This document addresses the issue of false "nozzle detachment" errors occurring during the placement process on the Fuji NXT3 pick-and-place machine, even though the nozzle is not actually detached.  The equipment detects an abnormal signal. The following are possible causes and corresponding solutions:

 

I. Analysis of the Cause of the Fault

 

1. Vacuum System Anomaly

- Insufficient vacuum pressure: The vacuum pressure of the nozzle does not reach the standard value, leading the sensor to mistakenly detect nozzle detachment. This may be caused by contamination of the vacuum filter element, pipeline leakage, or vacuum pump failure. 

- Vacuum release valve malfunction: Oil or foreign matter (such as the mentioned oil contamination in the filter element) exists in the vacuum release circuit, leading to abnormal vacuum release and triggering a false alarm.

 

2. Nozzle State Problems

- Nozzle blockage or wear: Internal blockage, deformation, or damage to the nozzle can cause unstable vacuum pressure, leading the sensor to report an anomaly. 

- Loose nozzle fixing device: The nozzle holder or mounting base is loose, causing the nozzle position to shift, and the sensor detects an abnormal signal.

 

3. Sensor Misjudgment

- Position sensor contamination or damage: The sensor that detects the nozzle status is affected by dust, oil, or aging, leading to signal misjudgment. 

- Vacuum sensor calibration deviation: Sensor parameters are offset or incorrectly calibrated, preventing accurate detection of the vacuum state.

 

4. Mechanical or Program Setting Problems

- Improper nozzle height setting: Incorrect Z-axis height parameters of the placement head cause abnormal contact between the nozzle and the component, triggering a false alarm. 

- Worn or loose moving parts: Wear of servo motors, bearings, or guide rails causes vibration in the placement head movement, affecting sensor judgment.

 

II. Solutions

 

1. Check and Clean the Vacuum System

- Clean or replace the vacuum filter element: Remove the filter element to check for oil contamination or blockage, and replace it with a new one if necessary. - Test vacuum negative pressure value: Use a vacuum gauge to check the pressure at the suction nozzle, ensuring it reaches 53.33 kPa or higher. If insufficient, check the vacuum pump, pipelines, and connectors for leaks.

 

2. Troubleshooting suction nozzles and fixing devices

- Clean or replace the suction nozzle: Use a special tool to clear the nozzle hole and check the nozzle surface for damage. Severely worn nozzles should be replaced promptly.

- Check the fixing device: Confirm that the nozzle bracket and mounting base are not loose or deformed, and adjust or replace parts as necessary.

 

3. Sensor calibration and parameter settings

- Clean the sensors: Wipe the surfaces of the position sensor and vacuum sensor with a lint-free cloth to remove dust or oil stains.

- Recalibrate sensor parameters: Adjust the nozzle position and vacuum sensor threshold through the equipment control panel to ensure they match the actual state.

 

4. Adjusting mechanical and program settings

- Optimize nozzle height parameters: In the program, adjust the Z-axis downward pressure height to 0.05mm after contacting the component surface to avoid excessive downward pressure causing false triggers.

- Check the motion mechanism: Lubricate and maintain the servo motors and guide rails, tighten loose mechanical parts, and reduce motion jitter.

 

5. Other maintenance suggestions

- Regularly maintain the vacuum release valve: Clean the oil stains inside the valve body to ensure normal vacuum release operation.

- Update equipment software: Check for firmware or software updates to fix potential program bugs.

 

III. Preventive Measures

 

- Daily maintenance plan: Clean the nozzles and sensors daily, check the vacuum system and filter elements weekly, and calibrate mechanical parameters monthly.

- Operator training: Standardize operating procedures to avoid human-induced collisions or parameter missettings.

- Spare parts management: Stock common wear parts (such as nozzles and filter elements) to shorten downtime. If the above steps do not resolve the problem, it is recommended to contact a professional Fuji pick-and-place machine repair service (such as Xinling Industrial) for further diagnosis.