Fused deposition modeling (FDM^TM) is a 3D-printing technology of rising interest for the manufacturing of customizable solid dosage forms. The coupling of hot-melt extrusion with FDM^TM is favored to allow the production of pharma-grade filaments for the printing of medicines. Filament diameter consistency is a quality of great importance to ensure printability and content uniformity of 3D‑printed drug delivery systems. A systematical process analysis referring to filament diameter variations has not been described in the literature. The presented study aimed at a process setup optimization and rational process analysis for filament fabrication related to influencing parameters on diameter inhomogeneity. In addition, the impact of diameter variation on the critical quality attributes of filaments (mechanical properties) and uniformity of mass of printed drug-free dosage forms was investigated. Process optimization by implementing a winder with a special haul-off unit was necessary to obtain reliable filament diameters. Subsequently, the optimized setup was used for conduction of rational extrusion analysis. The results revealed that an increased screw speed led to diameter fluctuations with a decisive influence on the mechanical resilience of filaments and mass uniformity of printed dosage forms. The specific feed load was identified as a key parameter for filament diameter consistency.

中文翻译：

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热熔挤出工艺波动及其对细丝和3D打印剂型的关键质量属性的影响。

熔融沉积建模（FDM ^TM）是3D打印技术，用于制造可定制的固体剂型，引起人们的关注。热熔挤出与FDM ^TM的耦合允许生产用于印刷药品的药用级长丝。细丝直径的一致性对于确保3D打印的药物递送系统的可印刷性和内容均匀性至关重要。文献中没有描述涉及细丝直径变化的系统过程分析。提出的研究旨在对与影响直径不均匀性的参数有关的细丝制造进行工艺设置优化和合理的工艺分析。另外，研究了直径变化对长丝的关键质量属性（机械性能）和印刷的无药物剂型质量均匀性的影响。为了获得可靠的长丝直径，必须通过使用带有特殊牵引装置的络筒机进行工艺优化。随后，将优化的设置用于进行合理的挤压分析。结果表明，增加的螺杆速度导致直径波动，对细丝的机械弹性和印刷剂型的质量均匀性具有决定性影响。特定的进料负荷被确定为长丝直径一致性的关键参数。