On forces, formability and geometrical error in metal incremental sheet forming

Abstract

The present paper deals with incremental sheet forming (ISF), a metal forming process developed in the last 20 years. Main advantages characterising this technology are its high flexibility and the possibility of reducing development times and costs. ISF consists of a simple hemispherical tool, moved by a CNC machine or a robot, which locally deforms a metal sheet moving along a defined path. The desired part profile can be obtained using three ISF techniques: single point incremental forming (SPIF) and two points incremental forming (TPIF) with either negative or positive die. In this work, a part, whose geometry was chosen to be representative for sheet formability through ISF, was formed considering the different ISF techniques. Moreover, the influence on the produced part of the adopted tool path step depth increment was investigated. Experimental tests were conducted and the results were analysed in terms of forming forces, material formability, process accuracy and final part thickness.

Application of artificial cognitive system to incremental sheet forming machine tools for part precision improvement

“…1c). As a consequence, the main limit of the technology is represented by the geometrical error that can be found on the final shape [8].…”

Part precision improvement in incremental sheet forming of not axisymmetric parts using an artificial cognitive system

“…Besides these advantages, the low geometrical accuracy is one of the main drawbacks of ISF [10] and errors exceeding 1 mm are commonly observed [5,11,12]. Errors are due to the sheet springback, stretching and bending [2,5] (Fig.…”

“…In particular, improvements were obtained acting on the tool path strategy, using a counter die with a consequent reduction of the process flexibility or limiting the scallop effect (h sc in Fig. 1b) that affects the finishing of the surface in contact with the punch [11,17,18].…”

Forming force prediction and process investigation for incremental sheet forming

“…et al [52], the fracture depth for forming a 70˚ conical cone was 23 mm. The fracture depth was used by Fiorentino et al [53,54] to evaluate the effect of tool path on the process formability in TPIF with steel sheets. Ambrogio et al…”