Experimental analysis of fluid‐assisted injection molding of pipe fittings with different angles by short‐shot method

Abstract

Abstract Based on the self‐assisted injection experimental platform, experimental studies on gas‐assisted injection molding (GAIM), and water‐assisted injection molding (WAIM) of 2 curved pipe fittings by adopting short‐shot method were carried out. UDF model was constructed for numerical simulation analysis. The influence rules of auxiliary medium and bending angle on the terminal morphology, inner wall surface quality at bending angle, medial and lateral residual wall thickness, variation range, and residual wall thickness deviation rate of short‐shot fluid assisted injection molding (SSFAIM) bending samples were compared. Meanwhile, the influence mechanism was investigated. The following experimental findings were obtained. SSFAIM had secondary penetration, while water produced multiple penetrations. There are multiple vacuum shrinkage pores in the unpenetrated area at the end of the SSWAIM sample, as well as serious shrinkage depressions on the surface. The shape of the penetration front of water is arc‐shaped with many penetration holes. The shape of the penetration front of the gas at the end of the SSGAIM sample is “pointy.” Compared with the SSWAIM sample, the residual wall thickness of SSGAIM has a narrow distribution range when the bending angle is 0°. With the increase of the bending angle, the “foaming” phenomenon of the inner wall surface quality at the bending angle of the SSGAIM sample becomes less and less obvious. Moreover, the deviation of the inner and outer residual wall thickness of SSGAIM is more obvious than that of SSWAIM due to the increase of bending angle.

Keywords

• bending angles
• gas‐assisted injection molding
• residual wall thickness
• short‐shot method
• water‐assisted injection molding