一. Feeding system failure
1. Material conveying deviation or slippage
Possible causes:
The tension of the feeding roller is uneven, or the parameters of the tension controller are set incorrectly.
The center of the material coil is not aligned with the feeding roller, resulting in skew.
The surface of the feeding roller is worn or stained with oil, resulting in insufficient friction.
Solution:
Recalibrate the tension controller to keep the tension fluctuation within 5% during high-speed operation. Check whether the tension sensor is sensitive.
Adjust the position of the coil material support to ensure that the material axis is perpendicular to the feeding roller. This can be calibrated with the assistance of a laser marking instrument.
Clean the surface of the feeding roller. Replace the roller when it is severely worn (the surface roughness is recommended to be Ra≤1.6μm).
2. The feeding length is inaccurate
Possible causes:
The photoelectric sensor is mispositioned or has insufficient detection sensitivity.
Abnormal encoder pulse counting (such as gear wear, loose connecting wires).
The parameters of the servo motor were set incorrectly (such as electronic gear ratio, pulse equivalent).
Solution:
Adjust the position of the photoelectric sensor to ensure that the detection light spot is aligned with the material reference line, and set the sensitivity to 80%-90%.
Check the meshing condition of the encoder gears and replace the worn parts. Tighten the connecting wires and, if necessary, use an oscilloscope to detect the pulse waveform.
Recalculate the servo parameters. For instance, set the electronic gear ratio as "motor encoder line number ×4÷ ball screw lead", with an error of no more than 0.01mm.
二 . Abnormal die-cutting accuracy
1. Rough edges on the cut or incomplete cutting
Possible causes:
The cutting edge of the mold is blunted (bluntness > 0.03mm) or has notches and is not ground in time.
Insufficient die-cutting pressure (such as the hydraulic system pressure being 10% lower than the set value), or uneven pressure distribution.
The material shifts during die-cutting and the positioning is inaccurate.
Solution:
Disassemble the mold to inspect the cutting edge. Measure the bluntness with a projector. If it exceeds the standard, grind it with metallographic sandpaper (1000 mesh or above), or return it to the factory for mold repair.
Check the pressure pump and relief valve of the hydraulic system, replenish the hydraulic oil (viscosity grade ISO VG32), and adjust the relief valve to the rated value (such as 10-15 mpa) when the pressure is insufficient.
Add positioning pins or vacuum adsorption devices. When performing high-speed die-cutting, the vacuum degree should be ≥-60 kpa to prevent material sliding.
2. The dimensional deviation of the product exceeds the tolerance
Possible causes:
The mold is installed misaligned, with a parallelism error to the worktable greater than 0.05mm/m.
Long-term operation of the equipment has led to wear of the guide rails and lead screws, resulting in a decrease in straightness.
Materials undergo tensile deformation due to changes in tension (for example, the tension of elastic materials is greater than 20N).
Solution:
Calibrate the flatness of the mold with a level, adjust the parallelism through a gasket, and measure the error with a three-coordinate measuring machine after trial cutting (allowing ±0.1mm).
Check the straightness of the guide rail (allowable deviation ≤0.02mm/100mm), and replace the guide rail slider when it is severely worn. When the backlash of the lead screw is greater than 0.02mm, the preload needs to be adjusted.
Reduce the material tension (such as controlling elastic materials at 10-15N), or add preheating rollers to eliminate internal stress.
三. Abnormal operation of the equipment
1. Abnormal vibration or noise
Possible causes:
The mold was not installed tightly, or the center of gravity of the mold shifted, causing an imbalance in dynamic balance.
Bearing wear (such as temperature rise > 40℃), or excessive gear meshing clearance (standard clearance 0.05-0.1mm).
The motor coupling is loose, or the tension of the belt is uneven.
Solution:
Lock the mold with a torque wrench at the specified torque (such as 30-35N · m for M10 bolts). If necessary, conduct a dynamic balance test (unbalance ≤5g · cm).
Disassemble the bearing to check the clearance (such as the standard clearance of 6205 bearing 12-27μm). Replace it when it exceeds the tolerance. Adjust the meshing clearance of the gears and apply gear oil (viscosity grade ISO VG220).
Calibrate the coaxiality of the coupling (allowable deviation ≤0.05mm), and measure the tension of the belt with a tensiometer (for example, the tension of the polyurethane belt is 80-100N).
2. The motor overheats or stops
Possible causes:
Excessive load (such as excessively high die-cutting pressure causing motor overload), or frequent starts and stops leading to insufficient heat dissipation.
Encoder failure can cause motor blockage, or the driver parameters can be set incorrectly (such as too low current limit).
Dust accumulates on the cooling fan or the insulation of the motor winding ages (insulation resistance < 1MΩ).
Solution:
Reduce the die-cutting pressure or speed and check if the mold is stuck. Set the driver overload protection value to 1.5 times the rated current.
Replace the encoder and re-debug the driver parameters (such as the speed loop gain of 1000-1500rad/s) to avoid motor jitter.
Clean the fan filter screen, and use a megohmmeter to test the winding insulation. If it ages, the coil needs to be rewound (the temperature rise limit for B-class insulation is 120℃).
四. Electrical and Control System Faults
1. The photoelectric sensor malfunctions
Possible causes:
Dust accumulates on the sensor lens or it is disturbed by strong light, and the detection distance exceeds the range (for example, the standard detection distance of the diffuse reflection sensor is 50-300mm).
The controller I/O port is faulty, or the signal line has poor contact (voltage fluctuation > ±10%).
Solution:
Clean the lens with alcohol cotton, adjust the detection distance to the standard range, and avoid direct strong light. Replace the through-beam sensor (which has stronger anti-interference performance) when necessary.
Use a multimeter to measure the signal line voltage (DC24V±10%), replace the faulty I/O module, and tighten the terminal blocks.
2. The system alarms and shuts down
Possible causes:
The safety light curtain is blocked or the emergency stop button is not reset (contact resistance > 1Ω).
Servo driver alarm (such as overload, encoder error), or PLC program abnormality.
Solution:
Check whether the optical path of the safety light curtain is unobstructed and clean the lenses. The emergency stop button needs to be rotated and reset. Use a multimeter to test the conductivity of the contacts.
Check the driver alarm code (such as "AL-01" representing overload), and investigate the cause according to the manual (such as reducing the load or adjusting the acceleration time); The PLC program can be reloaded after a restart.
https://www.labeldiecutter.com/productdetail/GW-MQ-320%20Automatic%20die-cutting-machine.html
