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

Ribs and Screw Boss creation

Aim :

To create the Rib for the drill handle considering the design rules for rib creation and Screw boss creation and then perform the Draft analysis for the final component.

Objective :

• Create the Tooling axis by using the bisecting method.
• Design the class-B and class-C surfaces and join them.
• Create the solid feature by surfaces we create.
• Design the required Ribs and Screw Boss and analysis them.
• Perform the Draft analysis for the final component.

Theory :

Tooling Axis :

Class-A surface is first analyzed to create the tooling axis or tooling direction that molds pull apart in injection molding. Tooling direction is important for plastic product design as it decides the direction for mold separation.

Step followed for the creation of tooling axis :

• Reference point is first created on the extracted surface.
• New axis system is deployed to plot clearance lines.
• The X-direction and Y-direction along the class-A were used to create the tooling axis.
• Graphic properties of the tooling axis were changed before publishing.

Draft Analysis :

The Draft angle is the amount of taper for molded or cast parts perpendicular to the parting line. It can be measured in degrees. A functional part for injection molding has to have Drafts facing both cavity and core sides to reduce the risk of damage to the parts and ensure ejection. And also important is to overcome the vacuum forces by letting air in between the metal to the plastic for the part to release properly. Adding maintaining a decent cosmetic finish.

The draft should be a part of the design for manufacturing and the plastic product Designer should be aware of its need at the outset of the design process. This allows considerations for design requirement's to be taken into account.

Nominal values for Draft angle :

• 3 Degrees is the nominal Draft angle.
• 7 Degrees of r textured surface.
• A minimum of 0.5 Degrees can be manufactured with special tools. But it will increase the manufacturing cost.

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.

And next is to create the reference line or axis from the Z-direction using the sketch and bisect line as shown in the figure.

Similarly from the Y-direction also the reference axis is created as shown in the figure.

The next step is to extrude these two lines as the surfaces as shown in the figure.

And now by using the intersection tool by intersecting the two surfaces, we created and as a result, we got online. this line is the tooling axis as shown in the figure.

And change the properties of the line to visually change the color and line type as shown in the figure.

Draft Analysis :

1. The part created has to be changed to the material modes in the display frame.
2. Compass is enabled aligned light along with the tooling direction.
3. Lock command is then applied to fix compass along with tooling axis.
4. Color codes are classified and Draft angle is applied.
5. Running point analysis is used to display permissible draft and angles

Draft analysis for Class-A surface :

Given class-A surface :

Created class-B surface :

Created class-C surface :

Closed surface :

Solid-body: Created by the close surface tool

Create Ribs and Screw Boss

Sketch for creating Ribs :

Sketch for creating Screw Boss :

Tree structure :

Component with Ribs and Screw boss :

Analysis for Ribs Dimension :

The analysis for the dimension is one of the very important analyses to avoid problems in the injection molding process for the component dimensions. the problems like sink marks, flow lines, weld lines, and warping. Then they create some for creating the ribs. That standard dimension is shown in the figure.

Now we need to check our part by intersecting lines in the sketch environment as shown in the figure.

Analysis and calculation: For Ribs

This analysis and calculation are done in an excel sheet for a better understanding of the status.

Analysis for Screw boss Dimension :

The analysis for the dimension is one of the very important analyses to avoid problems in the injection molding process for the component dimensions. the problems like sink marks, flow lines, weld lines, and warping. Then they create somesamendard for creating the ribs. That standard dimension for creating a Screw boss is as shown in the n figure.

Now we need to check our part by intersectilinesine in the sketch environment as shown in figure.

Analysis and calculation: For Screw boss

This analysis and calculation are done in an excel sheet for a better understanding ng the status.

Analysisnlysis :

1. The part created has to be changed to the material modes in the display frame.
2. Compass is enabled and aligned along with the tooling direction.
3. Lock command is then applied to fix compass along with tooling axis.
4. Color codes are classified and Draft angle is applied.
5. Running point analysis is used to display permissible draft angles.

Draft analysis for Class-A surface :

Iso-metric view :

Front view :

Side view :

Top view :

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 is successfully done.