CNC Machining Tolerances: What ±0.01mm Really MeansCNC 加工公差：±0.01mm 意味着什么
By Ruijin CNC作者：锐金峰汇Sep 02, 20262026年9月2日Engineering工程
Tolerance is the acceptable range of deviation from a nominal dimension. It is the single most important factor driving the cost and difficulty of a machined part — and the one most commonly over-specified.
Standard ISO 2768-m tolerances are loose enough for most parts; tight tolerances need explicit call-outs.标准 ISO 2768-m 公差对多数零件够用，精密公差需显式标注。
Standard vs Tight Tolerances
A typical CNC shop holds ±0.05 mm as standard and ±0.01 mm as precision. Tighter tolerances such as ±0.005 mm are possible on critical features but require slower cutting and more inspection.
How Tolerance Affects Cost
Every step toward tighter tolerance adds slower feed rates, specialized tooling, more set-ups and additional inspection. A ±0.01 mm part can cost several times more than a ±0.05 mm part of the same shape.
Tolerance tightness drives cost exponentially: ±0.05 mm is routine, ±0.01 mm requires care, ±0.005 mm needs special processes.公差精度指数级拉高成本：±0.05 mm 常规，±0.01 mm 需谨慎，±0.005 mm 需特殊工艺。
Avoid Over-Tolerancing
Only critical, mating features need tight tolerances. Loose tolerances elsewhere keep the part economical. Over-specifying tolerance on non-critical surfaces is the most common design mistake we see.
Geometric Tolerancing
Beyond size, GD&T controls flatness, position, concentricity, parallelism and run-out. Use it to communicate how features must relate to each other, not just their size.
Geometric tolerances (GD&T) — flatness, cylindricity, position — define form and orientation independently of size.几何公差（GD&T）——平面度、圆柱度、位置度，独立于尺寸定义形状与方向。
Specifying Tolerance Correctly
State a general tolerance in the title block, then flag only critical dimensions with tighter values. This keeps drawings clean and quotes accurate.
Need a tight-tolerance part? Send your drawing for a free DFM review and a quote within 24 hours.
公差每收紧一步，都要降低进给、使用专用刀具、增加装夹与检测。±0.01 mm 的零件可能比同形状 ±0.05 mm 的零件贵数倍。
Tolerance tightness drives cost exponentially: ±0.05 mm is routine, ±0.01 mm requires care, ±0.005 mm needs special processes.公差精度指数级拉高成本：±0.05 mm 常规，±0.01 mm 需谨慎，±0.005 mm 需特殊工艺。
Geometric tolerances (GD&T) — flatness, cylindricity, position — define form and orientation independently of size.几何公差（GD&T）——平面度、圆柱度、位置度，独立于尺寸定义形状与方向。
如何正确标注
在标题栏写明通用公差，再单独标注关键尺寸的严格公差。这样图纸清晰，报价也更准确。
需要高精度零件？发送图纸，免费 DFM 评审，24 小时内获取报价。
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Send us your drawings and get a free DFM review and quotation within 24 hours.发送图纸，24 小时内获取免费 DFM 评审与报价。
