CNC fundamentals

Understand safe clearance

See why the cutter lifts before travelling across the stock.

About 4 minCadivari 0.3.0Watch and try

Useful first: Understand axes and work zero

Safe Z is the ordinary linking height above stock-top Z0. Service / park Z is a higher work-coordinate height used for tool changes and program completion. Both must fit the real setup and the available machine travel.
Safe Z is the ordinary linking height above stock-top Z0. Service / park Z is a higher work-coordinate height used for tool changes and program completion. Both must fit the real setup and the available machine travel.

Safe Z is the ordinary linking height above stock-top Z0. Service / park Z is a higher work-coordinate height used for tool changes and program completion. Both must fit the real setup and the available machine travel.

Try it in Cadivari

  1. Find the clearance fields

    In CAM, choose Setup. Expand Stock to find Safe Z, then expand Machine to find Service / park Z. Both heights are measured above the top of the stock.

  2. Check the whole assembly

    Compare the required clearance with the real clamps and fixtures, cutter stick-out, holder and machine Z travel. The drawn stock margin does not represent your clamps.

  3. Set suitable heights

    Enter Safe Z for ordinary linking moves. Set Service / park Z higher than Safe Z while keeping it within the available travel. The defaults are starting values, not a clearance check.

  4. Inspect motion when a path exists

    After adding an operation, open the 3D preview and Simulate → Toolpaths. Watch the initial approach, linking lifts and final retract. Compare them with the G-code before export.

Over to you

A small exercise

Pause the animation just before sideways travel. Identify what the cutter has already done. Then locate both clearance fields in your practice project.

What you should see

You can distinguish ordinary Safe Z moves from the higher service height and explain why the cutter lifts before crossing a clamp.

Things to look out for

  • Cadivari does not model every clamp, fixture or holder collision.
  • Service / park Z is a work-coordinate height. It is not a command to move to machine home.
Check your understandingDoes a larger stock margin automatically give clamp clearance

No. Drawing margin and physical clearance are different. Check the actual workholding and available Z travel.

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Go deeper in the knowledge base

Instructions checked against the Cadivari 0.3.0 source and knowledge base on 2026-09-16. Lesson revision 1.