{
    "slug": "k-factor-bend-allowance",
    "title": "Facteur K et développé pour le pliage de tôle",
    "description": "Facteurs K par matériau et épaisseur pour le pliage à l'air, le pliage à fond et le frappage selon DIN 6935, avec des exemples calculés de développé et de déduction pour des plis à 90 degrés.",
    "lang": "fr",
    "tables": [
        {
            "caption": "Facteurs K par matériau, épaisseur et méthode de pliage (DIN 6935 calculé + fourchettes publiées)",
            "columns": [
                "Matériau",
                "t (mm)",
                "Matrice V (mm)",
                "R_i (mm)",
                "R/t",
                "K DIN 6935",
                "K air (DIN ↔ publié)",
                "K à fond",
                "K frappage",
                "y = K·t (mm)",
                "Source"
            ],
            "rows": [
                {
                    "Matériau": "DC01 mild steel",
                    "t (mm)": "0.5",
                    "Matrice V (mm)": "6",
                    "R_i (mm)": "0.96",
                    "R/t": "1.92",
                    "K DIN 6935": "0.40",
                    "K air (DIN ↔ publié)": "0.40–0.43",
                    "K à fond": "0.44–0.47",
                    "K frappage": "0.41–0.46",
                    "y = K·t (mm)": "0.20",
                    "Source": "S1/S2/S3"
                },
                {
                    "Matériau": "DC01 mild steel",
                    "t (mm)": "0.8",
                    "Matrice V (mm)": "6",
                    "R_i (mm)": "0.96",
                    "R/t": "1.20",
                    "K DIN 6935": "0.34",
                    "K air (DIN ↔ publié)": "0.34–0.43",
                    "K à fond": "0.44–0.47",
                    "K frappage": "0.41–0.46",
                    "y = K·t (mm)": "0.27",
                    "Source": "S1/S2/S3"
                },
                {
                    "Matériau": "DC01 mild steel",
                    "t (mm)": "1.0",
                    "Matrice V (mm)": "8",
                    "R_i (mm)": "1.28",
                    "R/t": "1.28",
                    "K DIN 6935": "0.35",
                    "K air (DIN ↔ publié)": "0.35–0.43",
                    "K à fond": "0.44–0.47",
                    "K frappage": "0.41–0.46",
                    "y = K·t (mm)": "0.35",
                    "Source": "S1/S2/S3"
                },
                {
                    "Matériau": "DC01 mild steel",
                    "t (mm)": "1.5",
                    "Matrice V (mm)": "12",
                    "R_i (mm)": "1.92",
                    "R/t": "1.28",
                    "K DIN 6935": "0.35",
                    "K air (DIN ↔ publié)": "0.35–0.43",
                    "K à fond": "0.44–0.47",
                    "K frappage": "0.41–0.46",
                    "y = K·t (mm)": "0.53",
                    "Source": "S1/S2/S3"
                },
                {
                    "Matériau": "DC01 mild steel",
                    "t (mm)": "2.0",
                    "Matrice V (mm)": "16",
                    "R_i (mm)": "2.56",
                    "R/t": "1.28",
                    "K DIN 6935": "0.35",
                    "K air (DIN ↔ publié)": "0.35–0.43",
                    "K à fond": "0.44–0.47",
                    "K frappage": "0.41–0.46",
                    "y = K·t (mm)": "0.70",
                    "Source": "S1/S2/S3"
                },
                {
                    "Matériau": "DC01 mild steel",
                    "t (mm)": "3.0",
                    "Matrice V (mm)": "25",
                    "R_i (mm)": "4.00",
                    "R/t": "1.33",
                    "K DIN 6935": "0.36",
                    "K air (DIN ↔ publié)": "0.36–0.43",
                    "K à fond": "0.44–0.47",
                    "K frappage": "0.41–0.46",
                    "y = K·t (mm)": "1.07",
                    "Source": "S1/S2/S3"
                },
                {
                    "Matériau": "DC01 mild steel",
                    "t (mm)": "4.0",
                    "Matrice V (mm)": "32",
                    "R_i (mm)": "5.12",
                    "R/t": "1.28",
                    "K DIN 6935": "0.35",
                    "K air (DIN ↔ publié)": "0.35–0.43",
                    "K à fond": "0.44–0.47",
                    "K frappage": "0.41–0.46",
                    "y = K·t (mm)": "1.40",
                    "Source": "S1/S2/S3"
                },
                {
                    "Matériau": "DC01 mild steel",
                    "t (mm)": "6.0",
                    "Matrice V (mm)": "50",
                    "R_i (mm)": "8.00",
                    "R/t": "1.33",
                    "K DIN 6935": "0.36",
                    "K air (DIN ↔ publié)": "0.36–0.43",
                    "K à fond": "0.44–0.47",
                    "K frappage": "0.41–0.46",
                    "y = K·t (mm)": "2.14",
                    "Source": "S1/S2/S3"
                },
                {
                    "Matériau": "DX51D+Z galvanized",
                    "t (mm)": "0.8",
                    "Matrice V (mm)": "6",
                    "R_i (mm)": "0.96",
                    "R/t": "1.20",
                    "K DIN 6935": "0.34",
