| authors |
Merz, R. |
| year |
1994 |
| title |
Shape deposition manufacturing |
| source |
Vienna University of Technology |
| summary |
This thesis addresses the issue of rapidly and automatically fabricating functional metal parts directly from CAD models. A newly developed process called Shape Deposition Manufacturing (SDM) is introduced. The process is based on the concept of layered manufacturing in SFF, but uses separate deposition and shaping steps to create a layer. Three dimensionally shaped layers are created using 5-axis CNC machining, to achieve the required geometric accuracy for fully functional shapes. Thermal deposition technologies (thermal spraying, welding) are used to achieve the required material properties. A novel, droplet based deposition process, microcasting, has been developed, to create well- bonded, high-strength material, while minimising the heat input into previously shaped layers. To create layers with a true three dimensional geometry, more detailed building strategies, than used by conventional SFF processes, are required by the SDM process. A CAD based planning system, which addresses these issues by decomposing a solid model of a part into layers and manufacturable, fully three dimensional segments is described. An automated testbed facility installed at Carnegie Mellon's Shape Deposition Laboratory is discussed, and shows the feasibility of automating the process. The microcasting process is explained in detail and its performance in the SDM environment is evaluated. Different strategies and material combinations for the support structure have been developed and are presented with detailed descriptions of several building strategies for parts with various complexity and material quality. Material properties of structures created by the SDM process are evaluated. Problems affecting the accuracy and material integrity of SDM created structures, which mainly involve the buildup of thermal stresses during material deposition, are identified and opened for future research. Finally, various parts, with different complexity, have been built with the SDM process, to show the feasibility and performance of the process. Building time and material usage are evaluated and compared to conventional SFF processes |
| series |
thesis:PhD |
| email |
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| more |
http://www.arcs.ac.at/dissdb/rn024248 |
| references |
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| last changed |
2003/02/12 22:37 |
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