Two gates and an overflow tab help fiber-reinforced resins defeat weld-line weakness

A two-gate design paired with an overflow tab improved the weld line strength of structural parts molded from Solvay's KetaSpire polyetheretherketone (PEEK) and AvaSpire polyaryletherketone (PAEK) resins by a minimum of 50% in terms of flexural strength. Those results from a new study by Solvay Specialty Polymers, which the company said supports the use of overflow tabs as a method to improve weld line strength, particularly when molding filled resins.

The study demonstrates a unique way to improve weld line quality for reinforced materials compounded with mineral fillers and fibers, according to Solvay. It is generally accepted that the strength of a reinforced polymer with a weld line is typically reduced by about 50% compared to a reinforced polymer with no weld line, due to an unfavorable orientation of the fillers at the weld line with respect to the load direction. An overflow tab, which is also known as spillover, relief tab, or overflow well, changes the fiber-orientation distribution....

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