The main part of the pipe bending machine is equipped with important parts such as a pipe bending die, a turntable and a main shaft of the pipe bending machine. The clamping of the tube is achieved by clamping the oil cylinder and clamping screw. The pipe bending part is fixed by a pipe bending main shaft, and rotates as the pipe bending die of the host part rotates, and the pipe bending is realized by cooperation with the pipe bending die of the main part of the tube bender machine. In the case of bending a pipe with a large diameter, but with a small bending radius and a thin pipe wall, an wiper die and a mandrel should be used.

When the pipe is bent, the material inside the centerline is compressed. When it is bent to a certain angle, the material will be pushed back due to the large compression force of the material and will exceed the tangent point. If the pipe wall in this area is not supported by the bending die, Wrinkles will form. Even after being flattened between the mandrel and the bending die, wrinkles cannot be eliminated. And when the bending is over, a large wrinkle will form on the tube.

The use of wiper die can increase the support in this area, so that the pipe wall is thickened uniformly after compression without wrinkles. However, due to improper adjustment, after the wrinkles have been generated, the wiper die cannot eliminate the wrinkles.

The shape of the wiper die is very important. The groove through which the pipe slides should be slightly larger than the outer diameter of the pipe, and its value can be 10% of the wall thickness. It should also be carefully polished to prevent the pipe from being scratched.

The front end of the wiper die should be made very thin and thin, reaching to the tangent point of the curved die, supported by the curved die, and fixed to form a closed cavity. In order to reduce the resistance during bending, the anti-crease mold should have a slight taper during installation. The pressure of the stamper should be adjusted appropriately. When installing and adjusting the wiper die, it is best to use the "adjustment mandrel", which is performed with the clamping mold clamped.

During the bending process, an appropriate amount of oil should be applied to the wiper die. But too much or too thick oil can also cause wrinkles in this area. When using wiper die, mandrel is often used at the same time. The wiper die is used to prevent the tube from wrinkling when it is bent; the mandrel can keep the tube from collapsing after leaving the mandrel support point.

When bending a thin-walled tube with a large diameter and a small bending radius, in order to avoid wrinkles, the following points should be noted:
① Reduce the resistance between the mandrel and the inner wall of the tube during bending. Before the tube is bent, the inner cavity is subjected to wet sand.
② The pipe bending machine for sale tool and spindle should have sufficient rigidity.
③ The mandrel must have sufficient rigidity to eliminate the trembling and stretching produced by the rod as much as possible.
④ The radial clearance between the inner diameter of the mandrel and the pipe should not be greater than 10% of the wall thickness.
⑤ The clamping mold, compression mold, mandrel and wiper die should be adjusted properly, especially the compression mold pressure should be carefully selected and adjusted.
Bending of large-diameter pipes and clamping of clamps is also a prominent problem. This requires a longer straight line between the two bends of the pipe and a wider clamping die to increase clamping force and ensure smooth bending. If the clamp is too narrow and there is not enough clamping force when bending, the tube will not slip forward and make bending impossible.
⑥ Choose the right amount of lubricant.
The supply status of plutonium materials is also very important. For stainless steel pipes, the hardness is HB = 180 ～ 220, and HB = 180 is the most suitable.