Surface Texture by 3D Printing

Three Dimensional Printing is a solid freeform fabrication process which creates parts directly from a computer model by depositing in layers. Each layer is created by depositing powder and selectively joining the powder with binder applied by a modulated ink-jet printhead. This paper explores the application of 3D Printing to the manufacture of surface textures, where the geometric freedom of 3D Printing is used to create repetitive millimeter and sub-millimeter surface structures with overhangs and undercuts. A related aspect of the work concerns the development of computer representations of these complex structures. In one investigation, a "mushroom field" surface texture was modeled and printed. Each mushroom consists of a cylinder with a ball on top. These features are printed in a hexagonal array with each feature parallel to the local surface normal of a complex curved surface. In another investigation, textures were printed into ceramic molds. The textures were transferred to metal (tin-lead, CoCr) castings as positive surface features with overhangs and undercuts and typical dimensions of 700 x 350 x 350Jlm. The application ofsuch cast textures to bone flXation in orthopaedic implants is discussed.