Industrial competitiveness in modern society depends on the ability to adapt a so-called job-shop production system to the ever-changing demands of consumers. This results in more emphasis being laid on more efficient trial manufacturing techniques the main targets of which lie in reducing the development period of products at lower cost. In the past decade, Rapid prototyping techniques have emerged as efficient methods of trial manufacturing. However, the materials being used for these techniques up to now have been limited to photopolymer, wax, plastic, paper, etc. which lack the mechanical properties of functional materials, such as metals, especially in strength and ductility. Thus, these techniques are being mostly used only for design review or indirect patterns for manufacturing parts or molds. This study attempts to develop a process which can produce three-dimensional shapes of metals directly from CAD data. Prototypes made from metals, can not only be used to test the material properties of the product, but also potentially become the actual die or product itself.
This study proposes a new direct rapid prototyping system, which overcomes the disadvantages of traditional rapid prototyping techniques. The design and manufacturing of a test model of the system has been tried, and its stability has been verified. The laser scanning method using a scanning path schedule composed of circle and arc elements, scanning speed variation method and dwell method have been developed, which resist warping phenomenon and increase the adhesiveness between the layers. The production and setup method of a support have been also developed. For the production of prototypes with pure iron powder or with mixed lead-and-iron powder, the optimal values of the principal process parameters have been determined. Cross-shaped and twisted clover-shaped prototypes have been fabricated through determined process parameters. In order to improve the strength of the prototype, the experimental studies of solid-phase sintering, and infiltration have been done.
