{
    "slug": "k-factor-bend-allowance",
    "title": "钣金折弯的 K 因子与折弯补偿",
    "description": "按 DIN 6935，给出空气弯曲、压底和校模下按材料与料厚的 K 因子与中性层说明，并附 V 槽开口、90 度折弯的折弯补偿与折弯扣除算例。",
    "lang": "zh",
    "tables": [
        {
            "caption": "按材料、料厚和弯曲方式列出的 K 因子（DIN 6935 计算值 + 已发表区间）",
            "columns": [
                "材料",
                "t（mm）",
                "V 槽（mm）",
                "R_i（mm）",
                "R/t",
                "K DIN 6935",
                "K 空气弯曲（DIN ↔ 已发表）",
                "K 压底",
                "K 校模",
                "y = K·t（mm）",
                "来源"
            ],
            "rows": [
                {
                    "材料": "DC01 mild steel",
                    "t（mm）": "0.5",
                    "V 槽（mm）": "6",
                    "R_i（mm）": "0.96",
                    "R/t": "1.92",
                    "K DIN 6935": "0.40",
                    "K 空气弯曲（DIN ↔ 已发表）": "0.40–0.43",
                    "K 压底": "0.44–0.47",
                    "K 校模": "0.41–0.46",
                    "y = K·t（mm）": "0.20",
                    "来源": "S1/S2/S3"
                },
                {
                    "材料": "DC01 mild steel",
                    "t（mm）": "0.8",
                    "V 槽（mm）": "6",
                    "R_i（mm）": "0.96",
                    "R/t": "1.20",
                    "K DIN 6935": "0.34",
                    "K 空气弯曲（DIN ↔ 已发表）": "0.34–0.43",
                    "K 压底": "0.44–0.47",
                    "K 校模": "0.41–0.46",
                    "y = K·t（mm）": "0.27",
                    "来源": "S1/S2/S3"
                },
                {
                    "材料": "DC01 mild steel",
                    "t（mm）": "1.0",
                    "V 槽（mm）": "8",
                    "R_i（mm）": "1.28",
                    "R/t": "1.28",
                    "K DIN 6935": "0.35",
                    "K 空气弯曲（DIN ↔ 已发表）": "0.35–0.43",
                    "K 压底": "0.44–0.47",
                    "K 校模": "0.41–0.46",
                    "y = K·t（mm）": "0.35",
                    "来源": "S1/S2/S3"
                },
                {
                    "材料": "DC01 mild steel",
                    "t（mm）": "1.5",
                    "V 槽（mm）": "12",
                    "R_i（mm）": "1.92",
                    "R/t": "1.28",
                    "K DIN 6935": "0.35",
                    "K 空气弯曲（DIN ↔ 已发表）": "0.35–0.43",
                    "K 压底": "0.44–0.47",
                    "K 校模": "0.41–0.46",
                    "y = K·t（mm）": "0.53",
                    "来源": "S1/S2/S3"
                },
                {
                    "材料": "DC01 mild steel",
                    "t（mm）": "2.0",
                    "V 槽（mm）": "16",
                    "R_i（mm）": "2.56",
                    "R/t": "1.28",
                    "K DIN 6935": "0.35",
                    "K 空气弯曲（DIN ↔ 已发表）": "0.35–0.43",
                    "K 压底": "0.44–0.47",
                    "K 校模": "0.41–0.46",
                    "y = K·t（mm）": "0.70",
                    "来源": "S1/S2/S3"
                },
                {
                    "材料": "DC01 mild steel",
                    "t（mm）": "3.0",
                    "V 槽（mm）": "25",
                    "R_i（mm）": "4.00",
                    "R/t": "1.33",
                    "K DIN 6935": "0.36",
                    "K 空气弯曲（DIN ↔ 已发表）": "0.36–0.43",
                    "K 压底": "0.44–0.47",
                    "K 校模": "0.41–0.46",
                    "y = K·t（mm）": "1.07",
                    "来源": "S1/S2/S3"
                },
                {
                    "材料": "DC01 mild steel",
                    "t（mm）": "4.0",
                    "V 槽（mm）": "32",
                    "R_i（mm）": "5.12",
                    "R/t": "1.28",
                    "K DIN 6935": "0.35",
                    "K 空气弯曲（DIN ↔ 已发表）": "0.35–0.43",
                    "K 压底": "0.44–0.47",
                    "K 校模": "0.41–0.46",
                    "y = K·t（mm）": "1.40",
                    "来源": "S1/S2/S3"
                },
                {
                    "材料": "DC01 mild steel",
                    "t（mm）": "6.0",
                    "V 槽（mm）": "50",
                    "R_i（mm）": "8.00",
                    "R/t": "1.33",
                    "K DIN 6935": "0.36",
                    "K 空气弯曲（DIN ↔ 已发表）": "0.36–0.43",
                    "K 压底": "0.44–0.47",
                    "K 校模": "0.41–0.46",
                    "y = K·t（mm）": "2.14",
                    "来源": "S1/S2/S3"
                },
                {
                    "材料": "DX51D+Z galvanized",
                    "t（mm）": "0.8",
                    "V 槽（mm）": "6",
                    "R_i（mm）": "0.96",
                    "R/t": "1.20",
                    "K DIN 6935": "0.34",
                    "K 空气弯曲（DIN ↔ 已发表）": "0.34–0.43",
                    "K 压底": "0.44–0.47",
