Characterization of Additive Manufactured Structures for the Development of Foam-Replacement Cushions

For an ergonomic and healthy sitting posture, the distribution of the seat load in the contact zone through a soft seat cushion is essential. Conventional polyurethane (PUR) foams have only a very limited ability to adapt the distribution of the seat load in the seat cushion to the individual person. In this paper, a potential analysis is conducted to show the extent to which a replacement model for PUR foams can be realized using thermoplastic polyurethane (TPU) materials in the fused-deposition modeling (FDM) process. Based on fundamental experiments and consideration of manufacturing restrictions, suitable structure families and types are investigated and characterized. The characterization is based on standards for foam testing. Grading and design parameters are presented for the use of the foam replacement model in cushioned units. This allows the replacement of PUR foam and also a customer-specific hardness grading in the context of a mass customization process chain.