What are the solutions for non-marking bending of CNC bending machines?

The competition in the sheet metal processing industry is becoming more and more fierce. If companies want to remain invincible, they must continuously improve their processing technology. In the bending applications of some precision stainless steel, aluminum alloy, aerospace parts and copper plate CNC bending machines, users are no longer satisfied with the functionality of the product, and have higher requirements for its manufacturability and aesthetics. The traditional bending process is more likely to cause damage to the surface of the workpiece, and an obvious indentation or scratch will be formed on the surface in contact with the mold, which cannot be removed, resulting in scrapped parts. Therefore, the user’s demand for seamless bending is becoming stronger and stronger. In this paper, five ways to reduce indentation are based on mold parameters (V opening size, shoulder fillet R value), WILA non-marking indentation film, WILA non-metallic material V groove, WILA rotor mold, and WILA roller Multi-V mold. Introduce WILA’s non-marking bending solution in detail.

What are the solutions for non-marking bending of CNC bending machines?

CNC bending machine

The influence of mold parameters on bending indentation

The influence of V opening size

When bending metal sheets of different thicknesses, the size of the opening of the lower mold V selected is different. Under the conditions of the same plate thickness and the same upper mold, the larger the size of the V opening, according to the principle of three-force balance, the smaller the pressure between the metal sheet and the shoulder of the V opening, the smaller the friction and the indentation The depth is also naturally reduced, so it is recommended to use a slightly larger V-opening lower mold.

The influence of the R value of the shoulder fillet

The R value of the rounded corner of the V opening shoulder is different, and the friction caused to the plate during the bending process of the plate is different. The larger the R angle of the shoulder of the V opening, the smaller the pressure between the plate and the shoulder of the V opening, and the lighter the indentation, and vice versa. It is WILA’s effect on the same plate and different R values ​​(Ra

WILA non-marking film

Anhui Yongya feels that from the perspective of friction pairs, it is possible to achieve seamless bending by avoiding direct contact between the upper and lower molds and the plate, and using a non-marking film to separate the upper and lower molds from the plate. There are three types of WILA non-marking film: K-003, K-004 and K-005. Table 1 lists the relevant parameters of WILA non-marking film. The non-marking indentation film mainly acts as a buffer between the workpiece and the shoulder of the lower mold and reduces the coefficient of friction, offsets the pressure between the mold and the plate, thereby preventing the workpiece from producing indentation during bending. Different types of WILA non-marking film

Non-marking lamination film has the advantages of low cost and convenient use. When using, only need to put the non-marking film on the lower mold. Figure 3 shows that the non-marking indentation film is being used for the bending test. The test results show that the use of the non-marking indentation film can effectively avoid the bending and indentation. Comparison chart of non-marking indentation test results

WILA non-metallic material V groove

From the perspective of the friction pair, it can be considered to change the V-groove shoulder to a non-metallic material that is softer than the plate, such as polyurethane, nylon and other materials, while ensuring the original required extrusion effect. As shown, WILA currently has a V-groove K-001/5 of polyurethane elastomer, which can be used in conjunction with the standard mold OZU-016/327. WILA’s unique INZU series V-groove is made of high-strength nylon material and used in conjunction with an extended mold. It is usually used for the bending of aluminum plates with a thickness of 0.4~0.5mm under specific occasions, and the effect is better. WILA non-metallic material V groove

WILA Rotor Mould

The WILA rotary wing mold changes the traditional V-opening structure of the lower mold. The inclined surfaces on both sides of the V-opening are set as a reversible mechanism. When the upper mold presses the plate, the reversing mechanism on both sides of the lower mold is replaced by the pressure of the upper mold. The apex of the upper die is turned inward, so that the sheet is bent into shape. There are three models of WILA rotor molds, which can bend plates with a thickness of ≤5mm. Three types of WILA rotor molds

Thanks to the most stringent tolerance standards, the CNC deep hardening technology of the contact surface and the rotatable V port, it is easy to use the rotor mold to produce parts with shorter flange edges and minimize part folding. The indentation on the surface during bending. The advantages of the rotor mold are:

(1) Holes and grooves are made without deformation in the area close to the bending centerline.

(2) Reduce the indentation produced on the surface when the part is bent.

(3) Very small bend inner corners can be obtained.

(4) The rotor and the contact surface have been hardened to ensure a long service life and accuracy.

(5) The rotor is easy to disassemble and assemble, easy to clean and maintain.

(6) Strict tolerance requirements during mold processing ensure the ultimate accuracy during bending operations.

(7) The compact die size design ensures the greatest bending freedom.

(8) The same mold can bend plates of various thicknesses.

(9) can be used in combination with some customized lower molds for 90° bending.

WILA rotor mold is equipped with tension spring and flap structure, which can realize the bending of shorter flange and hypotenuse parts through the built-in replaceable rotating V port. It shows that the rotor mold OZU-WRB-301 and the lower mold OZU-051 are being used for the bending test. The plate is made of ordinary steel with a thickness of 1mm, and the upper mold is the same BIU-021 upper mold. The test results show that the rotor is used. Compared with the conventional lower mold OZU-051, the mold can avoid bending and indentation more effectively. Comparison chart of WILA rotor mold test results

WILA Roller Type Adjustable V Port Multi-V Mode

Also based on the principle of reducing the friction coefficient of the friction pair between the plate and the lower mold V opening, the sliding friction pair between the plate and the lower mold V opening shoulder can be converted into a rolling friction pair, thereby greatly reducing the friction force on the plate and effectively avoiding it. Bending creasing. At present, this process has been widely used in the mold industry, and the roller-type adjustable Multi-V lower mold in the WILA program is matched with it. The mold is equipped with hardened rollers with low friction coefficient, which can greatly reduce the external creases of the bending parts, and at the same time reduce the bending force by about 10% to 30% compared with the traditional lower mold. Roller type Multi-V lower mold

To sum up, WILA can provide different non-marking bending solutions according to customer needs, and it can also provide technical support and measured non-marking bending effects (bending test) anytime and anywhere. In the fiercely competitive sheet metal industry, WILA will do its best to provide more efficient and higher return on investment bending products for the domestic sheet metal industry.