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Z Overtravel Error on CNC

Sadek Akl
  • Updated

First Step in Resolving Z-Positive Overtravel Errors

Overview

A Z-positive overtravel error occurs when the CNC attempts to move the spindle above its maximum allowable height. This typically means the G-Code is calling a Z-axis coordinate that exceeds the machine’s travel limits.

This article outlines the most common causes—especially when using Mozaik—and provides steps to resolve the issue.

Cause

In Mozaik-generated programs, Z-positive overtravel is most often caused by Z-Home or Z-Safety values being set too high. When these values exceed your machine’s capabilities, the spindle is instructed to move beyond its physical limit.

How to Address the Issue in Mozaik

Check Z-Home and Z-Safety Values in Mozaik

Verify that both values are within a safe and realistic range for your machine.

  • Z-Home Position
    Defines the spindle’s reference height. Setting this too high may cause the machine to overtravel.
  • Z-Safety Position
    Determines the rapid clearance height between toolpaths. Excessive values can push the spindle beyond its travel range.

Example:

Recommended Action

Lower these values and regenerate your G-Code. In many cases, this resolves the overtravel error immediately.

If the Problem Continues

If adjusting the Z settings does not correct the error, further investigation is needed.

Please provide the following to Support:

  • The full error message or overtravel code displayed on the controller
  • The G-Code file (.NC, .TAP, .TXT, etc.) that caused the error

This information helps determine whether the issue stems from:

  • G-Code output
  • Controller data
  • Machine configuration or limits

Need More Help?

If you’re still experiencing issues or need help locating these settings, contact Mozaik Support with the necessary files and details for further diagnosis.