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Analysis and trouble shooting of common faults of NC servo feeder

Dec. 18, 2019

The emergence of NC servo feeder has become a priority for small and medium-sized enterprises to buy a kind of feeder, because of its stability, high precision and other characteristics make it favored by production enterprises. Of course, in the use of equipment is also inevitable encounter large and small faults, Hao machinery as a NC servo feeder manufacturer, the following will give you a brief explanation of daily maintenance, common machinery, line failure and troubleshooting methods:

NC servo feeder, punch feeder

1. Daily maintenance

For the sake of mechanical properties and mechanical safety, please always do the following checks:

(1)The gear part of the roller, coated with gear butter and replenished with the replacement gear oil.

(2)Whether there is dirt between the rollers and whether there is any foreign matter between the gears.

(3)Whether the screws and nuts combined between the agencies are loose.

(4)Whether the feed roller has good parallelism.

(5)Whether there are abnormal phenomena such as damage deformation in each part.

  (6)  Whether the switch and display on the operator panel are abnormal.

2. Regular check:

This check should be performed every 6 months or 1000 hours of use。

(1)Whether the external wiring has deformation, damage, leakage or short circuit condition.

(2)Operator Panel button, contact whether it is conductive, whether there is oil attachment.

(3)Control whether the contact points of the in-disk relay are good。

(4)Whether the NC servo system often has a backlog of dust and oil, and whether the ambient temperature is too high.

There is a cooling fan in the electric control box to protect the motor from overheating, the cooling fan has a filter to protect the fan from dust, but if the filter is blocked, the cooling fan has a cooling fan in the electric control box is to protect the motor to avoid overheating function will fail, control box temperature rise, resulting in transistor damage.

3、Common mechanical faults and troubleshooting:

Fault phenomenon

Analysis of causes

Exclusion mode

Feeding error has a fixed direction

1、 Insufficient pressure of feeding wheel

1increase pressure

2、 Feeding length is too long

2、 The pull material is caused by poor on-mold stripping.

3Feed shortage

3、 Check that the reel width is appropriate for the position of the mold guide plate, or that the mold and NC are in a straight line

4、 There are bristles or objects in the mold.

4、 Check whether the retaining plate and stripping plate have bristles and foreign bodies

Sudden error in feeding

1、 Whether the NC feeder adjusts the material properly

1、 Whether the speed of the leveling machine and NC is matched or the intermediate distance between the leveling machine and NC and the height of the arc and the speed of the punch are appropriate

2、 The transmission gap between the roller and the servo motor is too large

2、 Tighten the belt.

3、 Conditions related to the coiling material

3、 Tighten the belt.

Coiled snake line

1、 The width of the material coil and the improper position of the retaining wheel

1adjustment again

2、 Uneven Roller pressure

2adjustment again

3dead of slip

3、 Check that the mold guide groove is in a straight line with the NC. Whether there is waste picking up in the mold, whether the material has bristles

4、 Roller pressure is too high

4adjustment again

Electrical fault

1NC can not start-up

1、 Check if there is an electrical input, or if there is a reversion after the last emergency stop

2、 Do manual, NC can not do this function when the single move

2、 Check that the external wiring is correct and that the button is off

3NC cannot start automatically

3、 Check whether the NC starter switch and terminal are in normal contact or have shedding phenomenon

4、 NC appears servo fault code

4、 Refer to Servo programming instructions

The amount of feed error and direction are not necessarily

1、 Metal or foreign matter on the feed roller or gear

1clean up

2、 Feeding start, relax and punch action interference

2、 Readjust as required

3roller slip

3、 Readjust as required

4Servo motor abnormalities

4、 Refer to Servo programming instructions

Relax unsmooth

1、 Poor function of positioning guide pin in Mould

1check and revise

2、 Relaxation time is incorrect

2、 Readjust as required

3、 There is an offset in the feed direction

3、 Check that the Working Party is correct and that the mold is normal

4、 Eccentric axis. Relaxation axle lost Oil card dead

4、 Wash and add butter

4、Fault Analysis and diagnosis:

