A hydraulic press is a machine that uses hydrostatic pressure to process metal, plastic, rubber, wood, powder, and other products. It is commonly used in pressing processes and press forming processes.
What Is a Hydraulic Press?
A hydraulic press is a machine that uses liquid as the working medium and is made according to Pascal's principle to transfer energy to realize various processes. The hydraulic press is generally composed of three parts: the main engine, the power system, and the hydraulic control system. Hydraulic presses are classified into valve hydraulic presses, liquid hydraulic presses, and engineering hydraulic presses. In addition to forging and forming, hydraulic presses can also be used for straightening, pressing, packing, pressing blocks, and pressing plates.
The Function of the Hydraulic Press:
It is suitable for bending, forming, flanging, and other processes of central load parts. After being equipped with a punching buffer device, it can also be used for punching and blanking processing. It is a product in the shipbuilding industry, pressure vessel industry, chemical industry, and other industries.
The total pressure generated by the hydraulic press is large and is often used in forging and stamping. Forging hydraulic press is divided into die forging hydraulic press and free forging hydraulic press. Die forging hydraulic presses use molds, while free forging hydraulic presses do not use molds.
The Working Principle of the Hydraulic Press:
The basic principle of a hydraulic system is to transmit a force from one point to another through an incompressible liquid. Usually, oil is used as a liquid medium. During this process, the force usually increases.
The principle of the hydraulic press is a machine made by using Pascal's law that uses hydraulic pressure transmission. Using oil or other liquids, the pressure is transmitted in the liquid, so that small pressure can control large pressure. The compressibility of liquids is generally very small, so in hydrostatics, liquids are considered incompressible; in incompressible static liquids, the effect of external force at any point will be instantly transmitted to all points of the fluid.
A hydraulic press is a machine that uses liquid as the working medium to transfer energy to realize various processes. In addition to forging and forming, hydraulic presses can also be used for straightening, pressing, packing, pressing blocks, and pressing plates. Hydraulic presses include hydraulic presses and hydraulic presses. A hydraulic press that uses a water-based liquid as the working medium is called a hydraulic press. A hydraulic press that uses oil as the working medium is called a hydraulic press. The specifications of hydraulic presses are generally expressed in terms of nominal working force or nominal tonnage.
Types of Hydraulic Presses:
- Classification by principle: Hydraulic press, mechanical press, pneumatic press.
- Classified by function: Forging press, punching machine, pressure bending machine, etc.
- Classification by structure: Knuckle-joint press, screw press, etc.
- Classification by control: Traditional presses and servo presses.
Working Medium of the Hydraulic Press:
The function of the working medium used by the hydraulic press is not only to transmit the pressure but also to ensure that the working parts of the machine are sensitive, reliable, long-lived, and less leaking. The hydraulic press initially used water as the working medium, and later switched to an emulsion made by adding a small amount of emulsified oil to the water to increase lubricity and reduce rust.
- Have suitable fluidity and low compressibility to improve transmission efficiency.
- Can prevent rust.
- Have good lubricating properties.
- Easy to seal.
- Stable performance, long-term work without deterioration.
The Structure of the Hydraulic Press:
The drive system of the hydraulic press mainly includes two types of pump direct drive and pump-accumulator drive. The pump directly drives the pump of this drive system to provide high-pressure working liquid to the hydraulic cylinder, the distribution valve is used to change the direction of liquid supply, the relief valve is used to adjust the limited pressure of the system, and at the same time play a role of safety relief. This kind of drive system has few links and a simple structure. The pressure can be automatically increased or decreased according to the required working force, which reduces the power consumption. However, the capacity of the pump and its driving motor must be determined by the maximum working force and maximum working speed of the hydraulic press. This type of drive system is mostly used in small and medium-sized hydraulic presses, as well as large-scale free forging hydraulic presses directly driven by pumps.
- According to the structure, it is mainly divided into four-column type, single-column type (C type), horizontal type, vertical frame, universal hydraulic press, etc.
- According to the use, it is mainly divided into metal forming, bending, stretching, punching, powder (metal, non-metal) forming, press-fitting, extrusion, etc.
Process Advantages of the Hydraulic Press:
Compared with the traditional stamping process, the hydroforming process has obvious technical and economic advantages in reducing weight, reducing the number of parts and molds, improving stiffness and strength, and reducing production costs, and has been widely used in the industrial field, especially in the automotive industry. more and more applications.
In the automotive industry, aviation, aerospace, and other fields, reducing structural mass to save energy during operation is the goal pursued by the industry, and it is also one of the trends in the development of advanced manufacturing technology. Hydroforming is an advanced position-forming technology to achieve lightweight structure.
Hydroforming is also known as internal high-pressure forming. Its basic principle is to use the tube as a blank, apply ultra-high-pressure liquid inside the tube, and apply axial thrust to both ends of the tube blank for replenishment. Under the combined action of the two external forces, the tube blank material undergoes plastic deformation and finally fits with the inner wall of the mold cavity to obtain a hollow part whose shape and precision meet the technical requirements.
