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Predicting parting plane separation and tie bar loads in die casting using computer modeling and dimensional analysis.

机译：使用计算机建模和尺寸分析预测压铸件中的分型面分离和拉杆载荷。

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摘要

Die Casting dies and machines are high performance products that are subjected to clamp load, cavity pressure loads and thermal loads during normal operation and the dies and machine deflect under the action of these loads. The ability of the dies to withstand loads and preserve the integrity of the cavity dimensions depends on the structural design of the dies. Die castings dies are expensive products with long production lead times and the structural behavior of the dies has to be predicted at the design stage. The other common problem in die casting is the tie bar load imbalance. The machine clamp load is distributed among the four tie bars depending upon the location of the dies and the location of the cavity center of pressure on the platen. Tie bar load imbalance causes the die parting surface to close unevenly and leads to problems such as flash and premature tie bar failure. The problem is over come by adjusting the length of the tie bars between the machine platens until all the tie bars carry equal loads. Tie bar load predictions are necessary to determine the individual length adjustments needed on each tie bars.;Numerical methods such as the finite element method are the most effective way to predict the distortion of the dies and the machine at the design stage. Performing a full FEA during the initial stages of the die design is time consuming and it is not cost effective. So off the shelf design tools such as closed form expressions, design charts and guidelines are needed to make design improvements during the initial stages of the design.;In this dissertation research work the relative contribution of the major structural design variables of the die casting die and machine to the mechanical performance of the dies and machines was investigated using computational (FEA) experiments. The maximum parting plane separation was chosen as the performance measure for the structural behavior of the dies and the machine. The computational experiments were designed using Design of Experiments approach and closed form power law models were developed to predict the maximum cover and ejector side parting plane separation. The functional form for the power law model was obtained using dimensional analysis based on Pi-theorem. These power law models were then used to explain the sensitivity of maximum parting plane separation to the design variables. The power law models can also be used to compare the performance of different dies and machines and make structural design improvements of the die. In addition a methodology to characterize the stiffness of the machine platens is also developed.;In the second part of the research power law models were developed based on dimensional analysis to predict the loads on the tie bars of the die casting machine as a function of the die location, the location of the cavity center of pressure, clamp load and the magnitude of cavity pressure. The power law model to predict die bar loads can be used to determine the length adjustments needed on the tie bar to balance the tie bar loads. The relative contributions of the die location and cavity location on tie bar load imbalance were also studied using the exponents and coefficients of the power law model. The adequacy of the model was also studied by using tie bar load measurements from a die casting machine.
机译：压铸模头和机器是高性能产品，在正常运行期间会承受夹紧载荷，型腔压力载荷和热载荷，并且在这些载荷的作用下，模头和机器会偏转。模具承受载荷并保持型腔尺寸完整性的能力取决于模具的结构设计。压铸模具是昂贵的产品，具有较长的生产交货期，并且必须在设计阶段预测模具的结构性能。压铸中的另一个常见问题是拉杆负载不平衡。根据模具的位置和压板上的型腔压力中心的位置，机器的夹紧载荷分布在四个拉杆之间。拉杆负载不平衡会导致模具分型面闭合不均匀，并导致飞边和拉杆过早损坏等问题。通过调节机器压板之间拉杆的长度，直到所有拉杆承受相等的载荷，问题才得以解决。拉杆载荷预测对于确定每个拉杆所需的各个长度调整是必要的。数值方法（例如有限元法）是在设计阶段预测模具和机器变形的最有效方法。在模具设计的初始阶段执行完整的FEA既费时又不合算。因此，需要现成的设计工具，例如闭式表达式，设计图表和指导原则，以在设计的初始阶段进行设计改进。;本论文的研究工作是压铸模具主要结构设计变量的相对贡献。使用计算（FEA）实验研究了模具和机器的机械性能。选择最大的分型面间距作为模具和机床结构性能的性能指标。计算实验是使用“实验设计”方法进行设计的，并开发了封闭形式的幂律模型来预测最大覆盖层和喷射器侧分离平面的间距。幂律模型的函数形式是使用基于Pi定理的量纲分析获得的。然后使用这些幂律模型来解释最大分型面分离对设计变量的敏感性。幂律模型也可以用于比较不同模具和机器的性能，并对模具的结构设计进行改进。此外，还开发了一种表征机器压板刚度的方法。在研究的第二部分中，基于尺寸分析开发了幂律模型，以预测压铸机拉杆上的载荷随压力的变化。模具的位置，型腔压力中心的位置，夹紧载荷和型腔压力的大小。用来预测模头负载的幂律模型可用于确定拉杆上所需的长度调整，以平衡拉杆负载。还使用幂律模型的指数和系数研究了模具位置和型腔位置对拉杆载荷不平衡的相对贡献。还通过使用压铸机的拉杆载荷测量研究了模型的充分性。

著录项

  • 作者

    Murugesan, Karthik S.;

  • 作者单位

    The Ohio State University.;

  • 授予单位 The Ohio State University.;
  • 学科 Engineering Industrial.;Engineering Mechanical.
  • 学位 Ph.D.
  • 年度 2008
  • 页码 203 p.
  • 总页数 203
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 一般工业技术;机械、仪表工业;
  • 关键词

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