方管短玻纤增强聚合物水辅注射成型穿透模拟及实验
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摘要
制件的穿透过程一直是水辅助注塑成型(WAIM)研究的热点。基于描述聚合物复合材料的黏弹性方程White-Metzner及流体动力学三大控制方程,采用有限体积法(FVM)开发的软件对由直线构成的方形截面管材短玻璃纤维增强聚合物水辅注射成型的穿透行为进行了数值模拟分析,并通过实验进行验证。分析中主要考虑工艺参数(熔体温度、注水压力、熔体注射量、纤维含量和注水延迟时间)及不同成型方法对制件性能的影响规律。结果表明,熔体温度和注水压力的增加会使制件的中空率增大,而随着延迟时间和注射量的增大,中空率减小;其他工艺参数不变,玻璃纤维含量越高中空率越小,这些现象进一步印证了前人的实验结果。溢流法成型制件的穿透截面形状趋于圆形,玻纤含量越高,圆率越大;短射法成型制件的穿透截面形状趋于型腔截面,且注射量和玻纤含量越高,穿透截面形状越偏离型腔截面;实验结果与模拟相符。
The penetration process of workpiece had always been the focus of water-assisted injection molding( WAIM) research. Based on the viscoelastic equation White-Metzner and the three-control equations for fluid dynamics of description of polymer composites,the penetration behavior of water-assisted injection molding of short glass fiber reinforced polymer with square section pipe composed of straight lines was numerically simulated using software developed by the finite volume method( FVM), and verified by experiments. The analysis mainly considered the process parameters( melt temperature, water injection pressure,melt injection amount,fiber content and water injection delay time) and the influence of different molding methods on the performance of the parts. The results show that the increase of melt temperature and water injection pressure could increase the hollow rate of the parts. As the increase of delay time and injection volume,the hollow ratio will decrease. When the other process parameters remain unchanged,the hollow rate would decrease with the increase of the glass fiber contents. And these phenomena further confirm the experimental results of the predecessors. The shape of the penetration cross-section of the overflow molded parts tends to be circular,and the higher of the glass fiber content,the greater the round rate could achieve.The penetration cross-section shape of the short-shot molded parts tends to be the cavity section. And as the increase of the glass fiber content and injection volume,the shape of the penetration section could deviate from the cavity section. The experimental results are consistent with the simulation.
The penetration process of workpiece had always been the focus of water-assisted injection molding( WAIM) research. Based on the viscoelastic equation White-Metzner and the three-control equations for fluid dynamics of description of polymer composites,the penetration behavior of water-assisted injection molding of short glass fiber reinforced polymer with square section pipe composed of straight lines was numerically simulated using software developed by the finite volume method( FVM), and verified by experiments. The analysis mainly considered the process parameters( melt temperature, water injection pressure,melt injection amount,fiber content and water injection delay time) and the influence of different molding methods on the performance of the parts. The results show that the increase of melt temperature and water injection pressure could increase the hollow rate of the parts. As the increase of delay time and injection volume,the hollow ratio will decrease. When the other process parameters remain unchanged,the hollow rate would decrease with the increase of the glass fiber contents. And these phenomena further confirm the experimental results of the predecessors. The shape of the penetration cross-section of the overflow molded parts tends to be circular,and the higher of the glass fiber content,the greater the round rate could achieve.The penetration cross-section shape of the short-shot molded parts tends to be the cavity section. And as the increase of the glass fiber content and injection volume,the shape of the penetration section could deviate from the cavity section. The experimental results are consistent with the simulation.
引文
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[12]章凯,匡唐清,柳和生,等.注水工艺对水辅共注过程影响的数值模拟[J].高分子材料科学与工程,2013,29(11):177-182.
[13]KUANG T Q,ZHOU K,WU L X,et al.Experimental study on the penetration interfaces of pipes with different cross-sections in overflow water-assisted co-injection molding[J].J Appl Polym Sci,2016,133:42866.
[14]LIU S J,LIN M J,WU Y C.An experimental study of the water-assisted injection molding of glass fiber filled poly-butylene-terephthalate(PBT)composites[J].Compos Sci Technol,2007,67:1415-1424.
[2]YANG J G,ZHOU X H.Numerical simulation on residual wall thickness of tubes with dimensional transitions and curved sections in water-assisted injection molding[J].J Appl Polym Sci,2013,128(3):1987-1994.
[3]LIU S J,CHEN W K.Experimental investigation and numerical simulation of cooling process in water assisted injection moulded parts[J].Plast Rubber Compos,2004,33(6):260-266.
[4]丁加新,陈英龙,周华.水辅成型浮动芯注射对制品残余壁厚的影响[J].浙江大学学报,2017,51(5):937-945.
[5]汪志泳,黄汉雄,汪斌.水辅助注塑中高压水穿透过程的数值模拟[J].化工学报,2013,64(4):1170-1175.
[6]章凯,匡唐清,柳和生,等.基于黏弹本构的水辅注塑充填过程的仿真分析[J].高分子材料科学与工程,2014,30(9):93-96.
[7]YANG J G,ZHOU X H,NIU Q,et al.Model and simulation of water penetration in water-assisted injection molding[J].Int J Adv Manuf Technol,2013,67(1-4):367-375.
[8]周华,陈英龙,张增猛,等.水辅成型非圆截面制件残余壁厚的仿真与试验研究[J].机械工程学报,2010,46(18):169-176.
[9]HUANG H X,ZHOU R H,YANG C,et al.Fiber orientation propelled by high-pressure water penetration in water-assisted injection molded fiber-reinforced thermoplastics part[J].J Compos Mater,2013,47(2):183-192.
[10]匡唐清,余春丛,邓洋,等.型腔截面对水辅助注塑成型水穿透的影响[J].化工学报,2014,65(10):4176-4182.
[11]黄淑慧,林军,匡唐清,等.不同截面型腔的溢流法流体辅助注塑工艺的实验分析[J].塑料工业,2016,44(4):54-58.
[12]章凯,匡唐清,柳和生,等.注水工艺对水辅共注过程影响的数值模拟[J].高分子材料科学与工程,2013,29(11):177-182.
[13]KUANG T Q,ZHOU K,WU L X,et al.Experimental study on the penetration interfaces of pipes with different cross-sections in overflow water-assisted co-injection molding[J].J Appl Polym Sci,2016,133:42866.
[14]LIU S J,LIN M J,WU Y C.An experimental study of the water-assisted injection molding of glass fiber filled poly-butylene-terephthalate(PBT)composites[J].Compos Sci Technol,2007,67:1415-1424.