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Experimental study of transcription of smooth surfaces in injection molding
Author(s) -
Yoshii Masaki,
Kuramoto Hiroki,
Kato Kazunori
Publication year - 1993
Publication title -
polymer engineering and science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.503
H-Index - 111
eISSN - 1548-2634
pISSN - 0032-3888
DOI - 10.1002/pen.760331905
Subject(s) - mold , materials science , polycarbonate , molding (decorative) , surface roughness , composite material , surface finish , substrate (aquarium) , geology , oceanography
Signal deterioration of optical discs depends strongly on the substrate surface roughness. Characteristics of surface roughness of the molded substrate have been studied in order to clarify the transcription mechanism of smooth surfaces in injection molding of polycarbonate resin. When the melt temperature, mold temperature, and injecting rate are low, microscopic flow marks more than 5 nm deep are observed on the surface. These flow marks are formed when the melted resin near the mold wall is cooled to the no‐flow temperature of resin before it comes into contact with the mold wall. Molding transcription improves by optimizing the molding conditions for preventing these flow marks. As a result, the surface roughness of the molded substrate obtained is 3.2 nm in maximum height R max , which is nearly equal to that of the mold stamper at 2.7 nm in R max .