Chain Guide Rail Definition
A type of polyethylene with ultra – high molecular weight (usually over 1.5 million). It features excellent impact resistance and self – lubrication.
Product Performance
The extremely high molecular weight of UHMWPE endows it with outstanding performance. It is a thermoplastic engineering plastic with a moderate price and good properties. It almost combines the advantages of various plastics, having comprehensive properties such as wear resistance, impact resistance, self – lubrication, corrosion resistance, impact energy absorption, low – temperature resistance, non – adhesion, low water absorption, and low density, which are unrivaled by ordinary polyethylene and other engineering plastics. In fact, no single polymer material has so many excellent properties simultaneously.
Wear Resistance of UHMWPE: UHMWPE has the best wear resistance among plastics and even exceeds that of some metals. Figure 1 shows the comparison of wear resistance between UHMWPE and other materials. From Figure 1, compared with other engineering plastics, the mortar wear index of UHMWPE is only 1/5 of that of PA66, and 1/10 of that of HEPE and PVC. Compared with metals, it is 1/7 of carbon steel and 1/27 of brass. Its wear resistance is so high that it’s difficult to test its degree of wear using general plastic wear – testing methods. Thus, a special mortar wear – testing device has been designed. The wear resistance of UHMWPE is directly proportional to its molecular weight. The higher the molecular weight, the better the wear resistance.
Impact Strength: The impact strength of UHMWPE ranks high among all engineering plastics. Figure 2 shows the comparison of impact strength between UHMWPE and other engineering plastics. As can be seen from Figure 2, the impact strength of UHMWPE is approximately 2 times that of impact – resistant PC, 5 times that of ABS, and over 10 times that of POM and PBTP. Its impact resistance is so high that it’s difficult to break it using common impact – testing methods. Its impact strength increases with the increase of molecular weight, reaching the maximum when the molecular weight is 1.5 million, and then gradually decreases as the molecular weight continues to rise. It’s worth noting that it can maintain excellent impact strength in liquid nitrogen (- 195 °C), a characteristic that other plastics don’t have. Additionally, its surface hardness becomes higher under repeated impacts.
Coefficient of Friction: UHMWPE has an extremely low coefficient of friction (0.05 – 0.11), so it has excellent self – lubrication. Table 1 shows the comparison of the coefficient of friction between UHMWPE and other engineering plastics. From Table 1, the dynamic coefficient of friction of UHMWPE under water – lubricated conditions is 1/2 of that of PA66 and POM. Under non – lubricated conditions, it is second only to polytetrafluoroethylene (PTFE), which has the best self – lubrication among plastics. When it works in a sliding or rotating form, its lubricity is better than that of steel and brass with lubricating oil. Therefore, in the field of tribology, UHMWPE is regarded as a friction material with an ideal cost – performance ratio.
Corrosion Resistance: UHMWPE has excellent chemical resistance. Except for strong oxidizing acid solutions, it can resist various corrosive media (acids, alkalis, salts) and organic media (except for naphthalene solvents) within a certain temperature and concentration range. When immersed in 80 organic solvents at 20 °C and 80 °C for 30 days, there is no abnormal appearance, and other physical properties hardly change.
Noise – related Property: UHMWPE has excellent impact – energy absorption. Its impact – energy absorption value is the highest among all plastics, so it has good noise – damping performance and an excellent noise – reduction effect.
Application in Nuclear Industry: UHMWPE has excellent low – temperature resistance and still has ductility at liquid – helium temperature (- 269 °C), so it can be used as low – temperature components in the nuclear industry.
Non – toxicity: UHMWPE is hygienic and non – toxic and can be used in contact with food and medicine.
Adsorption Capacity: The surface adsorption capacity of UHMWPE is very weak. Its anti – adhesion ability is second only to PTFE, which has the best non – stickiness among plastics. Therefore, the surface of products is not easy to adhere to other materials.
Water Absorption: UHMWPE has a very low water absorption, generally less than 0.01%, only 1% of that of PA66. Therefore, it is generally not necessary to dry it before molding and processing.
