(1) What is sheet metal bending?
Sheet metal bending is the process of transforming flat metal sheets into three-dimensional shapes using pressure equipment and specially designed molds.
Due to the different materials, thicknesses, lengths, widths of the sheets, as well as the desired shapes and angles to be formed, there are bending machines of different tonnages and sizes, equipped with special molds of different heights, shapes, and V-widths.
(2) What are the types of bending processes?
Bending processes can be divided into three types: air bending, coining, and bottoming.
① Air bending is a method of performing right-angle and obtuse-angle bends using an upper die with an angle of 88 degrees or less and a lower die with a V-width (V represents the groove width, t represents the material thickness) of 12t.
② Coining is a method of performing right-angle and obtuse-angle bends using an upper die with an angle of 90 degrees. The lower die for coining typically has a V-width of 6~12t.
③ Bottoming is a method of performing right-angle bends using an upper die with an angle of 90 degrees. The lower die for bottoming typically has a V-width of 5~6t.
(3) How to use a bending machine?
Currently, there are many types of bending machines used in sheet metal processing, which can be divided into mechanical (servo motor) and hydraulic types based on the rotation method. They can also be classified into simple manual bending machines, ordinary domestic digital positioning bending machines, and process-controlled digital full-function bending machines based on the control system. Bending machines can also be classified into 4-axis, 8-axis, 12-axis, and so on based on the action parts.
① Before using the bending machine, check if the power supply is on, if there is sufficient air pressure, if the hydraulic system is adequately filled, if the machine is clean, and if there are any obstacles on the slide path. Only after confirming these, proceed to the next steps.
② Turn on the power switch of the machine, start the oil pump to set the origin of the L-axis, D-axis, CC-axis, and Z-axis, and complete the startup process.
③ After selecting the appropriate mold, set the machine's gear switch to the cutting position. Install the base, lower die, and upper die. Then, set the machine's switch to the inching or single-action position. Use the foot pedal switch to move the upward handle or knob to bring the upper and lower dies together and apply pressure, aligning the zero point of the D-axis. Lock the lower die to complete the mold installation process.
④ Perform pattern recognition to understand the bending sequence and dimensions. Program the bending machine accordingly. There are two methods of programming input: angle input and depth input. The depth input method is commonly used. Firstly, put the computer into the programming state and enter numerical values such as bending dimensions (L, D values), Z value, speed, time, and number of repetitions. Then, check and confirm the program. Once confirmed, put the computer into the running state. Use scrap material for trial bending to modify the program and optimize the angles and dimensions. Then, perform a trial bend on the actual product. After confirming the accuracy of the trial bend, mass production can be carried out.
(5) In order to increase the bending speed during the bending process, the gear switch can be set to single-action or continuous-action mode. However, for safety reasons, it is generally sufficient to use single-action mode. When bending long workpieces with large angles in the middle, the CC-axis can be adjusted to change the middle angle and make it consistent with the angles on both sides. During the bending process, the principle of center bending should be observed, which is an important prerequisite for ensuring the accuracy of bending processing. Bending at one end of the bending machine is not allowed, as it not only affects the angle but also damages the machine.
(6) When taking a short break, it is not allowed to turn off the power supply. Turning off the oil pump is sufficient. This can save electricity costs and avoid the need to reset the origin when starting work again, saving time and improving efficiency.
(7) When finishing the production or at the end of the work shift, first lower the lower die to the lowest position, then turn off the oil pump, and finally turn off the power supply. If the batch of products is completed, the molds must be removed, placed back on the mold rack, and returned to the operating panel.
(8) It is strictly prohibited to operate the bending machine in violation of regulations to avoid unnecessary harm to personnel, equipment, and molds. It is important to keep the machine clean and properly maintained, and develop good habits of caring for the equipment and molds.
(4) How to use bending molds?
Bending molds include L-shaped, R-shaped, U-shaped, Z-shaped, and other types of bends. The upper dies are available in various angles such as 90 degrees, 88 degrees, 45 degrees, 30 degrees, 20 degrees, and 15 degrees. The lower dies include double-slot and single-slot dies with different V-widths ranging from 4 to 18V, as well as R dies, acute angle dies, flattening dies, and so on. The upper and lower dies can be segmented or integral. The segmented upper dies are typically available in lengths of 300mm, 200mm, 100mm, 100mm, 50mm, 40mm, 20mm, 15mm, and 10mm, while the integral length is 835mm. The lower dies are usually segmented into lengths of 400mm, 200mm, 100mm, 50mm, 40mm, 20mm, 15mm, and 10mm, with an integral length of 835mm.
