Weld line improvement of short fiber reinforced thermoplastics with a movable flow obstacle

Marian Janko, Bernhard Spiegl, Andreas Kaufmann, Thomas Lucyshyn, Clemens Holzer

Research output: Contribution to journalArticleResearchpeer-review

Abstract

Short fiber reinforced (SFR) thermoplastics are ideal materials from which to manufacture complex technical parts in high volumes with low energy expenditure. The orientation of the fibers, and hence their reinforcing effect, depends strongly on the nature of the cavity and on the injection molding process. One disadvantage of SFR thermoplastics is a significant decrease in mechanical properties in the areas of the weld lines, due to suboptimal fiber orientation as the melt streams reunite at these points. Common mold-based and process-based optimization techniques alter the fiber orientation after the formation of the weld line. The mold-based approach presented here, on the other hand, operates at the time the weld line is formed: by redirecting the melt streams, it moves the weld line and improves the fiber orientation. A prototype mold is described, and samples produced from it with both standard and modified weld lines are compared with flawless specimens. The new technique yields a large rise in flexural strength and a smaller but significant improvement in tensile properties.
Original languageEnglish
Article number42025
Number of pages12
JournalJournal of Applied Polymer Science
Volume132.2015
Issue number23
DOIs
Publication statusE-pub ahead of print - 12 Feb 2015

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