1. High precision With the development of proportional servo technology, the stopping accuracy and speed control accuracy of hydraulic presses are getting higher and higher. In hydraulic presses that require high precision, closed-loop PLC control (variable pumps or valves) with displacement grating detection and proportional servo control is often used. For example, the stopping accuracy of the slider can reach ±0. Olmm. In an isothermal forging hydraulic press that requires extremely low slide speed and good stability, when the working speed of the slide is 0.05"---0.30mm/s, the speed stability error can be controlled within ±0.03mm/ s. The combined closed-loop control of the displacement sensor and the proportional servo valve also greatly improves the correction and leveling performance and synchronization of the movable crossbeam (slider) under eccentric load, and keeps the horizontal accuracy of the slider to 0.04 under eccentric load. "-0.05mm/m level. In 2005, at the China International Machine Tool Show (CIMT2005), the ASTR0100 (nominal force 1000kN) automatic bending machine exhibited by Amada, Japan had a sliding block positioning accuracy of 0.001mm, and the backgauge was repeated in front and rear positions The positioning accuracy is 0.002mm. 2. Integration and precision of hydraulic system Now poppet valves are rarely used, and the use of general valve blocks is correspondingly reduced, and cartridge valves are widely used. According to the requirements of different circuits, the cartridge valve is integrated into one or several valve blocks, which greatly reduces the connecting pipeline between the valves, thereby reducing the loss of liquid pressure in the pipeline and reducing shock vibration. The variety of control cover plates in the cartridge valve greatly enriches the control performance, control accuracy and flexibility of various cartridge valves. The large number of applications of proportional and servo technology in control valves and variable pumps have also greatly refined the hydraulic control technology. 3. Numerical control, automation and networking In the digital control of hydraulic presses, industrial control machines have been widely used as the upper computer, and the programmable logic controller (PLC) is a dual machine system that directly controls and operates each part of the equipment. Huazhong University of Science and Technology is studying the control system of the fast forging hydraulic unit, forming an on-site control network system with an industrial control machine and PLC to realize centralized monitoring, decentralized management, and decentralized control. Amada Company puts forward the FBDIII-NT series network connection corresponding high-precision bending machine in the hydraulic bending machine, and uses the ASISIOOPCL network service system to uniformly manage the CAD/CAM. In the automated numerical control technology, multi-axis control has become quite common. In hydraulic bending machines, many equipment use 8 control axes, and some even up to 10. 4. Flexibility In order to adapt to more and more multi-variety, small-batch production trends, the flexibility requirements of hydraulic presses have become more and more prominent, which is mainly reflected in various rapid mold changing technologies, including rapid loading and unloading of abrasive tools, Establishment and management, rapid delivery of abrasive tools, etc. 5. High productivity and high efficiency High productivity is not only reflected in the high speed of the equipment itself, but also mainly reflected in the automation and high efficiency of auxiliary processes, which minimizes the auxiliary process occupying the main machine's motor time. Such as the use of loading and unloading manipulators, automatic detection of abrasive (tool) wear, automatic lubrication systems, automatic sorting systems, automatic palletizing, high-speed opening and opening of mobile worktables, and accurate positioning and locking. 6. Environmental protection and personal safety protection In addition to safety locking devices that prevent the slider from sliding down, infrared light curtain protection systems are also used in many occasions. In the hydraulic system, the pollution of oil leakage has prompted many improvements to various sealing systems. In the extrusion production line, sawing noise has a great impact on the environment, so the sawing process is sealed in a box-shaped device, and equipped with an automatic sawdust collection and transportation device, which greatly improves the extrusion production environment. 7. In-line and complete Modern production requires equipment suppliers not only to supply a single piece of equipment, but also to supply a complete set of equipment for the entire production line to achieve a turnkey project. For example, the production line of automobile covering parts cannot only supply a few large hydraulic presses, and the conveying manipulator or conveying device between each hydraulic press is also an important part of the supply. Another example is the aluminum extrusion production line. In addition to the extrusion hydraulic press, there are dozens of extrusions such as ingot heating, tension and torsion straightening, online quenching, cooling bed, interrupted sawing, fixed-length sawing, and aging treatment. Auxiliary equipment before and after. Therefore, the supply method of complete set and line has become the mainstream of the current supply method.