Minimum Quantity Lubrication - How it Works and Troubleshooting Guide

How it Works

The Minimum Quantity Lubrication (MQL) system delivers a steady flow of compressed air and a small quantity of cutting oil directly to the cutting tool or tap.

The MQL system consists of two parts: a spray nozzle atomizer with a needle valve [1], and an oil reservoir with a pressure regulator and gauge [2]. You control the necessary flow of oil using the atomizer needle valve. The air pressure regulator at the oil reservoir controls the MQL air pressure and is used for fine adjustment.

The AAG solenoid in the lube panel provides air pressure for the AAG and also supplies pressure to the MQL reservoir. The MQL system mixes cutting oil with the stream of air at the AAG on the spindle head. The oil and air mixture then sprays the cutting zone.

To manually start and stop the AAG/MQL:

Press SHIFT and then COOLANT. Repeat this command or press reset to stop the air/oil flow.

Start and stop in Program Mode

The M83 code starts the AAG/MQL. M84 stops the AAG/MQL.

An M83 Pnnn code can also be programmed. This starts the AAG/MQL for nnn milliseconds, and stops the AAG automatically.

Example: M83 P5000 will turn on the AAG/MQL for 5 seconds.

Symptom Possible Cause Corrective Action Section
Low or no oil from MQL nozzle Needle valve not properly adjusted. Adjust needle valve 1
Clogged filter Service the MQL filter 3
MQL reservoir air regulator not properly adjusted Adjust air pressure at the reservoir 1
The reservoir is out of oil. Fill the reservoir with oil. 4
Too much oil from MQL nozzle Needle valve not properly adjusted. Adjust needle valve 1
MQL reservoir air regulator not properly adjusted Adjust air pressure at the reservoir 1
No air pressure to reservoir or from the AAG Solenoid does not operate. Check solenoid power. 2

Section 1

Symptom: Low or no oil from MQL nozzle.

Possible Cause: Needle valve not properly adjusted

Corrective Action:

Close the atomizer needle valve. Then open it 1/2 to 1 turn.

Set the pressure for the MQL oil regulator to 30 psi (2.1 bar).

Press SHIFT and then COOLANT. Press RESET to stop the air/oil flow.

With the system on hold, place a small piece of paper or cardboard approximately 3" from the atomizer. A round wet pattern will show if oil is being supplied from the MQL nozzle.

note: Some oils have a higher viscosity. Oils with higher viscosity flow slowly. The oil flow may need to be adjusted for different tools, workpieces, programs and the type of oil that you use. Adjust the reservoir air pressure high enough to atomize the oil and carry the oil to the tool. To correct oil flow, adjust the air pressure at the regulator on the reservoir and the atomizer needle valve as needed until the correct flow is achieved.

Section 2

Symptom: No air pressure to reservoir or from the AAG.

Possible Cause: Solenoid does not operate.

Corrective Action:

Measure the voltage to the solenoid. Make sure the solenoid receives 120 VAC.

If the solenoid does receive voltage, go to Solenoid - How it Works and Troubleshooting Guide to troubleshoot the solenoid.

If the solenoid does not receive voltage, go to I/O PCB - How it Works and Troubleshooting Guide (Classic Haas Control) to troubleshoot the I/O PCB.

Section 3

Symptom: Low or no oil from MQL nozzle.

Possible Cause: Clogged filter

Corrective Action:

Lock out and tag out the machine and wear proper PPE (personal protective equipment)

Remove these components: the reservoir bowl [1] from the oil-reservoir assembly for the MQL, the oil hose [2], and the fitting [3] for the oil hose.

Blow debris out of the filter. Use compressed air and hold a towel under the reservoir to catch the debris.

Install these components: the fitting [1] for the oil hose, the oil hose [2], and the reservoir bowl [3] for the MQL assembly. Fill the reservoir bowl with oil before the installation.

Power on and zero return the machine. Purge the air from the system:

  1. Find the atomizer needle valve [1].
  2. Turn the needle valve counterclockwise (2) full turns from the closed position.
  3. Set the oil regulator pressure to 40 PSI (2/8 bar).
  4. Command this code in MDI mode: M83;
  5. Run the MQL system [2] until no air is in the system.

Operate the purge until the spray nozzle disperses mist continuously for (20) seconds.

Press RESET to cancel the purge cycle.

Section 4

Symptom: Low or no oil from MQL nozzle

Possible Cause: The reservoir is out of oil.

Corrective Action:

Visually check the oil level in the reservoir. If the oil level is too low, or empty, the MQL nozzle will not spray oil. Fill the reservoir with oil.

Be aware: Many service and repair procedures should be done only by authorized personnel. The service technicians at your Haas Factory Outlet (HFO) have the training, experience, and are certified to do these tasks safely and correctly. You should not do machine repair or service procedures unless you are qualified and knowledgeable about the processes.

Danger: Some service procedures can be dangerous or life-threatening. DO NOT attempt a procedure that you do not completely understand. Contact your Haas Factory Outlet (HFO) and schedule a service technician visit if you have any doubts about doing a procedure.

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