                    "K 校模": "0.41–0.46",
                    "y = K·t（mm）": "0.27",
                    "来源": "S1/S2/S3"
                },
                {
                    "材料": "DX51D+Z galvanized",
                    "t（mm）": "1.5",
                    "V 槽（mm）": "12",
                    "R_i（mm）": "1.92",
                    "R/t": "1.28",
                    "K DIN 6935": "0.35",
                    "K 空气弯曲（DIN ↔ 已发表）": "0.35–0.43",
                    "K 压底": "0.44–0.47",
                    "K 校模": "0.41–0.46",
                    "y = K·t（mm）": "0.53",
                    "来源": "S1/S2/S3"
                },
                {
                    "材料": "DX51D+Z galvanized",
                    "t（mm）": "3.0",
                    "V 槽（mm）": "25",
                    "R_i（mm）": "4.00",
                    "R/t": "1.33",
                    "K DIN 6935": "0.36",
                    "K 空气弯曲（DIN ↔ 已发表）": "0.36–0.43",
                    "K 压底": "0.44–0.47",
                    "K 校模": "0.41–0.46",
                    "y = K·t（mm）": "1.07",
                    "来源": "S1/S2/S3"
                },
                {
                    "材料": "304 stainless",
                    "t（mm）": "0.8",
                    "V 槽（mm）": "8",
                    "R_i（mm）": "1.60",
                    "R/t": "2.00",
                    "K DIN 6935": "0.40",
                    "K 空气弯曲（DIN ↔ 已发表）": "0.40–0.45",
                    "K 压底": "0.46–0.48",
                    "K 校模": "0.44–0.47",
                    "y = K·t（mm）": "0.32",
                    "来源": "S1/S2/S3"
                },
                {
                    "材料": "304 stainless",
                    "t（mm）": "1.5",
                    "V 槽（mm）": "16",
                    "R_i（mm）": "3.20",
                    "R/t": "2.13",
                    "K DIN 6935": "0.41",
                    "K 空气弯曲（DIN ↔ 已发表）": "0.41–0.45",
                    "K 压底": "0.46–0.48",
                    "K 校模": "0.44–0.47",
                    "y = K·t（mm）": "0.61",
                    "来源": "S1/S2/S3"
                },
                {
                    "材料": "304 stainless",
                    "t（mm）": "3.0",
                    "V 槽（mm）": "32",
                    "R_i（mm）": "6.40",
                    "R/t": "2.13",
                    "K DIN 6935": "0.41",
                    "K 空气弯曲（DIN ↔ 已发表）": "0.41–0.45",
                    "K 压底": "0.46–0.48",
                    "K 校模": "0.44–0.47",
                    "y = K·t（mm）": "1.23",
                    "来源": "S1/S2/S3"
                },
                {
                    "材料": "316L stainless",
                    "t（mm）": "1.0",
                    "V 槽（mm）": "10",
                    "R_i（mm）": "2.10",
                    "R/t": "2.10",
                    "K DIN 6935": "0.41",
                    "K 空气弯曲（DIN ↔ 已发表）": "0.41–0.45",
                    "K 压底": "0.46–0.48",
                    "K 校模": "0.44–0.47",
                    "y = K·t（mm）": "0.41",
                    "来源": "S1/S2/S3"
                },
                {
                    "材料": "316L stainless",
                    "t（mm）": "2.0",
                    "V 槽（mm）": "20",
                    "R_i（mm）": "4.20",
                    "R/t": "2.10",
                    "K DIN 6935": "0.41",
                    "K 空气弯曲（DIN ↔ 已发表）": "0.41–0.45",
                    "K 压底": "0.46–0.48",
                    "K 校模": "0.44–0.47",
                    "y = K·t（mm）": "0.82",
                    "来源": "S1/S2/S3"
                },
                {
                    "材料": "316L stainless",
                    "t（mm）": "3.0",
                    "V 槽（mm）": "32",
                    "R_i（mm）": "6.72",
                    "R/t": "2.24",
                    "K DIN 6935": "0.41",
                    "K 空气弯曲（DIN ↔ 已发表）": "0.41–0.45",
                    "K 压底": "0.46–0.48",
                    "K 校模": "0.44–0.47",
                    "y = K·t（mm）": "1.23",
                    "来源": "S1/S2/S3"
                },
                {
                    "材料": "5052-H32 aluminium",
                    "t（mm）": "0.8",
                    "V 槽（mm）": "6",
                    "R_i（mm）": "0.96",
                    "R/t": "1.20",
                    "K DIN 6935": "0.34",
                    "K 空气弯曲（DIN ↔ 已发表）": "0.34–0.40",
                    "K 压底": "0.42–0.46",
                    "K 校模": "0.38–0.44",
                    "y = K·t（mm）": "0.27",
                    "来源": "S1/S2/S3"
                },
                {
                    "材料": "5052-H32 aluminium",
                    "t（mm）": "1.5",
                    "V 槽（mm）": "12",
                    "R_i（mm）": "1.92",
                    "R/t": "1.28",
                    "K DIN 6935": "0.35",
                    "K 空气弯曲（DIN ↔ 已发表）": "0.35–0.40",
                    "K 压底": "0.42–0.46",
                    "K 校模": "0.38–0.44",
