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Optimization of Injection Molding to Minimize Sink Marks for Cylindrical Geometry  

Kwon, Youn-Suk (부경대학교 대학원)
Jeong, Yeong-Deug (부경대학교 기계공학부)
Publication Information
Journal of the Korean Society for Precision Engineering / v.25, no.7, 2008 , pp. 111-115 More about this Journal
Abstract
This paper describes the optimization of injection molding conditions to minimize sink marks. Sink marks, which refer to a small depression on the surface opposite a thick wall thickness, are often encounted in injection molded plastic parts. Part geometry, material properties and processing conditions during injection molding can affect the sink mark depth. We designed the runner system which is possible balanced filling to cavities using CAE program $Moldflow^{TM}$ and then obtained optimal processing conditions by Taguchi's Robust Design technique. By actual injection molding using optimized mold and molding conditions, it confirmed that sink mark depth decreased zero compared to 1mm level in the conventional mold and process.
Keywords
Sink marks; Filling balance; Taguchi method; Volumetric shrinkage; ABS; S/N ratio;
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