摘要
提出了一种基于数值模拟的模具温控凝固成形控制参数的选取方法.针对两个较易于控制的关键控制参数进行了研究,对模具预热温度取743、693、673K和冷却控制阈值取753、293、673K等多种工艺条件的成形过程进行了三维非稳态传热模拟,模拟值与实验值的误差在8%以内.结果表明:模具预热温度稍高于材料熔点时有利于减少缩孔缺陷,提高成形质量,同时应结合成形效率和工艺误差合理选取模具预热温度;冷却控制阈值取753K时,全部冷却管道同时开启,材料中上部形成了明显的缩孔;阈值取673K时成形质量较好,此时7组冷却管道依次开启,固液界面基本保持平面形状,凝固速度较快.
A method for selecting the control parameters of the mold-temperature-control solidification （MTCS） is presented based on numerical simulations, and two significant parameters which are easy to control, are adopted to carry out the investigation. Then, a 3D transient heat transfer analysis is performed in various conditions with the mold-preheated temperatures of 743, 693 and 673 K and the cooling thresholds of 753, 293 and 673 K, and a deviance between the numerical and experimental data of less than 8% is obtained. The results indicate that （ 1 ） a mold-preheated temperature higher than the melting point of the workpiece contributes to the reduction of shrinkage cavities and the improvement of forming quality; （2） the mold-preheated temperature should be determined by considering both the molding efficiency and the process error; and （3） at a cooling threshold of 753 K, all the cooling channels simultaneously open and obvious shrinkage cavities form in the upper center of the workpiece, while at a cooling threshold of 673 K, seven groups of cooling channels open in sequence and excellent forming quality is achieved since the solid-liquid interface maintains a near-planar surface and the solidification velocity remains fast.
出处
《华南理工大学学报（自然科学版）》
EI
CAS
CSCD
北大核心
2007年第8期27-31,共5页
Journal of South China University of Technology(Natural Science Edition)
基金
广东省科技计划项目(2006B12001001)
关键词
模具
温控
凝固成形
控制参数
数值模拟
mold
temperature control
solidification
control parameter
numerical simulation
