Warning

MillMage is in active development and in a prerelease state. Many operations and functions are not feature complete. Please report any unexpected behavior by searching for and reporting the issue or question in the MillMage Beta User Forum. Please include screenshots and as much detail as possible.

Beta Users: Finding Help

Find help and download the latest release candidate of MillMage in the MillMage Beta User Forum.

Users new to MillMage should follow the Getting Started guide.

Warning

This documentation is in active development and in a prerelease state. These documents are not complete and may include missing pages, broken links, and placeholders. Content is being updated as feedback is reviewed. Your patience is appreciated.

Tool Length Probing

This guide covers using a Tool Length Probe with the Probing Wizard to automatically calculate the length of the installed tool to determine and apply the tool offset needed to maintain the project Z axis zero point.

Tool Length Probes will vary in type, location, and material, but typically work the same — a sensor or mechanical switch is triggered when the tip of the tool reaches the Tool Length Probe activation point.

Using a probe to do this isn't strictly necessary for basic CNC work – you can find and reset your Z axis zero manually after changing tools — but it will reduce operation cycle time by removing the need to re-zero the Z axis after changing bits.

This is especially helpful when the Project Z Axis Zero Point is set to Top and has been machined away during previous operations, and can aid in project recovery and completion when the spindle, router, or tool has slipped and been re-secured but potentially at a different height.

To follow this guide, you'll need:

• A CNC machine with a built-in Tool Length microswitch or sensor
• Tooling & bits
• Wrench(s) to loosen and tighten the router or spindle collet holding the tool.

How Tool Length Probing Works

Once triggered in MillMage, the Probe Wizard will:

1. Move the tool to the user-defined probe location along the X and Y axis
2. Home the Z axis
3. Move the tool down the user-defined Search Z distance at the Fast probe feed speed on the Z axis until the probing switch or sensor is triggered
4. Move the tool up away from the sensor
5. Approach the sensor again, this time at the slower Precise probe feed speed until the probing switch or sensor is triggered
6. Set the new tool Z axis zero point

Setting Up a Tool Length Probe

Define the parameters needed for successful tool length probing by selecting CNC Tools → Probe Settings → Tool Length Probe to open the Tool Length Probe configuration panel.

Access these settings within the Probing Wizard by selecting Manage Probe Configuration on the first page of the wizard.

If you've already set up Tool Length Probe, skip ahead to Probing.

Settings

Position X and Position Y

• Position X is the machine coordinates (G53) of the Tool Length Probe on the X axis.
• Position Y is the machine coordinates (G53) of the Tool Length Probe on the Y axis.

Finding Position X and Position Y

Use MillMage to determine the Tool Length Probe location.

1. Close the Probing Wizard if open
2. Select the Move Window
3. Use the jogging buttons to move and roughly center the tool above the Tool Length Probe location
4. Note the machine X and Y axis coordinates in the Move window, labeled Tool Position (M)
5. Open the Tool Length Probe settings and update the Position X and Position Y values

Search Z

Search Z is the distance the tool will move down seeking the Tool Length Probe.

Fast Probe Feed and Precise Probe Feed

• Fast Probe Feed is the initial speed at which the tool will move down towards the Tool Length Probe. This can be fairly fast depending on your risk tolerance.
• Precise Probe Feed is the typically lower speed at which the tool will search for the probe block after initial contact. This movement will be a very short distance and should be kept to a fairly low speed for accuracy.

Activating Tool Length Probing

Warning

Make sure that before you start probing for tool length that the spindle or router collet is tight and the tool secure. The spindle or router must be off and not rotating.

Probing

Open the Probing Wizard by selecting CNC Tools → Probing Wizard, or by clicking the Probing button in the Move window.

1. Select Tool Length Probe

2. Ensure Spindle or Router is Powered Off

Warning

Make sure that before you start probing for tool length that the spindle or router collet is tight and the tool secure. The spindle or router must be off and not rotating.

3. Verify Probing Distance

The tip of the tool must be within the displayed user-set Search Z value of the probe trigger point.

Check the distance between the tip of the installed tool and the approximate trigger point of the Tool Length Probe. Loosen and lower the installed tool if needed to ensure proper probe activation.

Alternatively, change this value in the Tool Probe Configuration window if needed, or manually edit the Tool Length Probe value in the Custom GCode tab of the Device Settings window and reopen the Probe Wizard.

Updating the Z Axis Search Distance in Custom GCode

Update the Tool Length Probe Z Axis Search Distance manually by updating the Tool Length Probe value in the Custom GCode tab of the Device Settings window, on the line starting with:

G38.2 Z-YourValueHere F600

4. Start Tool Length Probing

Select Execute Tool Length Probe

5. Monitor Probing Process

Once executed in MillMage, the Probe Wizard will automatically and without further user input:

1. Move the tool to the user-defined tool length probe location along the X and Y axis
2. Home the Z axis
3. Move the tool down the user-defined Search Z distance at the Fast probe feed speed on the Z axis until the probe is triggered
4. Move the tool up away from the probe
5. Approach the probe again, this time at the slower Precise probe feed speed until the probe is triggered
6. Set the new tool Z axis zero point

That's it! Run the remaining tool-specific operations in the project or until the next tool change is needed. Run the Tool Length Probe in the Probing Wizard again after additional tool changes within the current project.

Additional Probing Methods

XYZ Probe Block

Place a machined block over the material stock or in a known position within the work area and set the Z Axis zero point.

Tool Length Probe

Establish tool length offsets when changing tooling in multi-operation jobs without changing the work Z axis zero point.

Related Topics

• Add Tabs
• Safety and Warnings
• Project Setup Wizard
• MillMage User Interface Guide

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For more help using MillMage, please visit our forum to talk with MillMage staff and users, or email support.

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