PROBOTIX :: wiki PROBOTIX :: wiki

PROBOTIX spindle / Z-axis assembly

PROBOTIX Automatic Tool Changer System User Manual

🔧 Quick Reference

Item	Details
Air supply	Clean, dry 90 PSI compressed air
Cooling	Run the spindle with the chiller operating and coolant circulating
Tooling	Clean, dry ISO20 holders with secure pull studs
Tool change file	tool_change_rear_pneumatic.ngc
Break-in file	spindle_break_in.ngc

⚠	Critical safety reminders Never reach into the spindle or tool rack while the machine is enabled. Inspect pull studs periodically and never run with a loose or damaged pull stud. Treat every automatic tool change as powered machine motion.

🧭 Introduction

This manual covers the setup, operation, and maintenance of the PROBOTIX Automatic Tool Changer system. The automatic tool changer system includes the pneumatic tool rack, automatic tool change spindle, ISO20 tool holders, spindle cooling system, tool change software, and related maintenance procedures.

The system is factory configured prior to shipment. Under normal circumstances, the operator should not need to modify tool rack locations or tool pocket coordinates. The primary setup tasks for the customer are providing proper air, filling and checking the spindle cooling system, preparing the ISO20 tool holders, measuring tool lengths, and maintaining the machine.

⚠ Safety

General Safety

• Read and understand the machine manual before operating the machine.
• Keep hands, clothing, and tools clear of the spindle, tool rack, and moving machine components.
• Never reach into the tool rack or spindle area while the machine is powered and enabled.
• Always verify that the spindle is stopped before approaching the spindle or tool holder.
• Automatic tool changes involve machine motion, pneumatic actuation, and spindle tool retention. Treat the system as an automated machine tool, not a manual accessory.

Warning: Tool Holder Retention

WARNING: A loose pull stud can cause the tool holder to become improperly retained by the spindle. This can result in the tool holder being released during operation, potentially causing severe damage to the machine, workpiece, spindle, or tooling, and may result in serious personal injury or death.

Inspect all pull studs periodically for tightness, wear, or damage. Never operate the machine if a pull stud is loose or damaged.

🧩 System Overview

The PROBOTIX Automatic Tool Changer system is designed to allow the CNC machine to automatically store and retrieve tools during a machining program.

The system consists of:

• Automatic tool change spindle
• Pneumatic tool rack
• ISO20 tool holders
• Pull studs
• Collets and collet nuts
• Pneumatic drawbar actuation
• Automatic taper air purge
• Closed-loop spindle water chiller
• Factory-configured tool pocket locations
• LinuxCNC tool table and tool length offsets
• Tool change subroutine file

💨 Air Requirements

The automatic tool changer requires a clean, dry 90 PSI compressed air supply.

The air supply is used for pneumatic tool release and for the spindle taper air purge function.

Important

• Air pressure should be maintained at 90 PSI.
• Air should be clean and dry.
• Insufficient air pressure may result in unreliable tool changes or failure of the drawbar mechanism to actuate.
• Contaminated air can damage pneumatic components and may introduce contamination into the spindle taper purge system.

💾 Software Components

The automatic tool change sequence is controlled by the G-code file:

<syntaxhighlight lang="text"> tool_change_rear_pneumatic.ngc </syntaxhighlight>

This file contains the automatic tool change logic used by the system. The controller executes this routine whenever a tool change command is issued.

ℹ	Factory note: Tool pocket locations are factory-configured. In normal use, the customer is responsible for air, cooling, tool preparation, tool measurement, and maintenance — not rack geometry changes.

🗄 Tool Rack Configuration

The pneumatic tool rack and the locations for all tools are pre-configured by PROBOTIX at the factory before shipping.

Under normal circumstances, the tool positions should not require adjustment.

Tool positions only need to be recalibrated if:

• The machine home switch locations change, or
• The mounting position of the automatic tool changer spindle changes.

Any changes that affect the machine home position or spindle mounting position may alter the relationship between the spindle and the tool rack. If this occurs, the tool pocket coordinates may need to be reset.

📍 Tool Pocket Calibration

The automatic tool change sequence is contained in:

<syntaxhighlight lang="text"> tool_change_rear_pneumatic.ngc </syntaxhighlight>

Tool 1 serves as the master reference pocket for the tool rack.

If the machine home switch locations or spindle mounting position change, the Tool 1 location in the `.ngc` file must be updated.

All remaining tool pocket locations are based on this reference position and normally do not require adjustment.

Important Concept

Tool pocket positions define where the machine stores and retrieves tools.

Tool length offsets define where the cutting tip of each tool is located.

These are separate adjustments and should not be confused.

🧰 ISO20 Tool Holders

PROBOTIX automatic tool change spindles use ISO20 tool holders.

