The process of the pipe bending machine is a complex process of elastic and plastic deformation. The elastic or plastic deformation of a material mainly depends on the stress and strain inside the material, and the stress or strain inside the material is mainly caused by the external load acting on the material. During the process of bending the pipe, the stress and strain inside the bent part of the pipe will undergo complicated changes. The magnitude, direction and speed of change of the stress and strain will affect the quality of the bent pipe. Various quality defects in the process of pipe bending, such as cracks in the outer pipe wall, wrinkles in the inner pipe wall, cross-sectional distortion, etc., are related to the nature of the material on the one hand; on the other hand, it is related to the external load imposed on the pipe by the pipe bending machine The relative position among size, direction, speed and external load. Today we will talk about the maintenance methods and quality standards of the pipe bender, as follows:

1 Pre-test

1.1 Hydraulic system
a. Test the pressure loss of the oil pump.
b. Check the loss of hydraulic parts.

1.2 Mechanical system
a. Detect worm gear wear.
b. Check the chain sprocket for wear.

2 Inspection method

2.1 Use the bed as the basic component to repair wear and deformation and restore the geometric accuracy of the mating part.
2.2 Equipped with various sliding parts to meet the requirements of geometric accuracy.
2.3 Trim the worm gear and match the worm.
2.4 Trim the sprocket and replace the chain.

3 Quality standards of tube bender

3.1 Base and foundation
a. After the equipment is aligned, the tightening bolts are not loose or cracked.
b. The longitudinal flatness of the base is 0.05/(1000mm), the tolerance of the full-length flatness is 0.15mm, and the lateral flatness is 0.04/(1000mm).

3.2 Angle control and clamping
a. The positioning accuracy error of the angle control part is less than 1 degree.
b. The tolerance of the parallelism between the clamping rail and the base is less than 0.1/(1000mm).
c. The tolerance of the contour height of the clamping member mandrel guide member is less than 0.05/(1000mm).

3.3 Guide and master cylinder
a. The parallel deviation between the guide rail and the base rail is less than 0.05/(1000mm).
b. The axial displacement of the guide part under load is less than 0.5mm.
c. There is no leakage of the components of the master cylinder under rated load conditions, and the movement is smooth and without impact.
d. The clearance of the guide sleeve of the cylinder is 0.03～0.05mm. There is no jamming during operation.

3.4 Hydraulic system
a. No leakage at rated pressure, volumetric efficiency is greater than 70%. The noise is less than 90 dB.
b. Continuously operating oil pump temperature rise is less than 30ºC, maximum temperature is less than 65ºC, and pressure fluctuation is less than 0.5Mpa.
c. The pressure loss of the cylinder piston movement is less than 0.5Mpa.
d. The pressure regulating valve should change evenly during the pressure regulation.