简体中文
When bending thin-walled, large-diameter pipes with a small bending radius, to avoid wrinkles, the following points should be noted:
- Reduce the resistance between themandrel and the pipe’s inner wall during bending. Before bending, the pipe’s inner cavity should be wet-blasted.
② The machine tool and spindle must have sufficient rigidity.
③ The mandrel rod must have sufficient rigidity to minimize vibration and stretching.
④ The radial clearance between the mandrel and the pipe’s inner diameter should not exceed 10% of the wall thickness.
⑤ The clamping, pressing, mandrel, and anti-wrinkle molds should be properly adjusted, especially the pressure of the pressing mold, which requires careful selection and adjustment. When bending large-diameter pipes, the clamping force of the clamping mold is a significant concern. This requires a longer straight section between the two bends and a wider clamping mold to increase the clamping force and ensure smooth bending. If the clamping mold is too narrow, there will be insufficient clamping force during bending, causing the pipe to slip and fail to bend smoothly.
⑥ Select an appropriate amount of lubricating oil.
⑦ The supply condition of the material is also crucial. For stainless steel pipes, the hardness should be HB=180~220, with HB=180 being the most suitable. When bending large-diameter pipes, the clamping force of the clamping mold is a significant concern. This requires a longer straight section between the two bends and a wider clamping mold to increase the clamping force and ensure smooth bending. If the clamping mold is too narrow, there will be insufficient clamping force during bending, causing the pipe to slip and fail to bend smoothly.
⑧ Select an appropriate amount of lubricating oil.
⑨ The supply condition of the material is also crucial. For stainless steel pipes, the hardness should be HB=180~220, with HB=180 being the most suitable. To minimize the loss of material on each pipe, the trolley is designed to move forward as much as possible. However, this can lead to collisions between the trolley and the die mechanism. To ensure the pipe completes its final bend smoothly, prevent collisions, and minimize material loss, an interference zone is set up in the pipe bender. When the trolley enters this zone, the die retracts, the trolley continues to advance, the bending arm returns, a spatial turn (POB) occurs, the die clamps are tightened, the chuck releases, the trolley exits the interference zone, the die presses, and the pipe bends.
When using anti-wrinkle dies, ball core rods are often used alongside them. The anti-wrinkle die prevents wrinkles from forming during the bending process, while the ball core rod ensures that the pipe remains supported after leaving the support point, preventing it from collapsing.
