Plastic pillow blocks are bearing housings typically constructed from engineered thermoplastics such as nylon, acetal, polycarbonate, or PTFE. They are designed to support and align rotating shafts in mechanical power transmission systems. The key function of a pillow block is to securely hold the bearing in place, while allowing the inner race to rotate freely around the stationary outer race. This enables the shaft to turn smoothly within the bearing.
Plastic is increasingly selected over metals for manufacturing pillow blocks due to its lightweight properties and resistance to corrosion or chemicals. The material can be injection molded into complex designs for attaching the blocks to machinery. Selecting the optimal grade of plastic is vital based on load capacity, temperature, lubrication needs, and environmental conditions.
Popular plastic materials used for pillow blocks include:
- Nylon - Offers high strength, stiffness, abrasion resistance, and cost-effectiveness. Withstands moderate temperatures.
- Acetal (POM) - Excellent strength, low friction and wear properties. Handles higher continuous use temperatures up to 175°F.
- Polycarbonate - Extremely strong yet transparent material. Withstands temperatures up to 250°F. High impact resistance.
- PTFE (Teflon) - Unmatched chemical resistance and low friction. Continuous use to 500°F. Food-grade options available.
- Polypropylene - Resistant to acids, bases and solvents. Low moisture absorption. Operates down to -20°F.
- PEEK - Superior temperature resistance up to 500°F. Excellent chemical compatibility and mechanical properties.
Other factors like FDA compliance, UL ratings, manufacturing method, and bearing interface can dictate material selection for optimal performance and safety.
Using plastic pillow blocks offers several notable benefits compared to metal alternatives:
- Lightweight Construction - Plastic blocks are far lighter than stainless steel or cast iron models, reducing energy consumption in motion applications. This allows easier handling and installation. Weight reductions of 50% or more over cast iron are typical.
- Corrosion Resistant - Plastics are unaffected by moisture, water, or a wide range of chemicals. This makes them ideal for harsh industrial environments vulnerable to rust and corrosion damage. Plastic maintains integrity where metals would degrade.
- Low Noise and Vibration - Equipment downtime and disruptive noise can be reduced by utilizing plastic pillow blocks. The material dampens vibrations and provides quiet operation. This makes plastic ideal for noise-sensitive settings like offices, homes or hospitals. The impact-resistant properties also minimize external damage from knocks and bumps.
- Chemical Resistance and Hygiene - With broad chemical compatibility, plastic blocks suit applications where corrosive substances are handled, such as chemical processing or wastewater treatment. The non-porous surface also prevents bacterial growth, meeting hygiene needs in food/beverage, pharmaceutical and healthcare sectors. Easy to clean.
- Electrical and Thermal Insulation - Plastics provide electrical insulation to prevent current leakage and resist arc tracking. Materials like PEEK have very low thermal conductivity, reducing heat transfer to surroundings.
- Safety and Product Protection - Plastic blocks cushion loads, absorb impacts, and fail gradually if overloaded. They won't damage shafts or housings as compared to sudden metal failures. Clear materials allow visual inspections while running.
- Versatile Design - Plastic pillow blocks accommodate various shaft sizes, bearing types (ball, roller, sleeve), and mounting configurations. Their flexibility suits diverse applications with customizable engineering. Industry standards can be readily met.
- Cost Effectiveness - Molded plastic blocks offer cost savings over metal machining and fabrication. Quick assembly reduces labor. Long service life provides value over years of reliable performance.
- Environmental Benefits - Many plastics used for pillow blocks are recyclable, which is a key advantage over metal alternatives. Some materials also comply with sustainability standards or contain recycled content. As technology progresses, plant-based and biodegradable plastics will provide more eco-friendly options.
Plastic pillow blocks provide optimal bearing solutions across a diverse range of industrial and commercial applications:
- Packaging Equipment - Bottling machinery, conveyors, labeling, filling and capping systems benefit from plastic blocks that resist moisture, chemicals, and impacts while operating smoothly at high speeds. Quiet operation is also important around workers.
- Food Processing - Stainless steel pillow blocks are often still used, but plastics like acetal and polypropylene provide excellent hygienic and non-corrosive properties for mechanical drives in bakeries, meat packing, beverage production and other food plants. Cleanability and sanitation are improved.
- Pharmaceutical Industry - Strict hygiene requirements and extensive stainless steel surfaces characterize pharmaceutical facilities. Plastic blocks avoid exterior rust and contamination while insulating drives from excessive motor heat. They are robust, easily cleaned, and help protect sterile processes.
- Semiconductor Industry - The ultra-clean manufacturing environment for semiconductors demands high-purity and non-contaminating components. Plastic blocks eliminate potential metal and lubricant contamination. Materials like PEEK resist chemicals and acids used in wafer fabrication processes.
- Pulp and Paper - Moist and chemically aggressive environments permeate pulp and paper mills. Plastic pillow blocks withstand these conditions while running problem-free for years to maximize uptime. Lightweight construction reduces energy demands on drives.
- Chemical Processing - Corrosive chemicals abound in plants producing industrial acids, solvents, fertilizers and other products. Only plastics can resist these extreme environments alongside stainless steel. Improved safety, lower maintenance, and longer service life result.
- Textile Industry - Textile manufacturing machinery involves high speeds, vibration, moisture and airborne contamination. Plastic blocks perform reliably despite fluff and fibers while operating quietly. They require infrequent maintenance.
