Week 8 - Challenge 1 - Base Bracket Design
Base Bracket Design
Introduction
Create the Base Bracket Plastic component through the given Class-A surface. To begin with, the tooling axis for the given Class-A Surface should be created meeting the requirements of the draft angle and at the end perform the Draft analysis on the model.
Tooling axis Creation
In injection molding, the Class A surface is first analyzed to determine the axis or tooling direction that separates the molds. Tooling direction is critical for plastic product design because it determines mold direction
Steps followed
On the extracted surface, a reference point is first created.
To plot clearance lines, a new axis system is used.
The x- and y-axes along with class A were used to develop the tooling axis using the Intersection curve
To form the Tooling axis, two clearing lines were bisected as shown below
The tooling axis's graphic properties are changed to identify the Tooling axis
With reference to the 2 Lines plotted along the X plane, and Bisecting line is drawn using these lines
What is Draft Analysis?
Draft Analysis
For molded or cast parts, the draft angle is the amount of taper perpendicular to the parting line. It is measurable in degrees. Because plastic shrinks and sticks on molding surfaces as it cools, we draft the walls of the plastic part so that it ejects or breaks free from the molding surfaces more easily and without dragging. To reduce the risk of damage to the parts and ensure ejection, a functional injection molding part must have drafts on both the cavity and core sides.
Nominal values for Draft angles
- 3 Degrees is a nominal draft angle
- 5 Degrees can also be manufactured. Increasing the manufacturing cost
- 7 Degrees is considered for Textured surface parts
Importance of Draft in injection molding
- Reduces the possibility of part damage due to friction during the release
- Reduces mold wear and tear
- Ensures a uniform, smooth, unscratched finish
- Ensures the integrity and uniformity of other surface finishes and textures
- Reduces overall cooling time by reducing or eliminating the need for unusual ejection setups
Steps followed for Draft Analysis
- The created part must be changed to the material mode in the display frame
- Compass is enabled and placed in the direction of the Tooling Axis
- The lock command is then used to fix the compass along the tooling axis
- Colour codes are classified and Draft angle is applied
- Running point analysis is used to display permissible draft angle
Input is given: Class A Surface
Creation of Class B Surface
It is the offset surface of the Class A Surface the offset value depends on the thickness of the material, here the offset value is 2.5mm
Class C surface
The surface that Joins both Class A and Class B surfaces are considered to be Class C Surface
Class (A+B+C)
Here we combine all the surfaces into one closed surface using the Trim tool Command
Conversion of Closed surface into Solid Part
Using Solid Command, we convert the closed surface to a solid surface in the Part model
Performed draft analysis closed surface.
The green color indicates drafted walls above 3 deg.
The red color indicates drafted walls from 0-3 deg.
The blue color indicates negative deg.
Analysis shows the drafted walls of the base bracket are above 3 degrees which is permissible for manufacturing in injection molding
Views of the parts
Feature Tree of the parts
Conclusion
Creating the Base Bracket Plastic component through the given Class-A surface. The tooling axis for the given Class-A Surface should be created meeting the requirements of the draft angle and at the end perform the Draft analysis on the model.