Do you know the application of casting nylon? Of course, I don’t know if it has anything to do with it, but Wang Laoji, Nongfu Spring, Sany Heavy Industry, etc., you must know that it’s going backwards, so how can casting nylon be related to Wang Laoji? Still entangled? That is because the packaging in the food industry, mechanical transmission, and the pulleys of the lifting machinery have to be cast nylon, self-lubricating, safe and non-toxic, lighter than metal, easy to process into an important material to replace steel!
What is cast nylon?
MC nylon, Monomer castingnylon, also known as cast nylon, which is made by using a basic substance of molten raw material caprolactam monomer C6H11NO as a catalyst under normal pressure, together with an auxiliary agent such as an activator, to be directly injected. Preheating to a mold of a certain temperature, the material is quickly polymerized in the mold, condensed into a tough solid blank, and then processed to obtain a predetermined product. As one of the engineering plastics, MC nylon products are “excellent in terms of plastic and steel, excellent performance”. It has a variety of unique properties such as light weight, high strength, self-lubricating, wear-resistant, anti-corrosion, insulation, etc. It is widely used in engineering plastics, and it is distributed in almost all industrial fields.
What are the characteristics of cast nylon?
Its friction coefficient is 8.8 times lower than that of steel, 8.3 times lower than copper, and its specific gravity is only one-seventh of that of copper. MC nylon can directly replace metal products such as copper, stainless steel and aluminum alloy. MC nylon pulleys, sliders, gears, worm gears, support rollers, support wheels, walking wheels, pump impellers, bushings, bushings, pin pins, piston valve bodies, rubber plates, pulleys, rotating wheels, bars Pipes, plates, etc., not only replace the corresponding metal products, but also reduce the cost, extend the service life of the whole machine and parts, and significantly improve the economic benefits. MC nylon is mechanically used as a vibration-damping and wear-resistant material instead of non-ferrous metals and alloy steels. It is a 400 kg nylon product. Its actual volume is equivalent to 2.7 tons of steel or 3 tons of bronze. MC nylon parts are used to improve mechanical efficiency. Reduce maintenance and generally increase the service life by 4-5 times.
MC nylon is a new type of engineering plastic. Due to its excellent comprehensive performance, its position in engineering plastics has rapidly increased and become an important material, and its use is expanding.
(1) High strength, capable of bearing load for a long time;
(2) Good resilience, able to bend without deformation, while maintaining toughness and resisting repeated impacts;
(3) Wear-resistant self-lubricating property, which provides better performance than bronze cast iron carbon steel and phenolic laminate in oil-free (or deoiling) lubrication applications, reducing consumption and saving energy;
(4) Noise absorption and shock absorption, MC nylon modulus is much smaller than metal, and the attenuation of vibration is large, providing a practical way to prevent noise from metal;
(5) Compared with metal, MC nylon has low hardness and does not damage the grinding parts;
(6) Low mc coefficient, which provides wide application possibilities on friction parts;
(7) High chemical stability, alkali resistance, alcohol, ether, hydrocarbon, weak acid, lubricating oil, detergent, water (sea water), and has the characteristics of odorless, non-toxic, odorless and rust-free. It is used in the use of mechanical parts such as alkali corrosion resistance, environmental sanitation, food, textile printing and dyeing.
(8) Simplify maintenance and maintenance of the machine, save labor, excellent mechanical cutting performance and improve labor productivity.
(9) MC nylon is limited to use in the following environments and media:
a, the use temperature exceeds 120 °C for a long time;
b, strong acid, phenol, sodium chlorate, barium chloride, etc.;
c. Key components of high precision machines.
Classification of cast nylon
MC nylon manufactures different varieties depending on the application, mainly in the following types:
1:MC nylon (ivory white): The characteristics of unmodified cast nylon 6 are very close to that of nylon 66. It has good comprehensive performance, high strength, rigidity and hardness, creep resistance, wear resistance, heat aging resistance and good machinability. Wait.
