Bending method for producing special-shaped part of bucket side plate of U-shaped bucket dumper by using high-strength steel plate

The invention discloses a bending method for producing a special-shaped part of a bucket side plate of a U-shaped bucket dumper by using a high-strength steel plate. According to the bending method, a board is bent, processed and formed for three times by adopting specially-produced upper die and lower die, wherein the specially-produced upper die comprises a die head and a die shank; the die shank and the die head are connected by a connecting seat; a plurality of thread adjusting lead screws are arranged on the connecting seat; roller seats are arranged at the front ends of the lead screws; a plurality of rollers are arranged on the roller seats; the specially-produced lower die is provided with a die holder; and a bent V-shaped groove is formed in the upper surface of the die holder. The bending method comprises the following steps of mounting the upper die and the lower die on a numerical control bender; and then discharging, determining three bending parts, bending at the first part, bending at the third