{
    "slug": "minimum-wall-thickness",
    "title": "CNC 加工零件的最小壁厚",
    "description": "铝、钢、不锈钢、钛、铜和工程塑料的最小壁厚与推荐壁厚对照表，含薄壁的壁高限制、装夹方式选择，以及把壁厚做薄带来的公差与成本代价，可按材料与工艺直接查表，标注评审时直接引用。",
    "lang": "zh",
    "tables": [
        {
            "caption": "按材料划分的最小及推荐壁厚",
            "columns": [
                "材料",
                "绝对最小值",
                "推荐值",
                "太薄时会发生什么"
            ],
            "rows": [
                {
                    "材料": "Aluminium (6061, 7075)",
                    "绝对最小值": "0.5 mm",
                    "推荐值": "1.0 mm",
                    "太薄时会发生什么": "精加工时产生颤振，壁面偏离刀具，尺寸超出公差。"
                },
                {
                    "材料": "Steel (1045, 4140)",
                    "绝对最小值": "0.8 mm",
                    "推荐值": "1.5 mm",
                    "太薄时会发生什么": "壁厚为 0.5 mm 时，钢材加工的刀具挠曲严重，壁面向内弯曲。更硬的钢材会加剧这种情况。"
                },
                {
                    "材料": "Stainless steel (304, 316)",
                    "绝对最小值": "0.9 mm",
                    "推荐值": "1.5 mm",
                    "太薄时会发生什么": "不锈钢会迅速加工硬化。薄壁会过热、翘曲并可能开裂，同时刀具磨损会加快。"
                },
                {
                    "材料": "Titanium (Ti-6Al-4V)",
                    "绝对最小值": "1.0 mm",
                    "推荐值": "1.5 mm",
                    "太薄时会发生什么": "钛的导热性低，因此热量会在薄壁部位积聚并导致热变形。"
                },
                {
                    "材料": "Copper and brass",
                    "绝对最小值": "0.5 mm",
                    "推荐值": "0.8 mm",
                    "太薄时会发生什么": "材料较软是有利的，铜壁可以做到相当薄，但极薄的铜壁在搬运和装配过程中容易损坏。"
                },
                {
                    "材料": "Engineering plastics (Delrin, Nylon, PEEK)",
                    "绝对最小值": "0.4 mm",
                    "推荐值": "0.8 mm",
                    "太薄时会发生什么": "塑料在切削力作用下会发生挠曲，薄壁会向远离刀具的方向弯曲，从而产生毛刺并降低精度。"
                }
            ]
        },
        {
            "caption": "壁可以做到多高",
            "columns": [
                "规则",
                "指导原则",
                "为什么重要"
            ],
            "rows": [
                {
                    "规则": "",
                    "指导原则": "Wall thickness at least 1/5 of the adjacent feature height",
                    "为什么重要": "高而薄的壁表现得像悬臂梁。"
                },
                {
                    "规则": "",
                    "指导原则": "Maximum unsupported height = 8× wall thickness in aluminium, 5× in steel",
                    "为什么重要": "超过此比例，壁在加工过程中会振动。"
                },
                {
                    "规则": "",
                    "指导原则": "Keep walls within 20% of each other on the same part",
                    "为什么重要": "壁厚不均会导致热处理时冷却差异和应力不均。"
                },
                {
                    "规则": "",
                    "指导原则": "Gradual transitions between thick and thin sections",
                    "为什么重要": "壁厚的突然变化会形成应力集中。添加圆角或斜面。"
                },
                {
                    "规则": "",
                    "指导原则": "Rib thickness = 0.6× wall thickness, rib height at or below 5× rib thickness",
                    "为什么重要": "厚筋会在相对表面上产生缩痕。"
                }
            ]
        },
        {
            "caption": "壁厚要求过紧的代价",
            "columns": [
                "设计特征",
                "标准规范",
                "严格或困难的规范",
                "成本乘数"
            ],
            "rows": [
                {
                    "设计特征": "Wall thickness (aluminium)",
                    "标准规范": "at least 1.0 mm",
                    "严格或困难的规范": "0.5–0.8 mm",
                    "成本乘数": "1.3–1.8×"
                },
                {
                    "设计特征": "Wall thickness (steel)",
                    "标准规范": "at least 1.5 mm",