Density: The density of UHMWPE is relatively low compared with other engineering plastics.
Tensile Strength: Due to the structural characteristics necessary for unidirectional tensile orientation of UHMWPE, it has an unrivaled ultra – high tensile strength. Therefore, fibers with ultra – high elastic modulus and strength can be obtained through gel – spinning. Its tensile strength is as high as 3 – 3.5 GPa, and its tensile elastic modulus is as high as 100 – 125 GPa. The specific strength of the fiber is the highest among all commercially available fibers so far, 4 times that of carbon fiber, 10 times that of steel wire, and 50% higher than that of aramid fiber.
I. Processing Technology
Due to the extremely high viscosity of ultra – high molecular weight polyethylene (UHMW – PE) in the molten state, up to 108 Pa·s, and its extremely poor fluidity with an almost zero melt index, it is difficult to process using general machining methods. In recent years, the processing technology of ultra – high molecular weight polyethylene (UHMW – PE) has developed rapidly. Through the modification of ordinary processing equipment, the processing of ultra – high molecular weight polyethylene (UHMW – PE) has evolved from the initial pressing – sintering molding to extrusion, blow – molding, injection molding, and other special molding methods.
II. Application
- Machinery Industry: Used for instrument housings, some parts, and electrical parts, etc.
- Medical Devices: In class – III implants, it can be used as artificial – joint implants for the interface of friction pairs, such as tibial inserts, acetabular liners, etc.
- Mining Industry: Used to manufacture artificial trough linings, gate plates, chain plates, vibrating screen plates, conveyor plates, and mine – car linings.
- General Machinery Industry: Used to manufacture various bushings, gears, bushings, sliding plates, impellers, etc.
- Vehicle Manufacturing and Transportation Industry: The main products include linings for dump trucks and dump ships, and impact – resistant parts for train vehicles.
- Paper – making Industry: Mainly produces vacuum – suction box panels and wiper blades, compaction components, joints, motor – driven sealing shafts, sheet guide wheels, scrapers, filters, etc.
- Textile Industry: Used to manufacture various pickers, bobbins, picking sticks, gears, couplings, flower – sweeping rods, buffer blocks, shaft bushings, oscillating back beams, and other impact – resistant and wear – resistant parts.
- Food and Light Industry: Used to manufacture panels, cutting boards, working panels, cams, gears, etc.
- Ceramics Industry: Used to manufacture various – specification roller heads, filter plates, wheels, etc.
- Sports Industry: Ski liners, parts of tracked snow – and – ice vehicles, glider floor barriers, steel – ball device parts, various bearing bushings, rolling ball tracks, motor – driven sled parts, etc.
The chain guide rail has good low – temperature resistance and still has ductility at liquid – helium temperature (- 269 °C), so it can be used as low – temperature components in the nuclear industry. The surface adsorption capacity of the chain guide rail is very weak, and its anti – adhesion ability is second only to PTFE, which has good non – stickiness among plastics. Therefore, the surface of products is not easy to adhere to other materials. Due to its good wear resistance, anti – static property, buffering, wear resistance, moisture resistance, corrosion resistance, easy processing, shock absorption, no noise, economy, non – deformation, impact resistance, and self – lubrication, it is very suitable for making various wear – resistant mechanical parts, such as carrier wheels, bushings, nozzles, mixing blades, with a very wide range of applications.
III. Maintenance and Care of Chain Guide Rail
Linear slide rails are precision parts. Therefore, a cautious attitude is required during use. Even if high – quality linear slide rails are used, improper use may not achieve the expected performance and may easily damage the slide rails.
IV. Precautions during Use
- Keep the slide rail and its surrounding environment clean. Even tiny dust invisible to the naked eye entering the slider will increase the wear of the chain guide rail.
- Be careful during installation. Forcible stamping is not allowed, direct hammering of the chain guide rail is not allowed, and transferring pressure through rolling elements is not allowed.
- Use appropriate and correct installation tools. Try to use tools and avoid using items like cloth and short fibers as much as possible.