                    "y = K·t（mm）": "0.53",
                    "来源": "S1/S2/S3"
                },
                {
                    "材料": "5052-H32 aluminium",
                    "t（mm）": "3.0",
                    "V 槽（mm）": "25",
                    "R_i（mm）": "4.00",
                    "R/t": "1.33",
                    "K DIN 6935": "0.36",
                    "K 空气弯曲（DIN ↔ 已发表）": "0.36–0.40",
                    "K 压底": "0.42–0.46",
                    "K 校模": "0.38–0.44",
                    "y = K·t（mm）": "1.07",
                    "来源": "S1/S2/S3"
                },
                {
                    "材料": "6061-T6 aluminium *",
                    "t（mm）": "1.0",
                    "V 槽（mm）": "10",
                    "R_i（mm）": "1.80",
                    "R/t": "1.80",
                    "K DIN 6935": "0.39",
                    "K 空气弯曲（DIN ↔ 已发表）": "0.39–0.45",
                    "K 压底": "0.46–0.48",
                    "K 校模": "0.44–0.47",
                    "y = K·t（mm）": "0.39",
                    "来源": "S1/S2/S3"
                },
                {
                    "材料": "6061-T6 aluminium *",
                    "t（mm）": "2.0",
                    "V 槽（mm）": "20",
                    "R_i（mm）": "3.60",
                    "R/t": "1.80",
                    "K DIN 6935": "0.39",
                    "K 空气弯曲（DIN ↔ 已发表）": "0.39–0.45",
                    "K 压底": "0.46–0.48",
                    "K 校模": "0.44–0.47",
                    "y = K·t（mm）": "0.78",
                    "来源": "S1/S2/S3"
                },
                {
                    "材料": "6061-T6 aluminium *",
                    "t（mm）": "3.0",
                    "V 槽（mm）": "32",
                    "R_i（mm）": "5.76",
                    "R/t": "1.92",
                    "K DIN 6935": "0.40",
                    "K 空气弯曲（DIN ↔ 已发表）": "0.40–0.45",
                    "K 压底": "0.46–0.48",
                    "K 校模": "0.44–0.47",
                    "y = K·t（mm）": "1.20",
                    "来源": "S1/S2/S3"
                },
                {
                    "材料": "C110 copper",
                    "t（mm）": "1.0",
                    "V 槽（mm）": "8",
                    "R_i（mm）": "1.28",
                    "R/t": "1.28",
                    "K DIN 6935": "0.35",
                    "K 空气弯曲（DIN ↔ 已发表）": "0.35–0.40",
                    "K 压底": "0.42–0.46",
                    "K 校模": "0.38–0.44",
                    "y = K·t（mm）": "0.35",
                    "来源": "S1/S2/S3"
                },
                {
                    "材料": "C110 copper",
                    "t（mm）": "2.0",
                    "V 槽（mm）": "16",
                    "R_i（mm）": "2.56",
                    "R/t": "1.28",
                    "K DIN 6935": "0.35",
                    "K 空气弯曲（DIN ↔ 已发表）": "0.35–0.40",
                    "K 压底": "0.42–0.46",
                    "K 校模": "0.38–0.44",
                    "y = K·t（mm）": "0.70",
                    "来源": "S1/S2/S3"
                },
                {
                    "材料": "C260 brass",
                    "t（mm）": "1.0",
                    "V 槽（mm）": "8",
                    "R_i（mm）": "1.28",
                    "R/t": "1.28",
                    "K DIN 6935": "0.35",
                    "K 空气弯曲（DIN ↔ 已发表）": "0.35–0.40",
                    "K 压底": "0.42–0.46",
                    "K 校模": "0.38–0.44",
                    "y = K·t（mm）": "0.35",
                    "来源": "S1/S2/S3"
                },
                {
                    "材料": "C260 brass",
                    "t（mm）": "2.0",
                    "V 槽（mm）": "16",
                    "R_i（mm）": "2.56",
                    "R/t": "1.28",
                    "K DIN 6935": "0.35",
                    "K 空气弯曲（DIN ↔ 已发表）": "0.35–0.40",
                    "K 压底": "0.42–0.46",
                    "K 校模": "0.38–0.44",
                    "y = K·t（mm）": "0.70",
                    "来源": "S1/S2/S3"
                }
            ]
        },
        {
            "caption": "2 mm 低碳钢空气弯曲应该用多大 K 因子？",
            "columns": [
                "步骤",
                "量",
                "数值",
                "备注"
            ],
            "rows": [
                {
                    "步骤": "1",
                    "量": "R/t",
                    "数值": "2.0 / 2.0 = 1.00",
                    "备注": "DIN 6935：k = 0.65 + 0.5·log10(1.00) = 0.65"
                },
                {
                    "步骤": "2",
                    "量": "K = k/2",
                    "数值": "0.325",
                    "备注": "表值取整为 0.33；本算例使用未取整值"
                },
                {
                    "步骤": "3",
                    "量": "BA = (π/180)·A·(R + K·t), A = 90°",
                    "数值": "4.163 mm",
                    "备注": "1.5708 × 2.65"
                },
                {
