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The undeformed parts of the billets are always open in extrusion deformation, and have little influence by female dies, this technology is called open-extrusion. At room temperature, it is called open-die cold extrusion.Open-die cold extrusion is a high efficiency, energy and materials saving technology. Comparing to other types of cold extrusion, it has simple die structure, low forming force, simple technology process, no pollution, suitable for mass production characteristics. Thus, since the 1970s, people want high product quality with the developing of home appliance and automobile, open-die cold extrusion technology has a rapid development in industrially developed countries.Solid shafts and thick-walled tubes are widely used in industrial production, which are the most suitable parts machined by using open-die cold extrusion technology, and it is necessary to use open-die cold extrusion technology. In this paper, the Slab Method and upper bound method are used to have mathematical model of solid shaft and thick-walled tube in open-die cold extrusion progress. And studied influence of friction coefficient, die angle, and material yield strength on the extrusion power and the maximum deformation extent, got the influence curve of every factor. This paper studied the calculation method of optimum die angle in theory, which were compared to the experimental results, providing a theory basis for choosing appropriate extruding press, and be in favor for getting the optimal parameter combination, which can reduce extruding force and expand the application fields. The motor shaft open-die cold extrusion processing were studied, and the process flows was given. Compare with traditional machining processes, open-die cold extrusion technology has advantages in saving materials and improve processing efficiency, etc. Numerical simulation method is used to study the flow of metal under different combinations of the parameters when step fillets were machining. Compare with the experimental data, the numeric area of deformation extent and Radius of curvature in open-die cold extrusion were given.
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