ISO20 holders provide a repeatable and secure interface between the spindle and cutting tools. Use only clean, undamaged ISO20 tool holders to ensure reliable tool changes and maintain spindle accuracy.

Preparing New ISO20 Tool Holders

Before placing a new ISO20 tool holder into service, perform the following steps.

1. Remove the Shipping Rust Inhibitor

New ISO20 tool holders are typically shipped with a sticky rust inhibitor to protect the precision surfaces during storage and shipping.

Before installing a new tool holder in the spindle:

1. Spray the tool holder taper with WD-40.
2. Wipe away all of the rust inhibitor using a clean, lint-free cloth.
3. Inspect the taper to ensure it is clean and free of residue.
4. Wipe the pull stud and flange clean before placing the tool holder into service.

Important:

• Do not install a new tool holder with the shipping rust inhibitor still present.
• The spindle taper and tool holder taper should always be clean and dry before use.
• Any residue, oil, chips, or dust between the mating tapers can reduce accuracy, affect tool retention, and increase taper wear.

2. Install the Collet

Before tightening the collet nut, ensure that the collet is properly snapped into the retaining lip of the nut.

Never insert the collet into the tool holder first.

The collet must be clipped into the nut before the nut is threaded onto the tool holder.

Failure to properly seat the collet in the nut can result in poor tool retention or damage to the collet and nut.

3. Verify the Pull Stud Installation

Some ISO20 tool holders are shipped with the pull stud already installed. However, the pull stud may not have been installed with thread-locking compound.

Before placing a tool holder into service:

1. Remove the pull stud.
2. Clean the threads in both the pull stud and the tool holder.
3. Apply a medium-strength thread-locking compound such as Loctite Blue 242.
4. Reinstall the pull stud and tighten it securely.

WARNING: A loose pull stud can cause the tool holder to become improperly retained by the spindle. This can result in the tool holder being released during operation, potentially causing severe damage to the machine, workpiece, spindle, or tooling, and may result in serious personal injury or death.

Inspect all pull studs periodically for tightness, wear, or damage. Never operate the machine if a pull stud is loose or damaged.

🌀 Spindle Features

Automatic Taper Air Purge

The automatic tool change spindle incorporates an internal taper air purge function.

During every tool change, compressed air is blown into the ISO20 spindle taper. This air blast helps remove dust and debris and helps prevent contaminants from entering the taper while tools are being exchanged.

Benefits

• Helps maintain spindle accuracy.
• Reduces contamination between the spindle and tool holder.
• Improves tool retention reliability.
• Extends spindle and tool holder life.

Important

• The taper air purge is automatic and requires no operator intervention.
• The air purge helps reduce contamination but does not eliminate the need for periodic cleaning.
• Reliable operation of the purge system requires a clean, dry 90 PSI air supply.
• Keep the spindle taper and tool holders clean, even though the air purge provides additional protection.
• Do not intentionally blow chips or dust into the spindle taper.

❄ Spindle Cooling System

The automatic tool change spindle is supplied with a closed-loop water chiller.

Proper coolant flow is required for reliable spindle performance and long spindle life.

Always operate the spindle with the chiller running.

Coolant Mixture

We recommend filling the cooling system with:

• 80% distilled water
• 20% propylene glycol or automotive antifreeze

This mixture provides:

• Corrosion protection
• Biological growth inhibition
• Good heat transfer characteristics

Important

• Use distilled water only. Tap water can leave mineral deposits in the spindle and chiller.
• Do not use straight water, as it can promote corrosion and biological growth.
• Do not use straight antifreeze, as excessive concentration reduces cooling performance.
• Periodically inspect the coolant level and verify that coolant is circulating before operating the spindle.
• Inspect hoses and fittings periodically for leaks or restrictions.

Initial Setup

The water chiller system is shipped dry and is not filled or tested at the factory.

After filling the system and circulating coolant for the first time, inspect all hoses and fittings carefully.

Check for and correct any leaks before operating the spindle.

Recheck all connections after several hours of operation, as some fittings may require retightening after the tubing has relaxed.

📏 Tool Length Measurement

Before using the automatic tool changer, a method for establishing tool lengths must be selected.

Two common methods are supported:

• Tool measuring fixture
• Fixed machine reference location

Using a Tool Measuring Fixture

A dedicated tool measuring fixture may be installed on the machine.

Each tool is measured against the fixture, and the resulting tool length offsets are stored in the LinuxCNC tool table.

This method provides a repeatable and convenient means of maintaining tool lengths.

Using a Fixed Machine Reference

Tool lengths may also be established from a fixed location on the machine frame.

The reference surface should be rigid and remain unchanged over the life of the machine.

All tools must be measured from the same reference surface.