                    "步骤": "4",
                    "量": "OSSB = (R + t)·tan(A/2)",
                    "数值": "4.000 mm",
                    "备注": "4.0 × tan 45°"
                },
                {
                    "步骤": "5",
                    "量": "Flat legs from 50/30 outside",
                    "数值": "46.000 / 26.000 mm",
                    "备注": "A_flat = 50 − OSSB，B_flat = 30 − OSSB"
                },
                {
                    "步骤": "6",
                    "量": "L = A + B + BA",
                    "数值": "76.16 mm",
                    "备注": "BD = 2×4.000 − 4.163 = 3.837；50 + 30 − 3.837 = 76.163 ✓"
                },
                {
                    "步骤": "7",
                    "量": "If CAD default K = 0.44",
                    "数值": "L = 76.52 mm (+0.361)",
                    "备注": "BA = 4.524 mm；四道弯累计约 1.4 mm"
                }
            ]
        },
        {
            "caption": "CAD 软件为什么默认 K 因子为 0.44？",
            "columns": [
                "工况",
                "用哪个 K",
                "典型值",
                "下一步"
            ],
            "rows": [
                {
                    "工况": "Ductile mild steel, air bending, R/t 0.5–3",
                    "用哪个 K": "DIN 6935 Table / formula",
                    "典型值": "0.25–0.40",
                    "下一步": "试弯，反算真实 K"
                },
                {
                    "工况": "Mild steel, CAD default, V = 6–8t",
                    "用哪个 K": "Published medium air (t–3t)",
                    "典型值": "0.43 (defaults 0.44–0.45)",
                    "下一步": "只在模具和材料匹配时使用；否则改用 DIN"
                },
                {
                    "工况": "304/316 stainless, air bending",
                    "用哪个 K": "DIN 6935 at R/t 2.0–2.2",
                    "典型值": "0.40–0.41 (316 shop data up to 0.50)",
                    "下一步": "校核回弹、开裂和模具磨损"
                },
                {
                    "工况": "5052-H32 aluminium, air bending",
                    "用哪个 K": "DIN 6935 at R/t 1.2–1.3",
                    "典型值": "0.34–0.36",
                    "下一步": "校核开裂；软态取低端"
                },
                {
                    "工况": "6061-T6 aluminium, air bending",
                    "用哪个 K": "Published hard air / DIN upper bound",
                    "典型值": "0.39–0.45",
                    "下一步": "必须试弯；T6 易裂——优先放大半径"
                },
                {
                    "工况": "C110 copper / C260 brass",
                    "用哪个 K": "DIN 6935 at R/t 1.28",
                    "典型值": "0.35",
                    "下一步": "确认退火态；硬态取上限"
                },
                {
                    "工况": "Bottoming",
                    "用哪个 K": "Published t–3t tier of the class",
                    "典型值": "0.42–0.48",
                    "下一步": "绝不要沿用空气弯曲的 K"
                },
                {
                    "工况": "Coining",
                    "用哪个 K": "Published t–3t tier of the class",
                    "典型值": "0.38–0.47",
                    "下一步": "注意已发表表中校模低于压底（见校模与压底对比问题）"
                },
                {
                    "工况": "R/t > 5",
                    "用哪个 K": "K = 0.50",
                    "典型值": "0.50",
                    "下一步": "中性层回到板厚中间"
                },
                {
                    "工况": "R/t < 0.5",
                    "用哪个 K": "DIN Table low end",
                    "典型值": "0.15–0.25",
                    "下一步": "开裂风险高——放大半径或更换材料"
                },
                {
                    "工况": "New material / new tooling / no data",
                    "用哪个 K": "Test bend, back-solve",
                    "典型值": "measured",
                    "下一步": "把实测 K 锁定到 CAD 材料库"
                }
            ]
        },
        {
            "caption": "K 因子随内半径怎么变？",
            "columns": [
                "R/t",
                "k（DIN 6935）",
                "K = k/2",
                "y/t",
                "备注"
            ],
            "rows": [
                {
                    "R/t": "0.05",
                    "k（DIN 6935）": "0.00",
                    "K = k/2": "0.00",
                    "y/t": "0.00",
                    "备注": "中性层贴内表面；有开裂风险——不要设计到这一档"
                },
                {
                    "R/t": "0.07",
                    "k（DIN 6935）": "0.06",
                    "K = k/2": "0.03",
                    "y/t": "0.03",
                    "备注": "来源表值；DIN 公式本身在此 R/t 处给出 0.07（k）——上游文档在这里自相矛盾"
                },
                {
                    "R/t": "0.10",
                    "k（DIN 6935）": "0.15",
                    "K = k/2": "0.08",
                    "y/t": "0.08",
                    "备注": ""
                },
                {
                    "R/t": "0.20",
                    "k（DIN 6935）": "0.30",
                    "K = k/2": "0.15",
                    "y/t": "0.15",
                    "备注": ""