                    "K air (DIN ↔ publié)": "0.34–0.43",
                    "K à fond": "0.44–0.47",
                    "K frappage": "0.41–0.46",
                    "y = K·t (mm)": "0.27",
                    "Source": "S1/S2/S3"
                },
                {
                    "Matériau": "DX51D+Z galvanized",
                    "t (mm)": "1.5",
                    "Matrice V (mm)": "12",
                    "R_i (mm)": "1.92",
                    "R/t": "1.28",
                    "K DIN 6935": "0.35",
                    "K air (DIN ↔ publié)": "0.35–0.43",
                    "K à fond": "0.44–0.47",
                    "K frappage": "0.41–0.46",
                    "y = K·t (mm)": "0.53",
                    "Source": "S1/S2/S3"
                },
                {
                    "Matériau": "DX51D+Z galvanized",
                    "t (mm)": "3.0",
                    "Matrice V (mm)": "25",
                    "R_i (mm)": "4.00",
                    "R/t": "1.33",
                    "K DIN 6935": "0.36",
                    "K air (DIN ↔ publié)": "0.36–0.43",
                    "K à fond": "0.44–0.47",
                    "K frappage": "0.41–0.46",
                    "y = K·t (mm)": "1.07",
                    "Source": "S1/S2/S3"
                },
                {
                    "Matériau": "304 stainless",
                    "t (mm)": "0.8",
                    "Matrice V (mm)": "8",
                    "R_i (mm)": "1.60",
                    "R/t": "2.00",
                    "K DIN 6935": "0.40",
                    "K air (DIN ↔ publié)": "0.40–0.45",
                    "K à fond": "0.46–0.48",
                    "K frappage": "0.44–0.47",
                    "y = K·t (mm)": "0.32",
                    "Source": "S1/S2/S3"
                },
                {
                    "Matériau": "304 stainless",
                    "t (mm)": "1.5",
                    "Matrice V (mm)": "16",
                    "R_i (mm)": "3.20",
                    "R/t": "2.13",
                    "K DIN 6935": "0.41",
                    "K air (DIN ↔ publié)": "0.41–0.45",
                    "K à fond": "0.46–0.48",
                    "K frappage": "0.44–0.47",
                    "y = K·t (mm)": "0.61",
                    "Source": "S1/S2/S3"
                },
                {
                    "Matériau": "304 stainless",
                    "t (mm)": "3.0",
                    "Matrice V (mm)": "32",
                    "R_i (mm)": "6.40",
                    "R/t": "2.13",
                    "K DIN 6935": "0.41",
                    "K air (DIN ↔ publié)": "0.41–0.45",
                    "K à fond": "0.46–0.48",
                    "K frappage": "0.44–0.47",
                    "y = K·t (mm)": "1.23",
                    "Source": "S1/S2/S3"
                },
                {
                    "Matériau": "316L stainless",
                    "t (mm)": "1.0",
                    "Matrice V (mm)": "10",
                    "R_i (mm)": "2.10",
                    "R/t": "2.10",
                    "K DIN 6935": "0.41",
                    "K air (DIN ↔ publié)": "0.41–0.45",
                    "K à fond": "0.46–0.48",
                    "K frappage": "0.44–0.47",
                    "y = K·t (mm)": "0.41",
                    "Source": "S1/S2/S3"
                },
                {
                    "Matériau": "316L stainless",
                    "t (mm)": "2.0",
                    "Matrice V (mm)": "20",
                    "R_i (mm)": "4.20",
                    "R/t": "2.10",
                    "K DIN 6935": "0.41",
                    "K air (DIN ↔ publié)": "0.41–0.45",
                    "K à fond": "0.46–0.48",
                    "K frappage": "0.44–0.47",
                    "y = K·t (mm)": "0.82",
                    "Source": "S1/S2/S3"
                },
                {
                    "Matériau": "316L stainless",
                    "t (mm)": "3.0",
                    "Matrice V (mm)": "32",
                    "R_i (mm)": "6.72",
                    "R/t": "2.24",
                    "K DIN 6935": "0.41",
                    "K air (DIN ↔ publié)": "0.41–0.45",
                    "K à fond": "0.46–0.48",
                    "K frappage": "0.44–0.47",
                    "y = K·t (mm)": "1.23",
                    "Source": "S1/S2/S3"
                },
                {
                    "Matériau": "5052-H32 aluminium",
                    "t (mm)": "0.8",
                    "Matrice V (mm)": "6",
                    "R_i (mm)": "0.96",
                    "R/t": "1.20",
                    "K DIN 6935": "0.34",
                    "K air (DIN ↔ publié)": "0.34–0.40",
                    "K à fond": "0.42–0.46",
                    "K frappage": "0.38–0.44",
                    "y = K·t (mm)": "0.27",
                    "Source": "S1/S2/S3"
                },
                {
                    "Matériau": "5052-H32 aluminium",
                    "t (mm)": "1.5",
                    "Matrice V (mm)": "12",
                    "R_i (mm)": "1.92",
                    "R/t": "1.28",
                    "K DIN 6935": "0.35",
                    "K air (DIN ↔ publié)": "0.35–0.40",
