Automated simulation-driven analysis of lightweight design strategies for the efficient design of film extrusion dies – optimisation of both die mass and flow path length and reduction of thermal setup time

挤出模头用于连续地形成复杂的产品，例如宽度跨越数米的共挤出膜。由于高粘度而产生的高压、共挤出模头中的多个流动通道以及大的产品宽度的组合意味着高机械负载作用在挤出工具上。为了确保尽管有这些负载，各个模板仍保持彼此密封，模板的尺寸被保守地确定，即尺寸被确定为非常大，因此非常刚性。反过来，大体积或由此产生的大质量导致处理困难、长流动路径和长热设置时间。热设置时间发生在更换新产品时等待芯片加热或冷却时。到目前为止，对于不同类型和尺寸的挤出模头，偏离保守尺寸的程度是a）可能的和B）有益的，尚不清楚。因此，申请的研究项目创造了必要的基础知识。它通过使用仿真研究不同的轻量化设计策略来实现。在申请的研究项目中，不同的仿真驱动的轻量化设计策略进行了研究。其目的是根据挤出模头的尺寸和类型，找出哪种轻量化设计策略可以降低质量、减少流道和缩短加热时间。然而，为了实现这一目标，必须首先创建一个仿真环境，该仿真环境可以准确地捕获在流道中的强烈几何形状依赖的流与模板的流依赖的偏转之间发生的相互作用。此外，该模拟环境必须允许自动调整工具板的几何形状。这两个挑战都可以通过使用浸入边界面方法来满足，该方法迄今为止在塑料加工中几乎没有建立。首先，该方法将通过与传统计算方法的比较以及使用由PMMA制成的特别灵活的工具进行的实验室测试来验证。然后，自动应用以下轻量化设计策略：用铝替代钢、曲率加强、高精度机械设计、加强筋以及拓扑优化。两个根本不同的挤出模头设计和七个不同的模具尺寸之间的300和5000毫米的出口宽度进行了研究。详细分析了模具质量、流道长度和加热时间的模拟改进，并与工业模具进行了比较。有了这些数据，大多数挤出模头可以第一次评估轻量化设计的潜力。两个优化的模具制造和检查在挤压试验中，所以-除了计算方法-优化方法可以验证。

Extrusion dies are used to continuously form complex products such as a co-extruded film spanning several meters in width. The combination of high pressures due to high viscosity, multiplicity of flow channels in a co-extrusion die and the large product width means that high mechanical loads act on the extrusion tools. To ensure that the individual die plates remain sealed against each other despite these loads, the die plates are sized conservatively, i.e. sized to be very voluminous and thus very rigid. In turn, the large volume or the resulting large masses leads to difficulties in handling, long flow paths and long thermal setup times. Thermal setup times occur when waiting for the die to heat up or cool down when changing to a new product. It is - as of today - not known to what extent a deviation from the conservative sizing for extrusion dies of different types and dimensions is a) possible and b) beneficial. The research project applied for therefore creates essential basic knowledge. It does that by investigating different lightweight design strategies using simulation. In the research project applied for, different simulation-driven lightweight design strategies are therefore investigated. The aim is to find out - depending on the size and type of extrusion die - which lightweight design strategies lead to lower masses, reduced flow paths and shorter heating times. In order to achieve this goal, however, a simulation environment must first be created that can accurately capture the interactions that occur between strongly geometry-dependent flow in the flow channel and flow-dependent deflection of the die plates. In addition, this simulation environment must allow the geometry of the tool plates to be automatically adjusted. Both challenges can be met by using the immersed-boundary-surface method, which has hardly been established in plastics processing so far. First, this method will be validated by means of a comparison with conventional calculation methods and laboratory tests with a particularly flexible tool made from PMMA. Afterwards, the following lightweight design strategies are applied automatically: substitution of steel by aluminium, stiffening by curvature, highly precise mechanical design, ribbing as well as topology optimization. Two fundamentally different designs of extrusion dies and seven different die sizes between 300 and 5000 mm in outlet width are investigated. The simulated improvements regarding tool mass, flow path length and heating time are analyzed in detail and compared to industrial dies. With this data, a majority of the extrusion dies can be evaluated with regard to the potentials of lightweight design for the first time. Two optimized dies are manufactured and examined in extrusion tests, so that - in addition to the calculation method - the optimization method can be validated.