                },
                {
                    "R/t": "0.25",
                    "k（DIN 6935）": "0.35",
                    "K = k/2": "0.18",
                    "y/t": "0.18",
                    "备注": ""
                },
                {
                    "R/t": "0.33",
                    "k（DIN 6935）": "0.41",
                    "K = k/2": "0.21",
                    "y/t": "0.21",
                    "备注": ""
                },
                {
                    "R/t": "0.50",
                    "k（DIN 6935）": "0.50",
                    "K = k/2": "0.25",
                    "y/t": "0.25",
                    "备注": ""
                },
                {
                    "R/t": "0.75",
                    "k（DIN 6935）": "0.59",
                    "K = k/2": "0.30",
                    "y/t": "0.30",
                    "备注": ""
                },
                {
                    "R/t": "1.00",
                    "k（DIN 6935）": "0.65",
                    "K = k/2": "0.33",
                    "y/t": "0.33",
                    "备注": ""
                },
                {
                    "R/t": "1.25",
                    "k（DIN 6935）": "0.70",
                    "K = k/2": "0.35",
                    "y/t": "0.35",
                    "备注": ""
                },
                {
                    "R/t": "1.50",
                    "k（DIN 6935）": "0.74",
                    "K = k/2": "0.37",
                    "y/t": "0.37",
                    "备注": ""
                },
                {
                    "R/t": "1.75",
                    "k（DIN 6935）": "0.77",
                    "K = k/2": "0.39",
                    "y/t": "0.39",
                    "备注": ""
                },
                {
                    "R/t": "2.00",
                    "k（DIN 6935）": "0.80",
                    "K = k/2": "0.40",
                    "y/t": "0.40",
                    "备注": ""
                },
                {
                    "R/t": "2.50",
                    "k（DIN 6935）": "0.85",
                    "K = k/2": "0.43",
                    "y/t": "0.43",
                    "备注": ""
                },
                {
                    "R/t": "3.00",
                    "k（DIN 6935）": "0.89",
                    "K = k/2": "0.45",
                    "y/t": "0.45",
                    "备注": ""
                },
                {
                    "R/t": "3.50",
                    "k（DIN 6935）": "0.92",
                    "K = k/2": "0.46",
                    "y/t": "0.46",
                    "备注": ""
                },
                {
                    "R/t": "4.00",
                    "k（DIN 6935）": "0.95",
                    "K = k/2": "0.48",
                    "y/t": "0.48",
                    "备注": ""
                },
                {
                    "R/t": "4.50",
                    "k（DIN 6935）": "0.98",
                    "K = k/2": "0.49",
                    "y/t": "0.49",
                    "备注": ""
                },
                {
                    "R/t": "5.00",
                    "k（DIN 6935）": "1.00",
                    "K = k/2": "0.50",
                    "y/t": "0.50",
                    "备注": "R/t ≥ 5：中性层位于板厚中间"
                }
            ]
        },
        {
            "caption": "空气弯曲、压底和校模的 K 因子有什么区别？",
            "columns": [
                "材料类别",
                "弯曲方式",
                "R = 0–t",
                "R = t–3t",
                "R > 3t"
            ],
            "rows": [
                {
                    "材料类别": "Soft (aluminium 5052, copper, brass)",
                    "弯曲方式": "Air bending",
                    "R = 0–t": "0.33",
                    "R = t–3t": "0.40",
                    "R > 3t": "0.50"
                },
                {
                    "材料类别": "Soft (aluminium 5052, copper, brass)",
                    "弯曲方式": "Bottoming",
                    "R = 0–t": "0.42",
                    "R = t–3t": "0.46",
                    "R > 3t": "0.50"
                },
                {
                    "材料类别": "Soft (aluminium 5052, copper, brass)",
                    "弯曲方式": "Coining",
                    "R = 0–t": "0.38",
                    "R = t–3t": "0.44",
                    "R > 3t": "0.50"
                },
                {
                    "材料类别": "Medium (mild steel, galvanized)",
                    "弯曲方式": "Air bending",
                    "R = 0–t": "0.38",
                    "R = t–3t": "0.43",
                    "R > 3t": "0.50"
                },
                {
                    "材料类别": "Medium (mild steel, galvanized)",
                    "弯曲方式": "Bottoming",
                    "R = 0–t": "0.44",
                    "R = t–3t": "0.47",
                    "R > 3t": "0.50"
                },
                {
