间隙对电热变模温高光注塑模具加热效率的影响
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摘要
采用电热方式的高光注塑模具可以有效消除传统注塑成型过程中塑件的熔接痕、浮纤、银纹等缺陷。高光注塑成型技术要求对模具温度的快速动态控制,然而在电加热高光注塑成型中,电加热棒与模具安装孔之间不可避免地存在间隙,间隙层内的空气大大阻碍热量向模具传递。研究了电加热棒与模具安装孔之间的间隙对电热变模温加热效率的影响,构建了电加热高光注塑模具的三维热响应分析模型,利用有限元分析软件ANSYS进行了三维瞬态传热分析,得到了在不同间隙下的模具表面和电加热棒内部的热响应曲线,并通过大量实验证明了理论分析和模拟方法的正确性。结果表明,加热相同时间,间隙量越小,模具表面温度越高,电加热棒内部温度越低,加热效率越高,相较于间隙在0.32 mm,间隙在0.05 mm加热到60 s的模具表面温度至少高出50%,电加热棒内部的温度至少低55%。隙量对模具加热效率的影响并非成线性关系,而是间隙量在越小的区间,加热效率对间隙更加敏感,研究结果为电热变模温高光模具结构设计和电加热棒的选用提供依据。
The defects such as weld bond,floating fiber,sliver veins etc in traditional injection molding can be eliminated by rapid electric heating cycle injection molding technology. Rapid electric heating cycle injection molding technology requires rapid dynamic control of mold temperature. There is an unavoidable gap between the mounting holes and heaters,and the air in the gap layer greatly prevents heat from being transferred to the mold. Effect of the gap on thermal response efficiency in the heating process of rapid heat cycle molding(RHCM) was studied. By construcing the corresponding thermal response analytical 3D models for RHCM and conducting thermal response analysis on base of ANSYS,these simulation results was verified by experiments. These results show that smaller the gap is,higher the temperature of the mold surface is and lower the temperature of the electric heating rod is at the same time of heating,so higher the efficiency of heating is. When the gap is 0.05 mm and heating time is 60 s,the temperature of mould surface is 50% higher and the temperature of the electric heating rod is 55% lower at least than which is 0.32 mm. Effect of the gap on thermal response efficiency is not a linear relationship,the gap is smaller,the heating efficiency is more sensitive. These researches provide the basic information for structure design and selection of heat rod.
The defects such as weld bond,floating fiber,sliver veins etc in traditional injection molding can be eliminated by rapid electric heating cycle injection molding technology. Rapid electric heating cycle injection molding technology requires rapid dynamic control of mold temperature. There is an unavoidable gap between the mounting holes and heaters,and the air in the gap layer greatly prevents heat from being transferred to the mold. Effect of the gap on thermal response efficiency in the heating process of rapid heat cycle molding(RHCM) was studied. By construcing the corresponding thermal response analytical 3D models for RHCM and conducting thermal response analysis on base of ANSYS,these simulation results was verified by experiments. These results show that smaller the gap is,higher the temperature of the mold surface is and lower the temperature of the electric heating rod is at the same time of heating,so higher the efficiency of heating is. When the gap is 0.05 mm and heating time is 60 s,the temperature of mould surface is 50% higher and the temperature of the electric heating rod is 55% lower at least than which is 0.32 mm. Effect of the gap on thermal response efficiency is not a linear relationship,the gap is smaller,the heating efficiency is more sensitive. These researches provide the basic information for structure design and selection of heat rod.
引文
[1]赵国群,王桂龙,李辉平,等.快速热循环注塑技术的研究与应用[J].塑性工程学报,2009(1):190-195.Zhao Guoqun,Wang Guilong,Li Huiping,et al.Research and application of rapid heating cycle molding technology[J].Journal of Plasticity Engineering,2009(1):190-195.
[2]王桂龙,赵国群,李辉平,等.变模温注塑技术的研究与应用分析[J].现代化工,2009(2):24-27.Wang Guilong,Zhao Guoqun,Li Huiping,et al.Study of variotherm injection molding technology and analysis on its application[J].Modern Chemical Industry,2009(2):24-27.
[3]张明磊,于昕世,王小新,等.蒸汽高光无熔痕成型技术研究与应用[J].模具技术,2009(3):27-29+53.Zhang Minglei,Yu Xinshi,Wang Xiaoxin,et al.Study and application of high-gloss&no-weldline steam injection molding technology[J].Die and Mould Technology,2009(3):27-29+53.
[4]Yao Donggang,Chen S C,Kim B H.Rapid thermal cycling of injection molds:an overview on technical approaches and applications[J].Advances in Polymer Technology,2008,27(4):233-255.
