Week 8 - Challenge 3 - Switch Bezel Design

The class A surface come separately and not together. Hence, we need to join them together and then start performing the design.

1. Next Insert a geometrical set =>
2. To Create tooling Axis:

Insert Geometrical set => tooling Axis

• extract the Base
• create a Point (Point type => on surface).
• Insert an axis system.

3. Create tooling Axis along Y direction:

• create a sketch => Tooling Axis Along Y direction
• take an intersection of the component wall by clicking on the class A Surface Join.
• This will give us an intersect of the component along Y-Z plane
• Draw two Lines that are tangent to the intersection line, and then draw a bisecting line with the two tangent lines as a selection and the axis point 1 as the reference.
• Then keep the bisecting line this becomes the tooling axis clearing Y direction, and make the other geometry as construction lines.

4. Create tooling Axis along X direction:

• create a sketch => Tooling Axis Along X direction
• Cut part by sketch plane
• take an intersection of the component wall by clicking on the class A Surface Join.
• This will give us an intersect of the component along X-Z plane
• Draw a tangent line with respect to the Center wall intersection line.
• Then create a normal line from point 1 and using dimension tool measure an angle of 3 degree from the line to the Center wall line. Then keep the tooling axis line.
• Now We have two clearance lines along X and Y direction.
• Create a bisecting line with these two lines [ clearing axis line along X and Y] with the axis point 1 as reference. Hence, we get the tooling Axis for drafting of the component.

5. B Surface Creation:

To create a B surface There are 4 initial steps:

• extract the faces of the component
• Ignore fillets.
• Un-trim the extract
• and extrapolate the surfaces as per requirement

Next you can Trim or Split the surfaces,

(You can Trim and split it with other surfaces as well. Create a Geometrical set and name it.)

Class B surface.

1. Insert a geometrical set 1 with father as class b surface and name this set as upper bezel surface.

• Extract the upper surface from the class A surface and then un-trim the surface.

2. Insert a geometrical set 2 with father as class b surface and name this set as

• Extract the three walls separately.
• Un-trim the three walls.
• Extrapolate them by clicking on the edge of the Un-trimmed surface to extend and then click of the Un-trim surface as a reference.

Extrapolate settings:(Continuity: Curvature, Extremeties: Tangent, Propagation mode = Point continuity.)

• Trim the three extrapolated walls to make it one class A Surface reference.

3. Insert a geometrical set 3 with father as class b surface and name this set as

• Extract the surface and
• un-trim the surface
• extrapolate the surface

Insert a Geometrical set and name it as B surface trim

• Now trim the Upper Bezel surface with the walls which are already trimmed. Trim 3
• Then trim the trim 3 with the base extrapolate. This will give us trim 4
• Now offset the trim 4 by 2.5 mm Towards B surface.
•   

How To check fillet value:

• Extract a fillet
• Un-trim
• Then measure using measuring tool

Then Finally give the fillets for the class B surface. Make Sure to give proper dimensions because when you offset a surface you need to consider the fillet value to get Equal wall thickness.

Formula = thickness of the component – fillet radius.

Why make Equal wall thickness in a component?

• Flowlines: are caused by the varying speed at which the molten plastic flows as it changes direction through the contours and bends inside the mould tool.
• They also occur when the plastic flows through sections with varying wall thickness or when the injection speed is too low causing the plastic to solidify at different speeds.
• To avoid flow-lines we need to have Equal wall thickness.

6. Creating Class C Surface:

• Extrude the outer boundaries as two multiple extracts

Multiple Extract 1

• Multiple extract 2

• Next create smooth curves along the extracts
• Smooth curve 1
• Smooth curve 2
• Replace multiple extract with smooth curve Respectively.

This is done so that we get a smooth curve without patches in the component which may lead to Flash

Flash is a moulding defect that occurs when some molten plastic escapes from the mould cavity. Typical routes are through ejector pins and parting lines. This extrusion cools and remains attached to the finished product.

• Now using the smooth curve 1, use sweep to create the class C surface.
• Sweep 1=> extract surface=> choose a draft direction such as the tooling axis line. With a minimum draft angle of 3 degrees.
• Create another sweep 2 for curve 2/extract 2.
• Extrapolate the surface to make them join and the trim them respectively.

7. Final Join:

I faced a problem where I was not able to get a closed surface because there was an open curve on the class A surface

I first tried to

• Join class A and Class C with a maximum merging distance of 004
• trim it with the B surface to get a closed body.

But this would be wrong as the maximum merging distance cannot exceed 0.003.

Hence I have given a solution in the problems faced section down below

 

8. Go to part workbench:

• Get the Closed surface of the profile into the Part-body.

9. To Create a master section:

• Insert Geometrical set “Master Section”.
• Select sketch => positioned sketch = X-Z plane=>point projection = point 1
• Then take a half section along plane and using intersect 3d elements tool, take the intersection and highlight it.

10. Perform Draft Analysis:

I couldn’t get a perfectly drafted switch bezel but with proper guidance I can work with these topics confidently

• Go to customized view parameters and select on materials option and click ok.
• Then perform feature draft analysis
• Take the compass and fix it on the tooling axis, and the directions must be with respect to the original axis of the component.
• Lock the axis and check the color scale for the angle of draft.
• If it is constrained within maximum angle of draft = 3 degree, Then the component can be drafted.

Finally Publish the following items.

• Tooling axis
• Class A surface
• Master section.

TREE Structures

    

PROBLEMS FACED AND SOLUTION:

IF this helped please drop a Like.  It could help others as well who are in search of a Solution

1. Class A surface solution:

Problem: Connexity error with the Curve in class A surface (multiple Extract 1).

Instead of using Join command and joining my Class A and Class C surface and then trimming it with the B surface.

• I Extrapolate the class A Surface
• Next Extrapolate the class C surface (Multiple Extract 1 and 2 Separately).
• now trim them as per the requirement.
• Again trim the last trim with The class B surface to get the final output.

2. Class C surface closing solution

Problem:

the class C surface Draft analysis states that the surface cannot be drafted as it shows a draft with a negative Value and we need a positive draft value.

Solution: Increase sweep Angle of the surface  

• sweep the Multiple extract 1 with profile type as Line. Subtype with the draft direction.
• Guide curve 1: Curve smooth: 2 
• Draft Direction: Tooling Axis
• Wholly defined
• Angle: 5 deg
• Sweep Multiple extract 2 with the draft direction with an Angle of 4 deg
• Make sure to check draft analysis

I Hope this helped please drop a Like.  It could help others as well who are in search of a Solution.

Work done By kapil diwakar