Week 8 - Challenge 6 - Core & Cavity Design

Core and Cavity Design for Switch Bezel - Plastic Component Mold 

This report demonstrates the design of Core and Cavity Bloacks for an Automotive Plastic Component – Door Switch Bezel using industry principles such as Parting Surface and Parting Line definition, Draft angles, Draft Analysis, Determining and implementing of Tooling Axis, Class A, Class B, Class C surfaces and maintaining the Thickness of the part at 2.5mm. The Molds are designed using Surface Design and Solid Design techniques in CAD package CATIA V5.

The terms are briefly explained below:

Parting Surface:

• Generally Injection Molding has 2 major components: the Movable Half and the Fixed Half.
• During Injection Molding process, these 2 halves  are pressed together tightly to form a sealed hollow to avoid the melt flow leakage and maintain certain holding pressure.
• The pressed surface is called the Parting Surface.
• Usually the parting surface are the biggest projection outline of the part.
• Parting Surface directly affects the Product Quality, Ease of Construction and Operation of the Injection of the Mold, the Mold Design is one of the key factors to the success.
• Design of Parting Surface should follow the following Design Principles:
  
  • Designing the Mold Structures as simple as possible. 
  • Avoid or reduce side parting as much as possible to reduce complexity of mold making.
  • Ease of De-Molding. The plastic component must stay at the fixed half in most cases and ejected by the Ejection System and avoid side De-molding action.
  • Ensure Dimensional Acccuracy of the molded parts and try to make parts with similar dimensional accuracy requirements in the same module to reduce manufacturing and assembly errors.
  • Ensure Appearance Requirement of the molded parts.
  • Flash or mismatch usually occurs on the Parting Surface, so it shoul not be designed on a High quiality requirement Surface.
  • Ensure adequate Venting or De-Gassing. If possible Parting Surface should be placed at the end of the Mold Flow. This can be a good advantage for Filling and Venting.

Draft Analysis: