Different Types of Press Brake Common Faults and Troubleshooting Methods:
Mechanical Press Brake Faults:
1. Excessive clearance between the slide and the guide rails, causing abnormal noises. This fault occurs when the guide rails have been worn out over time, leading to increased clearance. Check the degree of wear on the guide rail pressure plate and determine whether to replace it based on the wear level. Readjust it to the required clearance.
2. Failure of the rear material stop transmission. This occurs when the transmission shaft disconnects from the synchronous pulley or when the timing belt slips. To resolve this fault, reassemble the key and timing belt and check the electrical components.
3. Excessive deviation between the straight guide rails of the rear material stop beam and the centerline of the die. Loosen the "X" axis synchronous belt and readjust it within the tolerance range of parallelism. Reinstall the synchronous belt.
4. Loose connection between the hydraulic cylinder and the slide, resulting in inaccurate bending angles or the machine's inability to find the reference point. In this case, recheck the tightening of the connection nut between the slide and the hydraulic cylinder.
Hydraulic Press Brake Faults:
1. No pressure in the hydraulic system.
- Check if the solenoid coil of the proportional relief valve is powered and if the voltage meets the requirements. If not, inspect the related electrical components.
- Check if the cartridge valve is stuck or if the main spool is stuck, as well as if the damping small hole is blocked. If so, disassemble the relief valve, clean it thoroughly, and reinstall it.
- Three-phase power supply phase shift causing motor reversal.
2. Slide moving from fast speed to slow speed with long pauses.
- Check if the oil level in the tank is too low and if the filling port is submerged. If the oil level is low during rapid movement, the upper chamber of the cylinder may not be fully filled. In this case, add oil to the tank until it is 5mm above the filling port to ensure it is completely submerged.
- Check if the rapid speed is too fast, causing insufficient filling. If so, modify the system parameters to reduce the rapid speed.
- Check if the filling valve is fully open. If the valve core of the filling valve is not flexible due to oil contamination, causing insufficient filling, clean the filling valve and reinstall it to ensure smooth movement of the valve core.
3. Normal return stroke of the slide, normal rapid movement, but manual slow downward movement and weak bending force.
- Check if the "two-position four-way" directional valve controlling the filling control oil circuit is working properly. If not, it may cause the filling valve to remain open, connecting the upper chamber with the filling port of the tank, preventing pressure buildup. The reasons for the malfunctioning of this valve could be lack of power or being stuck.
- Check if the filling valve is stuck. If so, clean the filling valve and reinstall it to ensure the flexibility of the valve core.
4. Slow return speed of the slide and high return pressure. This fault is mainly caused by the failure of the filling valve to open. It is the opposite phenomenon to Fault 3. Refer to the solution for Fault 3 to resolve this issue.
