SlewPro Blog

In the world of plastic manufacturing, precision isn’t a luxury—it’s a necessity. From automotive parts to consumer packaging, modern injection molding demands highly accurate, repeatable movements to maintain quality and meet production goals. And at the heart of that precision? Slewing rings.

Slewing rings play a critical role in improving machine stability, controlling motion, and ensuring that every cycle of the molding process happens exactly as it should. Here’s how they support high-performance injection molding and why equipment manufacturers around the world trust SlewPro slewing rings for the job.

Why Injection Molding Machines Rely on Slewing Rings

Injection molding machines must deliver thousands of precise, repeatable movements per day. Any mechanical instability can lead to misalignment, flashing, or part defects—all of which drive up scrap rates and downtime.

Slewing rings provide rotational support and load-bearing strength where it matters most: the moving platens, turntables, and rotary axes within the machine. They offer:

• Rigid load support for both axial and radial forces
• Smooth, controlled rotation for precise positioning
• Long-lasting performance with minimal backlash
• Design flexibility to fit into compact or complex assemblies

These capabilities are essential for multi-shot molding, vertical machines, and rotary stack molds where multiple components must move in synchronized motion.

Slewing rings are the workhorses behind rotational motion in cranes, excavators, wind turbines, military platforms, and more. But even the most ruggedly engineered slewing ring can fail prematurely without the right lubrication strategy. The truth is, long-term performance isn’t just about materials and tolerances. It’s about maintenance.

At SlewPro, we understand that protecting your investment starts with understanding how lubrication impacts performance and lifespan. Here’s what every equipment operator and engineer should know.

Why Lubrication Matters

Slewing rings operate under high loads and slow speeds, ideal conditions for metal-on-metal wear if not properly lubricated. Grease plays a critical role in reducing friction, displacing contaminants, and preventing corrosion. Poor lubrication can lead to early failure, costly downtime, and even safety hazards.

Slewing ring bearings are crucial components in machinery requiring rotational movement, load support, and high precision. Two of the most commonly used types are single row ball slewing ring bearings and cross roller slewing ring bearings. Each offers distinct advantages and is suited for specific applications based on load capacity, precision, and structural demands.

 

What Is a Triple Row Roller Slewing Ring Bearing?

A triple row roller slewing bearing consists of three separate raceways and sets of rollers. Each row is designed to handle a different type of load:

• Radial Load: Managed by one row of rollers.
• Axial Load (thrust): Managed by two separate rows of rollers.
• Tilting Moment: Managed efficiently due to the spacing between the load-bearing rows.

This three-row configuration delivers enhanced performance, making it ideal for equipment that operates under extreme conditions.

The division of load types across three rows allows for higher load capacities than any other slewing bearing design, including single-row ball or cross roller designs.

When it comes to choosing a slew drive for your application, one of the most important decisions you’ll make is whether to go with a single worm or double worm configuration. Each option has its own strengths and trade-offs, and understanding these differences can help you select the best fit for your equipment’s performance, safety, and precision needs.

At Potesta & Company, our SlewPro line includes both single and double worm slew drives, available with a variety of motor options and modular configurations. Here’s how the two compare:

 

Single Worm Slew Drives

How It Works:

A single worm drive uses one worm gear to rotate the slewing ring, offering smooth and controlled motion.

Pros:

• Compact design: Ideal for applications with limited space
  
• Lower cost: Fewer components mean reduced upfront investment

• Efficient for light to moderate loads: Perfect for applications where extremely high torque isn’t needed
  
  

Cons:

• Lower torque capacity: Not suitable for very heavy or off-center loads
• Less braking redundancy: Only one worm means fewer mechanical failsafes
  
  

Best-Fit Applications:

• Solar trackers
• Small utility lifts
• Light-duty truck cranes
• Agricultural equipment
  
  

Port operations are the beating heart of global trade. Every day, massive container ships pull into harbors around the world, unloading and loading goods with the help of material handling cranes that must operate with both muscle and precision. At the core of these cranes—and many other essential machines in maritime logistics—are slewing drives: compact powerhouses that handle heavy loads, provide smooth rotational movement, and stand up to some of the harshest environmental conditions on the planet.

 

The Demands of Port Environments

Unlike controlled factory floors or sheltered construction zones, ports are dynamic, unpredictable environments. Equipment must operate in a constant cycle of loading and unloading, often 24/7. On top of that, machinery faces:

• High winds and constant motion
• Corrosive saltwater exposure
• Heavy, uneven loads
• Space constraints for large rotating systems
• That’s where slewing drives shine.

When it comes to choosing the right slewing ring bearing for your machinery, getting the load calculations right is not just important—it’s essential. Axial, radial, and moment loads each play a role in how your slewing ring performs, and understanding these forces can make the difference between a long-lasting, high-performance component and costly downtime.

In this article, we’ll break down what each of these load types means, how they impact bearing selection, and how SlewPro’s customized slewing rings can be sized to meet your exact application needs.

 

What Are the Three Types of Loads?

1. Axial Loads

Axial loads are forces applied parallel to the axis of rotation. In slewing ring applications, this is typically the weight pressing down vertically through the bearing. Think of a crane lifting a heavy load or a wind turbine pushing down through its base—both exert strong axial loads.

Sizing Tip: Evaluate both static (non-moving) and dynamic (operational) axial forces to ensure your bearing can withstand the full range of pressure over time.

2. Radial Loads

Radial loads are forces that are applied perpendicular to the axis of rotation—essentially pressing in from the sides. These can occur from off-center loading or unexpected shifts during operation.

Sizing Tip: Radial forces often accompany axial loads, so bearings must be selected based on combined load scenarios. Misjudging this can lead to premature failure.

 

3. Moment Loads (Tilting Moments)
Moment loads, or overturning moments, are torques that try to tip the bearing around its center. These are common in applications with cantilevered arms—like excavators, cranes, or robotic devices. The longer the arm and heavier the load, the higher the moment force.

Sizing Tip: Moment loads put stress on the bearing structure and bolt connections. Choosing the correct raceway design—such as a triple-roller for high-moment environments—can dramatically increase durability.

When it comes to maintaining safe and efficient rail systems, precision and durability are non-negotiable. That’s where slewing ring bearings play a pivotal role—especially in railway maintenance and rail grinding equipment.

 

The Backbone of Maintenance Equipment: What Slewing Rings Do

Slewing rings are large-diameter bearings designed to handle axial, radial, and moment loads. In the world of railway maintenance, they are commonly integrated into machines that perform essential tasks such as:

• Rail grinding and resurfacing
• Track alignment and profiling
• Switch and crossing maintenance
• Heavy-duty lifting and rotation tasks

These operations require not only high load capacities but also smooth and precise rotational movement—two key features that SlewPro slewing rings deliver with consistency.

 

The Critical Role of Slewing Rings in Wind Turbines

Wind energy is a cornerstone of the renewable energy sector, and its efficiency depends on the seamless operation of wind turbines. At the heart of these turbines are slewing rings—precision-engineered bearings that enable the controlled rotation of turbine blades and nacelles. These components ensure turbines can effectively capture wind energy while maintaining structural integrity and operational safety.

 

The Role of Slewing Drives in Solar Tracking Systems

As the demand for renewable energy grows, maximizing the efficiency of solar panels has become a top priority. One of the most effective ways to increase solar panel output is by using solar trackers, which adjust the angle of the panels to follow the sun's path throughout the day. At the core of these tracking systems are slewing drives—precision-engineered components that provide the necessary rotational movement to keep solar panels optimally aligned with the sun.