Surface reconstruction for incremental forming

Abstract

In spite of extensive efforts being made with regard to virtual process optimization technology, the production of prototype parts is still a necessity. With respect to the production of sheet metal parts in low quantities, incremental sheet metal forming (ISMF) is a highly interesting process. ISMF allows the production of complex parts with drastically reduced costs in tooling and machinery compared to conventional processes like deep drawing. However, ISMF, with it's incremental nature, introduces the need for generating a tool path considering both final geometry and process-induced deviations or constraints. Consequently, for the generation of the tool path a (tool path) surface, with an adequate offset, is necessary. That is why, within the scope of extensive research work at the Institute of Forming Technology and Lightweight Construction (IUL), a special correction module has been developed, determining this offset e.g. depending on the workpiece geometry. This paper presents the algorithm, the application, and the effect on the produced parts. Furthermore, a concept for an extension regarding further constraints like elastic workpiece behavior is presented.

Optimization of relative tool position in accumulative double sided incremental forming using finite element analysis and model bias correction

“…1b), addresses this issued by using one tool on either side of the sheet, each tool moving along a predefined tool path to deform the sheet locally, giving the sheet a desired global shape as a result of the accumulation of these local deformations (Malhotra et al [9], Meier et al [10], and Tekkaya et al [11]). Even though DSIF produces parts with better geometric accuracy than SPIF, it still does not give an accurate enough geometric compared to the desired shape.…”

“…Fig. 1 Schematics of (a) SPIF (b) DSIF (c) ADSIF and (d) geometric accuracy obtained by these three approaches [11,12] ADSIF (Fig. 1c) is a new tool path strategy developed by this group [12,13], which deforms the sheet from the inner to outer circumferences without the tools moving in the Z-direction.…”

Design and validation of a fixture for positive incremental sheet forming

“…4 pillars: Four pillars serving as guide rails and fixture free to move vertically. 4. Scissors: Scissors design takes sheet holder down with pin in the middle.…”

“…Typically a multi-axis CNC machine with a hemispherical tipped tool and sheet clamper is used for ISF [2]. Although frequently referred to as being a die-less process [3]such configurations are the exception rather than the rule [4]. More generally dies are used and ISF process can be categorized by the convexity of tooling used [ Figure 1] [5].…”

Enhancement of process capabilities in electrically-assisted double sided incremental forming

“…Concerning the improvement of geometrical accuracy, Tekkeya et al [28] presented a surface reconstruction algorithm to minimize geometrical deviations. Macari et al [29] suggested a few strategies to improve the accuracy including use of a flexible support, application of a counter force, backdrawing incremental forming and use of optimized trajectories.…”