The common issues and solutions of bag making machine

When we use the bag making machine some failures occur. How do we deal with these issues? Let’s introduce to you.

Problem: Bag length（along machine direction）may varies time to time when the material is plain.

Potential Reasons: 

1. Tension of servo motor is not well adjusted.

2. Traction rollers do not drag the material.

3. Rubber Roller has diameter error

Solutions

1. Adjust the change rate of servo tension

2. Check whether the rubber roller is slipping, wipe it clean, or reduce the air pressure tension of the unwinding

3. Replace rubber roller.

Problem: Stand-up Hole Punch position varies occasionally during machine running.

Potential Reasons:

1. Dancing Roller of Servo Motor swing in a large arc

2. The film is stretched

3. The rubber roller slips 

Solutions:

1. Reduce the value of servo tension, or lift dancing roller to reduce its swing range.

2. Reduce heat sealing temperature. Check whether servo-driven system and sealing system are synchronized, make sure the RH between main servo and lift system is close to 90°

3. The hardness of rubber roller is too high and exceeds 75 degrees. Reduce the hardness of rubber roller or replace a new one; check if there is contamination from dust or dirt between the rubber roller and the film.

Problem：Machine stops abruptly during production.

       Potential Reasons:

1. Machine speed is too high and voltage is unstable.

2. The RH of the main motor is wrong, poor contact between hall switch and detection rod.

3. The servo driver alarms.

Solutions:

1. Pulse of main servo driver should be set correctly and voltage value should be checked as well.

2. Adjust the RH between lifting tool and the high-position Hall switch to90°, adjust the Hall switch to align the signal detection rod.  

3. Check alarm codes one by one shown for all Servo Motors and figure out root cause.

Problem:Machine is unable to start running.

Potential Reasons:

1. Servo system error 

2. Computer signal interruption

3. The main engine contactor is faulty or the circuit controlled by the contactor fails

4. PLC system alarms

Solutions:

1. Check whether the servo system and the motor work normally.

2. Connect the signal line.

3. Replace the contactor.

4. Check and re-connect the circuit to eliminate error alarm.

Problem: The bag is not sealed firmly

Potential Reasons:

1. Sealing bars are uneven.

2. The control circuit of the sealing knife bars is broken.

3. Thermocouple is damaged.

4. Pressure of sealing bars is not big enough.

Solutions:

1. Grinding sealing bars to make it smooth.

2. Replace heating plate and check whether all curcuits are well connected.

3. Repair or replace the thermocouple and the temperature control module.

4. Adjust spring pressure of the sealing bars.

Problem：Film wrinkles when passing through the middle rubber roller.

Potential Reasons:

1. Back side of the film is not perfectly cooling down.

2. Pressure of the middle rubber roller is uneven.

3. Air pressure of the dancing roller is too large.

4. There is too much dust on the surface of middle rubber roller.

5. Sealing temperature is too high.

Solutions:

1. Reduce temperature of the chiller to promise chilling outcome.

2. Check the air pressure on both sides of the rubber roller and adjust pressure accordingly.

3. Reduce pressure of the dancing roller.

4. Clean the rubber rollers.

5. Reduce the heat sealing temperature of the sealing bars.

Error between Setting Pouch Length and Real Pouch Length(along machine direction)

Normally, real pouch length is decided by a united system including Sealing, Cutting and Film Feeding units, no matter with printing film or non-printing film. This system is functional based on different eye marks. If any error occurs among the system, real pouch length will be a little bit different from setting pouch length.

Problem:The inaccurate photoelectric tracking during bag making

Potential reasons:

1. Photoelectric eye problem:  Improper selection of photoelectric eye adjustment method and working state. First of all, it is necessary to confirm whether the electric eye is adjusted well. Secondly, to confirm whether it is leading edge control or trailing edge control,  Finally, to confirm the tracking method, such as: scanning type, fixed-length check type.

2. Cursor printing or spacing problems.

3. Cursor design is unreasonable, the available scanning area is too narrow, and the contrast between the cursor and the surrounding area is not obvious.

4. The cursor spacing has changed.