Calculation of parameters of drawing-out the half-sphere parts in the stamp with an elastic element

Abstract

The method of forming parts of a half-sphere type in a stamp, where a die is the generatrix of the part, is presented. This is attained due to the use of an elastic steel element arranged along the puncheon contour in the stamp design. This process scheme makes it possible to combine drawing out and calibration in one stamp. Calibration when drawing out spherelike parts is necessary because of the fact that a large segment free of contact with the puncheon and a die, on which the billet losses stability and starts to corrugate, is formed in a billet. An elastic element made of spring steel and arranged along the contour of a rigid puncheon calibrates the part at the final drawing-out stage. The schematic of stamping for a half-spherical part with relative thickness S' = S/D₀ × 100% = 1.5–0.15 is presented in the article. In that work calculations of elastic element’s geometrical parameters were made. To develop semi sphere part from aluminum alloy 5056 with thickness elastic element made of steel 1060 was designed. Dimension of gap between punch and elastic element was determined as well. Maximum values of strengths happened in elastic element during stamping were calculated. It was investigated that elastic element do not have plastic flow deformation. Use of elastic element helps to produce parts with accurate geometrical dimensions and compensate elastic restitution. Also due to increase of friction elastic element allows block weakest section.