Why did my part come loose even though I added tabs?

Why this happens

1. Tab thickness is less than your overcut. Tab thickness is measured from the bottom of the cut depth, not from the bottom of the material (official documentation). If cut depth is material thickness + 0.1 mm (a normal through-cut), a 0.5 mm-thick tab has only 0.4 mm of real material, or none if the board runs thin. The tab gets machined away.
2. Tabs too small for the part weight and cutting forces, or placed where the tool approach deflects the part.
3. Tabs missing from the recalculated path. Some users report tabs disappearing after they changed toolpath settings and recalculated. This is an unconfirmed user report, not documented behavior, so always check the preview after any change.

The fix

1. Make tabs meaningfully thicker than the overcut: for example, cutting 0.1 mm past thickness, make tabs at least 0.6 mm thick, and scale up for heavy parts.
2. If you change toolpath settings after adding tabs, check the tabs still show and delete and recreate the profile toolpath with its tabs if they do not.
3. Always verify tabs are visible in the Toolpath Preview before saving G-code. If the preview shows the part fully separated, the tabs aren't in the path.

The onion-skin alternative

Instead of tabs: set cut depth to thickness minus about 0.5 mm, leaving a thin "skin" holding everything, then either run a final full-depth pass after securing the part or free it with a utility knife or flush-trim bit. There are no tab bumps to sand, and small parts can't launch.

Pro tips

• 3D tabs (triangular profile) let the bit ramp over rather than stop and jump, giving cleaner edges on visible work.
• Painter's tape plus CA glue under the part is a tab-free workholding option for small pieces.