[5]Wang Xiaoxin,Zhao Guoqun,Wang Guilong.Research on the reduction of sink mark and warpage of the molded part in rapid heat cycle molding process[J].Materials&Design,2013,47:779-792.
[6]Wang Guilong,Zhao Guoqun,Li Huiping,et al.Research of thermal response simulation and mold structure optimization for rapid heat cycle molding processes,respectively,with steam heating and electric heating[J].Materials&Design,2010,31(1):382-395.
[7]刘斌,赵春振,吴明星.模具加热与温控方法剖析[J].模具工业,2009(5):1-6.Liu Bin,Zhao Chunzhen,Wu Mingxing.Analysis of heating and temperature control technique for injection mould[J].Die&Mould Industry,2009(5):1-6.
[8]Wang Guilong,Zhao Guoqun,Wang Xiaoxing.Development and evaluation of a new rapid mold heating and cooling method for rapid heat cycle molding[J].International Journal of Heat and Mass Transfer,2014,78:99-111.
[9]徐烈,杨军,徐佳梅,等.低温下固体表面接触热阻的研究[J].低温与超导,1996(1):53-58.Xu Lie,Yang Jun,Xu Jiamei,et al.The research of contact thermal resistance of solid surface at low temperature[J].Cryogenics&Superconductivity,1996(1):53-58.
[10]李志伟,徐烈,孙恒,等.低温真空下固体界面间接触热导实验分析[J].低温与超导,2004(1):55-58.Li Zhiwei,Xu Lie,Sun Heng,et al.Experimental research on thermal contact resistance under vacuum and low temperature[J].Cryogenics&Superconductivity,2004(1):55-58.
[11]毕冬梅,陈焕新,王丽萍,等.低温下接触界面热阻的实验与模拟研究[J].低温工程,2011(5):46-49+55.Bi Dongmei Chen Huanxin Wang Liping,et al.Simulation study on thermal boundary resistance between different metals at low temperature[J].Cryogenics,2011(5):46-49+55.
[2]王桂龙,赵国群,李辉平,等.变模温注塑技术的研究与应用分析[J].现代化工,2009(2):24-27.Wang Guilong,Zhao Guoqun,Li Huiping,et al.Study of variotherm injection molding technology and analysis on its application[J].Modern Chemical Industry,2009(2):24-27.
[3]张明磊,于昕世,王小新,等.蒸汽高光无熔痕成型技术研究与应用[J].模具技术,2009(3):27-29+53.Zhang Minglei,Yu Xinshi,Wang Xiaoxin,et al.Study and application of high-gloss&no-weldline steam injection molding technology[J].Die and Mould Technology,2009(3):27-29+53.
[4]Yao Donggang,Chen S C,Kim B H.Rapid thermal cycling of injection molds:an overview on technical approaches and applications[J].Advances in Polymer Technology,2008,27(4):233-255.
[5]Wang Xiaoxin,Zhao Guoqun,Wang Guilong.Research on the reduction of sink mark and warpage of the molded part in rapid heat cycle molding process[J].Materials&Design,2013,47:779-792.
[6]Wang Guilong,Zhao Guoqun,Li Huiping,et al.Research of thermal response simulation and mold structure optimization for rapid heat cycle molding processes,respectively,with steam heating and electric heating[J].Materials&Design,2010,31(1):382-395.
[7]刘斌,赵春振,吴明星.模具加热与温控方法剖析[J].模具工业,2009(5):1-6.Liu Bin,Zhao Chunzhen,Wu Mingxing.Analysis of heating and temperature control technique for injection mould[J].Die&Mould Industry,2009(5):1-6.
[8]Wang Guilong,Zhao Guoqun,Wang Xiaoxing.Development and evaluation of a new rapid mold heating and cooling method for rapid heat cycle molding[J].International Journal of Heat and Mass Transfer,2014,78:99-111.
[9]徐烈,杨军,徐佳梅,等.低温下固体表面接触热阻的研究[J].低温与超导,1996(1):53-58.Xu Lie,Yang Jun,Xu Jiamei,et al.The research of contact thermal resistance of solid surface at low temperature[J].Cryogenics&Superconductivity,1996(1):53-58.
[10]李志伟,徐烈,孙恒,等.低温真空下固体界面间接触热导实验分析[J].低温与超导,2004(1):55-58.Li Zhiwei,Xu Lie,Sun Heng,et al.Experimental research on thermal contact resistance under vacuum and low temperature[J].Cryogenics&Superconductivity,2004(1):55-58.
[11]毕冬梅,陈焕新,王丽萍,等.低温下接触界面热阻的实验与模拟研究[J].低温工程,2011(5):46-49+55.Bi Dongmei Chen Huanxin Wang Liping,et al.Simulation study on thermal boundary resistance between different metals at low temperature[J].Cryogenics,2011(5):46-49+55.