Normal press brake punch and die
Normal press brake punch and die, as shown below. To extend the life of the mold, use the round corners as soon as possible when designing the part. 
Too small flange height, even if using a bending die, it is not conducive to forming. Generally, the flange height L≥3t (including wall thickness).
Offset processing method
Some low-profile sheet metal Z-shaped steps are bent. Processing manufacturers often use simple molds to process on punching machine or hydraulic press machine. If the height size is not large, they can also be processed on the press brake with offset dies, as shown in the figure below. However, its height H should not be too high. Generally, it should be (0 ～ 1.0) t. If the height is (1.0 ～ 4.0) t, consider using a mold with a loading and unloading structure according to the actual situation.
The height of this mold step can be adjusted by adding shims. Therefore, the height H can be adjusted arbitrarily. However, there is also a disadvantage that the length L cannot be easily guaranteed. The verticality of the vertical edges cannot be easily guaranteed. If the height H size is large, it is necessary to consider bending on press brake.
The bending machine is divided into two types: NC bending machine and CNC bending machine. Due to high accuracy requirements and irregular bending shapes, sheet metal bending of communication equipment is generally bent by CNC bending machines. The basic principle is to use the bending knife (punch) and V-groove (Die) of the bending machine. It can be bending and forming sheet metal parts.
Advantages: convenient clamping, accurate positioning and fast processing speed;
Disadvantages: low pressure, only simple forming, low efficiency.
Basic principles of forming
The basic principle of forming is shown in the following figure
Bending mold (Punch)
The form of the bending mold is shown in the following figure. During processing, it is mainly selected according to the shape of the work piece. Generally, there are many bending mold shapes from processing manufacturers. Especially those with a high degree of specialization, to process various complex bending. Custom many shapes and specifications of the bending mold.
The die is generally V = 6t (t is the material thickness)
There are many factors that affect the bending process, mainly including the radius of the upper mold arc, material, material thickness, strength of the die, and die size of the lower mold. To meet the product demands, the manufacturer has serialized the bending mold under the safe condition of press brake. We need to have a general understanding of the existing bending mold in the structure design process. See the figure below for the punch and die
Basic principles of bending step
(1) Bending from inside to outside;
(2) Bending from small to large;
(3) Bending special shapes first, then bending general shapes;
(4) No impact or interference on the subsequent process after the previous process is formed.
The current bending forms are generally shown in the following figure:mal press brake punch and die.
