Production industry, especially in high wage countries, iscuirently challenged by a highly dynamic environment, whichleads to development and manufacture of products at anincreasing level of flexibility while maintaining high qualityand low costs [1]. For flexible sheet metal production systemscomputationally-numerically-controlled (CNC) IncrementalSheet metal Forming (ISF) has gained importance since theearly 1990s [2]. The ever since achieved technological im-provements and technology extensions enables manufacturing
of components for industrial applications. In addition thecomplete process chain may now be executed within singlemachine set-up with short ramp-up times [3].To fiilly cover the complete process chain (conventionallyconsisting of drawing, trimming and. flanging operations) viaISF ftmdamental process understanding of finishing operationssuch as flanging (i.e. incremental flanging) is mandatory. Recentresearch showed high technological potential of incrementalflanging operations in terms of flexibility and process limits butalso revealed deficits in geometiical accuracy. The absence ofsurrounding material and local load in ofi&et to the flange edge inincremental flanging operations allow the formation of unwmtedbulges in the flange shoulder area that cannot be avoided solelyby adapted tool path strategies [4], Allwocxi et al [5] presents anapproach to reduce this phenomenon by introducing partial cut-outs to locally weaken the sheet blank. Even though this idea
theoretically seems promising, the conducted study showed mi-nor impact on the overdl geometrical accuracy. Hence additionaltooling seems required for reduction of these bulges.

This paper presents the state of the art of incremental flang-ing operations and the influences of flange length and radius.Subsequently, various blank holder concepts (static and adap-tive) are presented and compared with respect to their potentialfor bulge reduction. Finally, the most promising concept is putinto practice and validated by experimental trials.