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Bending means that the metal sheet undergoes elastic deformation under the pressure of the upper or lower die of the bending machine, and then enters the plastic deformation. At the beginning of plastic bending, the sheet is free to bend. With the upper or lower die pairing when pressing the sheet, the sheet becomes closer to the inner surface of the V-groove of the lower mold, and at the same time, the radius of curvature and the bending arm gradually reduces.
Continue to press until the stroke ends, so that the upper and lower molds are in full contact with the sheet at three points. At this time, a V-shaped bend which completed, we commonly called it is bending.
What is the press brake tooling ?
It is a tool used by the bending machine to form and process sheet materials. This tool is composed of various parts, and different molds are composed of different parts. Bending machine molds are divided into upper and lower molds of the bending machine, which are used for sheet metal stamping forming and separating molds. The press brake tooling used for forming has a cavity, and the mold used for separation has a cutting edge.
Selection of press brake tooling material
There are many kinds of materials for the production of bending machine molds, including steel, cemented carbide, steel-bonded cemented carbide, zinc-based alloy, low melting point alloy, aluminum bronze, polymer materials and so on.
At present, most of the materials used to manufacture stamping and bending machine molds are steel. Commonly used materials for working parts of bending machine molds include: carbon tool steel, low-alloy tool steel, high-carbon high-chromium or medium-chromium tool steel, Medium-carbon alloy steel, high-speed steel, base steel, cemented carbide, steel-bonded cemented carbide, etc.
- Carbon tool steel
The most commonly used carbon tool steels in press brake tooling are T8A, T10A, etc. The advantages are good processing performance and low price. But the hardenability and red hardness are poor, the heat treatment deformation is large, and the bearing capacity is low.
- Low alloy tool steel
Alloy tool steel is based on carbon tool steel with a proper amount of alloying elements added. Compared with carbon tool steel, it reduces quenching deformation and cracking tendency, improves the hardenability of steel, and has better wear resistance. The low-alloy steels used to manufacture bending machine molds include CrWMn, 9Mn2V, 7CrSiMnMoV (code CH-1), 6CrNiSiMnMoV (code GD) and so on.
- High carbon and high chromium tool steel
Commonly used high carbon and high chromium tool steels are Cr12, Cr12MoV, Cr12Mo1V1 (code D2), they have good hardenability and wear resistance, heat treatment deformation is small, high wear resistance and micro deformation bending machine die steel. The bearing capacity is inferior to high-speed steel. However, the segregation of carbides is serious, and repeated upsetting (axial upsetting, radial upsetting) and forging must carry out to reduce the unevenness of carbides and improve the performance.
Types of press brake tooling
Bending molds include L-shaped, R-shaped, U-shaped, Z-shaped, etc. The upper mold mainly has different angles such as 90°, 88°, 45°, 30°, 20°, 15°, etc.
The lower dies have double grooves and single grooves with different groove widths of 4~18V, as well as R lower dies, acute angle lower dies, flattening dies, etc.
The upper and lower molds which divided into sections and the whole: the upper mold sections are generally 300mm, 200mm, 100mm, 100mm, 50mm, 40mm, 20mm, 15mm, 10mm, and the overall size is 835mm. The lower die generally divides into 400mm, 200mm, 100mm, 50mm, 40mm, 20mm, 15mm, 10mm, and the overall size is 835mm.
- Standard mold for torsion shaft bending machine
- CNC press brake machine standard mold
- Gooseneck punch
- U type mold
- Hemming tooling
How to choose press brake tooling
- The bending mold which made of high-quality 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 you must be correct when using the mold to choose the length of the mold. That is, how much pressure needs to apply 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 bending products with extremely hard hardness or too thick sheet, it is not allowed to use molds to bend steel bars or other cylindrical products.
- 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 workpiece, it is best not to use segmented molds to reduce the indentation of the knife, and it is best to 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 pressure mark.
- When using the mold, choose the appropriate upper and lower molds according to the material hardness, thickness and length of the metal sheet. Generally, use the lower mold according to the standard of 5~6T, and the length is longer than the sheet. For harder and thicker materials, lower molds with wider grooves should be used.
- When selecting the upper mold, which kind of upper mold using, 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 form.
- When using the mold, you should have a clear mind. After the machine aligned to the origin, the upper and lower molds need to lock. Don’t let the mold fall, hurt people or damage the mold. Pay attention to the pressure during the operation. Pressure, 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.
How to judge whether the press brake tooling meets the standard or not
- The degree of conformity between the upper arc of the die circle of the bending machine and the outer diameter of the pipe needs to bend.
- Whether the upper arc low warp of the die circle of the bending machine is consistent with the arc required by the drawing of the pipe need to bend.
- Whether the square hole in the mold of the bending machine matches the square axis of the pipe bending machine.
- The roughness of the arc on the die circle of the bending machine. Whether the size of the arc meets the requirements of the drawing.
- The parallelism between the upper arc and the upper and lower sides of the die circle of the bending machine.
- Whether the hardness of each part of the bending machine mold is required by the drawings.
Problems that should paid attention to when installing the mold of the bending machine
When installing the bending machine mold, be sure to check the status of the equipment. And then install and debug according to the steps, and pay attention to personal safety when debugging.
- Adjustment of bending machine
- Adjustment of the slider stroke of the bending machine
- Bending machine stroke module adjustment
- Adjustment of die gap of bending machine
- Bending machine mold angle adjustment
Daily use specification of press brake tooling
- Turn on the power of the bending machine, turn the key switch, press the oil pump to start. And the bending machine oil pump starts to rotate. At this time, the machine has not yet started to work.
- The stroke adjustment requires a test run when starting the bending machine mold. When the upper die of the bending machine descends to the bottom, there must be a gap of plate thickness. Otherwise it will cause damage to the mold and the machine. The stroke adjustment also has electric quick adjustment and manual fine adjustment.
- To choose the notch of the die of the bending machine, generally choose a notch of 8 times the width of the plate thickness. If you bend a 4mm sheet, you need to choose a slot of about 32.
- Check the overlap and firmness of the upper and lower molds of the bending machine; check whether the positioning devices meet the requirements of being processed. Frequently check the overlap of the upper and lower molds; whether the instructions of the pressure gauge meet the regulations.
- When bending the sheet, it has to compact to prevent the sheet from lifting up and hurting the operator during bending.
- The power supply needs to cut off when adjusting the sheet metal die, and the operation should stop.
- When changing the opening of the lower die of the variable bending machine, no material allows to contact the lower die.
- It can not use bending machine molds to fold over-thick iron plates or quenched steel plates, high-grade alloy steels, square steels, and sheets that exceed the performance of the sheet metal bending machine to avoid damage to the machine tool.
- Turn off the bending machine, and place wooden blocks on the lower molds under the cylinders on both sides to lower the upper slide plate onto the wooden blocks. Exit the control system program first, then cut off the power supply.