Incremental deformation: A literature review

Abstract

Abstract. Nowadays the customer requirements are in permanent changing and according with them the tendencies in the modern industry is to implement flexible manufacturing processes. In the last decades, metal forming gained attention of the researchers and considerable changes has occurred. Because for a small number of parts, the conventional metal forming processes are expensive and time-consuming in terms of designing and manufacturing preparation, the manufacturers and researchers became interested in flexible processes. One of the most investigated flexible processes in metal forming is incremental sheet forming (ISF). ISF is an advanced flexible manufacturing process which allows to manufacture complex 3D products without expensive dedicated tools. In most of the cases it is needed for an ISF process the following: a simple tool, a fixing device for sheet metal blank and a universal CNC machine. Using this process it can be manufactured axis-symmetric parts, usually using a CNC lathe but also complex asymmetrical parts using CNC milling machines, robots or dedicated equipment. This paper aim to present the current status of incremental sheet forming technologies in terms of process parameters and their influences, wall thickness distribution, springback effect, formability, surface quality and the current main research directions.

Design and manufacturing of a fixing device for incremental sheet forming process

“…Many authors suppose that the dimensional precision of the parts manufactured using SPIF process are more over ±0.5 mm, accuracy tolerance required for most of the industrial applications [2,9]. This processing precision depends of many aspects [1] including the fixing device rigidity. When it is mounted on the CNC milling machine table, the device assembly must support the action of the process developed forces in all directions, X, Y and Z.…”

“…In terms of cold pressing processes, a flexible and in the same time a low cost production process is incremental sheet forming (ISF). It is easy to be implemented and is suitable for small batch production series, rapid prototypes or unique products from different sheet metal forming industries [1]. In ISF, the sheet metal blanks are gradual deformed by a simple forming tool and it uses or not a blank support.…”

“…When any blank support is used, the process is called two points incremental forming (TPIF) because there are two or more contacts points between tools and sheet. If the sheet is deformed only by the forming tool, without any blank support on the other side of the sheet, the process it is called single point incremental forming (SPIF) [1][2]. One of the major advantages in comparison with conventional cold processes is that the ISF processes are avoiding the expensive and complicated tools necessary to be designed and manufactured.…”

“…If for TPIF implementation is needed a blank fixing device, the negative shape of the part or a simple local blank support, that are easier to be designed and more easy to be manufactured. The SPIF process is simple, the sheet metal blank is clamped in a fixing device, and the forming tool which follows a predefined path, produces the local plastic deformation, step by step, until the final shape is obtained [1]. Thus, it can be said that ISF are die less processes whereas only a simple fixing device and a forming tool are necessary to be implemented, especially when usually, with an common design of the forming tool and fixing device allow to perform different shapes.…”

Supporting plate edge radius and internal hole diameter relation effect on the springback in incremental forming, part B

“…The limitations of IF processes are that the dimensional precision of the deformed products are affected by the springback effect [2].…”