Introduction of Rapid Prototyping Manufacturing
Rapid Prototyping Manufacturing (RPM) technology is a kind of advanced manufacturing technologies driven directly by CAD model aimed at the rapid completion of arbitrary shape complex three-dimensional parts. Rapid Prototyping Manufacturing (RPM) system is in the category of the CIMS object production areas. Because it is directly driven by computer data information, and belongs to digital manufacturing.
CIMS theme of national high-tech Research and Development Program (863 Program) fixed Rapid Manufacturing as the target major project of its objective production. This project aimed at the developing China's own intellectual property rights for Rapid Manufacturing technology of computer software, researching the most promising RP technology -- such as melt extrusion manufacturing (MEM) and LOM (SSM) , developing RPM products based on the above development process and the specific materials used in various RPM equipments (including single function and multifunction), and ultimately forming the RPM Products with Chinese characteristics. Then in the end of 2000 certain sales scale and the emerging of a high-tech industry through a series of products can be achieved.
In support of the national 863 plan, the personnel of this project has managed to complete the design and development of many RP equipments as M-RPMS-III, MEM-300 - I, MEM-600, SSM-800 and SSM-1600. The fourth generation of Lark '2000 and Cark '2000 software for RP Data Processing is finished. And the direct slicing software based on domestic 3D CAD modeling software with its own intellectual property rights is developed. The research and development of rapid tooling has been completed. This technology has reached the advanced international level in general, and a leading international standard in part.
The Achievements ofRapid Prototyping
SSM Objects
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PCM technology
The PCM (Patternless Casting Modeling) process is based on disperse/deposit forming principle of RM technology, and it is a kind of new modeling method that is different from the traditional ones. In one word, the modeling process of PCM can be illustrated by figure 1. In every layer of sand, the first nozzle scans along a given path and deposits resin, then the other also scans along the same path and deposits catalyst. On the profile of the cross section of a mold, resin and catalyst interacts with each other and the relation between them binds the sands together. Where there is no liquids, the sand is still loose and can be cleaned easily. After all layers are finished building, the mold is complete. After loose sand is taken out, the mold is covered by dope and is ready to casting.
The machining process along profile of |
The cross section that is finished machining |
The whole impeller casting mold |
The casting mold of solenoid |
The casting mold of sleeve |
The prototype of impeller |
MEM technology (in making human skull-absent substitutes)
The design and manufacture of a skull-absent substitute is a complicated clinical problem. By now every method that is adopted to repair a skull contains many defects under operation. They take a long time and are hard to ensure the accurate shape. Using MEM (Melted Extrusion Manufacture) rapid prototyping technique, which is based on the scattering/piling-up principle, a patient’s skull and the skull-absent substitute solid models can be manufactured from CT scanning data. The substitute made by MEM technique fits the original skull very well. In this paper we introduce the theory of the MEM technique and describe the manufacturing process of the skull and skull-absent substitute. We also discuss the problems in making skull-absent substitutes using the MEM technique, which need to be solved in the future.
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