                    "K à fond": "0.42–0.46",
                    "K frappage": "0.38–0.44",
                    "y = K·t (mm)": "0.53",
                    "Source": "S1/S2/S3"
                },
                {
                    "Matériau": "5052-H32 aluminium",
                    "t (mm)": "3.0",
                    "Matrice V (mm)": "25",
                    "R_i (mm)": "4.00",
                    "R/t": "1.33",
                    "K DIN 6935": "0.36",
                    "K air (DIN ↔ publié)": "0.36–0.40",
                    "K à fond": "0.42–0.46",
                    "K frappage": "0.38–0.44",
                    "y = K·t (mm)": "1.07",
                    "Source": "S1/S2/S3"
                },
                {
                    "Matériau": "6061-T6 aluminium *",
                    "t (mm)": "1.0",
                    "Matrice V (mm)": "10",
                    "R_i (mm)": "1.80",
                    "R/t": "1.80",
                    "K DIN 6935": "0.39",
                    "K air (DIN ↔ publié)": "0.39–0.45",
                    "K à fond": "0.46–0.48",
                    "K frappage": "0.44–0.47",
                    "y = K·t (mm)": "0.39",
                    "Source": "S1/S2/S3"
                },
                {
                    "Matériau": "6061-T6 aluminium *",
                    "t (mm)": "2.0",
                    "Matrice V (mm)": "20",
                    "R_i (mm)": "3.60",
                    "R/t": "1.80",
                    "K DIN 6935": "0.39",
                    "K air (DIN ↔ publié)": "0.39–0.45",
                    "K à fond": "0.46–0.48",
                    "K frappage": "0.44–0.47",
                    "y = K·t (mm)": "0.78",
                    "Source": "S1/S2/S3"
                },
                {
                    "Matériau": "6061-T6 aluminium *",
                    "t (mm)": "3.0",
                    "Matrice V (mm)": "32",
                    "R_i (mm)": "5.76",
                    "R/t": "1.92",
                    "K DIN 6935": "0.40",
                    "K air (DIN ↔ publié)": "0.40–0.45",
                    "K à fond": "0.46–0.48",
                    "K frappage": "0.44–0.47",
                    "y = K·t (mm)": "1.20",
                    "Source": "S1/S2/S3"
                },
                {
                    "Matériau": "C110 copper",
                    "t (mm)": "1.0",
                    "Matrice V (mm)": "8",
                    "R_i (mm)": "1.28",
                    "R/t": "1.28",
                    "K DIN 6935": "0.35",
                    "K air (DIN ↔ publié)": "0.35–0.40",
                    "K à fond": "0.42–0.46",
                    "K frappage": "0.38–0.44",
                    "y = K·t (mm)": "0.35",
                    "Source": "S1/S2/S3"
                },
                {
                    "Matériau": "C110 copper",
                    "t (mm)": "2.0",
                    "Matrice V (mm)": "16",
                    "R_i (mm)": "2.56",
                    "R/t": "1.28",
                    "K DIN 6935": "0.35",
                    "K air (DIN ↔ publié)": "0.35–0.40",
                    "K à fond": "0.42–0.46",
                    "K frappage": "0.38–0.44",
                    "y = K·t (mm)": "0.70",
                    "Source": "S1/S2/S3"
                },
                {
                    "Matériau": "C260 brass",
                    "t (mm)": "1.0",
                    "Matrice V (mm)": "8",
                    "R_i (mm)": "1.28",
                    "R/t": "1.28",
                    "K DIN 6935": "0.35",
                    "K air (DIN ↔ publié)": "0.35–0.40",
                    "K à fond": "0.42–0.46",
                    "K frappage": "0.38–0.44",
                    "y = K·t (mm)": "0.35",
                    "Source": "S1/S2/S3"
                },
                {
                    "Matériau": "C260 brass",
                    "t (mm)": "2.0",
                    "Matrice V (mm)": "16",
                    "R_i (mm)": "2.56",
                    "R/t": "1.28",
                    "K DIN 6935": "0.35",
                    "K air (DIN ↔ publié)": "0.35–0.40",
                    "K à fond": "0.42–0.46",
                    "K frappage": "0.38–0.44",
                    "y = K·t (mm)": "0.70",
                    "Source": "S1/S2/S3"
                }
            ]
        },
        {
            "caption": "Quel facteur K utiliser pour de l'acier doux de 2 mm en pliage à l'air ?",
            "columns": [
                "Étape",
                "Quantité",
                "Valeur",
                "Remarque"
            ],
            "rows": [
                {
                    "Étape": "1",
                    "Quantité": "R/t",
                    "Valeur": "2.0 / 2.0 = 1.00",
                    "Remarque": "DIN 6935 : k = 0.65 + 0.5·log10(1.00) = 0.65"
                },
                {
                    "Étape": "2",
                    "Quantité": "K = k/2",
                    "Valeur": "0.325",
                    "Remarque": "La valeur du tableau s'arrondit à 0.33 ; cet exemple garde la valeur non arrondie"
                },
                {
                    "Étape": "3",
                    "Quantité": "BA = (π/180)·A·(R + K·t), A = 90°",
