Effects of Printing Direction and Multi-material on Hardness of Additively Manufactured Thermoplastic Elastomers for Comfortable Orthoses and Prostheses

Paweł Michalec, Sakine Deniz Varsavas, Florian Arbeiter, Robert Weidner, Lisa-Marie Faller

Research output: Chapter in Book/Report/Conference proceedingChapterResearch


Medical assistive devices such as orthoses and prostheses (O P) are essential for people with physical limitations to provide them with more active, productive and independent lives. However, studies show that the rejection rate of O P is high, mostly due to the lack of comfort caused by improper fitting and the usage of rigid materials. Additive manufacturing makes possible development of a fully customized O P with soft materials what can result in better fitting and more homogeneous distribution of loads on the limb. Therefore, in this study, the effects of printing direction on the hardness, and the thickness ratio between soft materials in multi-material printed samples on the combined hardness are investigated. The following materials are used to produce samples with the extrusion-based 3D-printer Pollen New PAM Series P: PLA, TPE 45 Shore-A and TPE 30 Shore-00. Furthermore, 12 specimens are printed and tested with the Shore hardness method. As a result, the printing direction does not cause a significant change in the final hardness of the soft materials. The increased TPE 30 Shore-00 layer's height in combined materials changes hardness from 68.9 to 48.0 Shore-00. In addition, the increased TPE 45 Shore-A thickness increases combined hardness from 60.9 to 76.4 Shore-00. The change in thickness of both materials causes almost linear change in combined hardness. These results can be used to achieve the optimum comfort for individuals and a rise in the acceptance rate of O P.
Original languageEnglish
Title of host publicationAdditive Manufacturing in Multidisciplinary Cooperation and Production
EditorsIgor Drstvensek, Snehashis Pal, Nataša Ihan Hren
Place of PublicationCham
PublisherSpringer International Publishing
Number of pages9
ISBN (Print)978-3-031-37671-9
Publication statusPublished - 2024

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