Exploring flexible structures in 3D- printed bio-based materials for specific product applications

Sammanfattning

This master thesis investigates possibilities to use additive manufacturing in the form of Fused Fil- ament Fabrication (FFF) with the material Polylactic Acid, to replace polyurethane foams for less environmental impact. The mechanical properties of foam are difficult to mimic and there are few or no materials that are similar, hence the great challenge to replace it. The idea of using a flexible struc- ture instead of a flexible material is not a new one and can be seen in the field of mechanical springs for example. A lot of inspiration have been taken from other scientific areas of relevance through reviewing literature as well as previous projects in the field at LTH. By studying and testing different structures from previous projects as well as designing new structures a collection of samples was created for a study. The goal of the study was to test the different structures in a specific load condition to deter- mine their flexibility by measuring the elongation. During testing and printing, drawbacks of using a simple AM method revealed itself with a lot of print failures and lack of print quality. Adapting to appearing problems new designs as well as new printing settings were necessary to reach structures that were suitable for testing. The study resulted in several findings of which parameters could affect the flexibility and how they can be altered for desired results for different end use cases. The feasibility of using FFF as a method for replacing polyurethane is discussed as well as further research options needed to reach a sustainable and profitable solution.