on 11/06/2018



Project Name: Improving Surface Quality of Automotive Fog Lamp Bezels

By Chieh-Wen Chen, Li-Ju Su, Pei-Rong Chen, Chung-Hao Wu


Tong Yang engineers were tasked with solving aesthetic defects in a plastic fog lamp injection molded part. Since it’s an automotive exterior component, weld lines should be avoided if possible. In addition, weld lines should not appear in the surface of the locking component as well. Tong Yang engineers used Moldex3D to understand how runner layouts can affect the position and the angle of weld lines. In addition, Moldex3D assisted Tong Yang in optimizing wall thickness to solve air traps, successfully solving aesthetic problems in the fog lamp part.


  • Weld lines
  • Air traps


With Moldex3D simulation tools, the Tong Yang team can save a great deal of time and effort in design iteration, accelerating design decision making process. Moldex3D allowed Tony Yang engineers to analyze various gate locations to optimize fill patterns to avoid weld lines in part surface. Moreover, based on Moldex3D’s flow analysis results, Tong Yang engineers were able to detect the air trap in the core side and make necessary design changes, including removing the overflow well and the gas vent, adjusting the wall thickness to resolve the air trap. As a result, Tong Yang engineers successfully moved weld lines to desired locations to improve the surface quality of the part.


  • Solved surface defects, including air traps and weld lines
  • Avoided costly mold rework
  • Accelerated design decision-making

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