The bending dies of the WC67K-30T1600 E21 CNC Press Brake are L-shaped, R-shaped, U-shaped, Z-shaped, etc. The upper die mainly has 90 degrees, 88 degrees, 45 degrees, 30 degrees, 20 degrees, 15 degrees; etc. angle. The lower mold has 4~18V double groove and single groove with different groove width, as well as R lower mold, acute angle lower mold, flattening mold, etc.
1 The bending mold is 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 when using the mold Correctly select the length of the mold, that is, how much pressure must be applied per meter, and must not exceed the pressure marked on the mold.
2 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.
3 When using molds, due to the inconsistent heights of various molds, only molds of the same height can be used when selecting molds on a machine, and molds of different heights cannot be used.
4 When bending products with extremely hard hardness or thick sheets, molds are not allowed to bend steel bars or other cylindrical products.
5 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.
6 When bending long workpieces, it is best not to use segmented molds to reduce the indentation of the knife, and it is best to use 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 .
7 When using the mold, choose the appropriate upper and lower molds according to the material hardness, thickness and length of the metal sheet. Generally, the lower mold is used according to the standard of 5~6T. The length is longer than the sheet. When the material is harder , The larger the thickness of the material, the application of the lower mold with a wider slot.
8 When selecting the upper mold, which kind of upper mold should be used, we should understand the parameters of all molds, and then decide which upper mold to use according to the shape of the product that needs to be formed.
9 When using the mold, you should have a clear mind. After the machine is aligned to the origin, the upper and lower molds should be locked. Don't let the mold fall, hurt people or damage the mold. During the operation, please 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.
10 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.
The WC67K-40T2500 E21 CNC Press Brake is a widely used bending machine, which has already been hydraulicized. As an important piece of sheet metal processing equipment, bending machines play an irreplaceable role and play a decisive role in product quality, processing efficiency, and accuracy.
Generally, the WC67K-30T1600 E21 CNC Press Brake is an upper piston press, which is composed of a frame, a sliding block, a hydraulic system, a front support frame, a back gauge, a mold, and an electrical system, as shown in Figure 1.
Two working hydraulic cylinders moving in parallel form vertical downward pressure to drive the mold on the bending beam to perform bending work. As the brain of the WC67K-40T2500 E21 CNC Press Brake, the hydraulic control system mainly controls the synchronous operation of the bending process and the positioning of the hydraulic cylinder when the machine is working at full load. I will take a certain type of universal bending machine as an example to analyze the hydraulic system.
Figure 2 shows the hydraulic system of the press brake. Every time a bending action is performed, the typical bending process motion cycle stages of the upper bending beam include:
⑴Oil pump start
The motor rotates in the direction marked by the pump arrow, that is, clockwise, driving the axial plunger pump to run. The oil enters the valve plate and the electromagnetic overflow valve return tank through the pipeline. When the No. 19 valve is closed, the No. 20 cylinder lower chamber The oil keeps the slider at a fixed position.
⑵ downward movement
The rapid downward movement of the WC67K-63T2500 E21 CNC Press Brake is generated by the weight of the bending machine beam and various accessories and the pressure of the oil. In this process, the rodless cavity of the hydraulic cylinder is filled with oil through the filling valve. The rod cavity will generate back pressure and the oil will flow back quickly. The fast-forward movement starts from the top dead center. After a short deceleration stage, the speed of the slider slows down at a certain distance close to the bent sheet.
When No. 9 YV1, No. 24 YV6, No. 13 YV4, No. 17 YV5 electromagnets work, the slider quickly descends, and the descending speed is adjusted by the No. 18 valve. The oil in the lower chamber of the No. 20 cylinder passes through No. 19, No. 18, and No. 17 No. enters the oil tank, and the oil in the upper cavity of cylinder 20 is injected through the No. 21 valve.
When the slider is lowered to the limit switch, the No. 9 YV1, No. 8 YV2, No. 11 YV3, No. 13 YV4, and No. 24 YV6 electromagnets work, and the slider enters the working speed. If the sliding block is not synchronized, it will be automatically corrected by the No. 15 valve, and the sliding position of the sliding block is restricted by the mechanical stop in the cylinder.
