Fabrication of Ti-6Al-4V Scaffolds by Direct Metal Deposition
- PDF / 1,130,984 Bytes
- 9 Pages / 593.972 x 792 pts Page_size
- 34 Downloads / 196 Views
SSUE engineering constitutes a promisingly alternative approach to the repair of damaged tissue or organs. Different biomaterials have been used as scaffolds, including bioactive metallic,[1] ceramics,[2] and polymers[3] for bone tissue engineering. Ideally, the materials should exhibit adequate mechanical and biological properties. The primary roles of scaffold are (1) to serve as an adhesion substrate for the cell, facilitating the localization and delivery of cells when they are implanted; (2) to provide temporary mechanical support to the newly grown tissue; and (3) to guide the development of new tissues with the appropriate function. Moreover, the scaffold should be biocompatible. A titanium alloy, specifically Ti-6Al-4V, is widely used as an implant material for biomedical applications due to its relatively low modulus, good biocompatibility, and enhanced corrosion resistance when compared to more conventional stainless steels and cobalt-based alloys. The principal focus of this study is to produce ideal scaffolds of Ti-6Al-4V by the direct metal deposition (DMD) technique for patient specific bone tissue engineering with good mechanical and metallurgical properties. Rapid prototyping, also known as solid freeform fabrication, is a manufacturing process that quickly produces physical prototypes directly from computer G.P. DINDA, Research Fellow, L. SONG, Research Investigator, and J. MAZUMDER, Professor, are with the Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI 48109. Contact e-mail: [email protected] Manuscript submitted April 16, 2007. Article published online September 17, 2008 2914—VOLUME 39A, DECEMBER 2008
aided design (CAD) solid models using a special class of fabrication technology. Direct laser deposition is a rapid prototyping method that can be used to manufacture near-net-shape components from their CAD files in one step. The DMD[4,5] technology developed at the University of Michigan, direct light fabrication (DLF)[6,7] developed at the Los Alamos National Laboratories, and laser engineering net shaping (LENS)[8,9] developed at the Sandia National Laboratories in the early 1990s are all successful examples of direct laser deposition technology. The basic principles of DMD, DLF, and LENS processes are similar in that they use a focused laser beam as a heat source to melt metallic powder and create a three-dimensional (3-D) object. In addition, the DMD and LENS have a feedback control system that provides a closed-loop control of dimension during the deposition process. In the present investigation, the DMD system developed at the University of Michigan was used to fabricate complex shaped metallic scaffolds for medical implants, which are very difficult to process for conventional methods. First, the CAD model of the component is sliced into a series of parallel layers with a certain build-height. During the DMD process, powder is fed at a controlled rate into the focal point of a high-power laser where the individual particles are melted. The CAD files control both movements of
Data Loading...