                    "Valeur": "4.163 mm",
                    "Remarque": "1.5708 × 2.65"
                },
                {
                    "Étape": "4",
                    "Quantité": "OSSB = (R + t)·tan(A/2)",
                    "Valeur": "4.000 mm",
                    "Remarque": "4.0 × tan 45°"
                },
                {
                    "Étape": "5",
                    "Quantité": "Flat legs from 50/30 outside",
                    "Valeur": "46.000 / 26.000 mm",
                    "Remarque": "A_flat = 50 − OSSB, B_flat = 30 − OSSB"
                },
                {
                    "Étape": "6",
                    "Quantité": "L = A + B + BA",
                    "Valeur": "76.16 mm",
                    "Remarque": "BD = 2×4.000 − 4.163 = 3.837 ; 50 + 30 − 3.837 = 76.163 ✓"
                },
                {
                    "Étape": "7",
                    "Quantité": "If CAD default K = 0.44",
                    "Valeur": "L = 76.52 mm (+0.361)",
                    "Remarque": "BA = 4.524 mm ; quatre plis accumulent environ 1.4 mm"
                }
            ]
        },
        {
            "caption": "Pourquoi les logiciels CAD prennent-ils par défaut un facteur K de 0.44 ?",
            "columns": [
                "État",
                "Quel K",
                "Valeur typique",
                "Étape suivante"
            ],
            "rows": [
                {
                    "État": "Ductile mild steel, air bending, R/t 0.5–3",
                    "Quel K": "DIN 6935 Table / formula",
                    "Valeur typique": "0.25–0.40",
                    "Étape suivante": "Essai de pliage, calcul inverse du vrai K"
                },
                {
                    "État": "Mild steel, CAD default, V = 6–8t",
                    "Quel K": "Published medium air (t–3t)",
                    "Valeur typique": "0.43 (defaults 0.44–0.45)",
                    "Étape suivante": "À utiliser uniquement si outillage et matériau correspondent ; sinon passer à DIN"
                },
                {
                    "État": "304/316 stainless, air bending",
                    "Quel K": "DIN 6935 at R/t 2.0–2.2",
                    "Valeur typique": "0.40–0.41 (316 shop data up to 0.50)",
                    "Étape suivante": "Vérifier retour élastique, fissuration et usure de matrice"
                },
                {
                    "État": "5052-H32 aluminium, air bending",
                    "Quel K": "DIN 6935 at R/t 1.2–1.3",
                    "Valeur typique": "0.34–0.36",
                    "Étape suivante": "Vérifier la fissuration ; l'état mou prend le bas de fourchette"
                },
                {
                    "État": "6061-T6 aluminium, air bending",
                    "Quel K": "Published hard air / DIN upper bound",
                    "Valeur typique": "0.39–0.45",
                    "Étape suivante": "Essai de pliage obligatoire ; le T6 fissure — préférer un rayon plus grand"
                },
                {
                    "État": "C110 copper / C260 brass",
                    "Quel K": "DIN 6935 at R/t 1.28",
                    "Valeur typique": "0.35",
                    "Étape suivante": "Confirmer l'état recuit ; l'état dur prend le haut de fourchette"
                },
                {
                    "État": "Bottoming",
                    "Quel K": "Published t–3t tier of the class",
                    "Valeur typique": "0.42–0.48",
                    "Étape suivante": "Ne jamais réutiliser un K de pliage à l'air"
                },
                {
                    "État": "Coining",
                    "Quel K": "Published t–3t tier of the class",
                    "Valeur typique": "0.38–0.47",
                    "Étape suivante": "Noter que le frappage se situe sous le pliage à fond dans le tableau publié (voir la question frappage-contre-fond)"
                },
                {
                    "État": "R/t > 5",
                    "Quel K": "K = 0.50",
                    "Valeur typique": "0.50",
                    "Étape suivante": "Fibre neutre de retour à mi-épaisseur"
                },
                {
                    "État": "R/t < 0.5",
                    "Quel K": "DIN Table low end",
                    "Valeur typique": "0.15–0.25",
                    "Étape suivante": "Risque de fissuration élevé — ouvrir le rayon ou changer de matériau"
                },
                {
                    "État": "New material / new tooling / no data",
                    "Quel K": "Test bend, back-solve",
                    "Valeur typique": "measured",
                    "Étape suivante": "Verrouiller le K mesuré dans la bibliothèque de matériaux du CAD"
                }
            ]
        },
        {
            "caption": "Comment le facteur K varie-t-il avec le rayon intérieur ?",
            "columns": [
                "R/t",
                "k (DIN 6935)",
                "K = k/2",
                "y/t",
                "Remarque"
            ],
            "rows": [
                {
                    "R/t": "0.05",
                    "k (DIN 6935)": "0.00",
                    "K = k/2": "0.00",
