Minimum wall thickness for CNC machining

Thin walls bend away from the cutter and vibrate. The shop has to take light passes, support the wall or accept that it ends up out of tolerance.

Practical minimums

Height matters as much as thickness. Keep the height of an unsupported wall below about 10–15× its thickness. A 1 mm wall 30 mm tall is hard to make; the same wall 8 mm tall is easy.

Lighter without thin walls

• Add ribs instead of making the whole wall thinner.
• Leave a floor or a top lip to stiffen tall walls.
• Use sheet metal for thin enclosures; it is cheaper than machining a thin box from solid.