Sharkfin Antenna

Objective

CAE Services was requested to help determine the number and location of gates/drops for balanced filling. The client was also concerned with an air trap that was forming during preliminary mold trials.

Preliminary Results

CAE’s initial analysis simulations confirmed the client’s concern to be true; that an air trap was forming in the part. Based on these results CAE Services ran multiple iterations and solved for a “best solution” process to prevent the air from trapping. The results from the initial simulation also calculated a significant amount of shrinkage near the end of the fill region, due to early gate freeze in the ejector pin. An excessive amount of shear heating was also present in the center of the part and along the perimeter. The following information will outline CAE’s recommendations to improve the processing and achieve the quality product the client intended.

Solution

Warpage Analysis

In order to Prevent the air trap from forming at the top of the part, CAE added a flow leader to the core side and determined the necessary thickness to help move the air trap to the parting line.

The 0.2 mm flow leader is shown to the left in yellow.

Processing

There was a fair amount of shrinkage present near the end of the fill. We discovered this was due to early gate freeze in the ejector pin. A constant pack pressure profile was recommended to achieve the least amount of shrinkage variation.

Flow Front Temperature

In order to help reduce the amount of shear heating, the nominal wall stock was increased.

Summary

Providing Answers

CAE Services made recommendations and provided solutions in order to strengthen the Sharkfin Antenna. Adding a flow leader to the core side along with increasing the wall thickness helped move the air trap to the parting line. CAE Services recommended an appropriate set of processing conditions and process setting and prevented excessive shear heating in the middle of the part and along the perimeter. CAE also minimized the amount of shrinkage at the end of the fill due to early gate freeze.