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PBH Section Bender Operation Manual Chapter 3

We’ve covered everything you need to know about the analysis and troubleshooting of common faults in the lubrication/hydraulic system of the PBH steel bending machines. You should also check out the PBH Section Bending Machine page.

Lubrication of PBH Section bending machine

Reasonable lubrication of the section bending machine is an effective measure to reduce power consumption and improve the life of the machine. Therefore, it is necessary to select a reasonable lubricating material and establish the necessary lubrication system.

Lubrication methodThe lubrication of this section bending machine is relatively simple, using oil cup lubrication and manual oiling. Lubrication of the oil cup and the surface of the transmission gear are required to be lubricated once a week. The remaining sliding surfaces and pin shafts of each other are manually filled with lubricating oil.

Other mutually moving sliding surface and pin shaft, each shift to manually add lubricating oil.

Read More: Profile Bending Machine: 5 Things Before Buy, 6 Steps to Bend

Selection of lubricating oil

  • For manual lubrication, use 40# mechanical oil. Oil cup lubrication point and gear surface, No. 2 calcium-based grease is used in summer, and No. 1 calcium-based grease is used in winter.
  • Lubrication system and precautionsThe user should establish a specific lubrication system according to the specific system, load and operation of the profile bending machine.
  • The lubrication points must be well lubricated before starting the machine.
  • When the section bending machine is in continuous operation, the interval between lubrications should be shortened.
  • The entire lubrication system of the section bending machine is cleaned once a year.

Hydraulic system

W24S series Section bending machine is fully hydraulically driven. The motor of the hydraulic system is Y132M-4 with a power of 11KW. The motor drives a double gear pump with a displacement of 25ml/rev and 10ml/rev. The hydraulic system has a maximum working pressure of 20 MPa and a rated working pressure of 16MPa. The oil pump with a displacement of 25ml/rev provides power to the main drive system (rotation of the work rolls in the forward and reverse directions), the oil pump with a displacement of 25ml/rev auxiliary drive system (each oil cylinder) provides power.

The hydraulic system is in the form of switch control. The electromagnet’s electric power makes the electromagnetic reversing valve work to perform the corresponding action. For the working condition, refer to the hydraulic system diagram (Fig. 6) and the solenoid valve action sequence table.

hydraulic oil

The working medium of this system is No. 46 anti-wear hydraulic oil. After being filtered by the fine oil-filtered vehicle, it is injected into the fuel tank, the tank level should reach the upper limit of the oil level gauge. After starting the motor and checking its rotation direction, starting up and turn on the action of each actuator several times, if leakage, shock, vibration, etc. occur, stop in time and check. After the oil has fully entered the pipeline and the oil cylinder, the oil should be replenished to the fuel tank again so that the oil level of the tank always reaches the upper limit of the oil mark.

When the oil pump starts or stops, the system should be in the unloading state. Once the set pressure value of the overflow valve is adjusted and determined, the lock nut of the overflow valve should be tightened, beware of accidents caused by section bending machine vibration or artificial random operation.. After a period of no-load test, the gas in the pipeline can be fully drained and the oil is fully filtered. After the movement of each actuator is stable and reliable, it can start load commissioning.

The oil temperature of the system should be appropriate, and the oil temperature of the fuel tank should not exceed 60 °C. Considering the specific environmental conditions, if the  section bending machine is working in a hot environment, the user may choose a hydraulic oil with a higher viscosity; in order to ensure a better working condition and a longer service life, the oil contamination should be minimized. Clean or replace the filter cartridge regularly. Check the degree of deterioration of the oil every six months. If it exceeds the limit of use, replace it in time.

Analysis And Elimination Of Common Faults In Hydraulic Systems

Fault phenomenon


Method of exclusion


A、The oil suction filter is blocked; the inner diameter of the suction pipe is too small; the oil temperature is too low; the oil viscosity is too high, etc.

Replace or clean the oil filter;

Increase the suction pipe diameter;

Warming the oil;

Use a hydraulic oil of appropriate viscosity.

B、The oil level is too low; the oil suction pipe leaks and the air enters the system by other means to cause the oil foam.

Fuel the oil tank;

Replace fittings, tubing or seals;

Venting the system;


C、The transmission center line is not correct; the coupling is loose; the vibration of the pipeline causes mechanical vibration

Align the center; tighten the screws; add pipe clamps to reinforce the pipe.

D、Pump or motor damage

Replace the oil pump or motor

E、Overflow valve instability

Change the valve

2、Insufficient or no pressure

A、Wrong rotation of oil pump, inhaling air

Correct the turn direction

B、Oil pump damage

Replace the oil pump

C、The pressure adjustment method is not appropriate;

There are dirty things in the overflow valve;

Poor sealing inside the cylinder causes leakage from the high pressure side to the low pressure side.

Correctly adjust the pressure;

Cleaning the relief valve;

Check and replace damaged parts or seals.

D、Coupling or motor is faulty

Check and replace

3、Pressure disorder, flow or pressure fluctuations

A、Oil pump suction empty

See fault1

B、Oil bubbles

C、Mechanical vibration

D、Uneven oil transfer from oil pump

Repair or replace the oil pump

E、The system is mixed with air


4、Flow is too small or noflow

A、Empty oil pump

See fault 2

B、Oil bubbles

C、Oil pump wear


D、Leakage of the high pressure side to the low pressure side of the cylinder

Repair or replacement, see fault 2

E、Wrong rotation of oil pump

Correct motor wiring

5、The oil temperature is too high

A、System pressure is too high

Correctly adjust the pressure

B、Too little oil

Add oil

C、The oil pump is damaged

Replace the oil pump

Download: PBH section bending machine operation manual PDF

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