A bending machine is a crucial piece of equipment in various industries, used to bend sheet metal into different shapes. This guide covers the operation and maintenance of a standard hydraulic bending machine and a CNC bending machine, focusing on safety procedures, operational steps, and troubleshooting.
Operating a Standard Hydraulic Bending Machine
Step-by-Step Operation
1. Power On the Machine:
- Connect the power supply.
- Turn on the key switch on the control panel.
- Press the oil pump start button to activate the hydraulic system.
2. Adjusting the Stroke:
- Before bending, adjust the stroke to ensure that when the upper die descends to its lowest point, there is a gap equal to the thickness of the sheet metal.
- Use electric rapid adjustment for large changes and manual fine-tuning for precise adjustments.
3. Selecting the Bending Slot:
- Choose a slot width that is eight times the thickness of the sheet metal. For example, for a 4mm thick sheet, select a 32mm slot.
4. Adjusting the Back Gauge:
- Adjust the back gauge using electric rapid adjustment or manual fine-tuning, similar to the method used in shearing machines.
5. Starting the Bending Process:
- Place the workpiece on the workbench and align it with the back gauge.
- Press the foot pedal to start the bending process. Release the pedal to pause bending, and press it again to continue.
Safety Procedures for Operating a Bending Machine
1. Wear Protective Gear:
- Always wear the required personal protective equipment, including safety glasses, gloves, and safety shoes.
2. Pre-Operation Checks:
- Inspect the motor, switches, wiring, and grounding to ensure they are in good condition and securely connected.
- Ensure all controls and buttons are in the correct positions.
- Check the alignment and secure fastening of the upper and lower dies. Make sure all positioning devices meet the processing requirements.
3. Returning to Origin:
- If the upper slide and positioning axes are not at their origin, run the return-to-origin program.
4. No-Load Operation:
- Run the machine in a no-load state for 1-2 minutes.
- Perform 2-3 full stroke movements with the upper slide to check for any abnormal sounds or issues.
5. Coordinated Operation:
- One person should be in charge of coordinating the operation, ensuring all personnel are in safe positions before starting the bending process.
6. Securing the Workpiece:
- Firmly secure the sheet metal to prevent it from lifting and causing injury during bending.
7. Power Off for Adjustments:
- Always cut the power and stop the machine before adjusting the sheet metal or dies.
8. Avoiding Contact:
- When changing the lower die opening, ensure no material is in contact with the lower die.
9. Prohibiting Rear Access:
- Do not allow anyone to stand behind the machine while it is operating.
10. Prohibiting Single-End Bending:
- Avoid bending sheet metal from only one end to prevent machine damage.
11. Prohibiting Manual Corrections:
- Do not use your hands to correct the position of the workpiece or die while the machine is running. Stop the machine to make corrections.
12. Avoiding Overload:
- Do not attempt to bend materials that exceed the machine's capacity, such as ultra-thick iron plates, quenched steel plates, or high-grade alloy steels.
13. Regular Checks:
- Regularly check the alignment and pressure settings of the upper and lower dies.
- Ensure the pressure gauge readings comply with the specified limits.
14. Handling Abnormalities:
- If any abnormalities occur, immediately stop the machine to investigate and resolve the issue.
15. Proper Shutdown:
- Before shutting down, lower the upper slide onto blocks placed under the lower die.
- Exit the control system program and cut off the power supply.
Operating a CNC Bending Machine
Similarities to Standard Bending Machines
CNC bending machines follow similar basic safety procedures as standard hydraulic bending machines but require additional steps for programming and parameter setting.
Specific Steps for CNC Bending Machines
1. Familiarize with the Control System:
- Operators must understand the CNC control system, including programming, parameter setting, and troubleshooting.
2. Set Parameters:
- Correctly set the bending angle, force, speed, and other parameters to ensure high-quality processing.
3. Inspect Tools:
- Regularly check the condition of bending tools and replace them if they are significantly worn.
Programming and Operation
1. Programming:
- Enter parameters such as bending angle, length, position, and sequence into the CNC system.
- Set the machine’s speed and pressure.
2. Material Placement:
- Place the material on the machine and ensure it is correctly aligned.
3. Tool Adjustment:
- Inspect and adjust the bending tools to ensure proper alignment and condition.
4. Initiate Bending:
- Start the bending process via the CNC control system.
- Monitor the machine’s operation and the quality of the bends.
5. Post-Bending Inspection:
- After bending, thoroughly inspect the final product for accuracy and quality.
Troubleshooting Common Issues
1. Continuous Pressure Application After Startup
Possible Causes:
- Throttle valve failure
- Air in the hydraulic cylinder
- Return oil pipe not submerged
Solutions:
- Disconnect the pressure relay to check for throttle valve issues.
- Bleed air from the hydraulic system.
- Ensure the return oil pipe is submerged below the oil surface.
2. Reduced Bending Speed
Possible Causes:
- Insufficient pressure
- Hydraulic system leakage
Solutions:
- Check the pressure gauge and inspect the relief valve and hydraulic pump.
- Inspect all hydraulic lines and components for leaks and repair or replace as necessary.
3. Machine Not Responding to Foot Pedal
Possible Causes:
- Power supply issue
- Faulty foot pedal switch
Solutions:
- Check the power supply connections.
- Test and replace the foot pedal switch if necessary.
Conclusion
Operating a bending machine safely and efficiently requires a thorough understanding of its operation, adherence to safety protocols, and regular maintenance. By following the steps outlined in this guide, operators can ensure high-quality bending results and minimize the risk of accidents. Always refer to the specific machine’s user manual for detailed instructions and consult the manufacturer for additional guidance.
