Robotic Die-Less Forming Strategy for Fiber-Reinforced Plastic Composites Production

Die-less forming of fiber-reinforced thermoplastic sheets and metal wire mesh

“…While the basic idea is comparable to Double-Sided Incremental Forming (DSIF), the organo sheet is clamped at a single point fixation only, to allow the fibers to be movable for the draping operations [27]. As any additional actuated gripper systems for the application of tension would add further complexity, we developed a draping strategy which mainly relies on the two tools deforming the fabric out-ofplane relative to a single point fixation [28]. The location of this fixation point on the sheet as well as the initial fiber orientations are selected by minimizing the global amount of shear in a kinematic draping simulation of the final geometry.…”

“…Thereby, as the fabric is locally bent, compressive in-plane stresses can be introduced into the area between already formed paths. These compressive stresses lead to in-plane deformation in the form of shear [28]. Therefore, the desired shear distribution is the main sequencing criterion in determining the order of forming.…”

“…Therefore, the desired shear distribution is the main sequencing criterion in determining the order of forming. As shear is added while the curvature increases and it is hardly reversible, forming paths requiring least shear are formed first [28]. The length of the forming paths can be set according to two different principles, depicted in Fig.…”

“…To conclude, a real die-less process for forming woven FRTP into complex, doubly-curved shapes while considering the actual material behavior and draping requirements would be desirable. Preliminary investigations on manufacturing options [27] and the development of a dieless draping strategy [28] showed that feasible process concepts exist. In the following, we will briefly outline this forming strategy and present a new die-less forming concept for woven FRTP.…”

Die-Less Forming of Fiber-Reinforced Plastic Composites

“…The die-less forming processes shall make use of just two robot guided standard tools similar to DSIF, which form and solidify small areas of the FRP while moving along tool paths determined according to a forming strategy published elsewhere [20]. The paths follow the required fiber orientations from an already rigid starting point until the edge of the fabric.…”