{
    "slug": "standard-tolerances",
    "title": "Tolérances générales pour les pièces CNC : ISO 2768 et grades IT",
    "description": "Tolérances générales ISO 2768 en quatre classes de précision, grades IT de IT01 à IT18 et ce que chaque procédé CNC tient réellement — avec la classe à indiquer sur votre plan.",
    "lang": "fr",
    "tables": [
        {
            "caption": "Tolérances générales ISO 2768-1 pour dimensions linéaires (mm)",
            "columns": [
                "Tranche de dimension nominale (mm)",
                "ISO 2768-f",
                "ISO 2768-m",
                "ISO 2768-c",
                "ISO 2768-v"
            ],
            "rows": [
                {
                    "Tranche de dimension nominale (mm)": "0.5 – 3",
                    "ISO 2768-f": "±0.05",
                    "ISO 2768-m": "±0.1",
                    "ISO 2768-c": "±0.2",
                    "ISO 2768-v": "—"
                },
                {
                    "Tranche de dimension nominale (mm)": "3 – 6",
                    "ISO 2768-f": "±0.05",
                    "ISO 2768-m": "±0.1",
                    "ISO 2768-c": "±0.3",
                    "ISO 2768-v": "±0.5"
                },
                {
                    "Tranche de dimension nominale (mm)": "6 – 30",
                    "ISO 2768-f": "±0.1",
                    "ISO 2768-m": "±0.2",
                    "ISO 2768-c": "±0.5",
                    "ISO 2768-v": "±1.0"
                },
                {
                    "Tranche de dimension nominale (mm)": "30 – 120",
                    "ISO 2768-f": "±0.15",
                    "ISO 2768-m": "±0.3",
                    "ISO 2768-c": "±0.8",
                    "ISO 2768-v": "±1.5"
                },
                {
                    "Tranche de dimension nominale (mm)": "120 – 400",
                    "ISO 2768-f": "±0.2",
                    "ISO 2768-m": "±0.5",
                    "ISO 2768-c": "±1.2",
                    "ISO 2768-v": "±2.5"
                },
                {
                    "Tranche de dimension nominale (mm)": "400 – 1000",
                    "ISO 2768-f": "±0.3",
                    "ISO 2768-m": "±0.8",
                    "ISO 2768-c": "±2.0",
                    "ISO 2768-v": "±4.0"
                },
                {
                    "Tranche de dimension nominale (mm)": "1000 – 2000",
                    "ISO 2768-f": "±0.5",
                    "ISO 2768-m": "±1.2",
                    "ISO 2768-c": "±3.0",
                    "ISO 2768-v": "±6.0"
                },
                {
                    "Tranche de dimension nominale (mm)": "2000 – 4000",
                    "ISO 2768-f": "—",
                    "ISO 2768-m": "±2.0",
                    "ISO 2768-c": "±4.0",
                    "ISO 2768-v": "±8.0"
                }
            ]
        },
        {
            "caption": "Quelle classe de précision spécifier ?",
            "columns": [
                "Classe",
                "Niveau de précision",
                "Usage typique",
                "Impact sur le coût"
            ],
            "rows": [
                {
                    "Classe": "f (fine)",
                    "Niveau de précision": "Niveau général le plus élevé",
                    "Usage typique": "Pièces de précision, surfaces d'accouplement n'exigeant pas d'ajustement spécifique, exigences esthétiques sévères",
                    "Impact sur le coût": "+15–30% par rapport à la classe moyenne"
                },
                {
                    "Classe": "m (medium)",
                    "Niveau de précision": "CNC standard",
                    "Usage typique": "Pièces CNC usinées générales. La classe la plus utilisée, adaptée à la majorité des composants usinés.",
                    "Impact sur le coût": "Référence de base"
                },
                {
                    "Classe": "c (coarse)",
                    "Niveau de précision": "Détendue",
                    "Usage typique": "Pièces en tôle, structures soudées, pièces moulées non critiques, grands ensembles",
                    "Impact sur le coût": "−10–20% par rapport à la classe moyenne"
                },
                {
                    "Classe": "v (very coarse)",
                    "Niveau de précision": "La plus détendue",
                    "Usage typique": "Structures soudées, moulages bruts, pièces fabriquées non précises, très grandes dimensions",
                    "Impact sur le coût": "−20–35% par rapport à la classe moyenne"
                }
            ]
        },
        {
            "caption": "Grades IT — ce que signifie un chiffre de tolérance",
            "columns": [
                "Grade IT",
                "Signification pratique",
                "1–3 mm",
                "6–10 mm",
                "18–30 mm",
                "50–80 mm",
                "120–180 mm",
                "250–315 mm"
            ],
            "rows": [
                {
                    "Grade IT": "IT01",
                    "Signification pratique": "Référence des cales étalons",
                    "1–3 mm": "0.3",
                    "6–10 mm": "0.4",
