Building of Polyurethane Foams Structures Using Additive Manufacturing Technology

Polyurethane (PU) foam is a versatile material due to its numerous properties, such as: biocompatibility, biodegradability, lightweight, and durability. The porous nature of PU foams enables them to be used for lightweight components and for medical applications where permeability allows nutrients to reach cell growth areas. The foam components are currently mainly manufactured by casting/moulding processes or material removals (i.e. subtractive machining) after a foam block has been casted or moulded. Additive manufacturing (AM) processes (3D printing), build components in 2D layers. The nature of parts produced by AM technologies makes it fit for lightweight products such as aerospace parts, medical scaffolds, automobile parts, etc., in metals and polymers, however, the technology has not been used to produce objects using PU as its material, due to the foaming nature of the material when its two base materials (Polyol and Diisocyanate) encounter each other. This paper has evaluated the suitability of Additive manufactured PU foam structures for further application such as medical scaffolds by comparing the foams produced using traditional method and have developed an AM production method (In-flight mixing system) for the material (PU). Based on the evaluations, a new technique has been proposed and tested which is able to generate PU 3D structures. Foam produced by the designed system has the same characteristics as the traditional casting method with an average pore size of 689µm which will allow the following: the flow of fluid such as blood, diffusion of waste products out of the scaffold, and cell infiltration and can therefore be suggested for the production of medical scaffolds.