Soonqian
How To Fix Strapping Machine
To fix a strapping machine, you must systematically diagnose the three core subsystems: the strap path, the sealing head assembly, and the electrical control circuit. First, inspect the strap path for accumulated polypropylene dust or debris blocking the track, and ensure the strap is threaded correctly according to the flow diagram (a backwards strap is the cause of feed failure). Second, examine the sealing head: verify the heater blade reaches the correct temperature (usually 230°C-270°C depending on strap thickness) and check that the gripper teeth and slide table are free of residue and moving smoothly without mechanical binding. Third, troubleshoot the electrical controls by testing the specific limit switches (LS) or proximity sensors that dictate the cycle logic—specifically the “Home Position” switch (often LS1) and the “Strap Feed” switch—and use a multimeter to verify 24V DC input to solenoids and continuity across the PCB fuses. Most failures are resolved by cleaning strap dust from the sensors or adjusting the tension spring gap, rather than replacing expensive motors.
Check The Belt And The Belt Feeding System
Most of the problems with balers are on the belt. Before you suspect that it is a major mechanical failure, you must first eliminate whether it is blocked or the tape is installed incorrectly.
Clean Up PP Belt Dust And Debris
Friction during baling produces a large amount of PP dust long, the powder will pile up in the track and guide belt groove, causing physical blockage.
Maintenance program: directly on the compressed air, the entire channel blown over. You have to take a closer look at the belt wheel. If there is molten plastic residue on it, the belt will slip and cannot be delivered.
Confirm The Threading Direction
The belt is worn backwards, which is the main reason for the failure of the belt. The design of the baler has specific requirements for the bending direction of the belt.
Maintenance plan: take a look at the schematic diagram of the wearing belt that is usually printed on the door cover of the machine. Make sure that the concave/convex orientation of the tape is consistent with the manufacturer’s specifications. If the installation is reversed (Upside down), the belt wheel cannot bite the belt at all, and the starts the circulating immediate card machine.
Diagnose The Ironing Head Assembly
If the tape was delivered but didn’t burn or cut, that’s the problem. You have to keep an eye on the ironing temperature and the action of the fixture assembly.
Calibration Of Ironing Temperature
The sheet must be hot enough to melt the surface of the tape, but not too hot to scorch or smoke the plastic.
Temperature range: The general rule is to set between 230°C and 270°C.
Adjust according to thickness: the thicker the belt, the higher the temperature will have to be adjusted. If the blade is too cold, the adhesion will be weak and the will collapse. If it is too hot, the tape will turn into a lump and directly paste the mechanism to death.
Check Fixture And Slide
The slide and the clamp rely on a smooth mechanical action to tighten the strap. Mechanical stuck: check the slide for that slimy residue. Old oil mixed with packing with dust, will become a “sludge”, causing the skateboard stuck.
Maintenance program: clean the plastic carbon deposits on the fixture teeth with a wire brush. The skateboard must move freely; if it gets stuck, the machine will not be able to complete the tightening cycle.
Diversified products &
comprehensive services
With over 30 specialized models, Soontrue provides pillow, vertical, and premade bag packaging solutions for diverse sectors like food, medicine, and hardware.Also offer professional customized services.
Check The Electrical Control Circuit
If the mechanical part is quite clean, but the machine is nervous (such as constantly playing, not resetting, or stopping halfway), the problem is mostly on the logic sensor or power supply.
Test Microswitches (LS) And Proximity Sensors
Where the machine goes depends on these switches to tell the PCB board.
LS1 (Origin Switch/Home Position): This is the most critical sensor. If the LS1 position is crooked or covered by ash, the machine will not know if it has finished turn, and may keep playing empty or not at all.
Strap Feed Switch: This is to detect whether the strap is in place to enter the bow frame.
Maintenance program: check these switches have no physical action. Note that hearing the “click” does not mean it is good. Be sure to use a multimeter to check whether the signal state jumps when pressed.
Check Power Supply With Multimeter
When a certain function is abandoned (for example, the tightening motor does not rotate), don’t come up and feel that the motor is burning.
Solenoid valve: measure whether there is 24V DC input on the solenoid valve terminal. If there is electricity but it cannot be sucked, the solenoid valve is broken; if there is no electricity, it is a board problem.
PCB fuse: measure the on-off of all fuses on the board. The fuse is usually burned because the solenoid valve is short-circuited or the motor is stuck, but how much does it cost to change the fuse? Much more cost-effective than changing the board.
Finally, remind the sentence that the vast majority of faults can be repaired by cleaning or fine-tuning, rather than changing parts. Before applying to buy an expensive motor or circuit board, look at the gap of the tension spring and check if the sensor is dirty. Sometimes adjusting the spring can solve the problem of insufficient tension, wipe off the dust on the photoelectric sensor, and the logic will be normal immediately.
Author: David
“I am a senior packaging machinery technician with over 17 years of field experience. I specialize in the maintenance and repair of industrial strapping systems, focusing on component-level diagnostics. I hope to help operators resolve issues through precise calibration of heater blades and logic sensors, rather than unnecessary and costly motor replacements.”