(1) In terms of production capacity and market, the output of domestic hydraulic presses has a great growth rate every year. In 2004, the sales of domestic hydraulic presses were about 1 billion yuan, and in 2005 it reached 1.3 billion! By 2012, it has exceeded the 10 billion mark! In 2019, tens of millions of tons of hydraulic presses were built, which are rare in the world. The domestic sales of domestic hydraulic presses exceed 90%, and the output value of export products accounts for a very small proportion of the total output value, less than 5%. Only a few companies have products that are eligible for export, and most of them are exported to third world countries. Most of the hydraulic presses imported in China are some hydraulic presses, most of which are imported products, and there are fewer products in Europe and America.

Compared with foreign products, my country's products still have the following shortcomings in terms of quality: ①In terms of reliability, the failure rate is still relatively large, mainly in the hydraulic system, mostly due to the low reliability of hydraulic and electrical components; ② Oil leakage is common in domestic hydraulic presses;

In the hydraulic system and its system, the sealing device is used to prevent the leakage of the working medium and the intrusion of external dust and foreign matter. The element that acts as a seal is the seal. External leakage will cause waste of working medium, pollute the machine and the environment, and even cause mechanical operation failure and equipment personal accidents. Internal leakage will cause the volumetric efficiency of the hydraulic system to drop sharply, failing to reach the required working pressure, or even unable to work. The tiny dust particles intruding into the system can cause or exacerbate the wear of the friction pair of the hydraulic components, and further lead to leakage. Therefore, seals and sealing devices are an important part of hydraulic equipment. The reliability and service life of its work is an important indicator to measure the quality of the hydraulic system. Except for gap seals, seals are used to control the gap between two adjacent coupling surfaces below the minimum gap through which the liquid to be sealed can pass. In the contact seal, there are two types of self-sealing compression seals and self-sealing self-tightening seals (ie lip seals).

Hydraulic presses are suitable for almost any process that requires pressure machining. At present, hydraulic presses are mainly used in the following fields: ① The stamping and deep drawing process of sheet metal parts is mainly used in the forming and processing of metal covering parts in the automobile and home appliance industries; ② Pressure forming of metal mechanical parts, mainly including die forming, extrusion forming of metal profiles, hot and cold die forging, free forging and other processing technologies;

According to the classification of structure, hydraulic presses mainly include single-column hydraulic presses, four-column hydraulic presses, frame hydraulic presses and other hydraulic presses. The single-column hydraulic press can be divided into two structures: the whole body and the combined body. During the work of the single-column hydraulic press, due to the deformation of the body, the slider and the table will have a certain angle, so it is mostly used for low precision requirements. applications, such as: press-fitting, sheet pressing, straightening and other processes.

1) Hydraulic presses or automatic production lines equipped with automatic loading and unloading devices will become the development direction of hydraulic presses in the future. At this stage, due to labor costs and technical problems, domestic enterprises mostly use manual loading and unloading. But in some developed countries, automatic production lines were basically popularized in the 1960s and 1970s.