Incremental Forming of Hollow Shapes

Abstract

Hollow shapes, particularly the shafts of road vehicle power trains, are a major potential for technical innovation since these components have to be especially strong while component weight and unit costs are highly restrictive. This strategy for innovation requires focusing on a wide range of disciplines of product and technology development and demands intensive and advanced interdisciplinary development of the required production technology. Hollow shapes can be produced with the spin extrusion process. Spin extrusion is a flexible rotatory pressure forming process which can be applied in dimensional ranges that cannot be attained by comparable processes, not in a cost‐effective fashion or for very expensive materials. Spin extrusion is an incremental technique, meaning there are also the known difficulties standing in the way of analytically describing processes and targeted process control. The energetic approach has proved to be the most practicable because it makes it possible to differentiate between a wide range of factors and parameters having an impact on the process while applying them to machine and process control. The results of process development was a new processing principle for manufacturing hollow shaft components by forming for specific needs of the automobile industry and other industries with major accuracy and safety requirements.

Influence of work hardening ratio of parent tube on undershooting phenomenon in cold tube extrusion

“…The lubricant used was an ordinary mineral oil. Before and after the experiments, the outside diameter of the pipes was measured using a caliper gauge.The amount of undershooting D is given by equation (2) D~D t ÀD d (2) where D t and D d are the outside diameter of cold extruded tube and the inside diameter of the bearing portion of die respectively. The measured decrease in the outside diameter of pipe, which is the intensity of undershooting and is defined by the outside diameter of cold extruded pipe subtracted by the inside diameter of the bearing portion of the die, is plotted against the mechanical property of the parent material in Fig.…”

“…Parts that have round geometry used for rotating parts are no exception and trials adopt steel pipes for these parts instead of steel bars. 1 In Europe, hollow parts have been adopted for a limited portion of rotary parts, 2 but not all the solid rotary parts have been replaced by hollow parts manufactured from pipes. Normally, the diameter of these hollow parts changes in the axial direction 3 and there is not an established method for manufacturing them with reasonable precision 4 and cost.…”

Characterisation of high strain rate material behaviour for high-speed forming and cutting applications

“…Regarding strain rate depending material behaviour Psyk et al has shown in [4] that forming with high strain rates can lead to extended forming limits. In addition, high velocity allows much more geometrically complex shapes [5]. Modelling high speed processes in detail requires suitable data of the plastic flow and failure behaviour for high strain rates [6].…”