use the join command to join the class C & Class A Surfaces.

F ) Final Creation :

• Use the Joined Surface & Class B Surface and make a trim.

• 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.

G ) Closed Surface :

• Go to Part > Body > Closed Surface command and we have a final solid part.

Tree Structure Class B & C Creation :

Draft Analysis For Class A Surface

Draft Analysis For Closed Surface

H ) RIB Creation :

• Extract the base patch of the part where you want to create the rib using the Extract Command .

• Create a positioned Sketch for the ribs.

• Use the Extrude Command , to get the Rib Shape.

• Use thicken Command , to get the rib thickness. Using 40% thickness we get 1.2 mm thickness of rib.

• use the draft command , for giving the draft of min 0.5 degree.

• Use the boolean operation, Union Trim , to merge the rib with closed body.

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I ) Screw Boss Creation :

• Extract the base patch of the part where you want to create the rib using the Extract Command .

• Create a positioned Sketch for the screw boss for a M5 bolt. Giving wall thickness 40% of thickness therefore 2.4mm for boss.

• Using Pad to give the feature height. hieght is 3:1 ratio for height = 9mm.

• use the draft command , for giving the draft of min 0.5 degree.

• We have to give fillet for the ribs and the screw boss.

Rib Root Thickness Analysis :

• We have to check weather the diameter made from the fillet and base of the intersection of the part is nearly same to the thickness of the part or maximum 1.3 times of thickness.

• Now our Drill Handle is created with ribs and screw boss.

Views :

Isometric

Front

Side

Top

Conclusion : Created the plastic component in Catia V5 using the given Class A Surface.

1. Created the tooling axis.
2. Ceated the Class B Surface.
3. Created the Class C Surface.
4. Created the Closed Surface from Surface geometry.
5. Published the Class A, B & C Surface, Tooling Axis & Drill Handle.
6. Created the Rib & Screw Boss.
7. Did the Rib Root Thickness Analysis.
8. Did the Draft Analysis.