                    "y/t": "0.00",
                    "Remarque": "Fibre neutre sur la surface intérieure ; risque de fissuration — ne pas concevoir ici"
                },
                {
                    "R/t": "0.07",
                    "k (DIN 6935)": "0.06",
                    "K = k/2": "0.03",
                    "y/t": "0.03",
                    "Remarque": "Valeur du tableau source ; la formule DIN elle-même donne 0.07 (k) à ce R/t — le document amont est incohérent ici"
                },
                {
                    "R/t": "0.10",
                    "k (DIN 6935)": "0.15",
                    "K = k/2": "0.08",
                    "y/t": "0.08",
                    "Remarque": ""
                },
                {
                    "R/t": "0.20",
                    "k (DIN 6935)": "0.30",
                    "K = k/2": "0.15",
                    "y/t": "0.15",
                    "Remarque": ""
                },
                {
                    "R/t": "0.25",
                    "k (DIN 6935)": "0.35",
                    "K = k/2": "0.18",
                    "y/t": "0.18",
                    "Remarque": ""
                },
                {
                    "R/t": "0.33",
                    "k (DIN 6935)": "0.41",
                    "K = k/2": "0.21",
                    "y/t": "0.21",
                    "Remarque": ""
                },
                {
                    "R/t": "0.50",
                    "k (DIN 6935)": "0.50",
                    "K = k/2": "0.25",
                    "y/t": "0.25",
                    "Remarque": ""
                },
                {
                    "R/t": "0.75",
                    "k (DIN 6935)": "0.59",
                    "K = k/2": "0.30",
                    "y/t": "0.30",
                    "Remarque": ""
                },
                {
                    "R/t": "1.00",
                    "k (DIN 6935)": "0.65",
                    "K = k/2": "0.33",
                    "y/t": "0.33",
                    "Remarque": ""
                },
                {
                    "R/t": "1.25",
                    "k (DIN 6935)": "0.70",
                    "K = k/2": "0.35",
                    "y/t": "0.35",
                    "Remarque": ""
                },
                {
                    "R/t": "1.50",
                    "k (DIN 6935)": "0.74",
                    "K = k/2": "0.37",
                    "y/t": "0.37",
                    "Remarque": ""
                },
                {
                    "R/t": "1.75",
                    "k (DIN 6935)": "0.77",
                    "K = k/2": "0.39",
                    "y/t": "0.39",
                    "Remarque": ""
                },
                {
                    "R/t": "2.00",
                    "k (DIN 6935)": "0.80",
                    "K = k/2": "0.40",
                    "y/t": "0.40",
                    "Remarque": ""
                },
                {
                    "R/t": "2.50",
                    "k (DIN 6935)": "0.85",
                    "K = k/2": "0.43",
                    "y/t": "0.43",
                    "Remarque": ""
                },
                {
                    "R/t": "3.00",
                    "k (DIN 6935)": "0.89",
                    "K = k/2": "0.45",
                    "y/t": "0.45",
                    "Remarque": ""
                },
                {
                    "R/t": "3.50",
                    "k (DIN 6935)": "0.92",
                    "K = k/2": "0.46",
                    "y/t": "0.46",
                    "Remarque": ""
                },
                {
                    "R/t": "4.00",
                    "k (DIN 6935)": "0.95",
                    "K = k/2": "0.48",
                    "y/t": "0.48",
                    "Remarque": ""
                },
                {
                    "R/t": "4.50",
                    "k (DIN 6935)": "0.98",
                    "K = k/2": "0.49",
                    "y/t": "0.49",
                    "Remarque": ""
                },
                {
                    "R/t": "5.00",
                    "k (DIN 6935)": "1.00",
                    "K = k/2": "0.50",
                    "y/t": "0.50",
                    "Remarque": "R/t ≥ 5 : fibre neutre à mi-épaisseur"
                }
            ]
        },
        {
            "caption": "Quelle est la différence entre pliage à l'air, pliage à fond et frappage pour le facteur K ?",
            "columns": [
                "Classe de matériau",
                "Méthode de pliage",
                "R = 0–t",
                "R = t–3t",
                "R > 3t"
            ],
            "rows": [
                {
                    "Classe de matériau": "Soft (aluminium 5052, copper, brass)",
                    "Méthode de pliage": "Air bending",
                    "R = 0–t": "0.33",
                    "R = t–3t": "0.40",
                    "R > 3t": "0.50"
                },
                {
                    "Classe de matériau": "Soft (aluminium 5052, copper, brass)",
                    "Méthode de pliage": "Bottoming",
                    "R = 0–t": "0.42",
                    "R = t–3t": "0.46",