                    "材料类别": "Medium (mild steel, galvanized)",
                    "弯曲方式": "Coining",
                    "R = 0–t": "0.41",
                    "R = t–3t": "0.46",
                    "R > 3t": "0.50"
                },
                {
                    "材料类别": "Hard (304/316 stainless)",
                    "弯曲方式": "Air bending",
                    "R = 0–t": "0.40",
                    "R = t–3t": "0.45",
                    "R > 3t": "0.50"
                },
                {
                    "材料类别": "Hard (304/316 stainless)",
                    "弯曲方式": "Bottoming",
                    "R = 0–t": "0.46",
                    "R = t–3t": "0.48",
                    "R > 3t": "0.50"
                },
                {
                    "材料类别": "Hard (304/316 stainless)",
                    "弯曲方式": "Coining",
                    "R = 0–t": "0.44",
                    "R = t–3t": "0.47",
                    "R > 3t": "0.50"
                }
            ]
        },
        {
            "caption": "折弯补偿怎么算？",
            "columns": [
                "术语",
                "公式",
                "读法"
            ],
            "rows": [
                {
                    "术语": "K factor",
                    "公式": "K = y / t, 0 ≤ K ≤ 0.5",
                    "读法": "中性层相对内表面的偏移量占料厚的比例"
                },
                {
                    "术语": "Neutral radius",
                    "公式": "R_neutral = R_i + K × t",
                    "读法": "真正保持长度不变的那层圆弧半径"
                },
                {
                    "术语": "Bend allowance BA",
                    "公式": "BA = (π/180) × A × (R_i + K × t)",
                    "读法": "中性层穿过弯曲区的弧长"
                },
                {
                    "术语": "Outside setback OSSB",
                    "公式": "OSSB = (R_i + t) × tan(A/2)",
                    "读法": "从尖角到折弯切点的切线长度"
                },
                {
                    "术语": "Bend deduction BD",
                    "公式": "BD = 2 × OSSB − BA",
                    "读法": "两个外角相对展开料损失的量"
                },
                {
                    "术语": "Flat length L",
                    "公式": "L = A + B + BA (flat legs); L = A_out + B_out − BD (outside dims)",
                    "读法": "K 正确时两种算法结果相同——混用 BA 和 BD 是典型的展开错误"
                },
                {
                    "术语": "Angle convention",
                    "公式": "A = 180° − included angle",
                    "读法": "90° 折弯：A = 90；内角 60°：A = 120；内角 120°：A = 60"
                }
            ]
        },
        {
            "caption": "折弯扣除怎么算？",
            "columns": [
                "情形",
                "项目",
                "数值"
            ],
            "rows": [
                {
                    "情形": "90°, t 2.0, R 2.0",
                    "项目": "OSSB = (2+2)·tan45°",
                    "数值": "4.000 mm"
                },
                {
                    "情形": "90°, t 2.0, R 2.0",
                    "项目": "BD = 2×4.000 − 4.163",
                    "数值": "3.837 mm"
                },
                {
                    "情形": "90°, t 2.0, R 2.0",
                    "项目": "L = 50 + 30 − 3.837",
                    "数值": "76.163 mm"
                },
                {
                    "情形": "A=120°, t 1.5, R 3.0, 304",
                    "项目": "K = (0.65 + 0.5·log10 2)/2",
                    "数值": "0.4003"
                },
                {
                    "情形": "A=120°, t 1.5, R 3.0, 304",
                    "项目": "BA = 2.0944 × (3 + 0.4003×1.5)",
                    "数值": "7.541 mm"
                },
                {
                    "情形": "A=120°, t 1.5, R 3.0, 304",
                    "项目": "OSSB = 4.5 × tan60°",
                    "数值": "7.794 mm"
                },
                {
                    "情形": "A=120°, t 1.5, R 3.0, 304",
                    "项目": "L = 52.206 + 32.206 + 7.541",
                    "数值": "91.95 mm"
                },
                {
                    "情形": "A=120°, t 1.5, R 3.0, 304",
                    "项目": "BD check: 60 + 40 − (2×7.794 − 7.541)",
                    "数值": "91.952 mm ✓"
                },
                {
                    "情形": "A=120°, t 1.5, R 3.0, 304",
                    "项目": "If hard-air K 0.45 instead",
                    "数值": "L = 92.11 mm (+0.156 vs DIN 0.40: 0.16 mm per bend)"
                }
            ]
        },
        {
            "caption": "2 mm 低碳钢应该用多大 V 槽开口？",
            "columns": [
                "t（mm）",
                "V（mm）",
                "R_i（mm）",
                "最小法兰（mm）",
                "吨位（t/m）",
                "来源"
            ],
            "rows": [
                {
                    "t（mm）": "0.5",
                    "V（mm）": "6",
                    "R_i（mm）": "0.96",
                    "最小法兰（mm）": "—",