- Automotive Industry - Powertrain, machining, and assembly automation relies on plastic bearings that offer precision operation and lightweight properties. The material also resists cutting fluids. Automotive-grade plastic blocks meet exacting quality standards.
- Appliances - Washing machines, blenders, fans and other appliances benefit from low-noise plastic blocks to improve quality and user experience. Resistance to detergents and humidity is vital alongside high cycle life capabilities.
- Agriculture & Farming Equipment - Tractors, conveyors, presses and other machinery require bearings that can withstand dirt, dust, moisture and shocks. Plastic blocks handle these tough conditions while operating smoothly to maximize uptime.
- Office Environments - Quiet and smooth operation is mandatory for scanners, printers, shredders, copiers and other office equipment. Plastic blocks dampen noise and protect precision components to maintain optimal performance in clean office settings.
- Aerospace Industry - Lightweight construction is paramount in aircraft, prompting use of plastic bearings for actuators, pumps, and other components. Advanced materials like PEEK withstand aviation fluids and high altitudes. Vibration damping maintains precision.
Proper design is critical to maximize the performance and lifespan of plastic pillow blocks. Key engineering considerations include:
- Load Rating - The expected shaft loading and speeds determine the bearing type, size, attachments and housing required to avoid premature failures. Proper safety factors must be used.
- Tolerances - Pillow blocks must maintain precise concentricity and squareness between shaft and housing. This ensures smooth operation free from excessive wear or binding.
- Lubrication - Most plastic blocks require greased bearings to reduce friction and prevent overheating. Oil lubrication is generally not recommended due to material compatibility issues.
- Fastening - Robust metal inserts molded into plastic blocks allow secure mounting to machinery via bolts, straps or clamps. Proper tightening torques must be followed.
- Alignment - Misalignment causes excessive bearing wear. Precision mounting surfaces and mounting hole design enables accurate installation and shaft alignment.
- Temperature - Operating temperature must be confirmed acceptable for the plastic grade based on application loads and environment. Increased clearances or exotic plastics may be required for high heat.
- Contamination - External contaminants can penetrate poorly sealed blocks, reducing bearing life. Robust sealing and shielding should be utilized. Internal plastic lubrication is also an option.
- Electrical Properties - Where current flow could create hazards, insulating blocks equipped with electrostatic dissipating properties are required for proper safety.
Material selection requires careful analysis of operating conditions to determine the optimal grade. Key choices include unfilled, glass or carbon reinforced, impact modified, and internal lubricated thermoplastics. Exotic grades offer high strength, chemical resistance, continuous-use temperatures over 500°F, non-contaminating formulations, and compliance with harsh industry standards.
Advanced plastic pillow blocks are manufactured via precision CNC machining or injection molding in environmentally-controlled facilities. Automated processes, certified suppliers, extensive quality control procedures, and statistical process control ensure high consistency, accurate dimensions, and long component life. Cutting-edge materials and engineering are utilized to deliver exceptional performance and reliability across a spectrum of demanding applications.
While plastic blocks are low maintenance, following proper procedures is important:
- Inspect routinely for damage/wear and replace bearings once worn. Monitor noise and temperature.
- Clean excess dirt, dust or grime to prevent contamination. Avoid harsh solvents.
- Lubricate bearings regularly per manufacturer instructions. Ensure proper grease compatibility.
- Check mounting torques. Tighten appropriately to avoid shifting and re-align as needed.
- Consider enclosing the block if operating in wet or dirty environments to protect from external contamination.
Switching from metal to plastic pillow blocks can increase uptime, reduce maintenance, improve safety and lower total cost of ownership. But thoughtful design and material selection is vital for optimal results. Consulting experienced manufacturers early in the application engineering process helps ensure all factors are considered correctly.
Plastic pillow blocks offer invaluable performance, safety, and efficiency benefits across manufacturing and processing industries. Their lightweight yet robust construction, noise reduction, chemical and impact resistance, hygienic properties, and versatility provide distinct advantages over metal alternatives. With careful material selection and design, plastic blocks can serve reliably for many years in the harshest conditions. Considering environmental factors, these versatile components are an important step toward more sustainable bearing solutions.
At Deyuan Smart Technology, we take great pride in the recognition our product quality and services have garnered from customers in the industry. We strive to provide exceptional products and services that meet and exceed customer expectations. You can trust us as your reliable partner in the pillow blocks industry. For further inquiries or to discuss your specific requirements, please contact kzhang@ldk-bearings.com or call +86-592-580 7618. We look forward to the opportunity to work with you.
References
Bahador, A., Layeghi, M., & Elyasi, M. (2020). Applications of Plastic Bearing Materials: A Comprehensive Review. Materials Science and Engineering: C, 110782.
BNL Industries. (n.d.). Advantages of Plastic Pillow Block Bearing Housings. Retrieved from
Budinski, K. G., & Budinski, M. K. (2010). Engineering Materials: Properties and Selection. Upper Saddle River, NJ: Prentice Hall.
Igus. (2021). Environmentally Friendly iglide Pillow Blocks - Igus. Retrieved from
Michler, J. R., & Bock, K. (n.d.). What materials can be used for pillow block bearings?
Norelem. (n.d.). Plastic Pillow Blocks | Norelem
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