                    "严格或困难的规范": "0.8–1.2 mm",
                    "成本乘数": "1.4–2.0×"
                },
                {
                    "设计特征": "Internal fillet radius",
                    "标准规范": "R3–R6 mm",
                    "严格或困难的规范": "R0.5 mm or smaller",
                    "成本乘数": "1.8–3.0×"
                },
                {
                    "设计特征": "Floor radius in pocket",
                    "标准规范": "R1–R3 mm",
                    "严格或困难的规范": "R0 (sharp)",
                    "成本乘数": "3.0–5.0×"
                },
                {
                    "设计特征": "Edge break",
                    "标准规范": "0.5 mm chamfer (default)",
                    "严格或困难的规范": "Sharp edges, no break",
                    "成本乘数": "1.0×, but higher handling risk"
                },
                {
                    "设计特征": "External radius",
                    "标准规范": "Sharp or 0.5 mm break",
                    "严格或困难的规范": "Large cosmetic radius, R5 and above",
                    "成本乘数": "1.1–1.3×"
                },
                {
                    "设计特征": "Deep pocket aspect ratio",
                    "标准规范": "depth at or below 4× width",
                    "严格或困难的规范": "depth above 6× width",
                    "成本乘数": "1.5–2.5×"
                },
                {
                    "设计特征": "Tall thin wall",
                    "标准规范": "height at or below 5× thickness",
                    "严格或困难的规范": "height above 8× thickness",
                    "成本乘数": "1.5–2.0×"
                }
            ]
        },
        {
            "caption": "加工薄壁时如何装夹",
            "columns": [
                "装夹方法",
                "最小壁厚",
                "材料兼容性",
                "典型挠度",
                "最佳用途"
            ],
            "rows": [
                {
                    "装夹方法": "Hard jaws (standard)",
                    "最小壁厚": "at least 6 mm",
                    "材料兼容性": "All metals",
                    "典型挠度": "0.1–0.3 mm",
                    "最佳用途": "仅适用于厚零件"
                },
                {
                    "装夹方法": "Soft jaws (machinable)",
                    "最小壁厚": "at least 1.5 mm",
                    "材料兼容性": "All metals",
                    "典型挠度": "0.02–0.05 mm",
                    "最佳用途": "一般薄壁"
                },
                {
                    "装夹方法": "Vacuum chuck",
                    "最小壁厚": "at least 0.3 mm (foil)",
                    "材料兼容性": "Non-porous, any metal",
                    "典型挠度": "0.01–0.03 mm",
                    "最佳用途": "平板件，轻切削"
                },
                {
                    "装夹方法": "Magnetic chuck",
                    "最小壁厚": "at least 1 mm",
                    "材料兼容性": "Ferromagnetic only",
                    "典型挠度": "0.02–0.08 mm",
                    "最佳用途": "钢制磨削平板"
                },
                {
                    "装夹方法": "Wax potting",
                    "最小壁厚": "at least 0.5 mm",
                    "材料兼容性": "All metals, avoid thermal exposure",
                    "典型挠度": "0.01–0.05 mm",
                    "最佳用途": "薄壁粗加工"
                },
                {
                    "装夹方法": "Low-melt alloy",
                    "最小壁厚": "at least 0.5 mm",
                    "材料兼容性": "All metals, check thermal history",
                    "典型挠度": "0.005–0.02 mm",
                    "最佳用途": "复杂薄壁型腔"
                },
                {
                    "装夹方法": "Sacrificial tabs or bosses",
                    "最小壁厚": "Any, by design",
                    "材料兼容性": "All metals",
                    "典型挠度": "Effectively zero",
                    "最佳用途": "最佳通用答案"
                }
            ]
        }
    ]
}