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

挤出模具用于连续成型复杂的产品，例如宽度为几米的共挤薄膜。由于高粘度、共挤模具中的多个流道以及较大的产品宽度而产生的高压相结合，意味着高机械载荷作用在挤出工具上。为了确保各个模板在这些载荷下保持彼此密封，模板的尺寸是保守的，即尺寸非常大，因此非常坚固。反过来，大体积或由此产生的大质量块导致处理困难、流路长和热建立时间长。更换新产品时，当等待模具加热或冷却时，会出现热设置时间。到今天为止，对于不同类型和尺寸的挤出模具，偏离保守尺寸的大小在多大程度上是a)可能的，b)是有益的，这是未知的。因此，申请的研究项目创造了必要的基础知识。它通过使用模拟来研究不同的轻量级设计策略来做到这一点。因此，在所申请的研究项目中，研究了不同的仿真驱动轻量化设计策略。目的是根据挤压模具的大小和类型，找出哪些轻量化设计策略可以降低质量、减少流动路径和缩短加热时间。然而，为了实现这一目标，必须首先创建一个模拟环境，该环境可以准确地捕捉流道中强烈依赖几何形状的流动与模板流动依赖于流动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刀盘的几何形状。这两个挑战都可以通过使用浸没边界面法来解决，这种方法到目前为止还很难在塑料加工中建立起来。首先，该方法将通过与传统计算方法的比较和使用PMMA制成的特别灵活的工具进行实验室测试来验证。然后，自动应用以下轻量化设计策略：以铝代钢、曲率加劲、高精度机械设计、加强筋以及拓扑优化。研究了两种完全不同的挤压模具设计和七种出口宽度在300 mm到5000 mm之间的模具尺寸。对模拟的刀具质量、流道长度和加热时间的改进进行了详细的分析，并与工业模具进行了比较。利用这些数据，可以第一次评估大多数挤压模具的轻量化设计潜力。制造了两个优化的模具，并在挤压试验中进行了检验，这样除了计算方法外，优化方法也可以得到验证。

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.