Why do you choose to withdraw mandrel in advance
When bending the pipe, the pipe bender will use the mandrel as the inner support of the pipe in order to prevent the pipe from wrinkling and deformation. In the system programming of pipe bending machine, there will be a data parameter "advance mandrel withdrawal angle". What is the advance mandrel withdrawal angle? Advance core withdrawal angle, in fact, is to set an angle can make the mandrel in the bending pipe forming before the backward convenient last piece. So when do you need to use this data?
The mandrel of cnc pipe bending machine can be divided into single ball and multiple balls. For single ball or few balls, this parameter can not be set, because the mandrel is not far away (Figure 1).
Figure 1 Single and less ball mandrel
The shape deformation after the end of bending does not have much influence on the mandrel withdrawal, so it is OK to set the value to 0, and the mandrel withdrawal action can be carried out after the complete completion.
Figure 2 Multi - ball mandrel
If the mandrel structure is multi-ball (Figure 2).It can be seen that in order to prevent deformation, the new baseball needs too much deep bending, so it is difficult to take out the pipe after shaping.
However, it is not necessary to wait for the pipe to be completely shaped before the withdraw mandrel action is carried out. As shown in the figure, the final curve of the pipe is 90 degrees, and the value can be set to about 28 degrees before the withdraw mandrel action can be carried out, as shown in Figure 3. It is much easier to remove the mandrel if the bending is not completed as shown in the picture.
Figure 3 Angle of early mandrel withdrawal of multi - ball mandrel