Systems and methods for improving backward flow forming of shafts
An apparatus for backward flow forming a material may comprise a mandrel having a headstock at a proximate end of the mandrel, the mandrel configured to rotate about an axis, a plurality of rollers disposed radially outward of the mandrel configured to exert force on the material to form a work piece at a plastic deformation zone, wherein the work piece flows from the plastic deformation zone between the plurality of rollers and the mandrel toward a distal end of the mandrel, and a catcher, coaxial to the mandrel, and removably coupled to the work piece at a traveling end of the work piece.
1. A method, comprising:
mounting a material in an apparatus for backward flow forming;
performing a backward flow forming step by operation of the apparatus, the backward flow forming step comprising:
applying a load to a plurality of rollers forming a plastic deformation zone in the material between the plurality of rollers and a mandrel, the mandrel defining a rotational axis;
advancing the plurality of rollers toward a headstock at a proximate end of the mandrel forming a work piece from the material, wherein the work piece flows from the plastic deformation zone between the plurality of rollers and the mandrel toward a distal end of the mandrel;
machining a coupling feature in the work piece proximate a traveling end of the work piece;
coupling the coupling feature of the work piece to a catcher at the traveling end of the work piece; and
oscillating the catcher rotationally with respect to the rotational axis and tending thereby to cause the traveling end of the work piece to deflect relative to the rotational axis; and
after the backward flow forming step, excising and discarding the coupling feature.
2. The method of claim 1 , further comprising applying a tension, defined between the catcher and the plastic deformation zone, at the traveling end of the work piece.
3. The method of claim 2 , wherein the coupling comprises clamping the work piece to the catcher.
4. The method of claim 2 , further comprising deflecting the traveling end of the work piece with respect to an axis of the mandrel to form a deflection.
5. The method of claim 4 , wherein the deflection with respect to the axis of the mandrel is 5° to 15.
6. The method of claim 4 , further comprising forming shear banding within the material at the plastic deformation zone in response to forming the deflection.