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Tube Benders: Essential Techniques for Efficient Bending

Tube Benders: Essential Techniques for Efficient Bending

In modern industrial production, the bending process of metal pipes is a key process, which provides important support for the manufacturing and construction of various industries. However, it is not easy to bend rigid metal pipes into complex shapes while ensuring both precision and efficiency. This is exactly why Tube Benders come into being. As an advanced processing equipment, the pipe bending machine serves industrial production with its high efficiency and precision. This article will provide you with detailed information about Tube Benders and give you some guidance on Tube Benders.

Table of contents

1. Basic classification of Tube Benders

2. Main features of pipe bending machine

3. Structural structure of pipe bending machine

4. Operation process of pipe bending machine

5. Operating procedures of pipe bending machine

6. Precautions

7. Main applications of Tube Benders

8. How to choose a suitable pipe bending machine?

1. Basic classification of Tube Benders

Tube Benders can be divided into many types according to their working principles and structural characteristics. Generally, they are classified into the following categories:

Hydraulic electric pipe bending machine:

It uses the power provided by the hydraulic system and cooperates with the electric motor control to achieve precise bending of metal pipes.

It has the characteristics of high efficiency and stability, and is suitable for bending processing of small and medium-sized metal pipes.

Horizontal hydraulic pipe bending machine:

The equipment has a horizontal structure, and the pipes are placed horizontally and are bent by applying force through the hydraulic system.

It is suitable for metal pipes with larger diameters and longer lengths, and has strong load-bearing capacity and stability.

Multifunctional rolling pipe bending machine:

The roller bending method is used to bend the metal pipe by adjusting the position and angle of the roller.

It has the characteristics of high flexibility and wide processing range, and is suitable for processing pipes of various shapes and sizes.

Digital display pipe bending machine:

Equipped with a digital display control system, it can monitor and display parameters such as bending angle and bending strength in real time.

It provides more precise control and adjustment functions and is suitable for engineering projects that require higher bending accuracy.

2. Main features of pipe bending machine

Structural aspects

  1. The pipe bending machine uses a touch screen and a CNC module to realize conversational operation, and the program setting is simple and easy. Operators can easily set the bending angle and other parameters through the touch screen, which improves the convenience and efficiency of operation.
  2. The bed structure is stable and not easily deformed. The bed structure made of high-quality materials ensures the stability and reliability of the pipe bending machine during long-term operation, effectively preventing the decline in processing accuracy due to vibration and deformation.
  3. Each gear can set 16 bending angles, and the memory can store 16 sets of files. The pipe bending machine has high program setting flexibility, which can meet the processing needs of different workpieces, and supports the memory of multiple sets of files, allowing users to quickly switch between different processing tasks.
  4. It has a slow-speed positioning function, a stable bending angle, and a repeatability accuracy of ±0.1°. The pipe bending machine is equipped with a precise positioning system, which can achieve precise control of the bending angle and ensure the consistency and accuracy of the processed products.
  5. Error messages are displayed on the screen to help the operator troubleshoot immediately. The pipe bending machine has an intelligent fault diagnosis function. Once an error occurs, the operator can quickly locate and solve the problem through the error information displayed on the screen, reducing downtime and production costs.
  6. We provide self-developed coordinate conversion bending processing values, and the software can be purchased and installed on a desktop computer for editing and calculation. The pipe bending machine is equipped with advanced coordinate conversion technology, which can edit and calculate the bending processing values through a desktop computer, further improving the accuracy and efficiency of processing.


  1. The pipe bending machine bends pipes similarly to the bending of sheets. In the case of pure bending, when the pipe bends under the action of external moment M, the outer wall of the neutral layer is acted upon by tensile stress σ1, and the pipe wall becomes thinner; the inner wall of the neutral layer is acted upon by compressive stress σ1, and the pipe wall becomes thinner. thick. The shape of the cross section changes from circular to approximately elliptical due to the action of the combined forces F1 and F2. When the deformation is too large, cracks will occur on the outer tube wall and wrinkles will appear on the inner tube wall.
  2. The degree of deformation of the pipe depends on the values of the relative bending radius R/D and the relative wall thickness t/D. The smaller the R/D and t/D values, the greater the degree of deformation. In order to ensure the forming quality of pipe fittings, the degree of deformation must be controlled within the allowable range. The forming limit of pipe fittings not only depends on the mechanical properties and bending method of the material, but also takes into account the usage requirements of the pipe fittings. The forming limits of pipe fittings should include the following contents:
  3. The maximum elongation deformation in the tensile deformation zone outside the neutral layer does not exceed the plastic allowable value of the material and cause rupture.
  4. In the compression deformation zone inside the neutral layer, the thin-walled structural part subject to tangential compressive stress will not become unstable and cause wrinkling.
  5. Control the distortion of its cross section if the pipe fitting has ovality requirements.
  6. Control the forming limit of wall thickness reduction if the pipe fitting has strength requirements to withstand internal pressure.

