Thin wall

A thin wall is a wall section thin enough, relative to its height and the cutting forces applied to it, that it risks deflecting, vibrating or distorting during machining, or warping afterward as internal stresses release. What counts as "thin" depends on material, height and how the wall is supported, not on a single universal ratio.

Why thin walls affect cycle time more than their volume suggests

Thin walls often force a slower feed rate, a lighter cut, or a different tool strategy (climb milling, multiple light passes) to control deflection, which can add meaningfully to cycle time even though the removed material volume is small.

Where thin walls show up

Implied by wall thickness dimensions relative to feature height and depth, rather than called out with its own explicit symbol.

Common mistakes

Judging wall thickness only in isolation, without checking it against the wall's height and the material's stiffness; a wall that is fine on one part can be genuinely thin on a taller, otherwise similar one.

Is there a fixed thickness that counts as a thin wall?

No, it depends on the wall's height, the material, and how it is supported during machining, not a single fixed ratio.

Why does a thin wall slow down machining?

Because a lighter cut, slower feed, or extra finishing passes are often needed to keep the wall from deflecting or vibrating.

Can a thin wall distort after machining is finished?

Yes, released internal material stresses can cause a thin wall to warp even after it measured correctly right off the machine.