                    "18–30 mm": "0.6",
                    "50–80 mm": "0.8",
                    "120–180 mm": "1.0",
                    "250–315 mm": "1.2"
                },
                {
                    "Grade IT": "IT0",
                    "Signification pratique": "Étalon de référence",
                    "1–3 mm": "0.5",
                    "6–10 mm": "0.6",
                    "18–30 mm": "0.9",
                    "50–80 mm": "1.2",
                    "120–180 mm": "1.5",
                    "250–315 mm": "2.0"
                },
                {
                    "Grade IT": "IT1",
                    "Signification pratique": "Calibre de précision",
                    "1–3 mm": "0.8",
                    "6–10 mm": "1.0",
                    "18–30 mm": "1.5",
                    "50–80 mm": "2.0",
                    "120–180 mm": "2.5",
                    "250–315 mm": "3.0"
                },
                {
                    "Grade IT": "IT2",
                    "Signification pratique": "Calibre de haute précision",
                    "1–3 mm": "1.2",
                    "6–10 mm": "1.5",
                    "18–30 mm": "2.5",
                    "50–80 mm": "3.0",
                    "120–180 mm": "4.0",
                    "250–315 mm": "5.0"
                },
                {
                    "Grade IT": "IT3",
                    "Signification pratique": "Travail d'ultra-précision",
                    "1–3 mm": "2.0",
                    "6–10 mm": "2.5",
                    "18–30 mm": "4.0",
                    "50–80 mm": "5.0",
                    "120–180 mm": "6.0",
                    "250–315 mm": "8.0"
                },
                {
                    "Grade IT": "IT4",
                    "Signification pratique": "Rectification de précision / EDM à fil",
                    "1–3 mm": "3",
                    "6–10 mm": "4",
                    "18–30 mm": "6",
                    "50–80 mm": "8",
                    "120–180 mm": "10",
                    "250–315 mm": "13"
                },
                {
                    "Grade IT": "IT5",
                    "Signification pratique": "Fabrication de calibres",
                    "1–3 mm": "4",
                    "6–10 mm": "6",
                    "18–30 mm": "9",
                    "50–80 mm": "13",
                    "120–180 mm": "16",
                    "250–315 mm": "20"
                },
                {
                    "Grade IT": "IT6",
                    "Signification pratique": "Usinage de précision",
                    "1–3 mm": "6",
                    "6–10 mm": "9",
                    "18–30 mm": "13",
                    "50–80 mm": "19",
                    "120–180 mm": "25",
                    "250–315 mm": "32"
                },
                {
                    "Grade IT": "IT7",
                    "Signification pratique": "Ajustement de précision (roulements, arbres)",
                    "1–3 mm": "10",
                    "6–10 mm": "15",
                    "18–30 mm": "21",
                    "50–80 mm": "30",
                    "120–180 mm": "40",
                    "250–315 mm": "52"
                },
                {
                    "Grade IT": "IT8",
                    "Signification pratique": "Usinage de précision général",
                    "1–3 mm": "14",
                    "6–10 mm": "22",
                    "18–30 mm": "33",
                    "50–80 mm": "46",
                    "120–180 mm": "63",
                    "250–315 mm": "81"
                },
                {
                    "Grade IT": "IT9",
                    "Signification pratique": "Usinage général (équivalent ISO 2768-m)",
                    "1–3 mm": "25",
                    "6–10 mm": "36",
                    "18–30 mm": "52",
                    "50–80 mm": "74",
                    "120–180 mm": "100",
                    "250–315 mm": "130"
                },
                {
                    "Grade IT": "IT10",
                    "Signification pratique": "Précision moyenne",
                    "1–3 mm": "40",
                    "6–10 mm": "58",
                    "18–30 mm": "84",
                    "50–80 mm": "120",
                    "120–180 mm": "160",
                    "250–315 mm": "210"
                },
                {
                    "Grade IT": "IT11",
                    "Signification pratique": "Usinage avec tolérances larges",
                    "1–3 mm": "60",
                    "6–10 mm": "90",
                    "18–30 mm": "130",
                    "50–80 mm": "190",
                    "120–180 mm": "250",
                    "250–315 mm": "320"
                },
                {
                    "Grade IT": "IT12",
                    "Signification pratique": "Usinage très grossier",
                    "1–3 mm": "100",
                    "6–10 mm": "150",
                    "18–30 mm": "210",
                    "50–80 mm": "300",
                    "120–180 mm": "400",
                    "250–315 mm": "500"
                },
                {
                    "Grade IT": "IT13",
