Blank-holder Force & Wrinkle Prevention
压边力控制与防皱
标签：压边圈, 防皱, 起皱阈值, 压边力曲线
压边力过小，凸缘区切向压应力使材料失稳起皱；过大则增加拉裂风险。经验公式 F_hold ≈ π/4·(D₀²−d²)·q，单位压边力 q 铜取 1.5–2.5 MPa。采用"拉深筋"或阶梯压边可随行程增大压边力，兼顾防皱与减阻，是深拉深模具常用设计。
Too little blank-holder force lets flange tangential compression cause wrinkling; too much raises fracture risk. Rule of thumb F_hold ≈ π/4·(D₀²−d²)·q, with specific pressure q≈1.5–2.5 MPa for copper. Draw beads or a stepped blank-holder that increases force with stroke balance wrinkle control against friction—a common deep-draw die design. ---