Thin Wall CNC Machining

Thin-wall CNC machining is about keeping geometry after the cutter leaves the part, not while it is cutting. We machine walls down to 0.3 mm in 6061 and 0.5 mm in stainless on 220 CNC machines in Shenzhen, holding plus or minus 0.005 mm, with prototypes in 3 to 7 days and MOQ from 1 piece.

Why thin walls move after machining

A 0.5 mm wall in 6061 does not move while the tool is cutting it - it moves afterwards, when the clamping pressure releases and the machining stress rebalances. On parts we receive for rescue jobs, the pattern is always the same: finished in one setup, clamped hard, measured flat, then bowed 0.02 to 0.05 mm by the next morning.

That is why we quote thin-wall work with the process, not just the price. If a drawing shows 0.4 mm walls with a 0.01 mm flatness callout, the process is the product.

How we hold geometry on 0.3 to 1.0 mm walls

Roughing leaves 0.15 to 0.25 mm on the wall, then the part rests overnight and the stress settles. Semi-finishing takes half of that away, another rest, and only the last pass is the finishing pass. It costs a day and saves a scrap bin.

Workholding matters more than feeds here. We bore soft jaws to the part profile, use expanding mandrels when the inside diameter is the datum, and switch to vacuum or adhesive fixturing when the wall is too thin to survive any through-slotted jaw. Finishing passes run climb-milling with light radial engagement, so the wall is pushed into support instead of pulled away from it.

Materials we thin-wall regularly

6061-T6 and 7075 down to 0.3 mm walls for optical and drone housings. 304 and 316L down to about 0.5 mm - stainless work-hardens, so each pass has to cut, not rub. Ti-6Al-4V walls stay above 0.6 mm for us; titanium springs more than aluminum at the same thickness and we would rather quote it honestly than fight it.

PEEK and other plastics are a different game: thermal growth beats cutting force, so the part cools between passes and we measure at 20 degrees Celsius, not on the machine.

How we measure a wall that flexes

A CMM probe presses on the part, so on the thinnest walls we measure with an air gauge or an optical comparator and record three orientations per feature. The inspection sheet notes the method next to the number - buyers auditing the report later see exactly how each figure was taken.