                    "R > 3t": "0.50"
                },
                {
                    "Classe de matériau": "Soft (aluminium 5052, copper, brass)",
                    "Méthode de pliage": "Coining",
                    "R = 0–t": "0.38",
                    "R = t–3t": "0.44",
                    "R > 3t": "0.50"
                },
                {
                    "Classe de matériau": "Medium (mild steel, galvanized)",
                    "Méthode de pliage": "Air bending",
                    "R = 0–t": "0.38",
                    "R = t–3t": "0.43",
                    "R > 3t": "0.50"
                },
                {
                    "Classe de matériau": "Medium (mild steel, galvanized)",
                    "Méthode de pliage": "Bottoming",
                    "R = 0–t": "0.44",
                    "R = t–3t": "0.47",
                    "R > 3t": "0.50"
                },
                {
                    "Classe de matériau": "Medium (mild steel, galvanized)",
                    "Méthode de pliage": "Coining",
                    "R = 0–t": "0.41",
                    "R = t–3t": "0.46",
                    "R > 3t": "0.50"
                },
                {
                    "Classe de matériau": "Hard (304/316 stainless)",
                    "Méthode de pliage": "Air bending",
                    "R = 0–t": "0.40",
                    "R = t–3t": "0.45",
                    "R > 3t": "0.50"
                },
                {
                    "Classe de matériau": "Hard (304/316 stainless)",
                    "Méthode de pliage": "Bottoming",
                    "R = 0–t": "0.46",
                    "R = t–3t": "0.48",
                    "R > 3t": "0.50"
                },
                {
                    "Classe de matériau": "Hard (304/316 stainless)",
                    "Méthode de pliage": "Coining",
                    "R = 0–t": "0.44",
                    "R = t–3t": "0.47",
                    "R > 3t": "0.50"
                }
            ]
        },
        {
            "caption": "Comment calculer le développé (BA) ?",
            "columns": [
                "Terme",
                "Formule",
                "Lecture"
            ],
            "rows": [
                {
                    "Terme": "K factor",
                    "Formule": "K = y / t, 0 ≤ K ≤ 0.5",
                    "Lecture": "Décalage de la fibre neutre depuis la surface intérieure, sur l'épaisseur"
                },
                {
                    "Terme": "Neutral radius",
                    "Formule": "R_neutral = R_i + K × t",
                    "Lecture": "Le rayon d'arc qui conserve réellement sa longueur"
                },
                {
                    "Terme": "Bend allowance BA",
                    "Formule": "BA = (π/180) × A × (R_i + K × t)",
                    "Lecture": "Longueur d'arc de la fibre neutre à travers le pli"
                },
                {
                    "Terme": "Outside setback OSSB",
                    "Formule": "OSSB = (R_i + t) × tan(A/2)",
                    "Lecture": "Longueur tangente du sommet aux points de tangence du pli"
                },
                {
                    "Terme": "Bend deduction BD",
                    "Formule": "BD = 2 × OSSB − BA",
                    "Lecture": "Ce que les deux coins extérieurs perdent par rapport au développé"
                },
                {
                    "Terme": "Flat length L",
                    "Formule": "L = A + B + BA (flat legs); L = A_out + B_out − BD (outside dims)",
                    "Lecture": "Les deux donnent la même réponse quand K est correct — mélanger BA et BD est l'erreur classique de développé"
                },
                {
                    "Terme": "Angle convention",
                    "Formule": "A = 180° − included angle",
                    "Lecture": "Pli à 90° : A = 90 ; angle au sommet 60° : A = 120 ; angle au sommet 120° : A = 60"
                }
            ]
        },
        {
            "caption": "Comment calculer la déduction de pliage (BD) ?",
            "columns": [
                "Cas",
                "Élément",
                "Valeur"
            ],
            "rows": [
                {
                    "Cas": "90°, t 2.0, R 2.0",
                    "Élément": "OSSB = (2+2)·tan45°",
                    "Valeur": "4.000 mm"
                },
                {
                    "Cas": "90°, t 2.0, R 2.0",
                    "Élément": "BD = 2×4.000 − 4.163",
                    "Valeur": "3.837 mm"
                },
                {
                    "Cas": "90°, t 2.0, R 2.0",
                    "Élément": "L = 50 + 30 − 3.837",
                    "Valeur": "76.163 mm"
                },
                {
                    "Cas": "A=120°, t 1.5, R 3.0, 304",
                    "Élément": "K = (0.65 + 0.5·log10 2)/2",
                    "Valeur": "0.4003"
                },
                {
                    "Cas": "A=120°, t 1.5, R 3.0, 304",
                    "Élément": "BA = 2.0944 × (3 + 0.4003×1.5)",
                    "Valeur": "7.541 mm"
                },
                {
                    "Cas": "A=120°, t 1.5, R 3.0, 304",
