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

Aim

1. To create the Door Handle Component from the given Class A surface
2. To Create the tooling axis for the given Class A surface meeting the requirement of Draft angle.
3. To Attach B side feature (ribs and screw bosses) in the component.
4. Create the rib for the Door Handle considering the design rules.

Class A Surface-

Creation of Tooling Axis –

• Extraction of surface where want to create the tooling axis.

• Surface Untrim

Draw a point at the centre of the surface.

• Create the tooling axis perpendicular to the surface by creating a line of the point in reference of ZX Plane.

Creation of Class B surface

• Offset of Class A surface is taken at the distance of 2.5mm. And as the surface is clear and free from gaps and patches. So, here our B- Surface is ready.

Creating Class C surface

1. 
   Extract the boundary from the class A surface using boundary command.
2. Using disassemble tool to divide the boundary as the boundary contains domains.
3. Use sweep command> choose profile type line > subtype as with draft direction > choose guide curve and draft direction > draft angle as 3 degrees > preview.
4. Or, Use sweep command> choose profile type line > subtype as with reference surface> reference surface will be Class A > angle 87 degree.
5. After getting sweep then the output with class B surface is join to get final output by extrapolation and trim command.
6. Now open part design workbench and using close body surface create a solid of the component.

Final Closed Surface

Closed Part Body

Attachment Feature Creation (Ribs & Screw Boss)

RIB Design:

To create the ribs on the solid part body, we need to follow the above-mentioned design guidelines. Initially, I create a line sketch for the rib and I extruded it in the tooling axis direction and I thicken the extruded surface to 1mm toward the inside,
after thickening the extruded surface I gave 0.5deg of draft angle to the rib, and I union trim the rib with the part body to remove the extra surface of the rib, by union trimming the rib with the part body the rib gets added to the main part body without the unwanted extra part. After adding the rib to the part body, I gave the fillet to the rib with a radius of 0.25mm (as per the design parameters 0.25mm is the maximum fillet radius). In the same way, I created the rib-2.

RIB Root Thickness:

To check the rib root thickness, I created a plane which is perpendicular to the base surface (if the plane is parallel to the base surface the intersection will be taken, but we can't see any rib intersection on it, so that is why the plane is created perpendicular to the base surface). After taking the intersection for the body and plane, we need to create a tri-tangential circle at the bottom of the rib. To create the circle, we need to extract the faces of the intersection (if we directly select the faces without extracting the required faces the input may take the entire intersection surface as an input) which we need to give as input for the tri-tangential circle. The tri-tangential circle is shown below, with the measurement of it.

SCREW BOSS Design:

To create the screw boss, I created the circular sketch in the sketcher workbench and I padded the sketch to 12.5mm. Now, I drafted the inside and outside surfaces with 0.5deg in the tooling axis direction. After creating the screw boss, I gave 0.25mm of the fillet to all sides. Now, I translated the screw boss toward the right side for 23mm. To keep the screw boss stiff and rigid.

Draft Analysis for the Solid Body:

To perform the draft analysis for the solid part body (which has ribs and screw bosses on it), I used the featured draft analysis tool in the generative shape design workbench. Initially, I aligned the compass to the tooling axis and I selected the solid part body, I gave a 0.9deg draft angle in the colour bar. If I gave a 3deg draft angle in the colour bar some faces are not clearing properly, due to the class A surface draft angle and curvatures on the bottom area the solid body has shown in red and cyan colours even though we gave 0.9 deg in the draft angle in the colour bar we can't decrease the draft angle to less than 05deg because the draft angle for the plastic component is 0.5deg to 3deg).

The draft angle is 3deg but to clear draft analysis of Ribs and screw boss we can take draft angle as 0.45 degree.

Different view of Model (Door Handle)

Isometric View

Front view

Left View

Right View

Top View

Conclusion

Here I have got knowledge of engineering features Ribs and screw boss on the B Surface.