                    "吨位（t/m）": "—",
                    "来源": "practical min V6, calc"
                },
                {
                    "t（mm）": "0.8",
                    "V（mm）": "6",
                    "R_i（mm）": "0.96",
                    "最小法兰（mm）": "—",
                    "吨位（t/m）": "—",
                    "来源": "S3 method, calc"
                },
                {
                    "t（mm）": "1.0",
                    "V（mm）": "8",
                    "R_i（mm）": "1.3",
                    "最小法兰（mm）": "> 5.5",
                    "吨位（t/m）": "8",
                    "来源": "S3"
                },
                {
                    "t（mm）": "1.5",
                    "V（mm）": "12",
                    "R_i（mm）": "2.0",
                    "最小法兰（mm）": "> 8.5",
                    "吨位（t/m）": "10",
                    "来源": "S3"
                },
                {
                    "t（mm）": "2.0",
                    "V（mm）": "16",
                    "R_i（mm）": "2.6",
                    "最小法兰（mm）": "> 11.0",
                    "吨位（t/m）": "12",
                    "来源": "S3"
                },
                {
                    "t（mm）": "2.5",
                    "V（mm）": "20",
                    "R_i（mm）": "3.3",
                    "最小法兰（mm）": "> 14.0",
                    "吨位（t/m）": "14",
                    "来源": "S3"
                },
                {
                    "t（mm）": "3.0",
                    "V（mm）": "25",
                    "R_i（mm）": "4.0",
                    "最小法兰（mm）": "> 17.5",
                    "吨位（t/m）": "16",
                    "来源": "S3"
                },
                {
                    "t（mm）": "4.0",
                    "V（mm）": "32",
                    "R_i（mm）": "5.0",
                    "最小法兰（mm）": "> 22.0",
                    "吨位（t/m）": "22",
                    "来源": "S3"
                },
                {
                    "t（mm）": "5.0",
                    "V（mm）": "40",
                    "R_i（mm）": "6.5",
                    "最小法兰（mm）": "> 28.0",
                    "吨位（t/m）": "27",
                    "来源": "S3"
                },
                {
                    "t（mm）": "6.0",
                    "V（mm）": "50",
                    "R_i（mm）": "8.0",
                    "最小法兰（mm）": "> 35.0",
                    "吨位（t/m）": "32",
                    "来源": "S3"
                }
            ]
        },
        {
            "caption": "304 不锈钢应该用多大 K 因子？",
            "columns": [
                "口径",
                "R≈t 处的 K",
                "适用对象",
                "来源"
            ],
            "rows": [
                {
                    "口径": "Shop-measured caliber",
                    "R≈t 处的 K": "0.46",
                    "适用对象": "304, air bending, R = t",
                    "来源": "S4"
                },
                {
                    "口径": "Shop-measured caliber",
                    "R≈t 处的 K": "0.50",
                    "适用对象": "316, air bending, R = t",
                    "来源": "S4"
                },
                {
                    "口径": "Published hard class (t–3t)",
                    "R≈t 处的 K": "0.45",
                    "适用对象": "Generic 304/316 hard tier — does not separate 304 from 316",
                    "来源": "S2/S5"
                },
                {
                    "口径": "DIN 6935 at R/t = 2",
                    "R≈t 处的 K": "0.40",
                    "适用对象": "Geometry only — no work-hardening difference",
                    "来源": "S1/S6"
                },
                {
                    "口径": "This page, Table 2",
                    "R≈t 处的 K": "0.41–0.45",
                    "适用对象": "316 takes the upper bound; test-bend",
                    "来源": "S1/S2/S3"
                }
            ]
        },
        {
            "caption": "5052 铝应该用多大 K 因子？",
            "columns": [
                "口径",
                "K",
                "适用对象",
                "来源"
            ],
            "rows": [
                {
                    "口径": "Shop-measured (R = t)",
                    "K": "0.33",
                    "适用对象": "5052-H32, air bending",
                    "来源": "S4"
                },
                {
                    "口径": "Published soft air (t–3t)",
                    "K": "0.40",
                    "适用对象": "Generic soft aluminium",
                    "来源": "S2/S5"
                },
                {
                    "口径": "DIN 6935 (R/t = 1.2)",
                    "K": "0.345",
                    "适用对象": "Geometry only",
                    "来源": "S1/S6"
                },
                {
                    "口径": "This page, Table 2",
                    "K": "0.34–0.40",
                    "适用对象": "Soft temper low end, hard temper or wide V high end",
                    "来源": "S1/S2/S3"
                }
