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Roughness Ra

Pick a roughness — see what it is for, which processes reach it and how to write it on the drawing.

Example: Ra 1.6 for an H7 fit → finish milling or turning; FDM printing cannot reach it.

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Surface roughness Ra

Ra is the arithmetic mean deviation of the profile in µm. The lower, the smoother — and the more expensive. Pick a value:

Which process gives which roughness (typical ranges)

    Ranges are typical values from practice, not guarantees. Real roughness depends on the tool, cutting data, material and machine. The Ra → Rz conversion is only approximate.

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