Bending Molds

In modern manufacturing industry, Bending, as a widely used sheet metal processing equipment, plays an important role. The performance of the Bending not only depends on the machine itself, but the selection of mold materials is also one of the key factors.

First of all, the strength and wear resistance of the mold material directly affect the service life of the mold. In the bending process, the mold needs to withstand high pressure and frequent deformation, which requires the mold material to have excellent mechanical properties. Molds are usually made of hard materials such as mold steel, 42CrMoD, etc. to ensure good stability and durability under complex working conditions.

Secondly, the heat treatment properties of the mold material are also important. Pressure will be generated during the bending process. If the mold material cannot withstand the extrusion, it will easily deform or be damaged. Therefore, mold materials usually need to undergo heat treatment processes such as quenching and tempering to improve their heat resistance and extend their service life.

In addition, the processing performance of mold materials cannot be ignored. Mold manufacturing requires forging, milling, fine grinding and other processing processes. The materials used must have good cutting performance to ensure the accuracy and surface quality of the mold. Although some special materials have excellent mechanical properties, they are difficult to process and are not suitable for manufacturing bending molds.

In short, the selection of bending mold materials is crucial to the entire molding process. Only by selecting the appropriate mold material can we ensure the dimensional accuracy, surface quality and production efficiency of the bent parts, and ultimately meet the needs of users.

The bending mold is roughly composed of four parts: Upper mold, lower mold, guide rail, and mold base. The angles are divided into three specifications: 88°, 90°, and 30° (except special molds)
Upper mold part: Straight sword knife, straight sword (large, small) curved knife, goose neck (large, medium, small) curved knife, 30-degree sharp knife, flattening knife, simple mold, special mold, arc tool, etc.
Lower mold part: Double V groove V4-V7 V5-V9 V6-V10 V7-V11 V8-V12 V15-V18, etc.
Single V groove V4 V5 V6 V7 V8 V10 V12, etc.
Mold base part: Single groove mold base and double groove mold base. Double groove is divided into three types: low position (55cm), medium position (75cm), and high position (135cm).

Different materials have different structures and use different tools, resulting in different acid and alkali resistance, tensile strength, material hardness, tensile coefficient, plasticity, etc. When choosing a mold, you can choose it according to the pressure, structure, material, workpiece expansion size, process requirements, surface treatment, etc. of the machine tool. Under normal circumstances, the width of the slot of the lower die can be selected for iron plates, which is 5-6 times the thickness of the material, not less than 4 times, and not more than 8 times. For stainless steel, the slot of the lower die can be selected to be 6-8 times the thickness of the material, not less than 5 times. For aluminum and copper, the slot of the lower die can be selected to be 8-10 times the thickness of the material (cracks on the surface should be avoided during bending).

The selection of the upper die should be reasonably selected according to the avoidance, nail avoidance, nut avoidance and other structures of the workpiece. When the workpiece needs to avoid left and right, you can choose a machete or a left and right ear knife, or you can use a special mold.
The lower die can be selected according to the shape of the workpiece. The lower die is installed positively or reversely, mainly used for avoidance, nail avoidance, etc. When the size of the workpiece is smaller than the conventional size and the unfolded size is small, the lower die eccentricity method can be used to complete it under the premise of safe production. The reasonable eccentricity is 1/4 of the V-groove width.
When the ratio of the V-groove to the material thickness is 6 times, the unfolded size of the workpiece should increase or decrease by 0.10mm for each increase or decrease of one unit (1mm). There is no obvious change when it increases to the limit.
The selection of special molds is based on the shape, performance, size, appearance of its structure, the safe height of the machine, the pressure of the machine, etc. The adjustment of the step-difference mold is to adjust the amount of filler in the middle of the mold according to the size requirements of the workpiece step to control the size of the workpiece.

The bending mold is made of steel by special heat treatment. It has the characteristics of high hardness, not easy to wear, and high pressure. However, each set of molds has its ultimate pressure: ton/m, so when using the mold Choose the length of the mold, that is, how much pressure should be applied per meter, and must not exceed the pressure marked on the mold.

