Laser direct fabrication of three-dimensional components.

摘要

A novel laser direct deposition of composite materials has been investigated to manufacture 3-D components. This process allows for either the direct production of an industrial component or rapid, and low-cost fabrication of tooling dies and injection molds.; In present research, an integrated powder feeding system is designed for laser cladding. It can provide a stable, continuous, and accurate powder feeding rate, and deliver the powder stream coaxially into the molten pool under the laser beam. The experimental results showed that this powder feeding system is suited for depositing high quality cladding tracks, along complicated geometric paths, on flat or curved surfaces. Due to the change of powder feeding mechanism, the characteristic of cone-shaped powder stream and interaction between the laser beam and the powder stream have also been investigated.; Although laser cladding is a complicated process, based on reasonable approximations, a simple but realistic process model, relating the clad thickness and processing parameters, is successfully developed. The calculated results of this model are in good agreement with the experimental ones.; A novel process for manufacturing tooling dies, with required geometric patterned cutting blades, has been successfully developed directly by laser cladding process. Fully functional prototype of an industrial rotary cutting die, for pilot testing, has been produced. This new process has been implemented in tooling-die manufacturing industry. In addition, various geometric laminated 3-D components have been directly produced by the same process. The laminated composites have relatively smooth surface and good planner interfaces, are free of pores and cracks, and good metallurgical bonding with the substrate.; Finally, the measurement of the thermal cycle, and the temperature distributions for laser cladding process has been made. Within optimized operation window, a wide range of processing parameters, and various clad materials have been used in laser cladding experiments. The clad-zone temperatures, under various processing conditions, lies between 1650°C and 1800°C. These results are in good agreement with those obtained by optical pyrometer and CCD techniques. In addition, in both cases of laser remelting and cladding processes, the temperature gradients along y-direction have Gaussian distribution.