Collection: Plastic Bearings

Plastic Bearing Application Scenarios

There is a common misconception that all corrosion-resistant bearings are suitable for underwater use, but this is not the case. Underwater robots, drones, propeller shafts, and underwater conveyors all require specific application design considerations and specialized bearings.

I. Bearing Operating Conditions Underwater

Some corrosion-resistant bearings can operate when exposed to fresh water, salt water, steam, or other chemicals, but not all are suitable for continuous use submerged. Full submersion affects a bearing's service life, depending on its material of construction. An example is 440-grade stainless steel bearings. They offer strong resistance to fresh water and weak chemicals, but if placed in salt water or fully submerged, they will corrode quickly.

Bearings often fail prematurely due to corrosion, lubricant failure, or contamination. If a bearing is not suitable for long-term underwater use, water can enter the assembly and exacerbate these common issues. If the housing seal fails, liquid enters the system, diluting the lubrication, creating extra friction that damages wider components. Salt water or chemicals can also corrode the bearing, leading to a shortened lifespan of the parts. Therefore, design engineers should consider the bearing's application and environment to ensure their equipment doesn't degrade unexpectedly and cause costly downtime.

II. Selecting the Appropriate Bearing

There are various types of bearings suitable for submersion, but selecting the correct one for the application is key.

• Ceramic bearings are unaffected by salt water, making them suitable for underwater drones at offshore energy sites. Zirconia dioxide or silicon nitride materials are highly durable and can withstand the high loads required by propellers or underwater conveyors.

• Plastic bearings also offer high corrosion resistance to both fresh and salt water and can operate effectively when fully submerged. Plastic alternatives are a lower-cost solution with low friction levels, although their load capacity is lower than steel or ceramic bearings.

• 316 stainless steel bearings operate effectively when fully submerged in fresh water and at high temperatures without corroding, making them suitable for low-load and low-speed applications in the marine industry, such as propeller shafts. They can also withstand submersion in salt water if there is a regular flow of water over the bearing to provide the oxygen needed to help prevent corrosion.

III. Plastic Bearings Primarily Comprise 5 Material Types:

• Polytetrafluoroethylene (PTFE): Extremely low coefficient of friction, self-lubricating, excellent chemical stability and corrosion resistance. Usable in temperatures from -200°C to 260°C. However, relatively low mechanical strength and higher price.

• Polyoxymethylene (POM): High mechanical strength, rigidity, and hardness. Good wear resistance, low and stable coefficient of friction. Strong fatigue resistance, good dimensional stability and chemical stability. Excellent molding and processing performance. Limited heat resistance; long-term use temperature generally below 100°C.

• Nylon (Polyamide - PA): High mechanical strength and toughness. Good wear resistance and self-lubrication. Maintains stable performance over a wide temperature range. Good oil and chemical corrosion resistance. High moisture absorption, which can affect dimensional stability and mechanical properties.

• Polyphenylene Sulfide (PPS): Excellent high-temperature resistance, can be used long-term above 200°C. High mechanical strength, great rigidity. Extremely strong chemical corrosion resistance. Excellent electrical insulation properties. Relatively poor toughness and more difficult molding/processing.

• Polyetheretherketone (PEEK): A high-performance engineering plastic. Outstanding high-temperature resistance, can work long-term above 250°C. Excellent mechanical properties - good strength, hardness, and toughness. Wear-resistant, corrosion-resistant. Excellent electrical insulation properties. However, expensive and requires high processing standards.

IV: CXE Bearing Marking System

• Example: POM608-316 This means the 608 bearing's inner and outer rings are made of plastic material POM, and the rolling elements are made of AISI 316 material.

• Example: PE608-glass This means the 608 bearing's inner and outer rings are made of plastic material PE, and the rolling elements are made of glass ball material.

• The bearing cage material will be displayed in the product description.

If you have unique design requirements, or need custom ball bearings with specific shapes, materials, or quantities, please contact CXE:
Sales@cxebearing.com