Week 9 - Attachment Feature Creation (Ribs & Screw Boss) - Challenge 1

AIM : Create the rib and Screw boss for the Drill Handle considering the design rules.

Tooling axis & Draft Analysis: The direction in which the mold or core and cavity opens is the tooling axis.

To create the tooling axis, I extracted a surface from class A and created a point in the middle of the surface by using the point command and created a line at that point through the x-axis.Now, I performed a draft analysis check from that line whether the created tooling axis is in the correct position or not. If, in the draft analysis check the surface highlighted with green colour on both sides of the surface the tooling axis is in the correct position and direction.

CLASS B SURFACE:

To create the class B surface, offset the class A surface inside as per our thickness requirement ( I offset the class A to 2.5mm inside). Once the offset is created, we can observe some patches on the offset surface by taking the boundary for the offset surface, those patches are formed due to the fillets on the class A surface. We need to cover those patches with the help of the multi-section surfaces command by extracting the patch boundaries. Once all the patches on the offset are covered properly join all the patches with the offset surface, to get the replicated surface of the class A surface.

CLASS C SURFACE:

To create the class C surface concerning the boundary of the class A surface, I used the sweep command. Initially, I extracted the boundary of the class A surface with tangent continuity, and I sweep the extracted boundary concerning the surface at 90deg (for reference Surface) for 5mm to intersect properly with the class B surface. Once we sweep all the surface boundaries of class A, extrapolate the sweeped surfaces until both surfaces got intersected properly, and trim them to remove extended extrapolated surfaces to get a proper sweep boundary throughout the entire surface, including the centre hole of the Drill Handle.

Class C Surface

Now, join both class A and sweep boundary to get the complete class C surface.

Now, unhide the class B and class C surfaces. Check whether all the sides of class B and Class C surfaces are intersecting properly with each other, to get a closed surface by trimming class B and class C surfaces. If the class B and class C sides are not intersected properly, we need to extrapolate the sides of the class B surface which are not intersecting with the class C surface. Now, check class B and class C surface boundaries whether all the sides are intersecting or not with each other. Once the surfaces are intersecting properly trim them together to get a closed surface.

In the above-given image, the sides are not intersected properly. I extrapolated the surfaces which are not properly intersected with each other like above.

The below-given image represents the sides which are extrapolated until the surfaces are intersected.

CLOSED SURFACE

Trim

PART BODY:

To create the solid part body from the closed surface, I used the closed surface command in the part workbench.

Attachment Feature Creation (Ribs & Screw Boss)

1)RIBS: - Ribs are usually designed to Improve Strength of Plastic Part without increasing the thickness of the component.

B SIDE FEATURES CREATION

RIB CREATION

• Design Principle for Rib Creation

• Ribs are thin wall protrusions that extend perpendicularly from a wall or plane. They are usually found in clusters offering support to a plane that would have otherwise been too thick, but can also be stand-alone support for a single wall. They are commonly used to provide additional support and strength to a part. Thickness and location are essential to rib design.

  First, the base surface where the rib has to be created is extracted using the Extract command. A positioned sketch is created and the profile for the rib is drawn.

• Next, the profile is extruded, to find the height,h=Wall thickness * 5

  =2.5*5

  = 12.5 mm

  Therefore, the height is 12.5 mm

• The extruded surface is thickened,

  Thickness,w=0.4*t

  =0.4 2.5

  =1mm

  Therefore, the thickness of the rib is 1 mm.

• 

2)Screw Boss: -

It helps to screw component together. Screws are secondary features which is on B surface. Bosses are used to attached & assembly features of many components.

SCREW BOSS DESIGN

• Design Principle for Screw Boss Creation

DRAFT ANALYSIS:

After creating a solid body from the closed surface I performed a draft analysis on it, to check the draft angle(0.48 deg) of the solid body.

CONCLUSION:

• The Tooling axis and the SolidCAT part with B Side Features is created from the given Class A Surface and Draft Analysis is Performed.