Alarm code

Alarm name

Alarm contents


Overload 1

Continuous operation with a torque exceeding 130% of the rated value


Main circuit under voltage

Main loop DC voltage is insufficient


Main return passing voltage

Main circuit DC voltage is unusually high


AC detection anomaly

AC Input Phase missing


Over speed

Motor speed is 1.5 times faster than its rated speed


Overload 2

Continuous operation with a torque exceeding 160% of the rated value


Overload 3

Continuous operation with a torque exceeding 200% of the rated value


Motor stall

Motor speed does not match the given speed for a long time


Position difference 1

Position offset pulse exceeds user parameter PA53 set value


Extreme overload

Current exceeding 250% rating


Parameter error

Parameter test anomaly


Power module alarm

Power module abnormality due to excessive current


Current Detection 1th Channel exception

Internal circuit anomaly


Current Detection 2nd Channel exception

Internal circuit anomaly


Encoder A B Pulse loss

Abnormal number of AB pulses for incremental encoders


Encoder U V W Error

Incremental Encoder UVW Error


Encoder UVW Disconnect

Incremental encoder Signal Line disconnection


Encoder Abz Disconnect

Incremental encoder Signal Line disconnection


Encoder Z Pulse Loss

Encoder Z Pulse Loss


Encoder State Error

Magnetic Encoder Initial State error


Electronic gear protection

Electronic gear ratio setting is too large


Input signal Configuration Error

Input signal pin configuration duplicate or meaningless


Output Signal Configuration Error

Duplicate or meaningless output signal pin configuration


Drive Power Error


Alarm match

Drive motor Current mismatch

5、Fault code

Alarm code


Confirm way

Treatment measures

A10:Undervoltage (voltage detected by the main loop power supply department inside the servo unit)

Supply voltage below specification range

Measuring power supply voltage

Adjust the supply voltage to the normal range

Power supply voltage drop in operation

Measuring power supply voltage

Increase power supply capacity

Instantaneous blackout

Measuring power supply voltage

If the instantaneous stop retention time (Pn509) is changed, it is set to a smaller value.

Fuse of servo unit

After replacing the servo unit and connecting the reactor to the DC Reactor Connection terminal (1, 2), use the servo unit

Servo Unit failure

It is possible that the servo unit is faulty. Replace the servo unit.

A.520alarm vibrate

Detect abnormal vibration of motor speed

Confirm the abnormal sound of the motor and the speed and torque waveform of the runtime.

Confirm the abnormal sound of the motor and the speed and torque waveform of the runtime. (Pn100)

The value of the moment of inertia is greater than the actual value or a large change is made Pn103

Confirm the moment of inertia ratio or mass ratio.

Correct setting of moment of inertia ratio (Pn103)

Vibration detection Value (Pn312 or Pn384) is not appropriate

Verify that the vibration detection value (Pn312 or Pn384) is appropriate

Properly set vibration detection values (Pn312 or Pn384)

 A.710:overload(instantaneous maximum)




             A.A720:overload(continuous maximum load)

Motor wiring, poor encoder wiring or poor connection

Confirm connection

Verify that there is a problem with the motor wiring and encoder wiring.

Motor operation exceeds overload protection characteristics

Confirm the overload characteristics and operating instructions of the motor

Revisit load conditions and operating conditions. or re-examine the motor capacity.

Motor is not driven due to mechanical factors, resulting in excessive load at run time

Confirm the operating instruction and motor speed.

Improvement of mechanical factors

Abnormal setting of grating size pitch (Pn282) for linear encoders

Confirm the set value of the Pn282.

Set the Pn282 to the appropriate value.

Motor phase sequence selection (Pn080 = N. port x Port) exception

Confirm the setting value of Pn080 = N. port x port.

Set the Pn080 = N. port x port to the appropriate value.

Servo Unit failure

It is possible that the servo unit is faulty. Replace the servo unit.

A.C90:Encoder communication Failure

Encoder connector contact is poor or connector wiring error

Confirm the status of the encoder with the connector.

Insert the Encoder connector again to confirm the wiring of the encoder.

The encoder uses cables to disconnect, short-circuit, or to use cables that exceed the specified impedance

Confirm the status of the cable with the encoder.

Cables for encoders using specification requirements

Corrosion caused by temperature, humidity and gas; Short circuit caused by water droplets and cutting oil; poor contact of connectors caused by vibration

Confirm use environment

Improve the use of the environment, replace the cable. Even if this still does not improve, replace the servo unit.

Wrong action due to noise interference

Correct wiring on the periphery of the encoder (separation encoder cable and servo motor main circuit cable, grounding treatment, etc.).

Servo Unit failure

When the servo motor is connected to another servo unit and connected to the control power supply, if no alarm occurs, it may be a servo unit failure. Replace the servo unit.