Recommended Fixed Reference Procedure

1. Install a tool in the spindle.
2. Lower the spindle until the nose of the spindle contacts the selected reference surface on the machine frame.
3. Zero the Z-axis digital readout in LinuxCNC.
4. Raise the spindle and install the tool to be measured.
5. Lower the tool until its tip contacts the same reference surface.
6. Record the Z-axis reading shown on the LinuxCNC digital readout.
7. Enter this value as the tool length for that tool before storing the tool in the automatic tool changer.

Tool Length Sign Convention

Tool length values are entered as positive numbers.

The tool length values create a positive Z offset when the tool is loaded.

Longer tools therefore have larger positive tool length values.

Entering a negative tool length value will result in incorrect tool positioning.

Important

• The automatic tool changer does not automatically determine tool lengths.
• The user is responsible for selecting and maintaining a consistent tool measurement method.
• Any change to the reference surface or measuring fixture requires the affected tools to be remeasured.
• Consistency is more important than the particular measurement method chosen.

🎯 Workpiece Z Zeroing

Once tool lengths have been established and entered into the tool table, any tool may be used to set the workpiece Z zero.

Procedure

1. Load any tool whose length has been entered into the tool table.
2. Ensure that the correct tool number and tool length offset are active.
3. Touch the tool to the workpiece or touch plate using your preferred method.
4. Set the work coordinate Z zero.

LinuxCNC automatically applies the active tool length offset, so the workpiece Z zero will remain correct regardless of which tool was used to establish it.

Important

• Any tool may be used to establish Z zero.
• The active tool length offset must be loaded before performing the touch-off.
• LinuxCNC automatically compensates for differences in tool length.
• No manual calculations are required.
• Once the workpiece Z zero is established, subsequent tool changes will maintain the correct cutting depth provided the tool length values are accurate.

🔄 Spindle Break-In Procedure

The spindle is capable of operating from 7,000 RPM to 24,000 RPM.

Prior to placing a new spindle into service, or after the machine has been idle for an extended period, PROBOTIX recommends performing a spindle break-in procedure to distribute grease evenly throughout the spindle bearings and promote long bearing life.

Break-In Notes

• Verify that the cooling system is operating properly before starting.
• Perform the break-in with no cutting load.
• Install a clean tool holder if applicable.
• Allow the spindle to accelerate and stabilize before increasing to the next speed.
• Monitor for abnormal noise, vibration, or excessive heating.
• If the spindle has been out of service for several months, repeating the break-in procedure is recommended before resuming normal operation.

Spindle Break-In

The spindle is capable of operating from 7,000 RPM to 24,000 RPM.

Prior to placing a new spindle into service, or after the machine has been idle for an extended period, PROBOTIX recommends performing the spindle break-in procedure to distribute grease evenly throughout the spindle bearings and promote long bearing life.

Included Break-In Program

A spindle break-in program is included with every machine.

The file is located in the LinuxCNC nc_files directory:

<syntaxhighlight lang="text"> spindle_break_in.ngc </syntaxhighlight>

Load and run this program directly from LinuxCNC.

The program automatically steps the spindle through the recommended break-in speeds and dwell times.

Before Running the Program

• Verify that the spindle cooling system is operating properly.
• Perform the break-in with no cutting load.
• Install a clean tool holder if applicable.
• Monitor the spindle for abnormal noise, vibration, or excessive heating.

The program performs the following schedule automatically:

⏱	Run time: approximately 1 hour and 45 minutes from start to finish.

Speed	Time
7,000 RPM	15 minutes
10,000 RPM	15 minutes
13,000 RPM	15 minutes
16,000 RPM	15 minutes
19,000 RPM	15 minutes
22,000 RPM	15 minutes
24,000 RPM	15 minutes

Spindle Break-In G-Code

This LinuxCNC G-code program is suitable for ATC and non-ATC spindles, and for water-cooled and air-cooled spindles.

<syntaxhighlight lang="text"> % ( PROBOTIX SPINDLE BREAK-IN PROGRAM ) ( Suitable for ATC and non-ATC spindles ) ( Suitable for water-cooled and air-cooled spindles ) ( Perform break-in with no cutting load ) ( Install a clean tool holder if applicable )

G17 G20 G40 G49 G54 G80 G90 G94

( Operator safety pause ) M0 ( Verify spindle cooling system is operating properly )

( Begin break-in cycle )

S7000 M3 G4 P900

S10000 G4 P900

S13000 G4 P900

S16000 G4 P900

S19000 G4 P900

S22000 G4 P900

S24000 G4 P900

M5

M0 ( Break-in complete. Verify normal spindle temperature, sound, and operation. )

M2 % </syntaxhighlight>

🛠 Maintenance

Proper maintenance is essential for reliable tool changes, spindle accuracy, and long machine life.

Major maintenance areas include:

• ISO20 spindle taper cleaning
• Tool holder cleaning and inspection
• Pull stud inspection
• Spindle cooling system inspection
• Air supply inspection

🧼 Cleaning the ISO20 Spindle Taper

Periodically inspect and clean the internal ISO20 spindle taper.

