Challenge

Week 8 - Challenge 1 - Base Bracket Design

PP.S.Balaji Neelakandan12 Jan 2023

Base Bracket Design

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.

GIVEN CLASS A SURFACE:

Class A Creation: Class A surface refers to those surfaces which are VISIBLE and abide to the physical meaning, in a product. For styling-class A surfaces of automobile ALIAS software is used. These class-A surfaces are used as an input for an Automotive Plastic Designers

TOOLING AXIS:

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

Steps followed for creation of tooling axis:

Reference point is first created on 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
Two clearing lines were bisected to form Tooling axis.
Graphic properties of tooling axis were change before publishing.

DRAFT ANALYSIS:

Draft Angle: The draft angle is the amount of taper for molded or cast parts perpendicular to the parting line. It can be measured in degrees or mm/mm (in/in). As plastic cools, it shrinks and therefore shrinks onto molding surfaces. Because of this and a few other reasons, we draft (angle) the walls of the plastic part, so as the part is removed it breaks free from the molding surfaces easier and without dragging. 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. What’s also important is to overcome the vacuum forces by letting air in between the metal and the plastic for the part to release properly. Adding an adequate draft angle ensures that warpage upon ejection is prevented while maintaining a decent cosmetic finish.

Draft angles are generally a requirement of injection molding design (though there are a select few soft materials, like nylon, that can get away with draft angles of zero).
Draft should be a part of design for manufacture, and Plastic Product Designer should be aware of its need at the outset of the design process. This allows considerations for design requirements to be taken into account.