                    "Élément": "OSSB = 4.5 × tan60°",
                    "Valeur": "7.794 mm"
                },
                {
                    "Cas": "A=120°, t 1.5, R 3.0, 304",
                    "Élément": "L = 52.206 + 32.206 + 7.541",
                    "Valeur": "91.95 mm"
                },
                {
                    "Cas": "A=120°, t 1.5, R 3.0, 304",
                    "Élément": "BD check: 60 + 40 − (2×7.794 − 7.541)",
                    "Valeur": "91.952 mm ✓"
                },
                {
                    "Cas": "A=120°, t 1.5, R 3.0, 304",
                    "Élément": "If hard-air K 0.45 instead",
                    "Valeur": "L = 92.11 mm (+0.156 vs DIN 0.40: 0.16 mm per bend)"
                }
            ]
        },
        {
            "caption": "Quelle ouverture de matrice V utiliser pour de l'acier doux de 2 mm ?",
            "columns": [
                "t (mm)",
                "V (mm)",
                "R_i (mm)",
                "Flasque min (mm)",
                "Tonnage (t/m)",
                "Source"
            ],
            "rows": [
                {
                    "t (mm)": "0.5",
                    "V (mm)": "6",
                    "R_i (mm)": "0.96",
                    "Flasque min (mm)": "—",
                    "Tonnage (t/m)": "—",
                    "Source": "practical min V6, calc"
                },
                {
                    "t (mm)": "0.8",
                    "V (mm)": "6",
                    "R_i (mm)": "0.96",
                    "Flasque min (mm)": "—",
                    "Tonnage (t/m)": "—",
                    "Source": "S3 method, calc"
                },
                {
                    "t (mm)": "1.0",
                    "V (mm)": "8",
                    "R_i (mm)": "1.3",
                    "Flasque min (mm)": "> 5.5",
                    "Tonnage (t/m)": "8",
                    "Source": "S3"
                },
                {
                    "t (mm)": "1.5",
                    "V (mm)": "12",
                    "R_i (mm)": "2.0",
                    "Flasque min (mm)": "> 8.5",
                    "Tonnage (t/m)": "10",
                    "Source": "S3"
                },
                {
                    "t (mm)": "2.0",
                    "V (mm)": "16",
                    "R_i (mm)": "2.6",
                    "Flasque min (mm)": "> 11.0",
                    "Tonnage (t/m)": "12",
                    "Source": "S3"
                },
                {
                    "t (mm)": "2.5",
                    "V (mm)": "20",
                    "R_i (mm)": "3.3",
                    "Flasque min (mm)": "> 14.0",
                    "Tonnage (t/m)": "14",
                    "Source": "S3"
                },
                {
                    "t (mm)": "3.0",
                    "V (mm)": "25",
                    "R_i (mm)": "4.0",
                    "Flasque min (mm)": "> 17.5",
                    "Tonnage (t/m)": "16",
                    "Source": "S3"
                },
                {
                    "t (mm)": "4.0",
                    "V (mm)": "32",
                    "R_i (mm)": "5.0",
                    "Flasque min (mm)": "> 22.0",
                    "Tonnage (t/m)": "22",
                    "Source": "S3"
                },
                {
                    "t (mm)": "5.0",
                    "V (mm)": "40",
                    "R_i (mm)": "6.5",
                    "Flasque min (mm)": "> 28.0",
                    "Tonnage (t/m)": "27",
                    "Source": "S3"
                },
                {
                    "t (mm)": "6.0",
                    "V (mm)": "50",
                    "R_i (mm)": "8.0",
                    "Flasque min (mm)": "> 35.0",
                    "Tonnage (t/m)": "32",
                    "Source": "S3"
                }
            ]
        },
        {
            "caption": "Quel facteur K utiliser pour l'inoxydable 304 ?",
            "columns": [
                "Calibre",
                "K à R≈t",
                "S'applique à",
                "Source"
            ],
            "rows": [
                {
                    "Calibre": "Shop-measured caliber",
                    "K à R≈t": "0.46",
                    "S'applique à": "304, air bending, R = t",
                    "Source": "S4"
                },
                {
                    "Calibre": "Shop-measured caliber",
                    "K à R≈t": "0.50",
                    "S'applique à": "316, air bending, R = t",
                    "Source": "S4"
                },
                {
                    "Calibre": "Published hard class (t–3t)",
                    "K à R≈t": "0.45",
                    "S'applique à": "Generic 304/316 hard tier — does not separate 304 from 316",
                    "Source": "S2/S5"
                },
                {
                    "Calibre": "DIN 6935 at R/t = 2",
                    "K à R≈t": "0.40",
                    "S'applique à": "Geometry only — no work-hardening difference",
                    "Source": "S1/S6"
                },
                {
                    "Calibre": "This page, Table 2",
                    "K à R≈t": "0.41–0.45",
