Extrusion-ploughing process model and experiment research on fabrication of micro groove with fin structure

Abstract

The fin-structure function-surface (FSFS), which is multi/micro dimensional segistration of macro-structure and sub-structure, even and micro-structure surfaces, can improve greatly the effectiveness of separation, extraction, absorption and heat changing, thus it is widely applied to modern environmental protection, petrochemical industry, medical industry, radiating of micro-electronics etc. In the paper, an extrusion-ploughing method was presented to process integral compound FSFS. The mechanism of extrusion-ploughing, as well as tool's geometry parameters and their influences on fin's structure was studied. According to fin's formation, the whole forming process can be divided into four stages, which were extruding, cutting, fin-forming and trimming. The compound FSFS, which comprised grooves, primary fins and compound fins, were generated because of plastic deformation and ductile tearing during the process. The experiments showed that extrusion angle, extrusion-ploughing depth and velocity were the main factors that affected fin's formation. It was greatly beneficial to fin's growth when the extrusion angle was between 15° and 25°; the increase in extrusion-ploughing depth can greatly increase the height of primary fin, but the optimum range was between 0.1 mm and 0.4 mm, considering the function of compound fin micro-structure in integrated fins; extrusion-ploughing process can only be performed at a low speed (3.07-3.78 m/min).