In order not to damage the mold, we stipulate that when aligning the origin, the upper and lower molds with a length of more than 300mm must be used for the origin. After the origin is aligned, the upper and lower molds of the same height can be used. It is strictly forbidden to use the split small mold to align the origin, and the origin must be based on the origin pressure inside the AMADA machine.

When using molds, due to the inconsistent heights of various molds, molds of the same height can only be used when selecting molds on a machine, and molds of different heights cannot be used.

When using the mold, the appropriate upper and lower molds should be selected according to the material hardness, thickness, and length of the metal sheet. Generally, the lower mold is used according to the standard of 5 to 6T, and the length is longer than the sheet. When the material is harder , The thicker the material, the lower die with a wider slot should be used.

When bending an acute angle or pressing a dead angle, you should choose 30 degrees, first bend the acute angle, and then press the dead edge. When bending R angle, R upper die and R lower die should be used.

When bending a long work piece, do not use segmented molds to reduce the indentation of the knife, and choose a single groove, because the outer angle R of the V groove of the single groove lower mold is large, and it is not easy to produce bending indentation.

When selecting the upper mold, which kind of upper mold should be used, we should understand the parameters of all the molds, and then decide which upper mold to use according to the shape of the product that needs to be formed.

When bending products with extremely hard hardness or thick sheets, it is not allowed to use molds to bend steel bars or other cylindrical products.

When using the mold, you should have a clear mind. After the machine is aligned with the origin, the upper and lower molds should be locked. Do not let the mold fall, hurt people or damage the mold. During the operation, pay attention to the pressure, and do not apply too much pressure at once. , Pay attention to the changes in the data displayed on the screen.

After using the mold, put it back on the mold rack in time and place it according to the label. Frequently clean the dust on the mold and apply anti-rust oil to avoid rust and reduce the accuracy of the mold.

Improper storage of tools
If the press brake tools are not stored properly, the tools will be affected by environmental factors, which will accelerate wear. For example, the tools are exposed to humid or corrosive environments and are prone to rust and corrosion. In addition, if the tools are stored in unstable or uneven places, they may be damaged by friction or collision.

Repeated operation of press brake tools without gloves
When operating a bending machine, repeatedly operating the tools without gloves will cause damage to the surface of the tools. The sweat and grease on the hands will corrode the tools, especially in the case of high-frequency operation, the surface of the tools may gradually be eroded and damaged.
To prevent this problem, operators should wear clean gloves to operate, reduce direct contact between the tool surface and the skin, and protect the surface integrity of the tool.

Metal flakes and residues left on the press brake tool after bending
During the bending operation, metal material chips and residues may adhere to the tool surface. If not cleaned in time, these residues will cause wear and scratches on the tool, affecting the accuracy and performance of the tool. For this reason, after each use of the tool, the metal flakes and residues on the tool surface should be carefully checked and cleaned to ensure the cleanliness and flatness of the tool surface and prevent the residue from continuing to damage the tool.

Daily maintenance steps for press brake tools

•  Apply mold maintenance wax or maintenance oil to the tools, or apply it to an industrial scouring pad. It is very important to choose a scouring pad with moderate hardness and softness, because a scouring pad that is too soft may not be able to completely wipe the mold clean, and a scouring pad that is too hard may leave scratches on the mold.
• The operator should wear gloves and hold the scouring pad to wipe along the height direction of the mold. When wiping, pay attention to only wiping in one direction, not rubbing back and forth, so as not to damage the mold surface.
• After maintenance, wipe the maintenance wax or maintenance oil on the mold surface with a rag to ensure that the mold surface is clean and free of residue.
• If there is no rust stain on the mold surface, you can spray the maintenance wax on the rag and then wipe the mold surface with the rag. This can prevent excessive maintenance wax from directly contacting the mold and keep the mold surface clean.
• In the case of high air humidity or frequent use of the mold, it is recommended to perform maintenance every two days. On the contrary, in a dry environment or when the frequency of use is low, it can be maintained once a week. This flexible maintenance frequency can be adjusted according to actual conditions to ensure that the mold is always in good condition.
• When loading and unloading the mold, the operator should wear gloves. This not only protects the hands, but also prevents the sweat and grease on the hands from corroding and contaminating the mold surface.