Residual wall thickness of water-powered projectile-assisted injection molding pipes

Tang Qing Kuang*, Jun Yu Pan, Qiang Feng, He Sheng Liu, Bai Ping Xu, Wen Wen Liu, Lih Sheng Turng

*Corresponding author for this work

Research output: Contribution to journalJournal Article peer-review

11 Scopus citations


Water-powered projectile-assisted injection molding (W-PAIM) is an innovative molding process for the production of hollow shaped polymer parts. The W-PAIM utilizes high pressure water as a power to drive a solid projectile to displace the molten polymer core to form the hollow space. The residual wall thickness (RWT) and its distribution are the important quality criteria. The experimental and numerical investigations were conducted. Experimental specimens showed that the RWT of a W-PAIM pipe was much thinner than that of a water-assisted injection molding pipe. The cross-section size of the projectile defined the basic penetration section size. The software FLUENT was used to obtain the instantaneous distributions of the flow field, which revealed the forming mechanism of the RWT. The experiments indicated that the processing parameters, such as melt temperature, melt injection pressure, mold temperature, and water injection delay time had obvious effects on the RWT, while the water pressure had little effect on it. The RWT of curved pipes was thin at the inner concave side while thick at the outer convex side. The RWTs at the bend portion are influenced by the deflection angle and bending radius, which is due to the pressure difference between the two sides. POLYM. ENG. SCI., 59:295–303, 2019.

Original languageEnglish
Pages (from-to)295-303
Number of pages9
JournalPolymer Engineering and Science
Issue number2
StatePublished - 01 02 2019
Externally publishedYes

Bibliographical note

Publisher Copyright:
© 2018 Society of Plastics Engineers


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