High-precision optics by application-optimized compression induced solidification (CIS)

在聚合物技术研究所开发的加工技术压缩诱导固化（CIS）有助于避免标准塑料加工的问题，如聚合物熔体经历两相冷却时出现的缩痕、残余应力和翘曲。CIS工艺是可能的，因为无定形塑料的玻璃化转变温度范围是压力依赖性的，并且随着压力的增加而向更高的温度转变。因此，塑料可以首先通过在腔体内施加压力而在较高温度下固化，而不管厚度如何，然后冷却为固体。DFG资助的项目“Grundplatz de Betrachtungen zum Einfluss hoher Drücke auf den Phasenübergang bei der Kunststoffverarbeitung”和“Übertragung der Grundlagen auf die Spritzgießvariante Druckverfestigung”阐述了对非晶热塑性材料的基本理解，并通过生产精确和均匀的部件展示了CIS背后的巨大潜力。随着实验模具的制造，CIS能够集成到自动化注塑成型工艺中。然而，尽管取得了这一进展，目前的周期时间太长，无法在目前的状态下将CIS用于工业目的。此外，试验模具背后的模具技术对于进一步的工业应用来说仍然过于复杂和昂贵。因此，转让项目“通过应用优化、压缩诱导固化实现高精度光学器件”的目的是通过创新方法缩短CIS周期时间。此外，模具和工艺控制概念将得到改进和简化，以进一步促进CIS在现有加工框架中的实施。从减少CIS周期时间的目标中产生了许多值得科学研究的问题。首先，压缩速度对组件体积和物理老化的影响仍然没有得到充分的描述。这对于在较高温度下使用的部件尤其重要。另一个重要的点是在压缩过程中，不同的熔体温度对模腔中的组分性质的影响。这种效应与聚合物熔体的压力依赖性粘度直接相关，这将通过新型科学设备“Gegendruckviskosimeter”进行分析。此外，由于工艺本身决定的高型腔压力，精确的微结构压印对于厚壁部件也非常有希望。通过制作标本“圆盘”，可以对上述各点进行科学和实证研究。一个组件“透镜”实际证明了利用CIS创新方法经济地生产高精度塑料光学器件的能力。

The processing technique Compression Induced Solidification (CIS), which was developed at the Institute of Polymer Technology, facilitates obviating problems with standard plastic processing like sink marks, residual stresses and warpage, which arise while the polymer melt undergoes a two phase cooling. The CIS process is possible because the glass transition temperature range of amorphous plastics is pressure dependent and shifts to higher temperatures with increasing pressure. Thus, the plastic can first be solidified at higher temperatures by applying pressure within the cavity, regardless of thickness, and then cooled as a solid. The DFG funded projects "Grundlegende Betrachtungen zum Einfluss hoher Drücke auf den Phasenübergang bei der Kunststoffverarbeitung" and "Übertragung der Grundlagen auf die Spritzgießvariante Druckverfestigung" have expounded upon the fundamental understanding of amorphous thermoplastic materials and shown the great potential behind CIS by producing precise and homogeneous parts. With the fabrication of experimental mold CIS was able to be integrated into automated injection molding processes. Yet, despite this progress the current cycle time is too long to be able to employ CIS for industrial purposes in its current state. Additionally, the mold technology behind the trial mold remains too complicated and expensive for further industrial applications. The purpose of the transfer project "High precision optics by application-optimized, compression induced solidification" is, therefore, to reduce CIS cycle time with innovative approaches. Additionally, the mold and process control concepts will be improved upon and simplified to further facilitate the implementation of CIS into existing processing frameworks. Numerous points meriting scientific research arise from the aim to reduce CIS cycle time. Firstly, the compression speeds effect on the components volume and physical aging remains insufficiently described. This is particular important for components employed at higher temperatures. Another important point is the varying melt temperatures effect on the component properties in the cavity during compression. This effect is directly related to the pressure dependent viscosity of polymer melts, which is to be analyzed with the novel scientific equipment 'Gegendruckviskosimeter'. Furthermore, the exact impression of microstructures is also very promising for thick walled components, because of the high cavity pressures as determined by the process itself. With the production of a specimen 'disc' the aforementioned points can be scientifically and empirically researched. A component 'lens' practically demonstrates the capability of economically producing high precision plastic optics with the innovative method of CIS.