2: MC901 (blue): This modified nylon 6 has a striking blue color. It has higher toughness, flexibility and fatigue resistance than ordinary cast nylon. It proves to be an ideal material for gears, racks and transmission gears.
3: PA6+ oil (green): This cast nylon 6 is a true self-lubricating nylon specially developed for parts that cannot be lubricated, has high loads and low running speed, greatly expanding the application range of nylon. It has a lower coefficient of friction than conventional nylon (50% reduction) and improved wear resistance (up to 10 times).
4: PA6+ molybdenum disulfide (grey black): Containing molybdenum disulfide powder, it can improve its load-bearing capacity and wear resistance without affecting the impact resistance and fatigue resistance of unmodified mold nylon. Used to make gears, bearings, star wheels and sleeves.
5: PA6+ Solid Lubricant (Gray): Formulated with patented cast nylon 6, containing a solid lubricant with self-lubricating properties, excellent friction, outstanding wear resistance and pressure velocity capability ( 5 times higher than ordinary cast nylon). Particularly suitable for high-speed, non-lubricating moving parts, it is the perfect complement to oily nylon.
Cast nylon application examples
Conventional pulleys are mostly made of cast iron or cast steel. Although they have large bearing capacity, they have poor wear resistance, and the steel wire is damaged. In addition, the cast steel pulley process is complicated, the actual cost is higher than that of the MC nylon pulley, and the pulley strength made of MC nylon is used. High and easy to process. As long as the formula is suitable, it can also be made into pulleys with different performance requirements. After adopting MC nylon pulley, the life of the pulley is increased by 4-5 times, the life of the wire rope is increased by 10 times, compared with “metal pulley” and “MC nylon pulley”, MC nylon The pulley can reduce the weight of the boom and the boom head by 70%, improve the production efficiency, enhance the lifting function and mechanical performance, and facilitate maintenance, disassembly and assembly, and no oil lubrication. Many crane manufacturers abroad, such as Liebherr in Germany and Kato, Japan, have been using MC nylon pulleys since the 1970s. At present, the domestic 12-125 seven-class truck cranes have been fully applied. Taking the LT40 truck crane as an example, the application of MC nylon pulleys only saves more than 100,000 yuan for wire rope and pulley maintenance.
Gear worm gear
The use of MC nylon to manufacture gears such as gears and worm gears can greatly reduce noise. Take 400Kg air MC nylon hammer and concrete mixer as an example. 400Kg air hammer (small) gear m=8, z=19, motor power is 40KW. The original phenolic-based press plate was manufactured for about half a year, and then changed to MC nylon and iron skeleton structure. After 7 years of use, the inspection was still not damaged. Concrete mixer (small) gear m=10, z=20, motor power is 7KW, the original metal gear transmission noise is large, the tooth surface wear is serious, after switching to MC nylon gear, the transmission is stable, the noise is small, the service life is 10 years. the above.
In construction machinery, the slider is almost an indispensable part, such as the slider for the crane crane boom support, which has been made of brass in the past. Now the MC nylon slider is used, the service life is increased by 4-5 times. The MC nylon slider has a long service life and can maintain lubrication performance for a long time after one-time refueling. At the same time, it also has the advantages of impact resistance, vibration resistance, fatigue resistance, low noise, light weight, convenient assembly and wear resistance.
Bushing, bearing bush, bearing
The use of MC nylon instead of copper and babbitt alloys for various sizes of bushings, bushings, etc., is very common in construction machinery. Features: good wear resistance, self-lubricating performance, high PV value in general thermoplastics; low friction coefficient, impact resistance, easy to hold shaft, sintering, no damage to the journal; long lubrication period, reduced maintenance, Adaptable in harsh environments and long life. For example, the WK-10 excavator’s rope balance wheel bushings are φ200×φ160×160. ZQA19-4 materials have always been used. Due to the dust during operation, the lubrication conditions are bad and the bushings wear quickly. After switching to MC nylon, according to the compressive strength of MC nylon, the theoretical calculation can bear the load of 288-345T, the actual use load is 140T, and it can be used in the open air for more than 5 years at the ambient temperature of 40-42 °C. After excavating 5.265 million tons of ore, the disintegration inspection revealed The surface is smooth and smooth, and a good oil film is formed, which proves to be substantially free of wear.
