Pipe benders can be divided into CNC pipe bender and NC pipe bender. Pipe bender is mainly used for pipeline laying and maintenance in electric power construction, public railway construction, boiler, bridge, ship, furniture and decoration. It has many functions, reasonable structure, simple operation, convenient operation and fast installation speed. However, there are also defects of pipe bender in the process of pipe. We will talk about how to prevent these deflects in this article.

1.The process characteristics of small radius bending of elbow determine the thinning of arc outer wall, which is inevitable.

In order to avoid excessive thinning, the commonly used effective method is to use the pipe bending machine with booster device on the side or ejector device on the tail to offset part of the resistance of the elbow, improve the stress distribution on the cross section of the pipeline, remove the neutral layer, and achieve the purpose of reducing the thinning of the outer wall of the pipeline.

2. Pipe fittings with severe flattening outside the arc.

When conducting coreless bend, the pressing die is designed as a structural form with reverse deformation groove: when conducting cored bend, appropriate mandrel shall be selected for correct installation. When installing the die, it shall ensure that the pipe groove axis of each component is on the same horizontal plane.

3. Wrinkling on the inside of the arc.

Corresponding measures shall be taken according to the wrinkled parts. If there are wrinkles at the front tangent point, the position of the mandrel shall be adjusted to achieve reasonable support for the pipe during bending; when the rear tangent point is wrinkled, the anti-wrinkle block shall be installed to make the anti-wrinkle block installed correctly, and the die force shall be adjusted to an appropriate position.

If the inner side of the arc is covered with wrinkles, it means that the diameter of the mandrel used is too small, so that the gap between the mandrel and the pipe wall is too large, or the die pressing force is too small, so that the pipe can fit well with the bending die and anti-wrinkle block in the bending process. Therefore, the mandrel should be replaced and the pressing die should be adjusted to make the die stress appropriate.

4. The bending crack on the outside of the pipe arc.

First, ensure that the pipe has a good heat treatment state, then check whether the pressure of the compression die is too large, and adjust the pressure appropriately to ensure good lubrication between the mandrel and the pipe wall, so as to reduce the elbow resistance and the friction between the inner wall of the pipe and the mandrel.