INTEGRATED SOLID FREEFORMING OF METAL PARTS

摘要

Technological advancements in rapid freeforming have dramatically reduced the lead-time in part manufacturing, resulting in an increase in overall process efficiency, however, due to the nature of layer manufacturing, dimensional accuracy and surface texture are still a major limitation of freeform product fabrication. Post-product finishing is estimated to significantly add to the cost of the production of freeformed parts. This problem will continue to exist despite continuous evolution of freeforming technology; thus, a new concept for rapid freeforming techniques that incorporates the need for increased dimensional accuracy and improved surface texture is clearly indicated. The aim of this study is to develop an innovative solid freeforming technique to allow freeforming parts to be interactively fabricated by the layer deposition process and material removal process. Depending upon the part geometry, several layers of the material will be initially deposited, and then the surface contour of the incomplete part will be processed to achieve the desired dimension and surface finish. Then, additional layers of the material will be deposited onto the incomplete part to build another segment of the designed part. These interactive processes will be reiterated until the part has been completed as designed. A post processor based on the concept of parallel kinematic structures with the capability of 5-axis motion will be built and integrated with an existing freeforming machine to form an integrated rapid fabrication cell. The post processor will be equipped with multiple tools to remove the excess material, which will be effectively based on the feature size and specifications on dimension tolerance and surface texture. A PC-based open architecture control environment will be established to provide the integrated freeforming cell with multi-tasking capabilities that allows machine trajectories and functions to be planned, sensed, and controlled instantaneously. The integrated cell will have representative database, datum, fixture, and control software.