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Weld line studies on transfer‐molded thermosetting composite materials
Author(s) -
Eduljee R. F.,
Gillespie J. W.
Publication year - 1989
Publication title -
polymer composites
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.577
H-Index - 82
eISSN - 1548-0569
pISSN - 0272-8397
DOI - 10.1002/pc.750100306
Subject(s) - materials science , weld line , thermosetting polymer , welding , composite material , molding (decorative) , transfer molding , mold , composite number , compression molding , line (geometry) , geometry , mathematics
Abstract Multiple gating and the presence of inserts make weld lines (also known as knit lines) almost unavoidable in commercially produced moldings. These weld regions may be significantly weaker in strength than the bulk material away from the weld line. Hence, a molded section containing a weld line will only be as strong as the weld line, no matter how strong the surrounding bulk material. The influence of processing history on weld line performance is essential to optimally designed transfer‐molded composite products with discontinuous‐fiber‐reinforced molding materials. This study has therefore been directed toward experimentally characterizing the weld line strength of a bulk molding compund (BMC) and a thick molding compound (TMC) as a function of the mold temperature, fill time/fill rate, and the postbake operation.