3. Structural structure of pipe bending machine

When bending metal pipes, it is necessary to organize the structure of the pipe bending machine. The following are the installation and adjustment steps for common components of Tube Benders:


Installation: a. Remove the wheel mold fixing nut in a counterclockwise direction. b. Place the wheel mold in and tighten the wheel mold fixing nut.


Installation: a. Pull out the clamping die to fix the centering shaft. b. Put the clamp mold in and insert the fixed mandrel.

Adjustment: a. Loosen the clamping base, then put the control panel in manual mode, and press the clamping button until the end of the clamping stroke. At this time, there needs to be a gap between the wheel mold and the clamping mold, which can be adjusted by the clamping mold base adjusting screw. b. Adjust the clamp base adjusting screw to make the clamp mold and wheel mold completely tight. c. Press the clamp retraction button to retract the clamp mold, and then rotate the clamp mold adjustment screw clockwise about 1/2-1/4 turn. d. Then tighten the clamp base fixing nut.


Installation: a. Remove the guide mold fixing screw, and then put the guide mold in. b. Tighten the guide mold screws.

Adjustment: a. Loosen the fixing nut of the guide die base, put the control panel in manual mode, and press the pipe clamping button to the end of the guide die stroke. At this time, there must be a gap between the wheel mold and the guide mold, which can be adjusted with the guide mold adjustment screw. b. Adjust the guide seat adjustment screw to make the guide mold and wheel mold completely tight. c. Press or release the clamp button, and then turn the guide die adjustment screw clockwise about 1/2-1/4 turn. d. Then tighten the guide die base fixing screw.

(4) Mandrel

Installation: a. Put the mandrel into the piercing rod in a clockwise direction. b. Then fix the mandrel fixing screw. (Please note that the mandrel must match the bending direction of the elbow)

4. Operation process of pipe bending machine

(1)Pipe type regularization

When designing and arranging pipes, avoid excessively large arcs, arbitrary curves, compound bends, and arcs greater than 180°. Excessively large arcs not only make the tooling bulky, but are also limited by the size of the pipe bending machine; the design of arbitrary curves and compound bends is very unreasonable, which greatly hinders mechanized and automated production, making it difficult for operators to get rid of heavy manual labor; Arcs larger than 180° prevent the pipe bending machine from unloading the mold.

(2)Bend Radius Standardization

The bending radius should be as close as possible to “one tube, one mold” and “multiple tubes, one mold”. For a pipe, no matter how many bends there are and what the bending angle is, there can only be one bending radius because the pipe bending machine does not change modules during the bending process. This is “one pipe, one mold”. “Multiple tubes and one mold” means that tubes of the same diameter should use the same bending radius as much as possible, that is, the same set of modules should be used to bend tubes of different shapes, which will help reduce the number of modules.

(3) bending radius

The size of the bending radius of the conduit determines the amount of resistance the conduit encounters when it is bent and formed. Generally speaking, pipes with large diameters and small bending radius are prone to internal wrinkles and slippage during bending, and the bending quality is difficult to guarantee. Therefore, it is generally better to use a pipe bending mold with an R value of 2-3 times the diameter of the pipe.

(4)Bending speed

The main impact of the bending forming speed on the forming quality is: if the speed is too fast, it is easy to cause the bending part of the conduit to be flattened and the roundness cannot meet the requirements, causing the conduit to be pulled or broken; if the speed is too slow, it is easy to cause the conduit to wrinkle and If the compression block slips, large-diameter pipes may easily cause the bending part of the pipe to sink. Based on a large number of tests on these two CNC Tube Benders, it is appropriate to determine the bending speed of the pipe to be 20%-40% of the maximum bending speed of the machine.

