Complete Troubleshooting & Maintenance Manual for Steel Bar Bender & Stirrup Bender
Combined with on-site common faults, classified into foot switch faults, electrical & display faults, angle & parameter faults, abnormal noise & jamming, mechanical faults, lubrication & oil leakage faults, and power supply faults for easy field operation.
1. Foot Switch Related Faults
Motor runs but working disc does not rotate when stepping on the foot switch
Swap two connecting wires of the motor. Press and hold the 135° reversing key for 5 seconds until the decimal point on the screen disappears.
No response and the whole machine fails to operate when stepping on the foot switch
Check for broken or loose foot switch and connecting wires. Confirm the emergency stop button is not pressed and reset it if needed.
Intermittent operation caused by poor contact
Replace the foot switch, reorganize circuits and fasten all wiring terminals.
The rotating disc fails to reset automatically after operation
Adjust the gap between the baffle and working disc to eliminate friction. Inspect the return tension spring; reattach or replace it if it falls off or breaks.
2. Display & Electrical Control System Faults
Three horizontal lines flashing on the screen
Reconnect the loose encoder plug and wrap damaged wires with insulation material.
Black screen with no display
Check the main power supply, power cords and air switch. Replace the fuse with a new one of the same specification if it is blown inside the electric control box.
Screen is on but all buttons stop working
Power off the machine, leave it idle for 3 minutes then restart. Clean dust and moisture on the button panel; replace the panel if it is worn out.
Garbled characters or fluctuating numbers on the screen
Power off the equipment, dry damp circuits and tighten all plugs and connectors.
3. Inaccurate Angle & Abnormal Parameter Faults
Large deviation: bending angle is too big or too small
Press and hold the minus key after startup. Fine-tune the angle with plus/minus keys when the countdown ends, then press the plus key to save settings.
Unstable positioning with fluctuating bending angles
Tighten the fixing screws of the loose or worn encoder; replace the encoder if severely damaged.
Settings cannot be saved and restore to default after restart
Replace the exhausted battery on the main control board inside the electric control box.
Disordered parameters and program malfunction
Press and hold the plus key after startup, release it when the countdown reaches zero to restore factory settings, then reconfigure parameters.
4. Motor & Power Operation Faults
Motor hums but fails to rotate
Check the three-phase power supply for phase loss or loose wiring. Lubricate or replace the bearing if the motor bearing is seized.
Low motor speed and insufficient power
Check for low voltage or under-sized power cords. Replace worn motor carbon brushes.
Overheated motor
Stop the machine for cooling if running under long-term overload. Check and eliminate mechanical jamming that increases operating load.
Motor runs normally but transmission parts idle
Inspect, refasten or replace damaged couplings, gears and drive keys.
5. Mechanical Jamming, Abnormal Noise & Vibration Faults
Stiff rotation and resistance on the turntable
Remove steel bar scraps and debris stuck in turntable gaps. Apply grease to shaft sleeves regularly for lubrication.
Harsh friction noise during operation
Adjust the gap to eliminate friction between baffles, dies and the working disc. Replace damaged bearings in a timely manner.
Severe machine vibration
Level the equipment if placed unevenly. Tighten loose anchor bolts.
Loose dies and offset steel bar bending position
Fasten the screws of dies and pin shafts.
6. Oil Leakage & Lubrication Faults
Oil leakage from gearbox or shaft end
Replace aging or damaged oil seals. Drain excess lubricating oil if overfilled.
Dry rotating parts and accelerated wear
Apply grease to main shafts, shaft sleeves and bearings every week for routine maintenance.
7. Overall Power Supply Faults
No power and all indicators off
Check external power supply, knife switch and residual current circuit breaker. Reset the tripped protector and rewire broken power cords.
Circuit trips immediately after power-on
Stop repeated switch operation. Check circuits section by section for short circuit, motor electric leakage or water ingress.