The taper should be kept free of dust, chips, resin buildup, and other contaminants.

Contamination between the spindle taper and tool holder can reduce accuracy and adversely affect tool retention.

Procedure

1. Stop the spindle.
2. Remove the tool holder.
3. Inspect the internal spindle taper.
4. Wipe the taper with a clean, lint-free cloth as needed.
5. Inspect the tool holder taper before reinstalling.

Important

• Never insert dirty tool holders into the spindle.
• Do not use abrasive materials that may damage the precision ground taper surfaces.
• The spindle's automatic air purge helps prevent contamination, but regular inspection and cleaning are still required.
• The spindle taper is a precision interface. Keeping both the spindle taper and ISO20 tool holders clean is one of the most important factors in maintaining accuracy and ensuring reliable tool changes.

🛤 Machine Motion Maintenance

Ball screw and linear rail lubrication / service information has been moved to EX/EXR Series Maintenance Guide.

For this ATC page, keep the focus on spindle, tool-holder, cooling, air, and tool-change-specific items.

📅 Preventive Maintenance Schedule

Maintenance Item	Recommended Interval
Check air pressure	Daily / before operation
Verify coolant circulation	Daily / before spindle operation
Inspect coolant hoses and fittings	During setup, then periodically
Clean ISO20 spindle taper	Periodically / as needed
Inspect tool holder tapers	Before loading tools
Inspect pull studs	Periodically and before placing new holders into service
Spindle break-in	Before first use, or after extended idle period

🔍 Troubleshooting

🔎	Use the symptom lists below as a quick triage guide. Start with air pressure, cleanliness, coolant flow, and tool length data before assuming a spindle or mechanical fault.

Tool Change Fails or Tool Does Not Release

Possible causes:

• Air pressure below 90 PSI
• Air supply restricted or disconnected
• Contaminated air supply
• Pneumatic drawbar issue
• Tool holder or pull stud issue

Corrective actions:

• Verify 90 PSI air pressure.
• Check air connections.
• Inspect tool holder and pull stud.
• Contact PROBOTIX if the problem persists.

Tool Does Not Seat Properly

Possible causes:

• Dirty ISO20 spindle taper
• Dirty tool holder taper
• Rust inhibitor left on new tool holder
• Damaged tool holder
• Loose or damaged pull stud
• Low air pressure affecting taper purge or drawbar action

Corrective actions:

• Clean the spindle taper.
• Clean the tool holder taper.
• Verify pull stud installation with Loctite.
• Inspect tooling for damage.
• Verify 90 PSI air supply.

Cutting Depth Incorrect After Tool Change

Possible causes:

• Incorrect tool length value
• Tool length offset not loaded
• Tool measured from a different reference
• Negative tool length value entered by mistake
• Workpiece Z zero set without active tool offset

Corrective actions:

• Verify the correct tool number is active.
• Verify the correct tool length offset is loaded.
• Remeasure tool length using the selected reference method.
• Confirm that tool length values are positive.
• Reset workpiece Z zero with the proper tool offset active.

Spindle Runs Hot

Possible causes:

• Chiller not running
• Coolant not circulating
• Low coolant level
• Coolant line restriction
• Improper coolant mixture
• Spindle not broken in

Corrective actions:

• Verify chiller operation.
• Verify coolant circulation.
• Inspect coolant hoses and fittings.
• Check coolant level.
• Perform spindle break-in if required.

📦 Appendix A: Recommended Consumables

Thread Locker

Loctite Blue 242 or equivalent medium-strength removable thread-locking compound.

Used for ISO20 pull studs.

Tool Holder Cleaning

WD-40 may be used to remove the sticky shipping rust inhibitor from new ISO20 tool holders.

After cleaning, wipe tool holders dry with a clean, lint-free cloth.

📁 Appendix B: Files

File	Purpose
tool_change_rear_pneumatic.ngc	Automatic tool-change sequence for the rear pneumatic tool changer
spindle_break_in.ngc	Recommended staged spindle break-in program

Tool Change File

tool_change_rear_pneumatic.ngc

This file contains the automatic tool change sequence for the rear pneumatic tool changer.

Spindle Break-In File

<syntaxhighlight lang="text"> spindle_break_in.ngc </syntaxhighlight>

This file contains the staged spindle break-in routine.

📝 Notes for Future Expansion

The following topics should be expanded as additional details, photos, or procedures are added:

• Tool rack photographs
• Tool pocket diagram
• ISO20 holder anatomy
• Pull stud photo
• Collet installation photo
• Grease zerk locations
• Z-axis removal procedure
• Ball nut block access procedure
• Cooling system plumbing diagram
• LinuxCNC tool table screenshots
• Tool length measurement example
• Tool change test procedure
• Recovery procedure after failed tool change