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Nowadays, single point incremental forming (SPIF) is a widely studied process and a lot is known about advantages and drawbacks arising from its use in sheet manufacturing. Not homogeneous material thinning along the formed walls is one of the process limitations. If this were reduced, the product quality would benefit with a possible increment of its industrial applications. Furthermore, products in service must resist not homogeneous loads. Therefore, a customized thickness distribution could be useful for a stress homogenization allowing, at the same time, the part weight reduction. The thinning of the sheet in SPIF can be altered using tailored blanks, whose resistance can be modified, appropriately, by changing their thickness by additive, subtractive or forming techniques or by heat treatments, which can affect their microstructures, locally. Implicit 3D numerical simulations have been used to highlight the effects of the proposed idea. Specifically, sheets with weakened zones have been modeled. The tailored sheets have been designed introducing pockets with different size, depth or position on the blank surface. A benchmark shape, i.e. a frustum of a cone, was the manufactured shape. The numerical results proved that the thickness distribution along the formed wall, typically of SPIF, can be altered if the process is performed on a sheet with a not homogeneous strength. Pockets placed, even far from the working area, can affect the sheet formability. This consequence can be exploited to avoid localized thinning or to concentrate the deformation in an area, which will be trimmed out or that will be under load in service. The obtained results must be confirmed for more complex shapes, using also experimental validations, to assess the relevance of this procedure in the improvement of components made by SPIF. [ABSTRACT FROM AUTHOR]

Despite innovative processes have been introduced in manufacturing field, some traditional ones are still utilised due to their advantages in terms of cheapness and assessment. Among them deep drawing represents a very diffuse process for manufacturing of several typologies of goods, ranging from automotive components to house products. The main drawback of deep drawing is the low Limit Drawing Ratio which imposes slow and expensive annealing stages when high strain is required. For this reason new effective processes such as the hydro-assisted ones have been proposed. An alternative way is to optimise the process by superimposing a thermal field on the sheet, using a simpler equipment. From an industrial point of view, in fact, the tooling cheapness is always a requested issue. In the paper the latter strategy has been experimentally implemented, obtaining interesting results in terms of formability. Furthermore the process was accurately simulated by using a modern finite element code. The process mechanics is accurately analysed and discussed. © 2004 American Institute of Physics [ABSTRACT FROM AUTHOR]

The request of highly differentiated products and the need of process flexibility have brought the researchers to focus the attention on innovative sheet forming processes. Industrial application of conventional processes is, in fact, economically convenient just for large scale productions; furthermore conventional processes do not allow to fully satisfy the mentioned demand of flexibility. In this contest, single point incremental forming (SPIF) is an innovative and flexible answer to market requests. The process is characterized by a peculiar process mechanics, being the sheet plastically deformed only through a localised stretching mechanism. Some recent experimental studies have shown that SPIF permits a relevant increase of formability limits, just as a consequence of the peculiar deformation mechanics. The research here addressed is focused on the theoretical investigation of process mechanics; the aim was to achieve a deeper understanding of basic phenomena involved in SPIF which justify the above mentioned formability enhancing. © 2004 American Institute of Physics [ABSTRACT FROM AUTHOR]

In the last years, the growing role of process flexibility in modern mechanical industries has driven a rising interest in optimisation of process/product design through innovative techniques. Moreover, the development of niche productions, which are characterised by low production volumes and small batches leads to the need of more flexible and rapid forming technologies. In this way, a great research effort is performed towards the study of new stamping processes: among them hydro forming finds a large interest in automotive industry since it allows to significantly reduce tooling costs and also to avoid some secondary operations. Different studies are available in the technical literature concerning the fundamentals of tube hydro forming processes as well as the industrial application of such operations. As process design issues are concerned, in the paper, the authors propose the integration of different tools, namely artificial intelligence techniques, numerical simulations and experimental knowledge to carry out tube hydro forming design. A fuzzy system was integrated with a FEM code for process simulation obtaining a sort of closed loop control system to be utilised in the process design phase. An experimental validation of the design procedure was developed as well proving the effectiveness of the proposed approach in order to obtain defect free components both as geometrical features and ductile fractures are concerned. © 2004 American Institute of Physics [ABSTRACT FROM AUTHOR]