EXTENDED FORMABILITY LIMITS FOR TUBULAR COMPONENTS THROUGH COMBINED INJECTION FORMING UPSETTING - A FINITE-ELEMENT ANALYSIS

In the injection forming/upsetting of tabular parts the ratio between inner and outer diameters of the tube, the ratio between wall thicknes s and gap height, together with the design of the die chamber are impo rtant dimensional parameters that determine the final geometry of a co mponent. Recent published work in this field opened a breakthrough in the understanding of the limits for obtaining sound components without folds. However, some difficulties were still encountered, namely in w hat concerns avoiding the presence of undesirable models of deformatio n. The paper presents comprehensive modelling of previous experimental work in this field, which leads to a re-examination of the process me chanics. This effort resulted in the development of a combined injecti on forming/upsetting technique. Numerical simulations performed using this technique indicate that a large extension of the formability limi t for tubular components is possible.