                    "S'applique à": "316 takes the upper bound; test-bend",
                    "Source": "S1/S2/S3"
                }
            ]
        },
        {
            "caption": "Quel facteur K utiliser pour l'aluminium 5052 ?",
            "columns": [
                "Calibre",
                "K",
                "S'applique à",
                "Source"
            ],
            "rows": [
                {
                    "Calibre": "Shop-measured (R = t)",
                    "K": "0.33",
                    "S'applique à": "5052-H32, air bending",
                    "Source": "S4"
                },
                {
                    "Calibre": "Published soft air (t–3t)",
                    "K": "0.40",
                    "S'applique à": "Generic soft aluminium",
                    "Source": "S2/S5"
                },
                {
                    "Calibre": "DIN 6935 (R/t = 1.2)",
                    "K": "0.345",
                    "S'applique à": "Geometry only",
                    "Source": "S1/S6"
                },
                {
                    "Calibre": "This page, Table 2",
                    "K": "0.34–0.40",
                    "S'applique à": "Soft temper low end, hard temper or wide V high end",
                    "Source": "S1/S2/S3"
                }
            ]
        },
        {
            "caption": "Puis-je utiliser un seul facteur K pour toutes les épaisseurs ?",
            "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": "Comment mesurer le vrai facteur K de ma presse plieuse ?",
            "columns": [
                "Étape",
                "Règle",
                "Valeur"
            ],
            "rows": [
                {
                    "Étape": "1",
                    "Règle": "Strip",
                    "Valeur": "200 × 50 mm, bend at 90° mid-length"
                },
                {
                    "Étape": "2",
                    "Règle": "Measure both outside flanges A_out + B_out",
                    "Valeur": "BD = 200 − (A_out + B_out)"
                },
                {
                    "Étape": "3",
                    "Règle": "Back-solve",
                    "Valeur": "K = [2(R+t)tan(A/2) − BD] / [(π/180)·A·t] − R/t"
                },
                {
                    "Étape": "4",
                    "Règle": "Write into CAD material library",
                    "Valeur": "per material + tooling pair"
                }
            ]
        },
        {
            "caption": "Où se trouve la fibre neutre dans un pli ?",
            "columns": [
                "Cas",
                "K",
                "t (mm)",
                "y = K·t (mm)",
                "Rayon neutre"
            ],
            "rows": [
                {
                    "Cas": "DC01 2.0 mm, R/t 1.28",
                    "K": "0.35",
                    "t (mm)": "2.0",
                    "y = K·t (mm)": "0.70",
                    "Rayon neutre": "R + 0.70 mm (R_i 2.56 → neutre 3.26 mm)"
                },
                {
                    "Cas": "DC01 3.0 mm, R/t 1.33",
                    "K": "0.36",
                    "t (mm)": "3.0",
                    "y = K·t (mm)": "1.07",
                    "Rayon neutre": "R + 1.07 mm"
                },
                {
                    "Cas": "304 1.5 mm, R/t 2.13",
                    "K": "0.41",
                    "t (mm)": "1.5",
                    "y = K·t (mm)": "0.61",
                    "Rayon neutre": "R + 0.61 mm"
                },
                {
                    "Cas": "DC01 6.0 mm, R/t 1.33",
                    "K": "0.36",
                    "t (mm)": "6.0",
                    "y = K·t (mm)": "2.14",
                    "Rayon neutre": "R + 2.14 mm"
                }
            ]
        },
        {
            "caption": "Pourquoi le frappage montre-t-il parfois un K plus bas que le pliage à fond ?",
            "columns": [
                "Méthode",
                "K mou (t–3t)",
                "K moyen (t–3t)",
                "K dur (t–3t)",
                "Source"
            ],
            "rows": [
                {
                    "Méthode": "Bottoming",
                    "K mou (t–3t)": "0.46",
                    "K moyen (t–3t)": "0.47",
                    "K dur (t–3t)": "0.48",
                    "Source": "S2/S5"
                },
                {
                    "Méthode": "Coining",
                    "K mou (t–3t)": "0.44",
                    "K moyen (t–3t)": "0.46",
                    "K dur (t–3t)": "0.47",
                    "Source": "S2/S5"
                },
                {
                    "Méthode": "Expectation",
                    "K mou (t–3t)": "—",
                    "K moyen (t–3t)": "—",
                    "K dur (t–3t)": "—",
                    "Source": "—"
                },
                {
                    "Méthode": "Second source confirming the ranking",
                    "K mou (t–3t)": "none found",
                    "K moyen (t–3t)": "none found",
                    "K dur (t–3t)": "none found",
                    "Source": "GAP"
                }
            ]
        }
    ]
}