                    "Signification pratique": "Modèles et travail d'ébauche",
                    "1–3 mm": "140",
                    "6–10 mm": "220",
                    "18–30 mm": "310",
                    "50–80 mm": "440",
                    "120–180 mm": "580",
                    "250–315 mm": "740"
                },
                {
                    "Grade IT": "IT14",
                    "Signification pratique": "Travail grossier de basse qualité",
                    "1–3 mm": "250",
                    "6–10 mm": "370",
                    "18–30 mm": "520",
                    "50–80 mm": "740",
                    "120–180 mm": "1000",
                    "250–315 mm": "1250"
                },
                {
                    "Grade IT": "IT15",
                    "Signification pratique": "Très grossier",
                    "1–3 mm": "400",
                    "6–10 mm": "600",
                    "18–30 mm": "840",
                    "50–80 mm": "1200",
                    "120–180 mm": "1600",
                    "250–315 mm": "2000"
                },
                {
                    "Grade IT": "IT16",
                    "Signification pratique": "Approximatif / non spécifié",
                    "1–3 mm": "600",
                    "6–10 mm": "1000",
                    "18–30 mm": "1400",
                    "50–80 mm": "2000",
                    "120–180 mm": "2600",
                    "250–315 mm": "3200"
                },
                {
                    "Grade IT": "IT17",
                    "Signification pratique": "Très approximatif",
                    "1–3 mm": "1000",
                    "6–10 mm": "1600",
                    "18–30 mm": "2400",
                    "50–80 mm": "3300",
                    "120–180 mm": "4300",
                    "250–315 mm": "5300"
                },
                {
                    "Grade IT": "IT18",
                    "Signification pratique": "Travail de fabrication général",
                    "1–3 mm": "1400",
                    "6–10 mm": "2500",
                    "18–30 mm": "3500",
                    "50–80 mm": "4800",
                    "120–180 mm": "6300",
                    "250–315 mm": "7600"
                }
            ]
        },
        {
            "caption": "Ce que chaque procédé CNC tient réellement",
            "columns": [
                "Procédé",
                "Standard (typique)",
                "Précision (coût supplémentaire)",
                "Ultra-précision (coût élevé)",
                "Équivalent IT"
            ],
            "rows": [
                {
                    "Procédé": "CNC Milling (3-axis)",
                    "Standard (typique)": "±0.025mm",
                    "Précision (coût supplémentaire)": "±0.005mm",
                    "Ultra-précision (coût élevé)": "±0.002mm",
                    "Équivalent IT": "IT8 → IT5 → IT3"
                },
                {
                    "Procédé": "CNC Milling (5-axis)",
                    "Standard (typique)": "±0.010mm",
                    "Précision (coût supplémentaire)": "±0.005mm",
                    "Ultra-précision (coût élevé)": "±0.002mm",
                    "Équivalent IT": "IT7 → IT5 → IT3"
                },
                {
                    "Procédé": "CNC Turning",
                    "Standard (typique)": "±0.025mm",
                    "Précision (coût supplémentaire)": "±0.005mm",
                    "Ultra-précision (coût élevé)": "±0.002mm",
                    "Équivalent IT": "IT8 → IT5 → IT3"
                },
                {
                    "Procédé": "Swiss-Type Turning",
                    "Standard (typique)": "±0.010mm",
                    "Précision (coût supplémentaire)": "±0.005mm",
                    "Ultra-précision (coût élevé)": "±0.002mm",
                    "Équivalent IT": "IT7 → IT5 → IT3"
                },
                {
                    "Procédé": "Surface Grinding",
                    "Standard (typique)": "±0.005mm",
                    "Précision (coût supplémentaire)": "±0.002mm",
                    "Ultra-précision (coût élevé)": "±0.001mm",
                    "Équivalent IT": "IT5 → IT3 → IT2"
                },
                {
                    "Procédé": "Jig Boring",
                    "Standard (typique)": "±0.010mm",
                    "Précision (coût supplémentaire)": "±0.005mm",
                    "Ultra-précision (coût élevé)": "±0.002mm",
                    "Équivalent IT": "IT7 → IT5 → IT3"
                },
                {
                    "Procédé": "Wire EDM",
                    "Standard (typique)": "±0.010mm",
                    "Précision (coût supplémentaire)": "±0.003mm",
                    "Ultra-précision (coût élevé)": "±0.001mm",
                    "Équivalent IT": "IT7 → IT4 → IT2"
                },
                {
                    "Procédé": "Sinker EDM",
                    "Standard (typique)": "±0.015mm",
                    "Précision (coût supplémentaire)": "±0.005mm",
                    "Ultra-précision (coût élevé)": "±0.002mm",
                    "Équivalent IT": "IT8 → IT5 → IT3"
                }
            ]
        }
    ]
}