The first is a punching hole machine, Figure. 1.

Figure 1  Punching Hole Machine

The pipe is punched before bending, and the pipe is bent after the hole position of the pipe fitting is processed. However, the stretching efficiency of the pipe cannot be controlled during bending, so the size of the first pipe may be correct after punching and bending, but the size of the second hole will be offset.

So there's a second way, Figure 2.

Figure 2  Pipe bender punching equipment

This way is to install a punching device on the pipe bender, so that the punching action can be carried out after the end of the bending action of the pipe bender, because it is the first to complete the forming and then punching, punching mold is fixed, so the processing size can be guaranteed. However, this has a disadvantage, the pipe fittings are bent, and there is no lining mold inside the pipe used by punching machines. When punching holes, the surface will collapse under the influence of cylinder pressure as shown in Figure 2.

The above is the processing method of the pipe surface, whether it is punching machine processing or adding punching device on the pipe bender can effectively improve the production efficiency of the pipe bending.