Production of Special Tubes with a Variety Cross-Sectional Shapes by Bunch Drawing and Fluid-Mandrel Drawing

Abstract:

Recently, special tubes for high efficiency heat exchangers, high functionality electrodes, and super-micro medical needles have attracted attention. In order to produce such special tubes, however, a special processing method or tool is required. In this study, fabrication of special tube by bunch drawing and fluid-mandrel drawing were attempted. And it was revealed that the fabrication of special tubes with a variety of cross-sectional shape is possible, when a bunch of tubes, or a tube of large diameter in which a number of fine tubes are inserted, is drawn. Presumption of cross-sectional shapes after bunch drawing was examined by FE analysis. Cross-sectional shapes and the distribution of Vickers hardness which has relation to equivalent strain were compared between tubes obtained virtually by FE analysis and fabricated actually in this study. It was found that they correspond very well and FE analysis is useful for the presumption of cross-sectional shapes after bunch drawing. Meanwhile, downsizing of medical needles and heat exchanger tubes has been required from the market. So it is necessary to fabricate an inner-grooved fine tube with thin wall-thickness, and at that time the inner grooved geometry must be homothetic. Hollow sinking was carried out to reduce the diameter of a tube. And cross-sectional shape, groove geometry, and the change of wall thickness after processing were examined. In hollow sinking, increase of wall-thickness, change of inner groove geometry, and poor inner surface quality were found. Therefore, newly-devised fluid-mandrel drawing was applied. And it was revealed that it is possible to obtain an inner grooved tube of which groove shape is nearly similar to that of pre-processed tube, even after the processing of diameter reduction. Also, it was clarified that the production of a medical painless needle of 0.2mm in diameter by fluid-mandrel drawing was possible.

• Periodical: Key Engineering Materials (Volumes 622-623)
• Pages: 731-738
• DOI: https://doi.org/10.4028/www.scientific.net/KEM.622-623.731
• Online since: September 2014
• Authors: Kazunari Yoshida*, Daichi Yokomizo, Takaaki Komatsu
• Keywords: Bunch Drawing, Fine Medical Needle, Fluid-Mandrel Drawing, Special Tube

References

[1] T. Furushima, et al.: Journal of Japan Institute of Copper, 46 (2007) pp.111-115.

[2] K. Yoshida, et al.: Proceedings of Conference on Materials and Processing Division of the Japan Society of Mechanical Engineers, 14 (2006) pp.173-174.

[3] The Japan Society for Technology of Plasticity: Encyclopedic Knowledge of Manufacturing –from hypodermic needles to aluminum foil- (1992, Corona Publishing Co., Ltd. )pp.2-3.

[4] K. Yoshida, et al.: Basis of Plastic Processing (1988, Sangyo Tosho Publishing Co., Ltd. ) pp.64-65.

[5] T. Furushima, et al.: Surface properties of microtubes fabricated by superplastic dieless drawing, Proceedings of 2005 Annual Conference of the Japan Society of Mechanical Engineers (2005) pp.623-624.