Piston ring, support ring
The characteristics of the piston ring made of MC nylon are: light weight (about 15% of the weight of bronze) reduces the movement loss and saves mechanical power; the sliding performance is good, the static and dynamic friction coefficients are small, so it is not sticky like metal. It has good performance for burying foreign objects and can avoid cylinder liner pulling; no oil self-lubricating, good sealing, easy to leak oil, long life and improve work efficiency. The MC nylon support ring of the hydraulic cylinder was tested on the HSG63/35×700 hydraulic cylinder test bench of the Yangtze River Hydraulic Components Research Institute. Under the high pressure and heavy load, after 170h continuous impact 320,000 cycles, the total stroke of the reciprocating operation is 150km. Durable and reliable, in line with national standards.
Since MC nylon has the properties of resistance to chemicals, abrasion resistance and self-lubrication, it is used as a roller or as an outer sleeve of a metal roller, and is suitable for conveying a guide roller, a reverse roller, and a traveling roller. MC nylon has longer service life than other materials, easy processing, less oiling, and no oil leakage, no rust, oil stains and rust stains.
In addition to the above introduction, MC nylon is used in many aspects, such as: mixer wheel, valve body, valve core, ball valve gasket, insulated MC nylon sleeve, guide plate, rubber plate, etc.; in the railway, there are moving axle boxes, liners , moving wheel springs, sling sleeves, retaining rings, crosshead pulleys, rocker small end small square tiles, etc.; in the shipbuilding industry there are bearings, rudder bearings, water pump bearings, pump impellers, pulley sliders, sprockets, handles, anti-electric , seals, etc.
MC nylon has a wider range of applications and more and more effective effects. People never realize the understanding, from trial use to application, and gradually realize the excellence and importance of MC nylon application. MC nylon has achieved great economics. benefit.
Machining and assembly of cast nylon
MC nylon polymer material, except that it can not be processed by calendering method, the other can be processed by processing metal or non-ferrous metal materials, but the method is slightly different, the following data and its means for reference.
(1) When turning, the rotation speed of the lathe should not be too fast. Generally, it is required to be at 200 rpm. The amount of feed should not be too large. Otherwise, the product will expand and expand, and the processing will not meet the size.
(2) The front corner of the turning tool should be larger than the turning steel part. The front corner of the turning tool is larger than the rear corner. The front angle is 15o-25o, and the back angle is about 15oC. Only the general oil steel knife can be used. Alloy tool.
(3) When the planer is processed, it should not be processed by a knife with a sharp knife. The back angle of the planer should be small. The hand knife will cause the smooth surface of the nylon piece to collapse.
(4) Apply oil when turning, not suitable for aqueous emulsion, because nylon absorbs water.
(5) When drilling, the lathe should not exceed 200 rpm. If drilling a 20mm upper hole, first use a small drill bit, then gradually expand to prevent cracking. When drilling the oil hole on the oil hole, the hole should be first Drilling the hole, if the hole is drilled first, it is easy to make the workpiece float with the drill bit (the term is on the tree) and it is easy to touch the processing personnel and waste.
(1) The assembly of nylon and sleeve is larger than the interference of metal, and the outer diameter of the interference is 1~1.2%, so that the bushing is pressed into the sleeve seat and has proper tension to prevent loosening. Generally, the static fit is between 0.10 and 0.15 mm, and the dynamic fit is between 0.5 and 0.8 mm.
(2) The matching size of the nylon sleeve and the shaft should also be increased, and the gap is 0.8~1.0% of the shaft diameter. After the bushing is pressed into the sleeve, the nylon sleeve shrinks, and sufficient clearance can be ensured to match the shaft. Otherwise, heat will cause a shaft hung in operation.
(3) The bushing and the seat should be assembled by pressing in. Do not hit the hard raft.
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