① Bending molds are made of high-quality steel and undergo special heat treatment. They have characteristics such as high hardness, low wear, and high pressure resistance. However, each set of molds has its limit pressure tolerance in tons per meter. Therefore, when using molds, it is important to correctly select the length of the mold, which indicates how much pressure should be applied per meter, and it should never exceed the marked pressure of the mold.
② To avoid damaging the molds, it is specified that when setting the origin, upper and lower dies with a length of 300mm or more must be used. Only after setting the origin correctly can upper and lower dies of the same height be used. It is strictly prohibited to use segmented small molds for setting the origin. The standard for setting the origin must follow the internal origin pressure of AMADA machines.
③ When using molds, due to the inconsistent heights of various molds, only molds of the same height can be used on one machine. Different height molds should not be mixed.
④ When using molds, suitable upper and lower dies should be selected based on the material hardness, thickness, and length of the metal sheet. Generally, the lower die should be used according to the standard of 5~6T, and its length should be slightly longer than the sheet. For materials with higher hardness or greater thickness, a lower die with a wider V-width should be used.
⑤ When bending sharp angles or closing angles, a 30-degree upper die should be used. Sharp angles should be bent first, followed by closing the edge. When bending R angles, R-shaped upper and lower dies should be used.
⑥ When bending longer workpieces, it is better not to use segmented molds to reduce the marks from the tool transitions. It is also preferable to use single-slot lower dies because they have a larger outside corner radius (R) and are less likely to produce bending marks.
⑦ When selecting the upper die, the specific type of upper die to be used should be determined based on understanding the parameters of all molds and considering the desired shape of the formed product.
⑧ It is not allowed to use molds to bend steel bars or other cylindrical products with extremely hard hardness or excessive thickness.
⑨ When using molds, clear thinking is required. After the machine sets the origin, the upper and lower dies should be locked to prevent the molds from falling off and causing injury or damage. During the operation, attention should be paid to the pressure and the changes in the displayed data on the screen.
⑩ After using the molds, they should be promptly returned to the mold rack and placed properly according to the markings. The molds should be regularly cleaned of dust and coated with rust preventive oil to prevent rusting and maintain mold accuracy.
Sheet metal bending is the process of transforming flat metal sheets into three-dimensional shapes using pressure equipment and specially designed molds.
Due to the different materials, thicknesses, lengths, widths of the sheets, as well as the desired shapes and angles to be formed, there are bending machines of different tonnages and sizes, equipped with special molds of different heights, shapes, and V-widths.
(2) What are the types of bending processes?
Bending processes can be divided into three types: air bending, coining, and bottoming.
① Air bending is a method of performing right-angle and obtuse-angle bends using an upper die with an angle of 88 degrees or less and a lower die with a V-width (V represents the groove width, t represents the material thickness) of 12t.
② Coining is a method of performing right-angle and obtuse-angle bends using an upper die with an angle of 90 degrees. The lower die for coining typically has a V-width of 6~12t.
③ Bottoming is a method of performing right-angle bends using an upper die with an angle of 90 degrees. The lower die for bottoming typically has a V-width of 5~6t.
(3) How to use a bending machine?
Currently, there are many types of bending machines used in sheet metal processing, which can be divided into mechanical (servo motor) and hydraulic types based on the rotation method. They can also be classified into simple manual bending machines, ordinary domestic digital positioning bending machines, and process-controlled digital full-function bending machines based on the control system. Bending machines can also be classified into 4-axis, 8-axis, 12-axis, and so on based on the action parts.
① Before using the bending machine, check if the power supply is on, if there is sufficient air pressure, if the hydraulic system is adequately filled, if the machine is clean, and if there are any obstacles on the slide path. Only after confirming these, proceed to the next steps.
② Turn on the power switch of the machine, start the oil pump to set the origin of the L-axis, D-axis, CC-axis, and Z-axis, and complete the startup process.
③ After selecting the appropriate mold, set the machine's gear switch to the cutting position. Install the base, lower die, and upper die. Then, set the machine's switch to the inching or single-action position. Use the foot pedal switch to move the upward handle or knob to bring the upper and lower dies together and apply pressure, aligning the zero point of the D-axis. Lock the lower die to complete the mold installation process.
