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

Abstract

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.

Popular Abstract

Flexible 3D-Printed Structures in Bio-Based Materials – Investigating
Sustainable Alternatives to Polyurethane foams

Polyurethane foam is a key material in modern furniture thanks to its softness and
elasticity, yet its fossil origin and complex recycling process result in major
environmental challenges. This thesis explores how flexible 3D-printed structures in
bio-based materials can mimic the cushioning behavior of foam, offering a
sustainable path forward for future product design.

Polyurethane foam can be found in nearly every sofa, mattress, or chair. It is valued
for its unique combination of softness, durability, and elasticity. However, behind the
comfort lies a material that is difficult to recycle, based on fossil resources, and
produced through processes involving toxic chemicals. Replacing it with something
sustainable is far from simple, as few materials share the same mechanical
properties.

In this thesis, carried out at Lund University in collaboration with the furniture
company Jonas Ihreborn AB, the idea was to create flexibility through design rather
than material. Using additive manufacturing in the form of Fused Filament Fabrication
(FFF), a series of lattice structures was designed and tested in a bio-based Polylactic
Acid (PLA). By altering design parameters such as wall thickness, cell size, and
geometric orientation, different degrees of flexibility could be achieved and evaluated
through compression testing.

The results indicated that geometry had a clear influence on how the printed
structures deformed under load. Some patterns, particularly diagonal and spring-
inspired designs, showed a more uniform deformation compared to others, resulting
in moderate levels of flexibility. A small seat cushion prototype was manufactured
using one of these designs to evaluate its practical feasibility. While the prototype
demonstrated a certain degree of resilience, it did not fully replicate the softness or
cushioning behaviour of polyurethane foam, highlighting both the potential and the
current limitations of the approach.

The study also revealed challenges connected to the printing process, such as print
failures and material limitations, which required iterative adjustments of both design
and printer settings. Despite these challenges, the project confirmed that 3D printing
can be used to engineer sustainable, flexible properties in bio-based materials.

While further research is needed to improve material performance and manufacturing
efficiency, the findings suggest a future where environmentally friendly materials and
digital design methods together can replace fossil-based foams in furniture and
beyond. By designing flexibility directly into the structure, it becomes possible to
rethink not only how we make products – but also how we make them sustainable.

• author: Evander, Sebastian
• supervisor: Axel Nordin
• organization: Innovation
• course: MMKM05 20252
• year: 2025
• type: H2 - Master's Degree (Two Years)
• subject: Technology and Engineering
• keywords: Design, Additive Manufacturing, Polyurethane Foams, Flexible Structures, Product De- velopment
• language: English
• id: 9224294
• date added to LUP: 2026-03-20 12:57:55
• date last changed: 2026-03-20 12:57:55