金属粉末注射成形工艺参数及浇口尺寸对流动性能的影响

【作者】 许静静；

【导师】 蒋炳炎；

【作者基本信息】 中南大学 ， 机械设计及理论， 2004， 硕士

【摘要】 本文对粉末注射成形(PIM)过程中W-Ni-Fe喂料熔体的流动性能作了深入的研究，通过讨论阿基米德螺旋线测试模具中喂料的流动长度，并根据设计的实验方案具体运用MPI(Moldflow Plastics Insight 3． 1) 模拟分析软件和实验分析的方法，着重研究了侧浇口的深度尺寸和注射工艺参数对喂料流动性能的影响。为了实现注塑成形软件在粉末注射成形上的应用，本文对W-Ni-Fe喂料的性能参数进行了计算分析，研究分析了该粉末材料的物性参数，优选出适合该粉末材料的粘度模型，并在MPI软件原有的塑料材料数据库的基础上扩充了W-Ni-Fe粉末喂料注射成形所需的各项参数数据，为MPI模拟仿真软件在PIM成形领域的应用提供了广阔的前景。本文根据设计的实验方案，经过模拟分析和上百次的现场实验之后，借助于浇口尺寸、工艺参数与螺旋线流动长度关系曲线图的描绘，找到了浇口尺寸以及工艺参数对流动性能影响的基本规律。研究表明：① 浇口尺寸与螺旋线测试模中喂料流动长度不成比例关系，是非线性的，L-H曲线为波浪状：② L-H曲线无论是模拟结果还是实验结果，都表现出流动长度随浇口尺寸的增加呈波浪式上升的整体变化趋势。当其它实验条件一定而注射压力改变的情况下，浇口尺寸均匀取0． 5-2． 1mm之间的6个值时，流动长度最长的浇口尺寸均在1． 8mm处，大于一般注塑成形时的最佳浇口尺寸值：③ 在实验结果中，相对注射压力而言，熔体温度和注射速率对L-H曲线关系的影响就相对较小些，波动方向一致且比较平坦；④ 浇口尺寸不变时，注射压力、注射速率以及熔体温度、模具温度等工艺参数值的增加都会引起流动长度的增长，它们与流动长度均成正比关系。正常的加工范围内，增加注射压力与提高熔体温度对流动长度的影响具有等效性；可见，工艺参数对粉末注射成形的成型性能的影响规律与注塑成形的影响是一致的。⑤ 经过本文的模拟和实验分析结果的比较分析后，认为模拟与实验结果之间的误差较小，二者具有可比性。更多还原

【Abstract】 This paper is concerned with the fluidity of W-Ni-Fe feedstock in the Power Injection Molding (PIM) by discussing the feedstock flow length, and the researched fluidity is affected mainly by the depth dimension of the gate and the technologic parameters, the main research approach is making use of the MPI (Moldflow Plastics Insight 3.1) simulation software and experimentations.For applying the simulation software of the plastic injection molding to the PIM, the character parameters and the best viscosity model of the W-Ni-Fe feedstock were discussed in this paper. In the databases of the MPI software, the parameters data of this PIM feedstock that we need in PIM flow simulation were extended, which provide a good development for the application of the MIP simulation software in the PIM field.After the MPI simulation and hundreds of the experiments and tests following the designed schemes, the basic law that the gate and the technologic parameters affect the fluidity was found by drawing their relation curves. My test research work is as follows: (1) The relation of the depth dimensions of the gate and the flow length isn’t linear, the H-L curve is obvious wave; (2)In the results of the simulation and the experiment, the H-L curve has the tendency that with the increasing of the depth dimension of the gate, the flow length increase wavily. When the injection pressure changed and the other conditions still are invariable, at the same time, the depth dimensions of the gate give averagely six values between 0.5mm and 2.1mm, The gate dimension of the longest flow length is 1.8mm.(3) Compared with the injection pressure, the effects that feedstock temperature and the injection velocity affect the H-L curve are smaller.(4)As to the technologic parameters, when the dimension of the gate is invariable, the flow length increased with the increasing of all of the technologic parameters such as the injection pressure the injection velocity the feedstock and the mold temperatures. Increasing the injection pressure and the feed-stock temperature have the same effect of going up the flow length. ㏕hrough analyzing the results of simulation and test, we found that the difference between them is small, the simulation and test can be compared.更多还原