Week 8 - Challenge 4 - Bumper

Bumper

Aim :

To create the Bumper plastic component through the given class A surface and create the required tooling axis and perform the Draft analysis on the model.

Objective :

• First create the required correct tooling axis and perform the Draft analysis on the class-A surface.
• Create the class-B surface and class-C surface by using the surface modeling tools.
• And make the closed surface of class-A, class-B and class-C as the single solid body.
• And perform the Draft analysis on the solid model.

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 direction for mold separation.

Steps followed for 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 tooling axis.
• Graphic properties of tooling axis were change 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 vaccume forces by letting air in between the metal and plastic for the part to release properly. Adding maintaining a decent cosmetic finish.

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

Nominal values for Draft angle :

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

Tooling Axis Creation :

First step is observe the given class-A surface deeply and we can say the hole present area will be perpendicular to the tooling axis. so we first create point on the surface which is near to the head light hole as shown in figure.

Then next step is to take the reference axis from the Y-direction by using the intersect and the bisect line tools the reference axis from Y-direction is created as shown in figure.

Next step is create the point on the line and plane which is parallel to the head light area by using the three point plane as shown in figure. And the sketch this plane as the reference and the Z-direction draw the bisecting line as shown in figure. and this will be the reference axis from Z-direction.

And then create the surface by using the lines by using the extrude surface tool as shown in figure. And the get the intersection line from this surfaces as shown in figure.

And now check for the draft analysis this created axis is give some area as red color which means we need to modify this line angle with small values as shown in figure.

And finaly by ussing the properties box change the color and type of the line as we need.

Steps followed for Draft analysis :

1. The part created has to be changed to material mode in display frame.
2. Compass is enabled and align it 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 angle.

Draft analysis for class A surface :

Tools used for create surfaces :

1. Surfaces

2. Operations

3. Wireframe

4. Surface-Based Features

Given Class-A surface :

Created Class-B surface :

Created Class-C surface :

Join all surfaces :

Solid body : Created by using closed surfaces tool.

Tree structure : For create class-B surface, class-C surface and solid body

Draft Analysis : For solid body

Iso-metric view :

Front view :

side view :

Top view :

Conclusion :

Hence the Bumper plastic component through the given class-A surface and created the required tooling axis and performed the Draft analysis on the model and also for the solid model. so this Draft Analysis feature is very useful to check the Draft angle and can check whether this part is make any problem while manufacturing that product. And the nominal Drafting angle is 3 Degree so we need to design the part with minimum of 3 Degrees has the Draft.