Vector drop-on-demand production of tungsten carbide-cobalt tooling inserts by three dimensional printing

Three Dimensional Printing (3DP) is a solid freeform fabrication process used to generate solid parts directly from three-dimensional computer models. A part geometry is created by selectively depositing binder into sequentially spread layers of powder. In slurry-based 3DP, a suspension of powder in a solvent is used to form the powderbed layer. This slurry-based powderbed yields higher green density and part resolution than dry powder-based 3DP because of smaller particle size. Vector printing requires that the printhead trace and define the external geometries of a part before raster filling the interior, a new approach in comparison to conventional, raster-only printing. Drop-on-demand (DOD) printheads allow binder droplets to be ejected when needed rather than relying upon charge-and-deflect mechanisms used in continuous jet printheads. Integrating these concepts for vector, DOD printing has the potential to enhance the 3DP process by providing greater part resolution and surface finish. The 3DP slurry-based process and vector, drop-on-demand printing are examined as potential methods to produce Tungsten Carbide-Cobalt (WC-Co) tooling inserts. The research focuses on three fundamental process steps: (1) development of a stable slurry, (2) determination of jetting parameter values for optimal powderbed deposition, and (3) implementation of vector, DOD printing for the binder. Due to unforeseen circumstances, the first two objectives are only briefly introduced in Chapter 1 and summarized in Chapter 3. Further details may be found in the Diplomarbeit document of Olaf Dambon. Two approaches are explored to develop a stable, jettable slurry. One method involves using a water-based Tungsten Carbide slurry and a

Department dc:contributor.department

Massachusetts Institute of Technology. Dept. of Mechanical Engineering.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2004

Author dc:creator

• Guo, David, 1976-

Advisor dc:contributor.advisor

• Emanuel M. Sachs.

• Mechanical Engineering.

Statement dc:rights

• M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

en_US

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/27064

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/27064