Troubleshooting of hydraulic presses

The troubleshooting of hydraulic press faults should follow the principle of "from the surface to the inside, from the easy to the difficult" ‌, combining sensory judgment with instrument detection to quickly locate and solve the problem.

Ⅰ. Basic Principles of Fault Detection

1. Safety first ‌ : Before any operation, ensure that the system has been depressinized, powered off, and a lock mark has been made to prevent injury caused by accidental startup.

2. Outside first, then inside ‌ : Prioritize checking external visible factors such as oil level, pipeline connections, and electrical signals to avoid blindly disassembling core components.

3. From simple to complex ‌ : First, check for common problems such as oil contamination, loose joints, and clogged filter elements, and then conduct an in-depth analysis of precision components such as pumps, valves, and cylinder blocks.

4. Analyze ‌ based on the schematic diagram: Familiarity with the schematic diagram of the hydraulic system, clarifying the direction of the oil circuit and the control logic, is helpful for accurately locating the fault area.

Ⅱ. Common Fault Phenomena and Troubleshooting Steps

1. Insufficient or no pressure in the ‌ system ‌

Possible cause ‌ :

The oil level in the fuel tank is too low or the suction pipe is blocked.

The hydraulic pump is worn or damaged;

The set value of the relief valve is too low or the valve core is stuck.

The viscosity of the oil is too low or air has been mixed in.

Troubleshooting method ‌ :

Check whether the oil level is within the normal range and observe whether the oil has emulsified or deteriorated.

Use a pressure gauge to measure the outlet pressure of the pump. If it is zero or low, check whether the pump has sucked in air or has internal wear.

Adjust the pressure of the relief valve, gradually increase the pressure and observe the response.

Check if there are any bubbles in the return oil pipe and confirm whether the system is well sealed.

2. The ‌ actuator moves slowly or weakly ‌

Possible cause ‌ :

The output flow of the hydraulic pump is insufficient.

Leakage or jamming of the directional control valve;

The aging of the sealing parts inside the oil cylinder leads to internal leakage.

Excessive pipeline resistance or local blockage.

Troubleshooting method ‌ :

Measure the flow rate entering the cylinder to determine if it has reached the design value.

Disassemble and inspect the directional control valve, clean the valve core, and check if the spring has failed.

Observe whether the cylinder retracts under load to determine if there is any internal leakage.

Check the opening degree of the throttle valve and the bending condition of the pipeline to eliminate any flow resistance issues.

3. Abnormal noise or vibration during the operation of ‌ equipment ‌

Possible cause ‌ :

The hydraulic pump sucks in air (making a "clicking" sound);

Improper pressure regulation of valve components causes resonance.

The pipeline is not securely fixed or the flow rate is too high.

Troubleshooting method ‌ :

Check the sealing of the oil suction port to ensure that the filter screen is not clogged.

Adjust the pressure of the pressure reducing valve and the relief valve to avoid frequent opening and closing.

Reinforce pipeline supports to reduce vibration transmission;

Replace the damaged hose or fitting.

4. The oil temperature of ‌ is too high (exceeding 60℃) ‌

Possible cause ‌ :

The efficiency of the cooler has declined or there is insufficient coolant.

The system has been operating at an overload for a long time.

Oil contamination leads to an increase in internal leakage.

The wrong viscosity grade of hydraulic oil was used.

Troubleshooting method ‌ :

Clean the heat sink of the cooler and check whether the fan or water pump is working properly.

Test the NAS contamination level of the oil and replace it with new oil if necessary.

Check the oil type recommended in the equipment manual, such as 46# anti-wear hydraulic oil;

Avoid prolonged high-pressure maintenance and arrange the work cycle reasonably.

5. Hydraulic oil leakage ‌

Possible cause ‌ :

The sealing ring is aged, cracked or improperly installed;

Loose joints or deformed flanges;

The surface of the piston rod of the oil cylinder is scratched.

Troubleshooting method ‌ :

Regularly inspect each connection point. If any leakage is found, tighten or replace the seal in time.

Check the surface finish of the piston rod and carry out chrome plating repair if necessary.

Select high-quality sealing materials that are resistant to high temperatures and wear to extend the service life.