(5)Mandrel and its location

During the bending process, the mandrel mainly plays the role of supporting the inner wall of the bending radius of the conduit to prevent its deformation. If domestic pipes are bent and formed on machine tools without the use of mandrels, it is difficult to guarantee their quality. There are many forms of mandrels, such as cylindrical mandrels, universal single, double, three and four ball head mandrels, directional single and multi-ball head mandrels, etc. In addition, the position of the mandrel also has a certain impact on the bending shape of the pipe: theoretically, its tangent line should be flush with the tangent line of the bending mold, but a large number of tests have proven that it is better to advance 1 to 2 mm in advance, and the quality of the bending pipe will be better at this time. Relatively ideal. Of course, if the advance amount is too large, it will cause the so-called “goose head” phenomenon to appear on the outer wall of the curved part.Tube Benders

5. Operating procedures of pipe bending machine

Before operation

  1.  The machine tool must be well grounded, and the wire must not be less than 4mm2 copper soft wire. It is not allowed to connect to a power supply voltage exceeding the specified range, plug-ins cannot be plugged in or out while the power is on, and the control circuit cannot be tested with a megohmmeter, otherwise the device may be damaged.
  2. When plugging or unplugging the connector, do not pull out the wire or cable to prevent the welding from pulling off.
  3. Proximity switches, encoders, etc. cannot be hit with hard objects.
  4. Do not hit the display unit with sharp objects.
  5. The electrical box must be placed in a ventilated place, and it is prohibited to work in dust and corrosive gases.
  6. No unauthorized installation or modification of PC input and output terminals is allowed.
  7. When changing the power supply of the machine tool, the motor rotation must be re-confirmed.
  8. The machine tool should be kept clean, and special attention should be paid to the fact that there should be no foreign objects in the sliding grooves such as the clamping block and the slider.
  9. Add lubricating oil to the chain and other sliding parts regularly.
  10. The power supply must be disconnected during cleaning and maintenance.
  11. Preparation before driving: Check whether the oil level in the fuel tank reaches the oil level line, add oil to each lubrication point, turn on the machine to confirm the motor rotation, check whether there is any abnormal sound in the oil pump, and check whether there is any oil leakage in the hydraulic system after starting the machine (the angle encoder is not allowed) come on);
  12. Pressure adjustment: Use the electromagnetic relief valve to adjust the pressure to ensure that the system pressure reaches the required working pressure, which is generally not higher than 12.5Mpa.
  13. Mold adjustment: When installing the mold, it is required that the mold and the clamping block are centered, and the clamping block can be adjusted with bolts; the boosting block is centered with the mold, and the boosting block is adjustable; the core head is centered with the mold, and the core head frame is loosened Bolts, adjust the center and tighten the bolts.

 In operation

  1. When starting the machine tool, be careful that the human body does not enter the range swept by the rotating arm.
  2. When the machine tool is working, all personnel are prohibited from entering the space swept by the rotating arm and pipe fittings!
  3. The machine tool hydraulic system uses YA-N32 ordinary hydraulic oil (original brand No. 20). Under normal circumstances, it should be replaced once a year, and the oil filter must be cleaned at the same time.
  4. When adjusting the machine tool (mold), the adjuster should press the button to make the adjustment. Never allow one person to make adjustments on the machine tool while another person operates on the control cabinet.
  5. The core rod should be removed when adjusting the machine tool or running the machine empty.
  6. The hydraulic system pressure cannot be greater than 14Mpa.
  7. When manually adjusting the speed of the side push cylinder, the swing arm should be adjusted when it rotates to ≥900. The adjustment speed is synchronized with the linear speed of the swing arm turning the edge of the bending mold. It is prohibited to push the side push speed faster than the line speed of the edge of the rotating mold in the manual state. speed.
  8. Generally, after using the machine for a period of time, the tension of the chain should be checked to keep the upper and lower chains consistent.
  9. In the core bending mode during automatic operation, before the bending arm returns, the operator must ensure that the core head is inside the tube, or ensure that the mandrel is not blocked when the bending arm returns. Otherwise, the core head or core rod may be Bend or break.

After the work is completed, cut off the power supply and do a good job of cleaning and lubrication.

6. Precautions

In order to ensure the safe operation and processing results of the pipe bending machine, the following are some matters that require special attention:

  1. Refer to the electric oil pump instruction manual. When using an electric oil pump, be sure to read and follow its instruction manual carefully. Understand the working principle, operation methods and safety precautions of the oil pump to ensure its normal operation and avoid accidents.
  2. Do not remove the quick connector when there is a load. During the operation of the pipe bending machine, if there is load or pressure, do not remove the quick connector at will. Doing so may cause a sudden release of hydraulic system pressure, causing accidental injury or equipment damage.
  3. Do a good job in cleaning and maintenance of the oil and the machine. The pipe bending machine uses oil as a medium to work, so the oil must be cleaned and replaced regularly to maintain the cleanliness and stable performance of the oil. At the same time, regularly clean and inspect all parts of the pipe bending machine itself to prevent oil clogging or leakage and ensure the normal use and life of the equipment.

