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

Create the Screw boss for the Drill Handle considering the design rules mentioned in the video. 

General Guidelines for Bosses:

•   Draft - 0.5 degrees on the walls of boss
•   Thickness - Typically 40% of the nominal wall at the base.
•   Height to Diameter Ratio - 3:1
•   Radii - 0.25mm maximum radii.  

NOTE: Considering the thickness of part is 3mm.

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1. Tooling axis creation:

      The first step is to observe the given class-A surface deeply and we can say the larger flat area which is perpendicular to the Tooling axis. So, by considering this thing for this class-A surface tooling direction will be in the X-direction. so we create the point on the flat surface as shown in the figure.

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Then create a line perpendicular to the flat surface through that point.

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 2. DRAFT ANALYSIS OF CLASS A SURFACE

                         The Draft Analysis command enables you to detect if the part you drafted will be easily removed. This type of analysis is performed based on colour ranges identifying zones on the analysed element where the deviation from the draft direction at any point, corresponds to specified values.

• Before going to drat analysis go to customized view parameter >under mesh > check material and then click ok.
• Now for draft analyses go to insert » analysis » feature draft analysis.
• Use the compass to define the draft direction.
• In the colour scale change the draft angle to 3 degrees.
• The component changes to green in indication of passing draft angle.
• Use running point to check the angle on the component.
• If the whole surface is green then angle given to tooling axis is correct and the part will be manufacturable along that direction.
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3. CREATING CLASS B SURFACE

Extract the surfaces from the class A using multiple extract and untrim them. Use Extrapolate to make sure that all the untrims are properly intersected to trim and offset the surfaces to 3 mm to create the thickness. Trim the extra surfaces using trim command. Insert them into new geometrical set and name it with respective part names. Apply fillets to the model after creating the entire surface. If the edges are outside the fillet value will be added to the thickness of the component and if the edges are inside, the fillet value will be subtracted from the thickness of the component, for instance the thickness of the component Is 3mm the fillet value is 15mm so the outside portion value should be 18 mm and inner edges should be filleted 12 mm to get uniform thickness. Perform trims one at a time so that it will be clear to understand.

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4. Class C Surface:

• Unhide the A Surface to Take a boundary as a reference to make C surface.
• Go to sweep line-> with Reference Surface 90-degree draft angle for all sweep.
• And join all the sweep parts to make a Class C surface.
• Then Publicize it.

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5. FINAL TRIMS:

<!-- [if !supportLists]-->·       <!--[endif]-->Join class C surface with class A surface.

<!-- [if !supportLists]-->·       <!--[endif]-->Trim the class B surface with the join of class A and C surface.

<!-- [if !supportLists]-->·       <!--[endif]-->A close surface body will be created.

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<!-- [if !supportLists]-->·       <!--[endif]-->Now go to the part workbench, use close body surface command and convert closed surface into solid part.

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Creation of Engineering features

• Rib

Rib provides an economical way to increase stiffness and strength to the mould parts without increasing the overall thickness of the wall. It is thin protrusion that extended perpendicular from the wall.

Design consideration of the Rib

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Rib root thickness analysis

To check the Rib root thickness, first take perpendicular intersection across the body and the Rib and then have to sketch a circle which tangent to the Rib base or root area by using Tri tangent type circle. The value must be within 30% of the wall thickness.

• Screw Boss

Screw boss are used as a point for attachment and assembly, most common in as cylindrical projection with hole design to receive screw or other types of fastening hardware.<!--[endif]-->

Design consideration of the Screw boss

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 2. DRAFT ANALYSIS OF FINAL SOLID PART

• Before going to drat analysis go to customized view parameter >under mesh > check material and then click ok.
• Now for draft analyses go to insert » analysis » feature draft analysis.
• Use the compass to define the draft direction.
• In the colour scale change the draft angle to 3 degrees.
• The component changes to green in indication of passing draft angle.
• Use running point to check the angle on the component.
• If the whole surface is green then angle given to tooling axis is correct and the part will be manufacturable along that direction.

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Conclusion:

     Hence the Rib for the drill handle considering the design rules for rib creation and Screw boss creation and Draft analysis is also performed for the final component successfully.