Skip to content 
This article will provide you with a detailed maintenance and repair guide for drawstring garbage bag making machine, helping you optimize production and reduce unplanned downtime.
Preventative maintenance is key to avoiding unexpected failures and ensuring equipment accuracy. It is recommended to develop and strictly adhere to the following maintenance plan.
Operational Status Monitoring: Pay attention to any abnormal noise or vibration from the motor, reducer, and bearings.
Temperature Monitoring: Monitor the temperature controllers in real time to ensure stability and that fluctuations are within acceptable ranges.
Film Quality Observation: Continuously check the stability of the film bubble, the uniformity of film thickness, surface gloss, and the presence of defects such as crystal points and fisheyes.
Heat Sealing and Cutting Quality: Periodically check the heat seal strength, cut smoothness, and cutting length accuracy at the handles of the garbage bags.
Thorough Cleaning: After shutdown, while the machine is still hot, clean any residual molten material from the die opening and heat-sealing blade (use copper or specialized tools to prevent damage).
Relax Tension: Return the winding tension to zero and release the film tension on all guide rollers and folding frames.
Power Off and Pressure Relief: Turn off the main power supply and, if necessary, release any residual pressure in the air circuit.
Record Keeping: Fill out the equipment operation log, recording the shift’s output, any abnormal situations, and maintenance procedures.
Transmission System: Check the gearbox oil level, clean and adjust the tension of the drive belt/chain.
Precision Calibration: Verify the heat sealing temperature (using a thermometer), check and calibrate the sensitivity of the photoelectric sensor (for fixed-length cutting) and tension sensor.
Deep Cleaning: Clean or replace the air filter, cooling fan blades, and vacuum suction holes.
Electrical Inspection: Tighten the wiring terminals inside the electrical cabinet, check for overheating and dust accumulation on components such as the PLC and frequency converter.
Fault: Unstable extrusion volume or no extrusion
Possible causes:
1) Poor hopper feeding (bridging);
2) Improper heating temperature setting;
3) Clogged filter;
4) Severe screw wear.
Troubleshooting: Inspect and clean the hopper, optimize the temperature profile (especially the feed section), replace the filter, and check the screw-barrel clearance.
Fault: Crystal points, black spots, or discolored lines appear in the membrane bubble.
Possible causes:
1) Raw material contamination or contamination with impurities;
2) Decomposed old material in the barrel or die;
3) Overheating in the heating zone causing material scorching.
Troubleshooting: Clean the raw material, thoroughly clean the barrel and die (perform a “machine wash”), and adjust and calibrate the temperature of each zone.
Fault: Unstable, wobbling, or ruptured film bubble
Possible causes:
1) Uneven airflow or improper air volume from the cooling air ring;
2) Uneven die head clearance;
3) Airflow interference in the room;
4) Insufficient melt strength of the raw material.
Troubleshooting: Adjust the airflow distribution of the air ring, clean the die lip, isolate ventilation in the production area, and consider changing or adjusting the raw material formula.
Fault: Uneven film thickness
Possible causes:
1) Uneven die head temperature;
2) Uncalibrated die head adjusting bolts;
3) Asymmetrical cooling system;
4) Fluctuating traction speed.
Troubleshooting: Inspect and repair the heating coil, manually or automatically readjust the die head clearance, check the symmetry of the cooling system, and stabilize the traction motor.
Fault: Inadequate heat sealing or missed sealing at the vest handle
Possible Causes:
1) Heat sealing blade temperature too low or uneven heating;
2) Insufficient pressure or pressure cylinder malfunction;
3) Waste material stuck to the blade edge;
4) Cooling time (pressure holding time) set too short.
Troubleshooting: Clean the heat sealing blade, calibrate the actual temperature with a thermometer, adjust the pressure and pressure holding time, and check the cylinder and solenoid valve.
Fault: Incomplete cut or burr-like cut
Possible Causes:
1) Worn, dulled, or chipped cutting blade;
2) Improper adjustment of the gap between the moving and stationary blades;
3) Inaccurate cutting sequence (in coordination with heat sealing).
Troubleshooting: Grind or replace the cutting blade, precisely readjust the blade gap, and fine-tune the cutting signal timing in the PLC or controller.
Fault: Uneven winding, inconsistent tension, or wrinkling
Possible causes:
1) Improper winding tension setting or unstable tension control system (magnetic powder clutch/frequency converter);
2) Non-parallel or bent guide rollers;
3) Excessive static electricity on the film surface.
Troubleshooting: Reset and calibrate the tension curve, check and correct the parallelism and levelness of all guide rollers, and activate or repair the static eliminator.
Fault: Inaccurate temperature control, frequent overheating or failure to reach the set temperature
Possible causes:
1) Damaged thermocouple or poor contact;
2) Solid-state relay (SSR) breakdown;
3) Burned heating coil.
Troubleshooting: Use a multimeter to check the thermocouple resistance, replace the damaged SSR or heating coil.
Fault: PLC program malfunction, actions not executed
Possible causes:
1) Power fluctuation or interference;
2) Damaged input/output (I/O) module points;
3) Loose connections.
Troubleshooting: Restart the system, check the I/O point status, back up and restore the program, tighten wiring and ensure proper shielding.
Extruder and Die Head
Maintenance: Clean regularly with professional cleaning materials. Never scratch the die lip with hard objects.
Replacement: Replace the screw and barrel if wear exceeds the standard (usually the clearance exceeds twice the design value). Severe internal corrosion or damage to the die head requires professional repair or replacement.
Cooling and Shaping System (Air Ring, Cooling Cylinder)
Maintenance: Clean the inside of the fan ring and air vents weekly to ensure there are no blockages. Check the cooling water circuit for scale and descale regularly.
Replacement: Replace any fan motor bearings that are making abnormal noise; correct or replace any deformed fan ring lips.
Take-Up and Folding System (Take-Up Roller, Folding Frame)
Maintenance: Clean the surface of the rubber traction roller daily to prevent material buildup. Keep the folding rod smooth and free of burrs.
Replacement: Re-rubberize the traction roller if the rubber layer is worn, hardened, or cracked. Replace damaged bearings immediately.
Heat Sealing and Cutter System (The Core of the Core)
Maintenance: The blade surface must be cleaned daily. Regularly check the blade’s parallelism and spring pressure.
Replacement: Damaged Teflon coating on the heat-sealed blade must be recoated. When the cutting edge wears to the point of affecting cutting quality, it must be sharpened or replaced promptly.
Electrical and Control System (Thermostat, Sensors, PLC)
Maintenance: Keep the electrical cabinet well-ventilated, dry, and clean. Back up the PLC program regularly.
Replacement: Replace devices promptly if the temperature controller display is drifting, the sensor is malfunctioning, or the contactor contacts are burnt out.
Winding System (Wound Roller, Tension Control)
Maintenance: Clean the tension detection roller and check the air pressure or magnetic powder clutch performance.
Replacement: Replace the winding shaft if it is bent or damaged. The tension sensor may malfunction and requires calibration or replacement.
The stable and efficient operation of a drawstring garbage bag making machine relies 70% on maintenance and 30% on repair.
Operators and maintenance personnel should have a thorough understanding of the equipment’s principles, be diligent in observation, and be adept at recording information to nip potential problems in the bud. When encountering complex malfunctions that cannot be resolved quickly, they should promptly contact the equipment supplier’s professional technicians to avoid blindly disassembling the machine and causing secondary damage.
If you have any questions or need help,
feel free to contact with our team.