The bending phase starts with pressure build-up in the rodless cavity. On the one hand, the bending speed is limited by the amount of oil supplied by the oil pump, on the other hand, it can be adjusted by the proportional valve directional valve. At the same time, the directional valve also controls the synchronous operation of the bending beam and the positioning of the bottom dead center. The limit of the bending force is accomplished by the proportional relief valve to limit the pressure of the pump. The corresponding given values of speed, synchronization, positioning and pressure all come from the CNC. No. 9 YV1, No. 8 YV2, No. 11 are controlled by foot switch or button.
YV3, No. 13 YV4, No. 24 YV6 electromagnets work for the length of time to realize the jog distance when the slide is lowered. The speed of the slide is adjusted by the No. 16 valve, and the slide upward is controlled by No. 11 YV3 and No. 24 YV6. The working time of the electromagnet realizes the upward jog distance of the slider.
The decompression of the rodless cavity starts when it reaches the bottom dead center, or after a short holding time, so that the material has enough time to shape and further improve the dimensional accuracy of the part. Pressure holding and decompression are completed by the proportional directional valve according to the instructions of the CNC. In order to improve processing efficiency, the decompression time must be as short as possible, but in order to avoid unloading impact in the entire system, it is required to extend the decompression time as much as possible. In short, the decompression curve should be as stable as possible and not too steep. The optimization of the whole process is realized by the proportional directional valve.
⑸Master cylinder return
The flow rate of the pump and the pressure area of the rod cavity of the hydraulic cylinder determine the maximum return speed, which is close to the maximum speed in most cases. The return stroke also requires synchronous operation, from the beginning of the decompression of the rod cavity to the end of the top dead center.
At the moment of the return stroke, the No. 8 YV2 electromagnet is required to reset for 2 seconds to relieve the pressure, and then the No. 11 YV3 and No. 24 YV6 electromagnets work, the slider returns, and the return speed is constant.
⑹ Pressure adjustment of the machine.
The No. 6 high pressure relief valve and No. 11 electromagnetic relief valve guarantee the rated force of the machine. The No. 14 overflow valve adjusts the return force of the machine so as not to damage the machine due to overload. The working pressure in the hydraulic system can be read from the No. 7 pressure gauge. The nitrogen charging pressure of No. 10 accumulator is mainly the pressure required to operate No. 19/No. 21 valve.
Development trend of hydraulic system
The development of hydraulic systems has promoted the rapid development of the machine tool industry. In order to meet the needs of the development of hydraulic systems in the direction of high performance, high precision and automation, new hydraulic technologies such as CNC hydraulic technology and electro-hydraulic servo technology are also developing rapidly. From a point of view, the development trend of hydraulic system will be reflected in the following aspects:
⑴Modern hydraulic technology is closely integrated with new technologies represented by microelectronic technology, computer control technology, sensor technology, etc., forming and developing into an automation technology including transmission, control, and detection. At present, hydraulic technology has made significant progress in realizing various requirements such as high pressure, high speed, high power, durability, and high integration; there are also many new achievements in improving the development of proportional control, servo control, and developing control technology. At the same time, the computer-aided design (CAD) and testing (CAT) of hydraulic components and hydraulic systems,microcomputer control, electro-mechanical-hydraulic integration (Hydromechatronics), fluid-electric integration (Fluitronics), reliability, pollution control, energy consumption control, etc. It is also the direction of hydraulic technology development and research.
⑵Virtualization uses CAD technology to fully support the entire process of hydraulic system from conceptual design, product design, performance design, reliability design to detailed design of parts and components, and integrates computer-aided design (CAD), computer-aided analysis (CAE), and computer-aided Process planning (CAPP), computer-aided inspection (CAI), computer-aided testing (CAT) and modern management systems are integrated, and the establishment of a computer manufacturing system (CIMS) enables a breakthrough development in design and manufacturing technology.
