What are the working principles of pipe bending machines?

Working Principle of Hydraulic Pipe Bending Machine

• The hydraulic pipe bending machine outputs high-pressure oil from an electric oil pump, which is then sent into the working cylinder through a high-pressure oil pipe. The high-pressure oil pushes the plunger inside the working cylinder to generate thrust, and then the pipe is bent by the pipe bending components.

• Taking the hydraulic system of a common hydraulic pipe bending machine as an example, it contains several basic circuits:

• Unloading Circuit: It is composed of a relief valve and a two-position four-way solenoid valve. After starting the hydraulic pump, the two-position four-way solenoid valve is normally in an unloading state, and the output of the hydraulic pump returns to the oil tank through the solenoid valve. When the electromagnet is energized, the solenoid valve switches to the working state, and the relief valve is adjusted to the working pressure.

• Speed Control Circuit: It adopts inlet throttling speed regulation and realizes pressure control through a pressure relay. This speed regulation method is convenient for adjustment and energy-saving. The flow rate entering the hydraulic cylinder is limited by the throttle valve, which can reduce the starting impact and meet the low-speed requirement of the hydraulic cylinder during pipe bending.

• Pressure Maintaining Circuit: A double pilot-operated check valve is set in the circuit. When the solenoid valve is in the middle position, the hydraulic cylinder can maintain pressure. Considering the leakage problem of the hydraulic cylinder, an accumulator is also added to compensate for the leakage volume.

Working Principle of Mechanical Transmission Pipe Bending Machine

• Through mechanical transmission devices such as gears, racks, worm gears and worms, the rotary motion of the motor is converted into the circular motion of the bending arm, thus driving the pipe to bend around the mold.

• The mechanical transmission pipe bending machine has a relatively simple structure and lower cost. However, its transmission accuracy and control flexibility are limited, and it is suitable for processing pipes with relatively low requirements for pipe bending accuracy, small diameters and relatively simple shapes.

Working Principle of CNC Pipe Bending Machine

• The CNC pipe bending machine adds a CNC system on the basis of the hydraulic pipe bending machine or the mechanical pipe bending machine. Operators input pre-programmed programs to set parameters such as the bending angle, radius, and length of the pipe, and the CNC system precisely controls each action of the pipe bending machine according to these instructions.

• It uses servo motors or stepping motors to drive components such as the bending arm and clamping devices, enabling high-precision and high-efficiency pipe bending processing. Moreover, it can change the program at any time according to different production requirements to produce pipes of various shapes and specifications, and is widely used in fields such as aerospace, automobile manufacturing, and precision machinery that have high requirements for pipe bending accuracy and quality.

Working Principle of Manual Pipe Bending Machine

• The manual pipe bending machine mainly relies on manual operation to achieve the bending of pipes. By manually rotating the handle or pressing down the lever, the bending mold is driven to apply pressure to the pipe, making it gradually bend and deform.

• The manual pipe bending machine is simple to operate and has a low cost, but it has high labor intensity and low production efficiency. It is suitable for small-batch and temporary simple pipe bending operations, such as home decoration and small-scale maintenance.