Intelligent hydraulic presses belong to high-end manufacturing equipment, primarily targeting the design, manufacturing, and use of hydraulic presses. They utilize advanced intelligent technologies such as information perception, decision-making, and safe execution to form a human-machine system comprised of human experts and intelligent machines. This achieves optimal organization and allocation of resources such as products, tools, environment, and workers, expanding, extending, and partially replacing the physical and mental labor of humans in the hydraulic forming manufacturing process. What are its development trends and key technologies?
1. Development Trends
(1) Intelligentization.
The slider motion curve can be optimized online according to different production processes and mold requirements (such as blanking, stretching, sheet metal extrusion, and progressive die stamping). Special working characteristic curves can be designed for high-difficulty, high-precision processing, achieving “free movement” of the slider.
(2) High Efficiency.
The number of slider strokes can be set within a wide range. Slider speed and stroke are easily adjustable. Depending on the forming process, the slider can work at its minimum stroke. With the help of multi-station technology and automatic feeding technology, production efficiency is greatly improved.
(3) High Precision.
Through servo control technology, the movement of the hydraulic press can be precisely controlled. Generally, a slider displacement detection device is installed, and the position of the slider can be accurately controlled. The slider motion characteristics can be optimized. For example, during stretching, bending, and stamping, an appropriate slider curve can reduce springback and improve the precision of the parts.
（4）Multifunctional
For new processes such as isothermal forging and superplastic forming, the press utilizes the space between the slide and the die to create a temperature-controlled heating environment, combining forging, stamping, and heat treatment processes into a single machine for multiple uses, ensuring product quality.
（5） Low Noise
The intelligent hydraulic press simplifies the transmission system and reduces noise. Setting a low-noise motion curve for the slide helps reduce blanking noise; compared to traditional blanking, the new two-step blanking process can reduce noise by at least 10dB.
（6）High Energy Efficiency
The servo hydraulic press uses direct drive, greatly reducing transmission links and lubrication, and improving maintainability. When the slide stops, the motor stops, significantly reducing energy consumption.
（7）WYSIWYG (What You See Is What You Get)
Modern software technology enables process simulation, allowing users to plan and optimize the entire manufacturing process on a computer, making operation more intuitive.
2. Key Technologies
The main key technologies for the development of intelligent hydraulic presses are as follows:
(1) Development of the main oil pump of the hydraulic press directly driven by a servo motor.
Currently, there are still many technical difficulties in directly driving hydraulic pumps with high-power servo motors. The hydraulic pump requires a very wide speed adjustment range, and it must be able to operate normally even below 10 rpm. Generally, the minimum speed of a hydraulic pump is 600 rpm, making it difficult to achieve a wide speed adjustment range.
(2) High-power AC servo motors and drive control systems.
Currently, switched reluctance motors (SMRs) are mainly used, which have advantages such as simplicity, reliability, efficient four-quadrant operation within a wide speed and torque range, fast response speed, and low cost. With the improvement of drive control system performance and the decrease in price, the realization and promotion of high-power AC servo drive technology have been promoted, making it possible to adopt AC servo drives in the field of forging equipment. Its disadvantages are: large torque fluctuations and high vibration; nonlinear characteristics of the system; high control cost; and low power density.
（3） Dedicated Control System.
Closed-loop control technology for hydraulic press pressure and position is achieved through changes in servo motor speed. Traditional hydraulic presses control hydraulic pressure and position via proportional valves or proportional servo valves. Specialized pump control algorithms are needed to ensure high stability and precision of the hydraulic system within the 1-25 MPa range.
（4）Energy Recovery and Management System.
To minimize energy loss, the potential energy from the slide’s descent and the energy generated by cylinder depressurization need to be recovered and reused. Regarding energy management, since instantaneous power is many times greater than average power, energy allocation in large intelligent hydraulic presses must be carefully managed to avoid impacting the power grid.
（5）Forming Process Optimization Based on Intelligent Hydraulic Press.
Different materials and shapes of parts require different production processes. For example, in the reverse extrusion forming of magnesium alloy cup-shaped parts, the slide needs to experience four different speeds within one work cycle. The process control system should be able to meet these requirements.
Intelligent hydraulic presses, when optimized in conjunction with various forming processes, require an understanding of the optimal process path to fully realize their advantages. Studying the forming mechanisms of various forming processes and establishing optimized parameters suitable for each process is crucial for improving product quality and production efficiency, while reducing production costs.
（6）Optimized Design of the Intelligent Hydraulic Press Body.
Compared to traditional hydraulic presses, intelligent hydraulic presses offer advantages such as energy saving, noise reduction, and multifunctionality. Therefore, their body design needs to consider more factors, primarily including potential thermal processing effects, extreme operating conditions, operating frequency, and the complexity of parts.
