How do I make 3D carvings faster without wrecking the finish?

Where the time goes

Finish-pass time is roughly area divided by (stepover times feed). Roughing time is roughly volume divided by removal rate. Attack each separately.

Roughing faster

1. Use the biggest tool that fits the geometry. A 1/2" or 3/8" end mill roughs several times faster than a 1/4" (collet permitting).
2. Deeper passes at moderate feed usually beat shallow-and-fast for roughing (machine rigidity is the limit).
3. Z Level strategy with a generous machining allowance (0.5 to 1 mm). Roughing exists to remove volume, not to look nice.
4. Set the boundary to the model, not the material (see the boundary entry).

Finishing faster (the big lever)

1. Stepover is the trade: the official documentation calls 8 to 12% of tool diameter typical. As a rough guide, 8% is a very fine finish, 10 to 12% is very good, and 15% shows visible lines but is sandable. Going from 8% to 12% cuts finish time by about 33%, so decide per piece, not by habit.
2. A larger ballnose where detail allows. A 1/2" ball at 10% stepover covers ground twice as fast as a 1/4" ball at 10%. At the same percentage, the ridges are twice as tall (a 1/2" ball leaves roughly twice the cusp height of a 1/4" ball), but they are still very small, on the order of 0.001". Use the tapered small-tip bit only where detail demands it.
3. Feed up. Finish passes remove little material, and most machines can run finish feeds well above roughing feeds. If the machine glides smoothly, try adding 20 to 30% (shop advice, test on scrap).
4. Split the job (the pro move): finish big smooth areas with a large ball at a bigger stepover, then run a second finish toolpath with the fine tapered ball ONLY inside boundary vectors drawn around detailed zones. Two right-sized toolpaths beat one conservative one, often halving total time.
5. Raster angle along the longest dimension (fewer direction reversals), and along the grain for looks.

What NOT to do

Don't skip roughing to "save a setup" (finishing in deep uncut material is slow AND rough), and don't chase sub-8% stepovers. Sanding for 5 minutes beats machining 2 extra hours.

Pro tips

• The Estimate Machining Time tool can use your machine's Acceleration values for a more realistic estimate. Enter your machine's real acceleration values (from your machine supplier) in the estimate settings before quoting.
• Preview the coarse-stepover result at high simulation quality before committing to the fine pass. Sometimes 12% already looks great.