Abstract: Induction assisted single point incremental forming
(IASPIF) is a flexible method and can be simply utilized to
form a high strength alloys. Due to the interaction between the
mechanical and thermal properties during IASPIF an evaluation for
the process is necessary to be performed analytically. Therefore, a
numerical simulation was carried out in this paper. The numerical
analysis was operated at both room and elevated temperatures
then compared with experimental results. Fully coupled dynamic
temperature displacement explicit analysis was used to simulated the
hot single point incremental forming. The numerical analysis was
indicating that during hot single point incremental forming were a
combination between complicated compression, tension and shear
stresses. As a result, the equivalent plastic strain was increased
excessively by rising both the formed part depth and the heating
temperature during forming. Whereas, the forming forces were
decreased from 5 kN at room temperature to 0.95 kN at elevated
temperature. The simulation shows that the maximum true strain was
occurred in the stretching zone which was the same as in experiment.
Abstract: Multi-point forming (MPF) and asymmetric incremental forming (ISF) are two flexible processes for sheet metal manufacturing. To take advantages of these two techniques, a hybrid process has been developed: The Multipoint Incremental Forming (MPIF). This process accumulates at once the advantages of each of these last mentioned forming techniques, which makes it a very interesting and particularly an efficient process for single, small, and medium series production. In this paper, an experimental and a numerical investigation of this technique are presented. To highlight the flexibility of this process and its capacity to manufacture standard and complex shapes, several pieces were produced by using MPIF. The forming experiments are performed on a 3-axis CNC machine. Moreover, a numerical model of the MPIF process has been implemented in ABAQUS and the analysis showed a good agreement with experimental results in terms of deformed shape. Furthermore, the use of an elastomeric interpolator allows avoiding classical local defaults like dimples, which are generally caused by the asymmetric contact and also improves the distribution of residual strain. Future works will apply this approach to other alloys used in aeronautic or automotive applications.
Abstract: In sheet metal forming process, raw material
mechanical properties are important parameters. This paper is to
compare the wall’s incline angle or formability of SS 400 steel and
SUS 304 stainless steel in single point incremental forming. The two
materials are ferrous base alloyed, which have the different unit cell,
mechanical property and chemical composition. They were forming
into cone shape specimens having 100 mm diameter with different
wall’s incline angle: 90o, 75o and 60o. The investigation was
continued until the specimens formed surface facture. The
experimental result showed that the smaller the wall incline angle
higher the formability with the both materials. The formability limit
of the ferrous base alloy was approx. 60o wall’s incline angle. By
nature, SS 400 has higher formability than SUS 304. This result can
be used as the initial data in designing the single point incremental
forming parts.
Abstract: Asymmetric incremental sheet forming (AISF) could significantly reduce costs incurred by the fabrication of complex industrial components with a minimal environmental impact. The AISF experiments were carried out on commercially pure titanium (Ti-Gr2), Timetal (15-3-3-3) alloy, and Ti-6Al-4V (Ti-Gr5) alloy. A special testing geometry was used to characterize the titanium alloys properties from the point of view of the forming zone and titanium structure effect. The structure and properties of the materials were assessed by means of metallographic analyses and microhardness measurements.The highest differences in the parameters assessed as a function of the sampling zone were observed in the case of alpha-phase Ti-Gr2at the expense of the most substantial sheet thinning occurrence. A springback causes a smaller stored deformation in Timetal (β alloy) resulting in less pronounced microstructure refinement and microhardness increase. Ti-6Al-4V alloy exhibited early failure due to its poor formability at ambient temperature.
Abstract: Shear spinning is closely related to the asymmetric incremental sheet forming (AISF) that could significantly reduce costs incurred by the fabrication of complex aeronautical components with a minimal environmental impact. The spinning experiments were carried out on commercially pure titanium (Ti-Gr2) and Ti-6Al-4V (Ti-Gr5) alloy. Three forming modes were used to characterize the titanium alloys properties from the point of view of different spinning parameters. The structure and properties of the materials were assessed by means of metallographic analyses and microhardness measurements. The highest value wall angle failure limit was achieved using spinning parameters mode for both materials. The feed rate effect was observed only in the samples from the Ti-Gr2 material, when a refinement of the grain microstructure with lower feed rate and higher tangential speed occurred. Ti-Gr5 alloy exhibited a decrease of the microhardness at higher straining due to recovery processes.
Abstract: Incremental forming is a complex forming process with
continuously local cumulative deformation taking place during its
process, and springback that forming quality affected by would occur.
The springback evaluation method based on forming error
compensation also was proposed, which it can be defined as the
difference between theory and the actual amount of compensation
along the measured direction. According to forming error
compensation evaluation method, experiments was designed and
implemented. And from the results that obtained it can be show, the
magnitude of springback average (δE) of formed parts was very small,
and the forming precision could be significantly improved by adopting
compensation method. Based on double tensile stress state in the main
deformation area, a hypothesis that there is little springback be arisen
by bending behavior on the formed parts that was proposed.