Definition: The bending process in which a material is bent in a zigzag pattern is referred to as Z bending.
Standard bending process range: The height of the Z bend must be greater than the sum of the apothem of the V groove and the thickness of the material being bent.
The minimum processing size is determined by the model of the machine used, while the maximum processing size is limited by the shape of the machine’s table.
Z Processing Procedures
- Processing to form a L bending
- Bend the horizontal side of the L bending to form a Z bending (or bend the vertical side of the L bending to form a Z bending)
Workpiece Placement Principles for Z-bending
A: Convenient, good stability.
B: Generally is similar to L-bending.
C: The workpiece is flat with the lower die during the 2nd placement.
Matters Need Attention for Z-bending
The angle of the L bend should be as precise as possible, usually ranging from 89.5° to 90°.
It is important to set up the back gauge to ensure that the workpiece is not deformed during the bending process.
General Processing Methods of Z bending
- The processing sequence should be considered as shown in the following picture, first bend 1 and then bend 2.
- First bend to form an L bending and then further processed to form a Z bending (if interfere with machine worktable, first bend 1 to form a large angle, then bend 2 and then press 1)
- Using two acute angles to form Z bending: first bend into a right-angle, then insert 2 and then insert 1
1) If there is a collision, first bend 1 to form a large angle, then bend 2 and then press 1.
2) if no collision, as per general Z bending processing method, first bend 1 and then bend 2.
Special Processing Method of Z bending
A: Lower die decentering processing
B: Processing with a small V-groove
C: Bending to form a large angle, followed by pressing
D: Select a lower die that can be ground.
Other Z Bending Methods
A: Processing with an offset die
B: Processing with a convertible die.
N Bending Processing
Definition: continuously process the same machining surface twice to form N bending
Precautions for N-bending Processing
The angle of the first bend should be no greater than 90°.
The back gauge for the second bend should be set based on the machined surface.
Special Processing Method of N Bending
If there is slight interference with the top punch after Y-sized N bending, the material should be flattened using a hemming die after the N bending process.
If there is significant interference with the top punch after Y-sized N bending, the material should first be bent to the collision position after the A bend press line, then positioned at point C and bent at point B. Finally, a hemming die and padding should be used to shape the material.
Processing using a shaping punch and die.
Arc processing can be divided into two categories: circular cutting with a bending model and circular cutting with an arc knife.
Arc knives come in two varieties: fixed and adjustable.
A: When machining with a 90° low die, there may be insufficient machining, in which case it is necessary to manually push the mold or, if possible, use an 88° low die.
B: Use a measuring device to verify the dimensional accuracy of the workpiece.
C: When processing a 90° arc, the low die should have a radius of 2 (R + T).