Experimental investigations of grain size effects in forward microextrusion

Abstract

Micromanufacturing has received good attention globally in terms of its manufacturing methods and processes. One of the most popular micromanufacturing processes is microforming. Although there were efforts made to realize microextrusion for industrial application, the technology itself was seen as being insufficiently mature and unlike conventional methods, there is no in-depth knowledge. It has become essential to develop a proper understanding which in turn could be used to develop dedicated processes for the manufacturing of metallic microcomponents. In this work, an attempt has been made to realize this special application of metal forming. A novel experimental setup consisting of forward extrusion assembly and a loading setup has been developed to obtain the force-displacement response. The effects of miniaturization on microcomponents and the material behavior during forward extrusion are investigated using a computerized universal testing machine (UTM). As per industrial requirement and application of micropart in micromanufacturing process, grain size is an important factor. By using a forming assembly in conjunction with a loading setup, the authors are able to investigate the force-displacement response for microextrusion with material of different grain sizes. Extrusion tests performed on the samples of different grain sizes demonstrated that decreasing grain size caused an increase of flow stress. The realization of such a productive forward extrusion assembly poses significant advantages when compared to the conventional manufacturing technologies in the production of microparts.