Generation of three-dimensional micro structure using metal jet

In recent years, various micro machining processes have been developed to meet the demand for micro machines. However, the material is limited to silicon or plastics. In this study, the authors developed a method to form micro models by a metal jet. This method is similar to an ink jet printing system. A thin layer is first formed by molten metal drops ejected through a nozzle, and a second layer is formed on the first layer. The repetition of this process produces 3-dimensional models. The diameters of hemispherical metal dots adhered on a base plate were about 400 μm. To perform forming, a computer-controlled X-Y-Z stage was used to move the base plate based on 3-dimensional CAD data. Suitable conditions for the metal jet head such as actuating voltage, temperature of molten metal, ejecting frequency and so on were studied to perform accurate and stable forming, and some typical examples of 3-dimensional electric circuits and functionally gradient material were shown.