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

Objective:

The main objective of this challenge is to create the B-side features RIBs and Screw Bosses for a given drill handle.

Overview:

Creating the class B and class C surfaces to the door handle, and creating the B side features (RIBs and Screw Bosses) by considering all the design parameters.Design parameters to create RIB for a plastic component.

Tooling Axis creation:

It is defined as the direction in which the mould/core and cavity open. Selection of the direction of the tooling axis depends on the ease at which components can be easily ejected. By analysing the component the most easily ejectable direction is somewhere close to the Z direction,(might be inclined to it) so we have made a sketch on the YZ plane of Axis System) to create a bisecting line considering the 2 faces which might be difficult to be tooled.

Draft analysis for class A surface:

To perform the draft analysis in class A, I selected the featured draft analysis tool in the Generative shape design workbench. Initially, I click on the 'use of the compass to define the new current draft direction' command to align the compass to the tooling axis. Once the compass is aligned the compass to the tooling axis, we need to select the surface to perform draft analysis. Class A surface will be highlighted (in green colour) according to the colour bar angle and colours we defined in it. If I gave a 3deg draft angle some faces are not getting cleared, so I have gradually reduced the draft angle to up to every face gets cleared.

The draft angle is 3deg:

Class B surface Creation:

To create the class B surface for the door handle, I offset the class A surface to 2.5mm inside. Once the class A surface is offset created, according to the thickness, we can observe some patches on the offset surface due to the fillets on the class A surface. Now, we need to close those patches. I used multi-section solid command to close the patches.

Offset patch:

I observed only one patch on the offset, I used a fill command to close the patch to create the proper 'Class B surface'.

Class C Surface creation:

I used the sweep command in the geometric shape design workbench to create the class C surface. Initially, I extracted the edges of the class A surface with tangent continuity by using the multiple extract command. After extracting the class A surface edges correctly, I sweeped the extracted edges with 90deg toward the class B surface. After sweeping the extracted class A surface edges, I extrapolated the edges of the sweep for 5mm to intersect the sweep edges with each other. Now I trimmed the extrapolated surfaces together to create a complete sweep surface towards the class B surface. I joined both the trimmed sweep surface and class A surface together, to get the class A+C surfaces as a single surface. Now, to create a solid body for the door handle we need a closed surface. I trim the class B surface with joined class A+C surface to make the closed surface of a door handle.

Class C surface:

Creating Solid body:

To create the solid body I used the closed surface command in the part workbench. Click on the closed surface command in the part workbench and give the closed surface as an input to create the solid part body.

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 i pattern it from 24mm from the first rib and i get the anthor rib.

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 35mm. To keep the screw boss stiff and rigid, I created 4 supporting ribs for each screw boss.

Screw Boss supporting Ribs:

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 0.5deg because the draft angle for the plastic component is 0.4deg to 2.9deg).

Different views:

Isometric view:

FRONT VIEW

LEFT VIEW

Right view