④ Perform pattern recognition to understand the bending sequence and dimensions. Program the bending machine accordingly. There are two methods of programming input: angle input and depth input. The depth input method is commonly used. Firstly, put the computer into the programming state and enter numerical values such as bending dimensions (L, D values), Z value, speed, time, and number of repetitions. Then, check and confirm the program. Once confirmed, put the computer into the running state. Use scrap material for trial bending to modify the program and optimize the angles and dimensions. Then, perform a trial bend on the actual product. After confirming the accuracy of the trial bend, mass production can be carried out.
(5) In order to increase the bending speed during the bending process, the gear switch can be set to single-action or continuous-action mode. However, for safety reasons, it is generally sufficient to use single-action mode. When bending long workpieces with large angles in the middle, the CC-axis can be adjusted to change the middle angle and make it consistent with the angles on both sides. During the bending process, the principle of center bending should be observed, which is an important prerequisite for ensuring the accuracy of bending processing. Bending at one end of the bending machine is not allowed, as it not only affects the angle but also damages the machine.
(6) When taking a short break, it is not allowed to turn off the power supply. Turning off the oil pump is sufficient. This can save electricity costs and avoid the need to reset the origin when starting work again, saving time and improving efficiency.
(7) When finishing the production or at the end of the work shift, first lower the lower die to the lowest position, then turn off the oil pump, and finally turn off the power supply. If the batch of products is completed, the molds must be removed, placed back on the mold rack, and returned to the operating panel.
(8) It is strictly prohibited to operate the bending machine in violation of regulations to avoid unnecessary harm to personnel, equipment, and molds. It is important to keep the machine clean and properly maintained, and develop good habits of caring for the equipment and molds.
(4) How to use bending molds?
Bending molds include L-shaped, R-shaped, U-shaped, Z-shaped, and other types of bends. The upper dies are available in various angles such as 90 degrees, 88 degrees, 45 degrees, 30 degrees, 20 degrees, and 15 degrees. The lower dies include double-slot and single-slot dies with different V-widths ranging from 4 to 18V, as well as R dies, acute angle dies, flattening dies, and so on. The upper and lower dies can be segmented or integral. The segmented upper dies are typically available in lengths of 300mm, 200mm, 100mm, 100mm, 50mm, 40mm, 20mm, 15mm, and 10mm, while the integral length is 835mm. The lower dies are usually segmented into lengths of 400mm, 200mm, 100mm, 50mm, 40mm, 20mm, 15mm, and 10mm, with an integral length of 835mm.
① Bending molds are made of high-quality steel and undergo special heat treatment. They have characteristics such as high hardness, low wear, and high pressure resistance. However, each set of molds has its limit pressure tolerance in tons per meter. Therefore, when using molds, it is important to correctly select the length of the mold, which indicates how much pressure should be applied per meter, and it should never exceed the marked pressure of the mold.
② To avoid damaging the molds, it is specified that when setting the origin, upper and lower dies with a length of 300mm or more must be used. Only after setting the origin correctly can upper and lower dies of the same height be used. It is strictly prohibited to use segmented small molds for setting the origin. The standard for setting the origin must follow the internal origin pressure of AMADA machines.
③ When using molds, due to the inconsistent heights of various molds, only molds of the same height can be used on one machine. Different height molds should not be mixed.
④ When using molds, suitable upper and lower dies should be selected based on the material hardness, thickness, and length of the metal sheet. Generally, the lower die should be used according to the standard of 5~6T, and its length should be slightly longer than the sheet. For materials with higher hardness or greater thickness, a lower die with a wider V-width should be used.
⑤ When bending sharp angles or closing angles, a 30-degree upper die should be used. Sharp angles should be bent first, followed by closing the edge. When bending R angles, R-shaped upper and lower dies should be used.
⑥ When bending longer workpieces, it is better not to use segmented molds to reduce the marks from the tool transitions. It is also preferable to use single-slot lower dies because they have a larger outside corner radius (R) and are less likely to produce bending marks.
⑦ When selecting the upper die, the specific type of upper die to be used should be determined based on understanding the parameters of all molds and considering the desired shape of the formed product.
⑧ It is not allowed to use molds to bend steel bars or other cylindrical products with extremely hard hardness or excessive thickness.
⑨ When using molds, clear thinking is required. After the machine sets the origin, the upper and lower dies should be locked to prevent the molds from falling off and causing injury or damage. During the operation, attention should be paid to the pressure and the changes in the displayed data on the screen.
⑩ After using the molds, they should be promptly returned to the mold rack and placed properly according to the markings. The molds should be regularly cleaned of dust and coated with rust preventive oil to prevent rusting and maintain mold accuracy.
