The main problem of this U-bolt part is to solve the springback problem, so after the U-bolt part is bent, the die should move left and right inward to press the part, so that the two sides of the U-bolt part are inclined inward, and the opening is narrowed to solve the springback problem . According to this idea, we have designed this set of molds by improving the working principle of traditional bending molds for bending parts less than 90° and hinges.
Process calculation:
(1) When calculating the unfolded length of the curved part blank, when the bar is bent, when the bending radius r≥1.5d, that is, 19≥12 (1.5×8), the cross section of the bending part has almost no change, and the neutral layer coefficient x is approximately 0.5. The expanded length of the blank can be calculated as follows:
(2) The radius of the punch bending fillet is determined. When the relative bending radius is small (r/t<10), the bending center angle changes after bending, but the bending radius does not change much.
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(3) Determine the fillet radius of the die. Generally, the fillet radius of the die should not be less than 3mm, so as to avoid scratches on the surface of the material during bending.
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Formulation process: blanking φ7mm×149mm (J23-10 press) → thread rolling M8 (thread rolling machine Z28-40C) → U-shaped bending forming (J23-40 press).
