Overview
Stay Down nesting is a nesting strategy in Mozaik where the router bit remains at cutting depth between consecutive cuts instead of retracting to Z safe height after each part. The machine moves laterally at cutting depth to the next cut start point, eliminating unnecessary Z lifts and saving cycle time on large nesting runs.
Key concept: Stay Down affects inter-part Z retracts only. It does not remove lead-ins, ramps, tabs, or the initial plunge. The machine will still lift automatically when the path between cuts crosses a previously cut area or kerf gap.
What Stay Down Changes
When Stay Down is enabled, the following behavior changes:
• The router stays at cutting depth between part cutouts instead of retracting to Z safe height
• Inter-part moves happen at cutting depth
• The machine travels the shortest clear path between the end of one cut and the start of the next
What Stay Down Does Not Change
The following behaviors are preserved regardless of Stay Down being enabled:
• Initial plunge and ramp entry into the first cut
• Final Z retract at the end of the cut sequence
• Tab placement and height — tabs are fully respected
• Lift logic — if the inter-part path crosses a previously cut kerf or boundary, the machine will still lift automatically for that move
• Ramp and lead-in settings configured at the tool definition level
When to Use Stay Down
Stay Down works best in the following scenarios:
• Large sheets with high part counts — more parts means more Z lifts eliminated
• Jobs running the same material thickness throughout the sheet
• Flat panel cutting: plywood, MDF, melamine, and similar sheet goods
• High-production environments where cycle time is a priority
• Machines where Z axis movement is slower than XY rapids
Avoid or use with caution in the following scenarios:
• Sheets with mixed material thicknesses
• Sheets with spoilboard fixtures, hold-down screws, or clamps in the inter-part travel path
• Machines with spoilboard irregularities or uneven surfaces
• Nested sheets with complex interlocking shapes where inter-part paths are not guaranteed to be clear
Symptoms of Incorrect Setup
• Ramp or lead-in not appearing in the toolpath after enabling Stay Down
• Tool contacting a hold-down screw or fixture during a lateral inter-part move
• Machine lifting between every cut despite Stay Down being enabled
• Unexpected errors when generating the nest after changing Stay Down settings
Most Stay Down issues are caused by one of the following:
• Ramp or lead-in settings being reset at the tool definition level — unrelated to Stay Down itself, but often noticed at the same time
• Hold-down hardware or spoilboard fixtures placed in the lateral inter-part travel path
• Stay Down being applied to a drilling tool group instead of routing/profiling only
• Nesting not being regenerated after the Stay Down setting was changed
Resolution
Ramp or lead-in disappeared after enabling Stay Down:
• Stay Down does not remove lead-ins — this is a tool setting issue
• Open the tool definition in Mozaik and confirm the ramp and lead-in are still configured
• If the tool was recently modified or the post was re-imported, ramp settings may have been reset to default
• Correct the tool definition and regenerate the nest
Tool contacted a fixture or screw during a lateral move:
• This is a setup issue, not a software issue
• Review fixture and hold-down screw placement to ensure all hardware is outside the nesting lateral travel paths
• Use Mozaik's clamp avoidance features if available, or adjust part placement manually
• Run a dry pass (spindle off, Z raised) to visually confirm all lateral paths are clear before cutting
Machine is lifting between some cuts but not others:
• This is correct and expected behavior
• Mozaik uses path logic to determine when staying down is safe — if the inter-part path crosses a previously cut kerf or boundary, the machine lifts for that move only
• This is not a malfunction
Stay Down changes not reflecting in the nest:
• Regenerate the nesting run — changes to nesting strategy require a fresh nest to take effect
Preview shows the bit traveling through material between parts:
• This is expected — the preview correctly shows the lateral move at cutting depth
• This is not an error; reassure the customer the toolpath is correct
Additional Notes
• Stay Down should only be enabled for routing and profiling operations — do not apply it to drilling tool groups
• Before enabling Stay Down on a machine for the first time, run a dry pass with the spindle off and Z raised to visually confirm all lateral inter-part paths are clear
• If tool contact or machine faults occur after enabling Stay Down and the above steps do not resolve the issue, escalate with the job file and a screen recording of the nesting preview for post processor review