The sheet metal processing industry is increasingly competitive. If an enterprise wants to be in an invincible position, it must continuously improve its processing technology. In bending applications such as precision stainless steel, aluminum alloys, aerospace parts and copper plates, users are no longer satisfied with the functionality of the product, but have higher requirements for its processability and aesthetics. The traditional bending process is easy to cause damage to the surface of the workpiece. Surfaces that come in contact with the mold can develop visible indentations or scratches that cannot be removed, resulting in scrapped parts. Therefore, the user's demand for seamless bending is getting stronger and stronger.
The effect of lower die parameters on bending indentation.
Influence of V opening size.
When bending metal sheets of different thicknesses, the V opening size of the lower die is also different. In the case of the same plate thickness and the same upper die, the larger the size of the V-shaped mouth, according to the principle of three-force balance, the smaller the pressure between the metal plate and the shoulder of the V-shaped mouth, the lower the friction force, and the natural indentation depth. decrease. Therefore, it is recommended to choose a slightly larger V-opening die.
Influence of shoulder fillet r value.
The size of the r value of the fillet of the shoulder of the V opening is different, and the friction to the plate during the bending process of the plate is also different. The larger the R angle of the shoulder of the V-shaped opening, the less pressure between the sheet and the shoulder of the V-shaped opening, and the lighter the indentation, and vice versa. Figure 1 is a plot of the wila indentation test of the same sheet with different R values (RA <; Rb). Obviously, the bending indentation of RA is significantly larger than that of Rb, so it is recommended to choose a lower die with a slightly larger shoulder fillet
The solution for non-marking bending.
Traceless lamination.
From the point of view of the friction pair, the upper and lower molds can be separated by a traceless lamination to avoid direct contact between the upper and lower molds and the plate. The upper non-marking lamination mainly acts as a buffer between the workpiece and the lower mold shoulder, reduces the friction coefficient, offsets the pressure between the mold and the plate, and prevents the workpiece from indentation when it is bent. The invention has the advantages of low cost and convenient use. When in use, the unmarked indentation film can be placed on the lower die. Figure 3 shows a bend test using an unmarked indentation film. The test results show that the use of non-marking indentation film can effectively avoid bending indentation.
Non-metallic material V-groove.
Non-metallic material V-groove....
Soft non-metallic materials, such as polyurethane, nylon and other materials. It is made of high-strength nylon material and is used with stretch dies. It is usually used to bend aluminum plates with a thickness of 0.4~0.5mm in specific occasions, and the effect is good
Rotor die.
The rotor mold changes the traditional V-shaped opening structure of the lower mold, and sets the inclined surfaces on both sides of the V-shaped opening as a turning mechanism. In the process of pressing the plate with the upper die, the turning mechanisms on both sides of the lower die turn inward from the top of the upper die with the help of the pressure of the upper die, thereby bending the plate.
Due to the tightest tolerance standard requirements, CNC deep quenching and hardening of the contact surfaces and rotatable V-ports, the use of rotor dies makes it easy to produce parts with shorter flange edges and reduce indentations on the surface when the part is bent to a minimum lowest. The advantages of the rotor die are: (1) Non-deformable holes and grooves are made in the area close to the centerline of the bend.
(2) Reduce the indentation on the surface when the part is bent.
(3) Very small curved fillets can be obtained.
(4) The rotor and contact surfaces have been hardened to ensure long service life and accuracy.
(5) The rotor is easy to assemble and disassemble for cleaning and maintenance.
(6) Strict tolerance requirements during mold processing ensure ultimate accuracy during bending operations.
(7) The compact die size design ensures maximum bending freedom.
(8) The same mold can bend plates of different thicknesses.
(9) Can be combined with some customized lower molds for 90° bending.
The rotor mold has a tension spring and flap structure, and through the built-in replaceable rotating V-port, the bending of short flange edge and bevel edge parts can be realized. The test results show that compared with the traditional mold, the rotor mold can avoid bending indentation more effectively, and the roller-type adjustable V-port is also based on the principle of reducing the friction coefficient of the friction pair between the plate and the plate. The sliding friction pair on the shoulder and the V-shaped mouth of the lower die can be converted into a rolling friction pair, which greatly reduces the friction force on the plate and effectively avoids bending indentation. At present, this process has been widely used in the mold industry. The die is equipped with hardened rollers with a low coefficient of friction, which greatly reduces external creases in curved parts. At the same time, compared with the traditional mold, the bending force can be reduced by about 10% to 30%. To sum up, we can provide different non-marking bending solutions according to the needs of customers, and can also provide technical support and actual non-marking bending effect (bending test) anytime and anywhere. In the highly competitive sheet metal industry, we will do our best to provide bending products with higher efficiency and higher return on investment for the domestic sheet metal industry.
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