Pipe Bending Machines: Types, Uses, and Features

The pipe bending machine refers to a machine used for bending pipes and can also serve as a jack.

It is broadly categorized into two types: a numerical control pipe bending machine and a hydraulic pipe bending machine. It finds applications in the construction of electric power, public railways, bridges, ships, and other related fields.

Basic introduction

Pipe bending machines can be broadly categorized into two types: CNC pipe bending machines and hydraulic pipe bending machines. They are primarily used in the construction of electric power, public railways, boilers, bridges, ships, furniture, decoration, and for pipeline laying and repair.

These machines have several advantages, including their multifunctional capabilities, reasonable structure, and ease of operation. In addition to the elbow function, the hydraulic pipe bending machine can also be used as a hydraulic jack. Compared to CNC pipe bending equipment, it is more affordable and user-friendly.

Basic classification

Hydraulic electric pipe bending machine

Horizontal hydraulic pipe bending machine

Multifunctional rolling pipe bender

Digital pipe bending machine

Main features

Structural aspect

The pipe bending machine features a touch screen and numerical control module for simple and easy setup through dialogue operation. Its bed structure is stable and resistant to deformation.

Each program allows for the setting of 16 bend angles, and up to 16 files can be stored in memory. The machine includes a slow positioning function for stable angle bending with a repeatability of ±0.1°.

In case of errors, the machine displays error messages on the screen to assist the operator in resolving them promptly. Additionally, it offers self-developed coordinate conversion elbow processing values, and the software can be installed and edited on a desktop computer.

Process aspect

The pipe bender is capable of bending pipes and sheets. When a tube with outer diameter D and wall thickness t is subjected to an external moment M, causing it to bend, the outer wall of the neutral layer experiences tensile stress σ1 and becomes thinner, while the inner wall of the neutral layer experiences tensile stress σ1 and becomes thicker.

The cross section shape transforms from a circular shape to an approximately elliptical shape due to the effect of resultant forces F1 and F2. If the amount of deformation is excessive, cracks may form on the outer tube wall, and wrinkles may appear on the inner tube wall.

The degree of deformation of a pipe is determined by the relative bending radius R/D and the relative thickness t/D values, with smaller R/D and t/D values leading to a greater degree of deformation. To ensure the quality of the tube forming process, it is necessary to control the degree of deformation within acceptable limits.

The bending limit of a pipe depends not only on the material’s mechanical properties and the bending method used, but also on the requirements of the pipe fittings.

The forming limit of pipe fittings should consider the following factors:

• The maximum elongation deformation in the outer tensile deformation zone of the neutral layer should not exceed the material’s plastic allowable value, as this may cause cracking.
• In the compression deformation zone inside the neutral layer, the thin-walled structure part subjected to tangential compressive stress should not wrinkle beyond the point of instability.
• If the pipe fitting requires an elliptical shape, the pipe section should be controlled to prevent distortion.
• If the pipe must withstand internal pressure, the forming limit of wall thickness reduction should be controlled to meet strength requirements.

Use condition

(1) Electric Oil Pump Instruction Manual

(2) Secure the working cylinder into the internal thread of the square block with the wheel on the rear end facing downward.

(3) Select the die that corresponds to the outer diameter of the pipe to be bent and place it on the plunger. Align the grooves with the two rollers towards the die and insert into the appropriately sized flower plate holes.

Next, cover the upper plate and insert the pipe to be bent into the groove. Then, pull back the movable part of the quick joint end of the high-pressure oil pipe and attach it to the joint on the working cylinder.

Tighten the oil drain screw on the electric oil pump to start the bending process. Upon completion of the bend, loosen the oil drain screw and the plunger will automatically reset.