Effect of Molding Process on Wall Residual Thickness Distribution and Glass⁃fiber Orientation of Short⁃glass⁃fiber⁃reinforced Polypropylene Molded Pipes

doi:10.19491/j.issn.1001-9278.2021.05.003

Abstract

Abstract:

A series of short-glass-fiber-reinforced polypropylene bending pipes were prepared via gas-assisted injection molding （GAIM）， water-assisted injection molding （WAIM）， gas-projectile-assisted injection molding （G?PAIM） and water-projectile-assisted injection molding （W?PAIM）. The effect of different molding processes on the residual wall thickness （RWT） and orientation distribution of glass fibers was investigated comparatively. The results indicated that the overall RWT of the pipes decreased by an order of GAIM > WAIM > W-PAIM > G-PAIM， and the difference of RWT between G-PAIM and W-PAIM pipes was small. The RWT variance of the pipe fittings obtained from the four forming processes was small， and the uniformity of the RWT was good. The glass fiber orientation of the WAIM pipes was generally higher than that of the GAIM. The introduction of projectile made the pipe fittings a higher orientation along the flow direction.

Key words: molding process, short-glass-fiber-reinforced polypropylene, residual wall thickness, variance, glass fiber orientation

CLC Number:

TQ320.66⁺2

ZHONG Luohao, KUANG Tangqing, LAI Jiamei, LIU Hesheng, LAI Dewei. Effect of Molding Process on Wall Residual Thickness Distribution and Glass⁃fiber Orientation of Short⁃glass⁃fiber⁃reinforced Polypropylene Molded Pipes[J]. China Plastics, 2021, 35(5): 11-16.

Figures/Tables 13

Fig.1. The structure of projectiles

工艺方法	熔体温度/℃	注水/气延迟时间/s	注射压力/MPa	保压时间/s	模具温度/℃	注水/气压力/MPa	注水温度/℃
GAIM	250	2	8	10	室温	3	-
WAIM						6	室温
G?PAIM						3	-
W?PAIM						6	室温

Tab.1. The process parameters

Fig.2. The five positions of bending pipes

Fig.3. The measurement position of cross section

Fig.4. Phase morphology observation

Fig.5. The residual wall thickness of four processing pipes

Fig.6. The overall wall residual thickness and standard deviation of the four molding processes

Fig.7. The variance of residual wall thickness of four processing pipes

Fig.8. SEM of GAIM pipes at different layers

Fig.9. SEM of WAIM pipes at different layers

Fig.10. SEM of G?PAIM pipes at different layers

Fig.11. SEM of W?PAIM pipes at different layers

Fig.12. Comparison of penetration speed between WAIM and W?PAIM

References 15

1	黄丽.聚合物复合材料［M］.北京：中国轻工业出版社，2012：1⁃3.
2	LI L， PENG Y， WEI W. Recent Advances on Fluid Assi⁃sted Injection Molding Technique. 2014， 7（1）：82⁃91.
3	KNIGHTS M. Water Injection Molding Makes Hollow Parts Faster， Lighter［J］. Plastics Technology， 2002，48（4）：42⁃47.
4	IIDA I.Manufacture of Hollow Body：JP，H04208425［P］.1992⁃07⁃30.
5	刘文文，匡唐清，赖德炜，等.管件流体⁃弹丸辅助注射成型实验初步研究［J］.塑料工业，2016，44（11）：138⁃142.
	LIU W W，KUANG T Q，LAI D W，et al. Priliminary Experimental Investigation on the Fluid⁃Projectile⁃Assisted Injection Molding Pipes［J］.China Plastics Industry， 2016，44（11）：138⁃142.
6	汪龙，孙囡，杨斌，等.玻纤增强HDPE气体辅助注射成型制品的形态［J］.高分子材料科学与工程，2011，27（4）：106⁃109.
	WANG L，SUN N，YANG B，et al. Morphology of GF Reinforced HDPE Composite Molded by Gas⁃Assisted Injection Molding［J］.Polymer Materials Science & Engineering，2011，27（4）：106⁃109.
7	周海迎，柳和生，那兵，等.短纤维增强聚丙烯水辅注射成型短纤维取向的数值模拟［J］.高分子材料科学与工程，2019，35（11）：109⁃115.
	ZHOU H Y，LIU H S，NA B，et al. Numerical Simulation of Short Fiber Orientation in Short Fiber Reinforced Polypropylene Water⁃Assisted Injection Molding［J］. Polymer Materials Science & Engineering，2019，35（11）：109⁃115.
8	YU Z， LIU H S， KUANG T Q， et al. The Study of Short⁃shot Water⁃assisted Injection Molding of Short Glass Fiber Reinforced Polypropylene［J］. Journal of Applied Polymer Science， 2020， 137（47）， DOI： 10.1002/APP.49555.
9	LIU S J， CHEN Y S. The Manufacturing of Thermoplastic Composite Parts by Water⁃assisted Injection⁃molding Technology［J］. Composites Part A： Applied Science and Manufacturing， 2004， 35（2）：171⁃180.
10	江青松，柳和生，熊爱华，等.长纤维增强聚合物注塑流动纤维取向分布数值模拟［J］.高分子材料科学与工程，2015，31（3）：123⁃127.
	JIANG Q S，LIU H S，XIONG A H，et al. Numerical Simulation on the Fiber Orientation Distribution During Flow in Injection Molding of Long Fiber Reinforced Polymer［J］. Polymer Materials Science & Engineering，2015，31（3）：123⁃127.
11	刘保臣，申长雨，刘春太，等.注射成型短玻纤增强PP微观结构及力学性能研究［J］.工程塑料应用，2009，37（6）：52⁃55.
	LIU B C，SHEN C Y，LIU C T，et al. Microstructure and Mechanical Properties of Injection⁃moulded Short⁃fiber⁃reinforced Polypropylene［J］. Engineering Plastic Applications，2009， 37（6）：52⁃55.
12	秦计生，彭雄奇，申杰，等.考虑纤维方向分布的玻纤增强PP复合材料拉伸性能［J］.复合材料学报，2013，30（4）：53⁃58.
	QIN J S，PENG X Q，SHEN J，et al. Tensile Properties of Glass Fiber Reinforced PP Composite Considering Fiber Orientations［J］. Journal of Composite Materials，2013，30（4）：53⁃58.
13	杨帆，匡唐清，刘文文，等.水驱动弹丸辅助注塑弯管的壁厚分布［J］.高分子材料科学与工程，2017，33（11）：112⁃118.
	YANG F，KUANG T Q，LIU W W，et al. Distribution of Residual Wall Thickness of Water⁃Projectile⁃Assisted Injection Molding Pipes with Curved Sections［J］. Polymer Materials Science & Engineering，2017，33（11）：112⁃118.
14	匡唐清，冯强，徐盼，等.玻纤含量对短玻纤增强聚丙烯复合材料水辅注塑制品壁厚与微观形态的影响［J］.高分子材料科学与工程，2020，36（2）：105⁃111，119.
	KUANG T Q，FENG Q，XU P，et al. Influence of Glass Fiber Contents on theResidual Wall Thickness and Microscopic Morphology of Water⁃Assisted Injection Molding Pipes of Short⁃Glass⁃Fiber Reinforced Polypropylene Composites［J］. Polymer Materials Science & Engineering，2020，36（2）：105⁃111，119.
15	KUANG T Q， FENG Q ， LIU T ， et al. Numerical Si⁃mulation on the Penetration Behavior of the Projectile during the Water Injection Stage of Water⁃Projectile⁃Assisted Injection Molding Process［J］. Advances in Polymer Technology， 2020（9）：1⁃15.