            ]
        },
        {
            "caption": "所有料厚能共用一个 K 因子吗？",
            "columns": [
                "t（mm）",
                "V（mm）",
                "R_i（mm）",
                "R/t",
                "K DIN 6935"
            ],
            "rows": [
                {
                    "t（mm）": "0.5",
                    "V（mm）": "6",
                    "R_i（mm）": "0.96",
                    "R/t": "1.92",
                    "K DIN 6935": "0.40"
                },
                {
                    "t（mm）": "0.8",
                    "V（mm）": "6",
                    "R_i（mm）": "0.96",
                    "R/t": "1.20",
                    "K DIN 6935": "0.34"
                },
                {
                    "t（mm）": "2.0",
                    "V（mm）": "16",
                    "R_i（mm）": "2.56",
                    "R/t": "1.28",
                    "K DIN 6935": "0.35"
                },
                {
                    "t（mm）": "3.0",
                    "V（mm）": "25",
                    "R_i（mm）": "4.00",
                    "R/t": "1.33",
                    "K DIN 6935": "0.36"
                },
                {
                    "t（mm）": "6.0",
                    "V（mm）": "50",
                    "R_i（mm）": "8.00",
                    "R/t": "1.33",
                    "K DIN 6935": "0.36"
                }
            ]
        },
        {
            "caption": "怎么测量我这台折弯机的真实 K 因子？",
            "columns": [
                "步骤",
                "规则",
                "数值"
            ],
            "rows": [
                {
                    "步骤": "1",
                    "规则": "Strip",
                    "数值": "200 × 50 mm, bend at 90° mid-length"
                },
                {
                    "步骤": "2",
                    "规则": "Measure both outside flanges A_out + B_out",
                    "数值": "BD = 200 − (A_out + B_out)"
                },
                {
                    "步骤": "3",
                    "规则": "Back-solve",
                    "数值": "K = [2(R+t)tan(A/2) − BD] / [(π/180)·A·t] − R/t"
                },
                {
                    "步骤": "4",
                    "规则": "Write into CAD material library",
                    "数值": "per material + tooling pair"
                }
            ]
        },
        {
            "caption": "折弯时中性层在哪里？",
            "columns": [
                "情形",
                "K",
                "t（mm）",
                "y = K·t（mm）",
                "中性层半径"
            ],
            "rows": [
                {
                    "情形": "DC01 2.0 mm, R/t 1.28",
                    "K": "0.35",
                    "t（mm）": "2.0",
                    "y = K·t（mm）": "0.70",
                    "中性层半径": "R + 0.70 mm（R_i 2.56 → 中性层 3.26 mm）"
                },
                {
                    "情形": "DC01 3.0 mm, R/t 1.33",
                    "K": "0.36",
                    "t（mm）": "3.0",
                    "y = K·t（mm）": "1.07",
                    "中性层半径": "R + 1.07 mm"
                },
                {
                    "情形": "304 1.5 mm, R/t 2.13",
                    "K": "0.41",
                    "t（mm）": "1.5",
                    "y = K·t（mm）": "0.61",
                    "中性层半径": "R + 0.61 mm"
                },
                {
                    "情形": "DC01 6.0 mm, R/t 1.33",
                    "K": "0.36",
                    "t（mm）": "6.0",
                    "y = K·t（mm）": "2.14",
                    "中性层半径": "R + 2.14 mm"
                }
            ]
        },
        {
            "caption": "为什么校模有时比压底 K 更低？",
            "columns": [
                "方法",
                "Soft K（t–3t）",
                "Medium K（t–3t）",
                "Hard K（t–3t）",
                "来源"
            ],
            "rows": [
                {
                    "方法": "Bottoming",
                    "Soft K（t–3t）": "0.46",
                    "Medium K（t–3t）": "0.47",
                    "Hard K（t–3t）": "0.48",
                    "来源": "S2/S5"
                },
                {
                    "方法": "Coining",
                    "Soft K（t–3t）": "0.44",
                    "Medium K（t–3t）": "0.46",
                    "Hard K（t–3t）": "0.47",
                    "来源": "S2/S5"
                },
                {
                    "方法": "Expectation",
                    "Soft K（t–3t）": "—",
                    "Medium K（t–3t）": "—",
                    "Hard K（t–3t）": "—",
                    "来源": "—"
                },
                {
                    "方法": "Second source confirming the ranking",
                    "Soft K（t–3t）": "none found",
                    "Medium K（t–3t）": "none found",
                    "Hard K（t–3t）": "none found",
                    "来源": "GAP"
                }
            ]
        }
    ]
}