Tube Benders

7. Main applications of Tube Benders

As a key metal processing equipment, the pipe bending machine plays an important role in various fields. The following is a description of the main application areas of Tube Benders:

  1. Car manufacturer:In the automobile manufacturing process, Tube Benders are widely used to manufacture automobile chassis, exhaust systems, hydraulic pipelines and other components. It can accurately bend automobile pipes, ensure the connectivity and reliability of the pipes, and improve the performance and safety of the car.
  2. construction project:In construction projects, Tube Benders are often used to process various types of metal pipes for the construction of stair handrails, railings, piping systems and other structures. Pipes processed by Tube Benders have precise dimensions and bending angles, which can meet the requirements of architectural design and improve the aesthetics and functionality of the building.
  3. Aerospace:In the aerospace field, Tube Benders are used to manufacture aircraft piping systems, control lines, hydraulic systems and other components. These components require extremely high precision and reliability, and the pipe bending machine can provide high-precision pipe bending processing to ensure the performance and safety of the aircraft.
  4. Petrochemical:In the petrochemical industry, Tube Benders are often used to manufacture pipes, pipe connections, petroleum storage tanks and other equipment. These equipment need to withstand harsh environments such as high pressure, high temperature and corrosion. The pipe bending machine can provide pipe bending processing that meets standard requirements to ensure the safe operation and production efficiency of the equipment.
  5. Steel structure manufacturing:In the field of steel structure manufacturing, Tube Benders are widely used to manufacture various types of steel components, such as steel beams, steel columns, steel pipes, etc. The steel components processed by pipe bending machine have precise size and shape, which can meet the design requirements of the building structure and improve the stability and load-bearing capacity of the structure.

8. How to choose a suitable pipe bending machine?

If you’re in the metalworking industry, you probably know the importance of purchasing the right equipment. The end result of any metalworking project depends on the quality and type of equipment used. Therefore, if you want to buy a pipe bending machine, it needs to consider various factors. Let’s discuss the factors that can help you choose the right pipe bending machine.

Understand the types of Tube Benders: Generally, Tube Benders are classified according to their working mechanism. Let’s discuss some basic types of press brakes.

  1. Open Rotary Stretch Pipe Bender: This type of pipe bender bends pipe by pulling it into the curvature. It uses molds of specific radius, suitable for bending metal pipes.
  2. Mandrel Bending Machine: Mandrel bending machines use a series of steel balls called steel ball mandrels. This series of balls is supported by the bending radius as it passes through the tube to bend it. This machine is used for batch pipe bending operations.
  3. Pipe Bending Machine: These Tube Benders have a pyramid structure with three rollers arranged in a triangular shape. The pipe is rolled on rollers to bend to a specific diameter.
  4. Plunger Bending Machine: In this type of bending machine, the mold is pushed into the pipe with the help of a plunger to bend the pipe into a specific shape. The plunger can be hydraulically, pneumatically or manually driven.
  5. In addition to these main types of Tube Benders, there are several types of Tube Benders named after their power source. These types include hydraulic press brakes, pneumatic press brakes, manual press brakes, electric press brakes, and CNC/CNC electromechanical press brakes. The function of each elbow depends on the type of actuator and its efficiency. To choose the right pipe bending machine, you need to consider the model and choose according to your requirements.

Analyze your operation needs: When choosing the best pipe bending machine for your needs, you must analyze your needs. Depending on your operational requirements, consider the following important factors.

  1. Operating speed: If high-speed bending is required, a manual pipe bender may not be the right choice. Generally speaking, electric and pneumatic actuators are ideal for high-speed operation. Therefore, an electric or pneumatic pipe bender would be the choice for high-speed mixing. In low-speed or heavy-duty bending situations, hydraulic press brakes are suitable because hydraulic actuators respond well to high-load applications.
  2. Production batch size: When choosing the right pipe bending machine, production batch size should be considered. For batch bending, mandrel bending or CNC bending is preferred.
  3. Operating costs and requirements: Budget and requirements are two important factors in selection. Increase investment only when demand is greater. For high demand, operators should invest in high-efficiency CNC press brakes or electric mixers. If bending operations are minimal, the operator can choose a less expensive manual press brake.
  4. Matching machine and material: The press brake must be compatible with the material used. You have to consider pipes, wall thickness, pipe diameter, etc. Based on these considerations, a suitable pipe bending machine must be selected.
  5. Explore Tools and Accessories: Tube Benders come with a set of dies and bending tools. When choosing a press brake, you must look for accessories such as press brake kits, roller presses, and multi-purpose press brakes.


This guide provides a basic understanding of Tube Benders. To learn more about metalworking machines, visit our tutorials, or visit the KRRASS supplier discovery platform to find potential sources or view details for a specific product.


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