[1]	MA Xiuqing, SUN Kaixin, LI Rui, ZHANG Yajun, FAN Yiqiang. Experimental Study on Optimal Injection⁃molding Process of PMMA Microfluidic Chip [J]. China Plastics, 2021, 35(4): 47-52.
[2]	PENG Xinlong, ZENG Yuqing, LIANG Zhuoen, XIE Yi. Curing reaction kinetics of epoxy/glass fiber prepregs for compression molding [J]. China Plastics, 2021, 35(12): 81-87.
[3]	YUAN Zhihuan, KUANG Tangqing, LAI Jiamei, LIU Hesheng, XU Pan. Influence of Processing Parameters on Wall Thickness and Properties of Water⁃assisted Co⁃injection Molding Pipes of Polypropylene/Polyamide 6 Blends [J]. China Plastics, 2021, 35(11): 77-83.
[4]	WANG Yanqing, KUANG Tangqing, LAI Jiamei, FENG Qiang, LIU Wenwen. Effect of Projectile on Residual Wall Thickness of Water⁃projectile⁃assisted Injection Molded Pipes [J]. China Plastics, 2021, 35(1): 60-66.
[5]	Yiren GAO, Minjie WANG, Hongxia LI. Reason and Regularity of Injection Mold Wear for Glass⁃fiber⁃reinforced Part [J]. China Plastics, 2020, 34(8): 44-49.
[6]	Hong YANG. Moldflow⁃based Optimization Analysis and Die Design of UAV Upper Cover [J]. China Plastics, 2020, 34(6): 92-99.
[7]	. Numerical Simulation of Water Injection Pressure Control Method in Short-Glass-Fiber-Reinforced Polypropylene Water-Assisted Injection Molding [J]. China Plastics, 2019, 33(3): 62-67，86.
[8]	. Research Progresses of Reinforced Thermoplastic Composite Pipes Used for Oil and Gas Industry [J]. China Plastics, 2017, 31(7): 16-22 .
[9]	. Study of Molding Process and Application of 3D Printing Technology [J]. China Plastics, 2016, 30(11): 76-83 .
[10]	. Numerical Simulation on Thermalfluidstructure Coupling Deformation of Chip Plastic Encapsulation Process [J]. China Plastics, 2016, 30(07): 62-68 .
[11]	. Injection Mold Design of Motor Canteen Rear Covers with Threads [J]. China Plastics, 2016, 30(03): 109-112 .
[12]	. Simulation Analysis and Experimental Study of the Molding Process for PA6/PE-LD Blends Casting Film [J]. China Plastics, 2015, 29(12): 62-66 .
[13]	. Effects of Injection Molding Process on Angular Deviation of Curved Transparent Polycarbonate Parts [J]. China Plastics, 2015, 29(11): 87-91 .
[14]	. Numerical Simulation on Thermalfluidstructure Coupling Deformation of Polymer Micromechanical Motion Pair In-mold Micro Assembly Molding Process [J]. China Plastics, 2015, 29(09): 60-66 .
[15]	. Trunk Lid Design of Rotary Molding Cars [J]. China Plastics, 2014, 28(11): 100-103 .