Abstract
Layered manufacturing (rapid prototyping) is a processing technique which creates a three-dimensional object of a complicated shape based on cross-section data sliced from three-dimensional data such as that produced using CAD (computer-aided design). In this study, we proposed a powder-layered manufacturing process, which is one technique for rapid prototyping, to produce the desired bone shape for a transplantation from a biomaterial powder. Formation was carried out using conventional inkjet-type equipment. In the experiment, we used orthopedic filling-paste powder (BIOPEX), of which the main component was alpha-tribasic calcium phosphate, as the forming material. To solidify the powder, we used a sodium chondroitin sulfate+dibasic sodium succinate anhydride aqueous solution—the solvent for mixing powder in clinics—as the binder liquid. The binder liquid was applied to the surface of the powder material using a bubble jet-type inkjet device. As a first trial, we formed difficult thin plate-shaped sample (0.1 mm to 1.0 mm in thickness) and circular hole samples (0.5 mm to 5.0 mm in diameter) to examine the formability of this technique for artificial bone. As a result, the shape of the sample was affected by the swelling ratio; in particular, the thickness and diameter dimensions were smaller. However, the powder was clearly fixed, showing that the formation of artificial bone is possible using this technique. The measured formation accuracy of the sample was about 0.6 mm, and the smallest diameter was about 2.0 mm. As the next trial, we formed an animal bone, creating a rabbit femur from CT image data. As a result, though there was a constraint due to powder discharge, an animal bone with an internal void was produced. These result suggest that powder-layered manufacturing can be used as a new forming technique for artificial bones.