⑶ Carry out the failure prediction of the hydraulic system and realize the active maintenance technology. It is necessary to modernize the fault diagnosis of the hydraulic system, strengthen the development and research of the expert system, establish a complete expert knowledge base with learning functions, and use the knowledge in the computer and the knowledge base to calculate the cause of the failure, and propose maintenance plans and preventive measures . It is necessary to further develop the general tool software of the hydraulic system fault diagnosis expert system, and develop the hydraulic system self-compensation system, including self-adjustment, self-correction, and compensation before the failure occurs. This is the direction of the hydraulic industry.
⑷ Combination of digital electronic technology and hydraulic technology. By installing the electronic control device in the servo valve or changing the structure of the valve, a wide variety of digital products have been formed. The performance of the valve is controlled by software, and the program can be changed to easily change the design scheme and realize multiple functions such as digital compensation.
⑸ Miniaturization. With the advancement of hydraulic technology and the intensification of competition, the technology of miniature servo valve has attracted more and more attention for its advantages such as small size, light weight, and high unit power. The research focuses on the advantages of increasing pressure, the application of advanced materials and composite materials to reduce weight, and the development of casting technology, such as the wide use of casting runners in valve bodies and manifold blocks, which can optimize the internal flow of components and achieve component miniaturization.
⑹ Greening reduces energy consumption, leakage control, and pollution control. It will develop technologies to reduce internal friction and throttling losses, as well as non-leakage components, such as pipeless connections, development of new types of seals, etc.; development of pollution-resistant technologies and new pollution detection methods, and online measurement of pollution; pressure liquids with rapid biodegradation can be used , For example, rapeseed oil-based and synthetic grease-based transmission media will be widely used to reduce the environmental hazards of oil leakage, adapt to environmental protection, reduce noise and vibration, and have no leakage.
Mold bending is usually completed on a bending machine. Workers or robots are required to assist in the bending process. The bending accuracy depends on the skill of the technician or the quality of the robot. This bending method It is widely used in the production of small parts with a single product category and simple process.
Due to the uneven material of the plate, it is difficult to accurately bend according to the calculated theoretical value during bending, and the bending angle needs to be compensated. The angle sensor provides support for the bending angle compensation operation. The use of the angle sensor can reduce the influence of the processing material on the bending angle, thereby improving the stability of the accuracy of the bending workpiece. This device is now a standard accessory of the bending machine. widely used.
The intelligent application of bending is sensing technology, which obtains the information required for the bending of the workpiece through sensing actions before, during and after bending, and performs automatic compensation and automatic confirmation feedback. For example, the deflection compensation device is born for the bending machine, and the same is true for the bending angle compensation, but in fact, the equipment without the deflection compensation function is the most ideal equipment.
The non-uniformity of the material determines the non-uniformity of the bent product, and it is the most ideal to collect the non-uniform information before bending. Due to the internal tension of the material, it is most ideal to control the warping deformation of the plate during the bending process. The craftsmen's union carries out compensation operations based on their accumulated experience and sense of body, so as to "intelligently" create excellent products. This is exactly the "craftsman's skill = craftsmanship", and only bending intelligence can replace these craftsmanship.
Bending automation can solve the problem of insufficient personnel. It is complementary to bending intelligence, but from the perspective of bending automation, the universal 6-axis robotic bending system is just one case. Bending machines are widely used in kitchen equipment, office furniture, construction steel structures, automobiles, electronic equipment and other industries. For the small-batch and multi-variety production modes of these industries, the use of general-purpose 6-axis robotic bending systems is still very limited Sexual.
There are many ways to realize bending automation. If a 6-axis robotic bending system is adopted, the key considerations should be the flexibility of robot programming, the flexibility of blanking and stacking, and the automatic compensation and confirmation of intelligent bending. At present, bending automation can check and confirm the situation before and during the bending process, but there is almost no automatic inspection of the finished product after bending. Therefore, the automatic and semi-automatic use of bending still needs a certain amount of time.
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