This guide summarizes the most frequent issues encountered in fully automatic blow molding machines and provides practical, service-oriented solutions. It helps ensure stable production, consistent bottle quality, and minimized downtime.

1. Heating System Issues

1.1 Uneven Preform Heating

Symptoms: Bottle wall thickness varies, deformation after blowing.
Possible Causes:

• Aging or malfunctioning heating lamps

• Improper temperature zone settings

• Conveyor speed mismatch

• Dirty or misaligned reflectors

Solutions:

• Inspect and replace damaged heating lamps

• Adjust temperature settings for each zone

• Match conveyor speed with heating intensity

• Clean or realign reflectors for optimal heat distribution

2. Air System Failures

2.1 Insufficient High-Pressure Air

Symptoms: Poor bottle shaping, weak bottom structure, bottle collapse.
Possible Causes:

• High-pressure valve leakage

• Damaged air hoses

• Low pressure in air storage tank

• Air compressor under-capacity

Solutions:

• Replace valve seals or complete valves

• Repair or replace cracked air pipes

• Restore air tank pressure to required level

• Confirm compressor output meets machine consumption

2.2 Air Leakage During Blowing

Symptoms: Audible hissing sound during operation.
Possible Causes:

• Worn blow pin sealing gasket

• Inadequate mold clamping force

• Damaged O-rings in air valves

Solutions:

• Replace blow pin seals

• Increase mold clamping pressure or repair cylinders

• Replace O-rings or service the air valve assembly

3. Stretching System Problems

3.1 Stretch Rod Fails to Move

Possible Causes:

• Solenoid valve failure

• Air cylinder lacking supply

• Misaligned or faulty proximity sensor

Solutions:

• Test and replace solenoid valve coil

• Check air supply to stretch cylinder

• Realign or change the position sensor

3.2 Insufficient Stretching Resulting in Soft Bottles

Possible Causes:

• Short stretching stroke

• Preform under-heating

• Incorrect blowing sequence timing

Solutions:

• Adjust stroke limit switches

• Increase heating temperature in critical zones

• Recalibrate first and second blow timing

4. Mold System Failures

4.1 Mold Incomplete Closing

Symptoms: Flashing, visible parting lines, unstable bottle shape.
Possible Causes:

• Insufficient clamping force

• Worn guide pins or bushings

• Foreign objects or water leakage in mold

Solutions:

• Increase mold clamping pressure

• Replace worn guide pins and bushings

• Clean mold surfaces and inspect cooling channels

4.2 Poor Bottom Formation or Collapse

Possible Causes:

• Low secondary blow pressure

• Excessive mold temperature

• Over-heating of preform bottom

Solutions:

• Increase secondary blow pressure

• Lower mold temperature or improve cooling

• Adjust heating temperature in bottom zone

5. Electrical and Control System Issues

5.1 Touch Screen Failure or Unresponsive Control

Possible Causes:

• PLC or controller freeze

• Loose communication cable

• Program fault

Solutions:

• Restart the control system

• Secure or replace communication lines

• Reload control program if necessary

5.2 Sensor Mis-Detection

Possible Causes:

• Misaligned photoelectric sensor

• Dust contamination

• Sensor aging

Solutions:

• Reposition and fix the sensor

• Clean sensor surface

• Replace malfunctioning sensors

6. Common Bottle Quality Issues

6.1 Whitening or Haze on Bottle Surface

Cause: Excessive heating
Solution: Reduce temperature or increase conveyor speed

6.2 Neck Deformation

Cause: Preform neck overheated
Solution: Add cooling air ducts or insulation shielding

6.3 Wrinkles on Bottle Surface

Cause: Uneven heating
Solution: Adjust heating zones and optimize cooling air