In the press system, the sealing performance of the piston rod is crucial, which directly affects the working efficiency and stability of the press. The surface roughness, as an important indicator of the surface quality of the piston rod, is closely related to the sealing performance. A deep understanding of this relationship is of great significance for optimizing the design of the press and improving the performance of the equipment.
The sealing of the press piston rod is mainly achieved by the close fit between the seal and the surface of the piston rod. When the press is working, the hydraulic oil generates pressure in the cylinder body and pushes the piston rod to move. The seal needs to prevent the hydraulic oil from leaking from the gap between the piston rod and the cylinder body, thereby ensuring the pressure stability and energy transfer efficiency of the system. Good sealing performance is the key to the normal operation of the press.
The surface roughness directly affects the contact state between the piston rod and the seal. If the surface roughness value of the piston rod is large, there will be more microscopic unevenness on the surface. These uneven parts will prevent the seal from being completely and tightly fitted with the piston rod surface, thus forming a tiny gap between the two. The hydraulic oil may leak through these gaps, resulting in a decrease in sealing performance.
When the surface roughness value of the piston rod is too high, the leakage channel between the seal and the piston rod increases and becomes larger. Not only will it cause a large amount of hydraulic oil leakage, making the pressure of the press system unstable, but it will also accelerate the wear of the seal. Because under high pressure, the hydraulic oil will continuously flush the contact area between the seal and the piston rod surface, and the rough surface will aggravate this flushing effect and shorten the service life of the seal.
Although a low surface roughness value can make the seal fit tightly with the piston rod surface, it may also cause some problems. A too smooth surface will increase the friction between the seal and the piston rod, which will increase the resistance of the press operation and consume more energy. At the same time, excessive friction may also cause the seal to heat up, affecting its performance and life.
There is a suitable surface roughness range that can achieve the best sealing performance. Generally speaking, for press piston rods, the surface roughness value between Ra0.8 - Ra1.6μm is more suitable. Within this range, the piston rod surface can not only fit well with the seal, reduce leakage, but also maintain low friction, reduce energy loss and wear of the seal.
In actual press applications, there are many cases where sealing problems are caused by inappropriate piston rod surface roughness. For example, a press manufacturer used piston rods with a surface roughness value of Ra3.2μm in a batch of equipment. As a result, after the equipment was running for a period of time, it was found that the hydraulic oil leaked seriously and the seal wear was aggravated. After reprocessing the piston rod surface, the roughness value was reduced to about Ra1.2μm, the sealing performance was significantly improved, and the stability and work efficiency of the equipment were greatly improved.
Manufacturing process is one of the main factors affecting the surface roughness of the piston rod. For example, the accuracy and parameter selection of grinding processing will directly affect the surface quality of the piston rod. In addition, the characteristics of the material also have a certain influence on the surface roughness. Piston rods of different materials may show different surface roughness under the same processing conditions. In order to control the surface roughness of the piston rod, it is necessary to strictly control the processing parameters during the production process, select appropriate tools and grinding parameters, and accurately measure and quality test the processed surface.
The sealing performance of the press piston rod is closely related to the surface roughness. Appropriate surface roughness is the key to ensure sealing performance. Too high or too low roughness will have an adverse effect on sealing performance. In actual production and application, it is necessary to reasonably control the surface roughness of the piston rod according to the specific working conditions and requirements of the press to achieve a good sealing effect and improve the overall performance and reliability of the press. By continuously optimizing the manufacturing process and strengthening quality control, the requirements of the press for piston rod sealing performance can be better met, promoting the continuous development and progress of press technology.
