Without a mandrel,the inner side of the pipe material may collapse and produce noticeable wrinkles,as shown in the figure.
Therefore,having a suitable mandrel is the first step in addressing the issue of inner-side wrinkling.However,since the material on the inner side is in a state of compression during deformation,there is always a tendency for wrinkling.Even with the support of a mandrel inside the pipe to prevent material from caving in,wrinkling can still occur,as shown in the figure.
this case,the solution to consider is the use of a wrinkle plate.What exactly is a wrinkle plate?The component numbered 5 in the mold assembly shown in the figure below is the wrinkle plate.
The actual installation on the equipment is shown in the figure.It is installed on the side of the forming die,with the inner dimension matching the outer diameter of the pipe,and the front edge is close to the forming die.
Therefore,when a wrinkling defect occurs,the actual sequence of handling methods(when using a mandrel)is as follows:
1,Add a wrinkle plate.
2,If wrinkles still occur after adding the wrinkle plate,bring the front edge of the wrinkle plate closer to the cutting point of the forming die.
3,If the best effect is still not achieved,reduce the inclination angle of the wrinkle plate.
4,If it still doesn't work,it may be necessary to consider whether the pipe material needs to be changed.For example,switching from hot-drawn pipe to cold- drawn pipe.
