Basic analysis and optimization of the flow behavior of thermoplastics by adjusting the surface of electrical discharge machined injection molds (EDSIMP)

通过调整放电加工注塑模具 (EDSIMP) 的表面对热塑性塑料的流动行为进行基本分析和优化

• 批准号: 447707042
• 负责人: Professor Dr.-Ing. Thomas Bergs
• 金额: --
• 依托单位: Institut für Kunststoffverarbeitung (IKV) in Industrie und Handwerk an der RWTH Aachen
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2020
• 资助国家: 德国
• 起止时间: 2019-12-31 至 2023-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/447707042?language=en
• 关键词: Basic; analysis; optimization; flow; behavior

Manufacturing of injection molds aims at functional surfaces being as smooth as possible in order to achieve uniform filling and maintaining low flow resistance at the same time. Studies in the field of fluid mechanics as well as preliminary experiments have shown that micro structured mold surfaces can reduce shear rate and flow resistance as well as enlarge flow path lengths.Basically, the reduction can have two consequences for injection molding: First, faster filling times for constant injection pressures can help reducing the cycle time of injection molding. Faster injection speeds can further lead to improved achievable flow lengths due to less cooling as well as a more homogeneous temperature distribution within the cavity, which improves the quality of the part. Second, decreased pressure loss over the flow path could reduce the amount of required gates and furthermore, for constant injection velocities, it could help to reduce shear of plastic melt and therefore thermal stress. Another direct advantage of lower injection pressure is the reduction of the required clamping force, which also decreases the energy consumption in the injection molding process and can enable the use of smaller injection molding machines. The reliability of the injection molding process can furthermore be increased due to less downtime because of maintenance of the injection mold caused by mechanical load and pressures. In addition, fundamental knowledge on the influence of microstructured mold surfaces on the plastic flow behavior can help to deterministically optimize the process in future.In this project, the influence of the electrical discharge machined (EDM) mold surfaces on the flow behavior of thermoplastic materials will be comprehensively analyzed. EDM is a frequently used process for mold manufacturing and allows for detailed tailoring of surfaces. As a first step, the discharge energy dependent structures of sinking EDM will be experimentally investigated in terms of different roughness regimes which are inherently connected to an according extend of a thermally altered rim zone during mold manufacture. For modelling and simulation of surface structures and the validation of their influence on plastics flow, the impact of the EDM surface integrity on the heat transfer coefficient (HTC) at the molds wall will be in experimental and simulation focus. This represents the distinct research point of WZL. In addition, the durability of created mold surfaces will be monitored by long term testing (WZL and IKV). The further investigations will be based on the coupling of Computational Fluid Dynamics (CFD) with heat transfer coefficient (HTC) simulations as function of the surface structure along with validation experiments and measurements during injection molding, representing the core research of IKV.

注塑模具的制造旨在使功能表面尽可能光滑，以实现均匀填充并同时保持低流动阻力。流体力学领域的研究和初步实验表明，微结构模具表面可以降低剪切速率和流动阻力，并增加流道长度。基本上，这种减少对注塑成型有两个影响：第一，在恒定注射压力下更快的填充时间有助于缩短注塑成型周期。更快的注射速度可以进一步改善可实现的流动长度，这是由于更少的冷却以及腔体内更均匀的温度分布，这提高了部件的质量。第二，流动路径上的压力损失降低可以减少所需浇口的数量，此外，对于恒定的注射速度，它可以帮助减少塑料熔体的剪切，从而减少热应力。较低的注塑压力的另一个直接优势是减少了所需的锁模力，这也降低了注塑过程中的能耗，并可以使用更小的注塑机。由于机械负荷和压力引起的注塑模具维护所导致的停机时间更少，注塑成型工艺的可靠性可以进一步提高。此外，微结构模具表面对塑性流动行为的影响的基础知识，可以帮助确定性地优化未来的process.In本项目中，电火花加工（EDM）模具表面对热塑性材料的流动行为的影响将被全面分析。电火花加工是模具制造中常用的工艺，可以对表面进行详细的裁剪。作为第一步，放电能量依赖结构的下沉电火花加工将实验研究在不同的粗糙度制度，这是固有的连接到一个相应的扩展的热改变的边缘区在模具制造过程中。对于表面结构的建模和模拟以及它们对塑料流动的影响的验证，EDM表面完整性对模具壁处的传热系数（HTC）的影响将是实验和模拟的重点。这代表了WZL的独特研究点。此外，将通过长期试验（WZL和IKV）监测所创建模具表面的耐久性。进一步的研究将基于计算流体动力学（CFD）与传热系数（HTC）模拟的耦合，作为表面结构的函数，沿着注射成型过程中的验证实验和测量，代表IKV的核心研究。