Papers by Author: Zhen Ping Wan

Abstract: Along with the wide applications of metal fibers in many fields, more and more attentions were paid on the preparation of metal fibers. Bifurcating chip cutting (BCC) is an effective method of manufacturing slim long metal fibers with high efficiency. In this paper, the chip-bifurcating states were studied in the process of BCC. The states can be classified into four kinds of circumstances according to the experimental results: thorough chip-bifurcating, incomplete chip-bifurcating, part chip-bifurcating and chip-bifurcating entirely but sticking together. Moreover, three chip-bifurcating criteria were proposed to keep the thorough chip-bifurcating state stable. The three chip-bifurcating criteria are found in good agreement with experimental results and can be used as a practical guide for producing slim long metal fibers by BCC.

Abstract: Using high-speed oil-filled spinning and multi-pass drawing composite machining methods, a micro straight groove of copper tube(MSGCT) with an outer diameter about 3 mm~6 mm was obtained, and the forming mechanism of micro straight grooves was investigated. The key factors of process parameters influence the drawing were analyzed. The experimental results show that the values of drawing elongation increases with reduction and die angle increasing. However, drawing elongation increases firstly and then becomes smooth with drawing speed increasing. Stable-quality MSGCT can be achieved by controlling the drawing process parameters and the configurations of micro straight grooves were observed by scanning electron microscope(SEM). In addition, the high-speed oil-filled spinning and multi-pass drawing composite manufacturing can further improve the capillary force of the micro straight grooves of copper heat pipe.

Abstract: Miniature heat pipe is one of promising means of removing high heat flux for electronics cooling in limited available space. How to produce narrow and deep microcapillary grooves is the critical issue in promoting performance of axially grooved miniature heat pipe. In this work, the microcapillary grooves for miniature cylindrical heat pipe was fabricated by using oil-filled high speed spinning method. The forming process of microcapillary grooves was investigated. The influence of technical parameters on characteristics of microcapillary grooves was analyzed and the optimal technical parameters were found out. The experimental results show that drawing speed ranging from 48cm/min to 64cm/min, spinning ball number of 4 and big distance between the end of multi-tooth mandrel and the center of spinning balls within 3.7 mm should be chosen to obtain narrow and deep microcapillary grooves. In addition, the forming mechanism was investigated by observing microstructure of cross-section of microcapillary grooved tubes.

Abstract: To meet the increasing application requirements of stainless steel fibers with rough surface morphology, a self-made multi-tooth tool which can bifurcate chip during the cutting process was utilized to manufacture stainless steel fibers. The novel cutting method can achieve efficient processing of continuous stainless steel fibers with complex surface morphology. The influence of cutting parameters (back engagement ap and feed rate f ) on forming process of fibers’ surface morphology was studied. The cutting experiments were carried out under the condition of selected tool and fixed workpiece rotating speed. The results show that: the surface morphology of stainless steel fiber is simultaneously effected by ap,and feed rate f .Between them, ap has more significant effect on it. In order to obtain stainless steel continuous fibers with coarse surface morphology, the optimum cutting parameters were recommended as follows: ap∈(0.1-0.2) mm, f ∈(0.1 -0.17) mm/r.