Development status and trend of rubber and plastic sealing technology

3. Rubber and plastic seal inspection

At present, rubber and plastic sealing products are developing in the direction of "high-end, extreme, high requirements and long life", in order to ensure the quality of rubber and plastic sealing products, more perfect inspection and testing are needed.

Rubber and plastic seal inspection and testing technology includes sealing material performance testing, product appearance size analysis and testing, sealing performance analysis and testing. Material performance testing is an important means to judge the quality of sealing material formula, the use of modern analytical instruments through the test of material composition, physical and chemical properties, mechanical properties, scientific and reasonable comprehensive evaluation of sealing materials. However, material properties cannot directly determine sealing performance, so product level performance testing must also be carried out. Product appearance size analysis test is the simplest means of preliminary screening of seals, which is divided into the appearance analysis of the working face and non-working face, and the measurement of macro size by contact or non-contact method based on national standards or industry standards. Seal performance analysis test, including product functional test, simulated life test, field installation test, etc., mainly used for seal structure selection, design, production and sampling test of the manufacturer. The functional test includes the sealing ring holding force, opening force, compression stress relaxation, static torque and so on. For the life test of the seal ring, due to the difficulty, long time and high cost of the field test, the current common way is to simulate the life test, and observe, analyze and compare the quality and working life of the seal ring in a short time. The installation test is the final application assessment of the seals that leave the factory after passing all the above tests, which is generally completed by the seal user.

Domestic rubber and plastic seal testing technology also mainly stays in the material physical property testing and product size and appearance testing, sealing performance testing methods and means are single, most of them rely on installed and real machine verification; At the same time, the testing equipment also uses the late 20th century technology, the lack of automation equipment, the lack of process control ability. Foreign detection technology has developed rapidly, and Freudenbezy and other companies have adopted the third-generation new optical system developed by KMK, completely replacing manual detection and detecting the tiniest defects on the surface of seals. Some domestic sealing companies have also introduced gas sensitive detector based on the oil seal lip tension, which evaluates the sealing performance of the oil seal lip by detecting the change of air pressure, and has a high detection rate, which can detect 1200 to 1800 oil seals per hour.

The future rubber seal testing technology is mainly to develop in the direction of the full life cycle and more accurate data:

Multi-condition joint test: In the actual service process, rubber and plastic sealing products in the working medium, the grinding surface and the overall environment under the combined effect, but also by friction heat, mechanical vibration, eccentric tilt and other uncontrollable factors, the working environment is very complex, and corresponding to the extreme environment or harsh conditions of rubber and plastic sealing. The effect of this effect can be amplified, resulting in a significant difference between actual service performance and test results. Therefore, the joint test of rubber and plastic seal multi-working condition environment is the future development direction to ensure product performance, improve detection accuracy and reliability.