The Development of Direct Metallic Rapid Tooling System

In recent years, rapid tooling (RT) has become increasingly important because of the requirement of rapid manufacturing. RT can be used to produce temporary molds as well as permanent molds in mass production. RT provides more benefits from the design stage to mass production. The objective of this research is to develop the direct metallic RT system and identify process parameters of laser cladding. A 2.5-kW Nd-AG laser system, a metallic powder feeder system, a lateral powder nozzle system, a PC-based motion controller, and a shielding gas-supply system are incorporated for the hardware architecture in the proposed RT system. The critical process parameters influencing the dimensional accuracy were analyzed with Taguchi's experimental design. From the analysis of variance computational results, the factors "Scanning speed" and "Tool path offset" are the influential factors affecting the layer thickness of RT parts. From the experimental results, the dimensional accuracy of the dual nozzle RT system is better than the single-nozzle RT system. Finally, the proposed RT system could fabricate the mold inserts. After finishing the mold inserts and assembling the plenary injection mold, the injection molding machine can generate acrylonitrile butadiene styrene plastic parts with excellent quality. Note to Practitioners-Rapid prototyping (RP) technologies have provided a new way of making models or producing visualization prototype in a fast fashion. However, there is an urgent demand from the industry for much faster ways to make physical prototypes, with the desired material using the appropriate production method. RP technologies have introduced a new generation of RT processes. Producing tooling directly from computer-aided-design (CAD) models is regarded as an important process of reducing the cost and time to market for new products. In this paper, a direct metallic rapid tooling (RT) system is developed to fabricate the metallic parts and molds directly from 3-D CAD models. The experimental investigations are implemented to study the proposed RT system. Using Taguchi's method, the critical performance process parameters have been analyzed. The analysis of variance method is used to decide the important process parameters. The developed RT system can produce the mold inserts directly. After assembling the plenary injection mold, the Acrylonitrile butadiene styrene ABS plastic parts have been generated from this RT mold to demonstrate the success of the process. In the future, it is possible to develop a grading alloy RT system, which can control the ratio of the alloy grading layers. Because the grading alloy rapid mold can use varied metallic powders with varied ratio, the cooling time and the residual stress can be reduced. Furthermore, the RT system can also adopt the coaxial nozzle which can be integrated with the optical system. The advantage of the coaxial nozzle is the independence of the powder supply direction in which the workpiece moves